posvim quick start manual - baoshunkj.com manual.pdf · node information of the root node "xxx...
TRANSCRIPT
PosVim Quick Start Manual
My first reliability analysis project
Guangzhou Baoshun Information Technology Co., Ltd.
2018.07.06
I
Catalog
1 Create project ............................................................................................................................................1
2 Input Product Structure Information ....................................................................................................2
2.1 Manual addition of product structure information ...............................................................3
2.2 Import product structure information through EXCEL file ...............................................6
2.3 Other operations and instructions ............................................................................................9
3 reliability prediction .............................................................................................................................. 11
3.1 Reliability prediction of manual mode ................................................................................ 11
3.2 Intelligent Reliability Prediction ........................................................................................... 13
3.3 Reliability Prediction of Mechanical Parts ......................................................................... 15
3.3 T-S simulation ........................................................................................................................... 16
3.4 failure statistics .......................................................................................................................... 17
3.5 report export ............................................................................................................................... 18
3.6 Other operations and instructions ......................................................................................... 18
4 Reliability Modeling (RBD) ............................................................................................................... 19
4.1 Creating Project and Product Structure Tree ...................................................................... 19
4.2 Creating mission Profiles(optional) ...................................................................................... 19
4.3 Create RBD ................................................................................................................................ 21
4.4 Drawing RBD ............................................................................................................................ 25
4.5 Setting RBD Node Parameters .............................................................................................. 26
4.6 RBD calculation ........................................................................................................................ 28
4.7 RBD Failure Rate Parameter Settings .................................................................................. 29
4.8 Creating Complex RBD .......................................................................................................... 30
4.9 sub graph management ............................................................................................................ 36
4.10 Add Node Pictures ................................................................................................................. 39
4.11 Result Viewing and Output .................................................................................................. 39
4.12 Other operations and instructions ....................................................................................... 40
5 Reliability allocation ............................................................................................................................. 41
5.1 reliability allocation.................................................................................................................. 41
5.2 Adjustment of Allocation results .......................................................................................... 43
5.3 Allocation of Fixed Element Reliability .............................................................................. 44
5.4 Settings do not participate in allocation .............................................................................. 44
5.5 Other operations and instructions ......................................................................................... 45
6 FMEA analysis ....................................................................................................................................... 46
6.1 Analytical method and standard predefinition ................................................................... 46
6.2 FMEA analysis .......................................................................................................................... 46
6.3 control plan &DVP ................................................................................................................... 51
6.4 Convert to Fault Relation Diagram....................................................................................... 53
6.5 Convert to Fault Tree ............................................................................................................... 53
6.5 Fault Mode Library Management ......................................................................................... 54
6.6 Computing configuration ........................................................................................................ 56
6.7 Detection Method Library Management ............................................................................. 58
6.8 Management of Fault Correction Action Lib ..................................................................... 58
II
7 Fault tree analysis .................................................................................................................................. 59
7.1 create fault tree .......................................................................................................................... 59
7.2 Fault Tree Computation and Analysis ................................................................................. 63
7.3 Multifunctional/Common Cause Analysis .......................................................................... 64
7.4 Other operations and instructions ......................................................................................... 66
8 Derating Analysis .................................................................................................................................. 67
8.1 Derating Standard Selection ................................................................................................... 67
8.2 Setting of Derating Parameters .............................................................................................. 67
8.3 Conformity Check of Derating .............................................................................................. 68
8.4 report output ............................................................................................................................... 68
8.5 Custom derating Criteria ......................................................................................................... 68
1
Description: This quick-use manual describes in detail how to operate from project creation,
product structure tree establishment, reliability prediction, reliability modeling, reliability allocation,
FMEA, FTA to derating analysis through a demo project "My first project". Its purpose is to have
an overall understanding of all functional modules of PosVim.
PosVim is an integrated platform for reliability, maintainability, safety, testability,
supportability analysis. It contains forty modules including Reliability Prediction, Reliability Model,
FMECA, FTA, RCMA, OMTA, LORA, LCC, ALT, Weibull analysis, POF, etc. The trial version
of PosVim just provide six modules (Reliability Prediction, Reliability Model, Reliability
Allocation, FMECA, FTA, Derating analysis). If you are interested in the other modules, you can
contact with us.
Phone:+86 20-89855283
Email: [email protected]
http://www.baoshunkj.com
1 Create project
After login to PosVim software, click on "Create a new project" and open the
editing window for creating a new project, as shown in Figure 1-1.
Enter the project name "My first project" (name can be taken by yourself), and
select the project manager, responsible department. The project name must be entered,
other information can be empty. As shown in Figure 1-2.
Click the Save button to create a project. After successful creation, the system
automatically opens the current project.
Note: If you have created a project, you don’t need to create it, just open it.
Figure 1-1 Enters the Welcome Window
2
Figure 1-2 project creation
2 Input Product Structure Information
After opening the newly created project "My First Project", the following Window
is displayed. As shown in Figure 2-1.
PosVim subsequent reliability prediction, FMEA, reliability modeling, reduction
design, maintainability prediction, maintainability allocation and other modules need
to use product structure tree information. So, after creating a project called "My First
Project", the first thing I recommend is to input information about the composition and
structure of the product. PosVim provides two ways to input product composition
structure information. One is to add them manually one by one; the other is to import
them through excel template files.
3
Figure 2-1 open the project
2.1 Manual addition of product structure information
2.1.1Create root node
After opening the project, right-click in the blank of the "Product Structure Tree"
window on the left side of the main Window and select the "Add sub-nodes" option of
the pop-up menu, or click directly on the icon above the Window to add sub-nodes, as
shown in Figure 2-2.
In the pop-up "Edit Node" information window, enter basic information such as
node name. For example, enter "XXX System" in the node name inputbox, and select
"System" in the drop-down list for the node type. At this point, the root node was
created successfully. As shown in Figure 2-3.
Note: It is important to note that when creating a node, remember to select the
type of node (PosVim product type is divided into system, subsystem, equipment,
module, board, components, mechanical components, computer software, etc.).
Otherwise, the system defaults that the node is a component/module, and later when
carrying out reliability prediction, it is impossible to use GJB/Z 299C, SR332 and
other standards for reliability prediction.
Product Structure Tree
4
Fig. 2-2 add node
Figure 2-3 Creates the root node
2.1.2 Enter child node information
Assuming that the object of our analysis is "XXX system", there are two modules
under the root node "XXX system", namely module A and module B. There are several
components under Module A and Module B. The operation steps of inputting the sub-
node information of the root node "XXX system" are as follows:
Step 1: First, add the sub-node of module A under the root node "XXX system":
click on the root node "XXX system", and then click on the right-click menu to select
5
"Add sub-node" or click directly on the icon above the Window to add sub-nodes. Enter
node information "Module A" and select "Module" for node type. As shown in Figure
2-4.
Step 2: Under the created "Module A" node, add components belonging to Module
A. The way to create is:
Select the "Module A" node, right-click on the pop-up menu, select "Add sub-
nodes" or click the icon above the Window directly to add sub-nodes. Input sub-node
information "2CW52", type selection "diode". As shown in Figure 2-5.
Using the same method, select "Module A" node, add sub-nodes "EPM703" and
"RJ45-01" respectively, and select "microcircuit" and "fixed resistor" respectively. If
necessary, you can continue to add components that need to be predicted. The operation
method is the same.
Step 3: In the same way, module B nodes parallel to module A are created. Under
module B, there are component resistors "RJ4501", "RJ4502" and mechanical parts
"M01". Refer to step 2 for the addition node of component resistors "RJ4501" and
"RJ4502". When adding mechanical parts "M01", the node type can be selected as
"mechanical parts". As shown in Figure 2-6.
Figure 2-4 Adding "Module A" Node
6
Figure 2-5 Component Nodes for Adding Module A
Figure 2-6 Mechanical component M01 with module B added
2.2 Import product structure information through EXCEL
file
In addition to the above component node information added manually one by one,
PosVim provides product information imported through Excel files. When importing
excel format files, the Excel file format should meet the template requirements provided
7
by PosVim. Template “SysTree. XLS” can be found in the PosVim installation
directory.
Operation procedure:
Step 1: Create Excel files in the template format provided by PosVim (see
\Template\SysTree.xls'in the PosVim installation directory).Keep in mind to
check whether the format conforms!!!
Step 2: Assuming that the components of Excel file are imported under module A
of XXX system, the operation method is as follows:
2A: Select Module A, then right-click and select the right-click menu "Excel
Import" to open the import editing Window.
2B: Import the editing Window in excel, select the browse button, and select the
excel file you need to import. Here we assume that the components in the template file
“SysTree. XLS” imported into PosVim are under Module A. Find "\ Template\ SysTree.
xls" in the PosVim installation directory and select it.
2c: Click the import button to import the components in the excel file under module
A. As shown in Figure 2-8a.
After import, a module name ‘Module’ has been imported to the Module A as
SubNode, as shown in Figure 2-8b.
Figure 2-7 import Excel
8
Figure 2-8a Imports Components to Module A
Figure 2-8b Module information has been Imported to Module A
9
2.3 Other operations and instructions
2.3.1 Product type specification
When creating a product structure tree, remember to select the product category of
the node, otherwise the reliability prediction process may not be able to predict because
the node type cannot be identified. PosVim’s product categories are shown in the
following figure.
Fig. 2-9 product category
2.3.2 Copying and pasting of product structure information
When creating a product structure tree, PosVim supports to copy any node of the
product structure tree, and any level of subtree, and pasting it under the new product
structure tree node. The operation is:
10
Copy:Select the node or subtree you want to copy, click on the icon of the toolbar
above the product structure tree form or right-click on "copy" or use the shortcut "CTRL
+ C" to copy.
Paste:Select the node you want to paste node information, click on the icon in the
toolbar, or right-click on "paste" or use the shortcut key "CTRL + V" to complete the
paste.
11
3 reliability prediction
PosVim provides manual reliability prediction and intelligent reliability prediction
method, which can be selected according to your demand.
It should be noted that the reliability index obtained by the reliability prediction
module is the basic reliability (usually can be the failure rate λ and MTBF)!!If you need
to get mission reliability index (such as mission reliability), you need to use PosVim’s
RBD module to get them.
Because the prediction mode of PosVim’s reliability prediction module is bottom-
up, that is, starting from the lowest component and component reliability prediction,
the reliability prediction of components is carried out first, then the reliability prediction
is carried out step by step, and then the reliability prediction results of components,
modules, subsystems and systems at all levels are obtained. Therefore, in order to
complete the follow-up reliability prediction work, we first need to establish the product
structure layer by layer according to the product composition structure, until the
component layer. How to construct the product structure tree and input the product
structure information, see Section 2.
3.1 Reliability prediction of manual mode
After creating the information of product composition and structure, click on the
icon of reliability prediction module in "Design Analysis" above the PosVim software
Window, and then the reliability prediction Module will be opened, as shown in Figure
3-1.
PosVim provides commonly used reliability prediction standards, including
GJB299C, SR332, NSWC and other electronic and mechanical components reliability
prediction standards. It is necessary to determine which standards to use for reliability
prediction according to user requirements or reliability prediction requirements.
Reliability prediction usually starts with the lowest components!!It is assumed that
the reliability prediction starts with the component of module A, and then proceeds to
the reliability prediction step by step. Specific operation steps:
Step 1: Confirm that you have opened the reliability prediction module. In the
product structure tree window on the left of the main Window, click on the "Module
A" node. The Window is shown as Figure 3-1 below. On the left side of the Window is
the product structure tree. The middle part shows the list of all the sub-nodes of the
current selected node "Module A", and below is the needed input parameter window of
component reliability prediction.
Step 2: In the list of nodes in the middle part of the software Window, double-click
on the node that needs reliability prediction. For example, double-click on the "2CE52"
node and pop up the reliability prediction parameters that the node needs to input.
Step 3: The choice of reliability prediction method, environment, sub-category
parameters, environment and sub-category options in turn is related to reliability
prediction standard/methods. That is to say, when different reliability prediction
12
standard/methods are selected, the choice of environment category and sub-category
parameters is different. The reliability prediction parameters of various components in
GJB299C, SR332, NSWC and other standards can be referred to the corresponding
standards. Assuming that the prediction method chooses "GJB299C stress method", the
environment chooses "GB ground benign ", and the subcategory chooses "General
Silicon diode". As shown in Figure 3-2.
Step 4: After selecting prediction methods/standards, environment categories and
subcategories, the corresponding reliability prediction parameters will pop up
according to the options you choose and need to be input. For example, "2CE52" diode
needs to input quality level, operating temperature and other parameters. As shown in
Figure 3-2.
Step 5: After entering the reliability prediction parameters of components, click on
the calculation above the input window of parameters. Button, the reliability
prediction results of the component can be calculated. As shown in Figure 3-3.
Figure 3-1 Open Reliability Prediction
Product
information
Prediction
parameter input
Prediction result
13
Figure 3-2 Reliability Prediction Parameter Input
Figure 3-3 Reliability Prediction Results View
Step 6: According to the same operation method, component reliability prediction
under module A and module B is completed. The reliability prediction results of module
A and module B can be obtained. To view the reliability prediction results of the root
node "XXX system", click "XXX system" on the product structure tree Window on the
left. If you can’t see the result, select XXX System and click on the top of the toolbar
Icon.
3.2 Intelligent Reliability Prediction
In addition to the manual reliability prediction, PosVim also provides an intelligent
reliability prediction method, which can quickly and complete the reliability prediction
Input Parameter here
14
work in batch. It can greatly improve the efficiency of reliability prediction work.
Especially when the product naming is more standardized, the one-button batch
predictable 70-80% of the components, greatly improving the efficiency of work.
Assuming that the reliability prediction of module A is needed now, the following
steps are taken to predict the reliability of module A by using intelligent reliability
prediction method:
Step 1:Confirm that you have selected the "Module A" node in the product
structure tree window on the left of the main Window, then click on the icon above the
reliability prediction to pop up the intelligent reliability prediction setup Window. As
shown in Figure 3-4.
Step 2:In the pop-up reliability intelligent prediction setup Window, select a
template. Suppose you choose the ‘satellite’ template. At this point, the window
displays the default setting information of the Satellite template, which can be changed.
For example, to modify the environment to " SF Space, Flight ", just select " SF Space,
Flight " in the environment bar and tick the box in front of "ReplaceBy" to modify the
configuration information in the template (Ps: Modified template can be saved as a new
template for subsequent use). As shown in Figure 3-4.
Step 3: After configuring, PosVim automatically performs reliability prediction by
clicking the Predict button. Please be patient.
Step 4: When you close the Intelligent Prediction Window, you will see that about
70% of the components automatically complete the reliability prediction.
Step 5: Nodes without predicted reliability results may be missing some
parameters. At this point, you need to double-click the components without reliability
prediction results one by one, and then input the missing reliability prediction
parameters, according to the manual reliability prediction method, the reliability
prediction can be done.
So far, the intelligent reliability prediction can be completed. As shown in Figure
3-5.
15
Figure 3-4 Reliability Intelligent Prediction Template Configuration
Figure 3-5 Intelligent Reliability Prediction Results
3.3 Reliability Prediction of Mechanical Parts
The former module A contains mainly electronic components. Module B includes
not only electronic components, but also mechanical components. How to predict the
reliability of mechanical components? The operation steps are as follows:
Step 1: Make sure you have selected Module B.
Step 2: In the list of nodes in the middle part of the reliability prediction main
Window, double-click the mechanical component node "M01" that we have created
before.
Nearly 70% components’ prediction
has completed auto.
16
Step 3: In the reliability prediction parameter input window below, the NSWC
standard has been selected by default. If it is not, select it manually.
Step 4: In the subcategory of reliability prediction parameter input window, choose
"static sealing, gasket". Note: The specific subcategory of this part needs to be selected
according to the actual situation of your product. The hypothesis here is "static sealing,
gasket ".
Step 5: After selecting the subcategory, the software will display the reliability
prediction parameters that the mechanical parts of this class need to input, and then
input them separately. For specific input of each parameter, refer to NSWC standard.
After inputting the reliability prediction parameters, click the calculation button to
get the reliability prediction results of the mechanical components.
Figure 3-6 Reliability Prediction of Mechanical Components
3.3 T-S simulation
PosVim’s TS simulation function can predict the reliability of products under
different temperature and electrical stress. For example, product A has already carried
out reliability prediction. If product B improves or replaces the platform and
environment based on product A, then TS simulation can be carried out to understand
the inefficiency of improved product B.
Assuming that TS simulation of module A is needed, the operation steps are as
follows:
Step 1: Confirm that you have currently selected Module A. Then click the T-
S simulation button. In the configuration of the pop-up TS simulation Window, two
modes of simulation are provided for selection. One is to simulate by temperature; the
other is to simulate by stress. Let’s assume that the "by-temperature" simulation is
selected.
Step 2: Input temperature start value, step length, cut-off value. Then click the
button to run the simulation.
Step1: Select
Module B
Step2: Select
‘M01’
Step3: Select
‘NSWC’
17
Step 3:View the simulation results. After running the simulation, the simulation
results are obtained, as shown in the following figure.
Figure 3-7 T-S simulation results
3.4 failure statistics
After completing the reliability prediction work of all components, you can click
on the product structure tree on the left side of the main Window to view the predicted
results layer by layer. If the predicted results are not updated, you can click on the icon
of the reliability predicted main Window and recalculate it.
Figure 3-8 Failure Rate Statistics
18
3.5 report export
After completing the reliability prediction, click the button above to export the
failure rate prediction results of components under the currently selected node (product
structure tree on the left).
3.6 Other operations and instructions
(1) Direct Input Failure Rate
For some components, there is generally no corresponding reliability prediction
standard for you to predict directly. In this case, direct input can be used. Assuming that
node "M01" cannot be predicted by reliability prediction standard, the specific
operation method of direct input failure rate is adopted at this time:
Step 1: Confirm that you have selected Module B.
Step 2: Double-click "M01". In the pop-up reliability prediction parameter input
Window, the calculation method chooses "direct input". In the input box of lambda p,
input failure rate, and then click Button.
Figure 3-9 Direct Input Failure Rate
19
4 Reliability Modeling (RBD)
The reliability index obtained by the reliability prediction module is the basic
reliability (usually the failure rate and MTBF)!!If you need to get task reliability index
(such as mission reliability) and analyze the mission reliability of the product, you need
to use the RBD module of to get them.
When using reliability modeling (RBD) to calculate product’s reliability, we need
to consider the relationships model of series, parallel, redundancy and voting of each
component of the product, as well as the working status and duty cycle of each
component in different stages of use.
4.1 Creating Project and Product Structure Tree
How to create a project, see Section 1 ,If created, skip this.
How to create a product structure tree, see Section 2, If created, skip this.
4.2 Creating mission Profiles(optional)
Because the working state of each component of the product may be different in
different time periods during the use of the product. So, it is generally necessary to
establish mission profiles. Of course, if the mission profile is relatively simple, you
don’t need to create the mission profile.
Suppose that the "XXX system" in the new project "My first project" is divided
into two mission phases in the use process. Among them, the duration of mission phase
1 is 0-24 hours, and that of mission phase 2 is 24-48 hours. Mission phase 1 requires
module A and module B to work together, and mission phase 2 requires module B to
work together. For "XXX system", the steps to create the mission profile of "XXX
system" are as follows:
Step 1: Make sure that you have opened a project called My First Project.
Step 2:Click on the Mission Profile Window (or switch to the Mission Profile
Modeling Window by clicking on the Window in the menu bar).
Step 3:After entering the mission profile Window, drag two stage boxes and two
mission nodes from the model list on the right into the task profile drawing area. Stage
boxes enter the names " Mission Stage 1" and "Mission Stage 2" respectively. As shown
in Figure 4-1 below.
Step 4:Double-click on one of the task nodes and name it mission 1. Enter 0 for
start time and 24 hours for end time. Click on the "Associated Products" option and
switch to the editing Window of the Associated Products. Double-click on Module A
and Module B, then add Module A and Module B to the list of related products of
mission 1 automatically. As shown in Figures 4-2 and 4-3 below.
20
Double-click on another mission node, named "mission 2", using similar operations
to complete mission time settings and related product settings, related product selection
module B.
Then click on the model list on the right and select the connection line to connect
Mission 1 and Mission 2. As shown in Figure 4-4.
Figure 4-1 Creating Mission Profile
Figure 4-2 Setting Mission Information
21
Figure 4-3 Setting up Mission Associated Products
Figure 4-4 Mission Node Connection
Note: PosVim’s mission profile modeling supports hierarchical mission profile
modeling, that is, missions can contain multi-level sub- missions. Select the mission
node, and then select "Open sub-mission" to enter the sub-mission settings Window.
Specifically, you can learn how to create submissions by yourself.
4.3 Create RBD
PosVim’s reliability model (RBD) can be associated with or not associated with
mission nodes in mission profiles. Creating RBD is divided into two modes of operation.
One mode is to select the corresponding mission node from the mission profile and
create the reliability block diagram of the corresponding mission node; the other mode
is to directly enter the reliability modeling (RBD) module, create RBD, and then select
22
whether the RBD is associated with the existing mission node. Here are the operation
methods.
4.3.1 Creating RBD of Associated Mission from Mission Profiles
We have created two Mission phases and two mission nodes (mission 1, mission
2) before. The method of creating mission 1’s Relevant Reliability Model (RBD) is as
follows:
Step 1: Make sure you are in the mission profile editing window. In the mission
profile Window, click the Mission 1 node, right-click and select Create RBD.As shown
in Figure 4-5.
Figure 4-5 create RBD
Step 2:In the RBD Create Edit Window, enter information in the following format.
23
Figure 4-6 Editing RBD Basic Information
Step 3:After clicking save, you can enter the RBD modeling Window, which is
as follows.
Fig. 4-7 main window of RBD
Step 4:After completing the creation of RBD, enter the drawing RBD operation,
see section 4.4.
RBD Model Lib RBD Draw RBD Node List
24
4.3.2 Create RBD directly
The method of creating RBD directly is as follows:
Step 1:Select the "RBD" icon in the "Design Analysis" section of the menu bar
and click Open. At this point, the RBD management window pops up and the basic
information of the created RBD needs to be input. Like the following diagram.
Figure 4-8 Creating RBD Records
Step 2:click Add an RBD record. Pop up the window shown in Figure 4-6
and enter the information like the following window. The name "RBD of Task 2" and
the mission Name drop-down list select " mission 2".
25
Figure 4-9 Setting up RBD Basic Information
Step 3:Click save button. At this point, it will open a window similar to Figure 4-
7.
Step 4:After completing the creation of RBD, enter the drawing RBD operation,
see section 4.4.
4.4 Drawing RBD
After creating the RBD record (assuming the example of "RBD of mission 1"
created in the previous section 4.3.1), the RBD graph can be drawn. Specific
operation:
Step 1:From the list of RBD model libraries on the right side of the RBD
Window, drag two nodes unit (node 1, node 2) to the drawing area, and then connect
the start node, node 1, node 2, and end node respectively. As shown in the following
figure.
Note: The above drag and drop is a simple single node model. You can drag
and drop other complex nodes to create RBD. For example, drag and drop from the
list of RBD models includes parallel, redundant, voting (k out of n) and other
nodes.
26
Figure 4-10 Creates two cell nodes
4.5 Setting RBD Node Parameters
Configuring RBD node parameters is the key work of RBD modeling and
calculation. The specific operation is as follows:
Step 1: Edit unit node information. Double-click on node 1 and pop up the node
information editing window like following diagram. Associate product selection
"Module A". The default node type is "unit". You can also change it to series group,
parallel group, etc. If you change it to series group or parallel group, you need to input
the number of combined units and other information.
Figure 4-11 Associate Product Settings
27
Step 2: Select reliability prediction for failure rate data source. PosVim provides
direct input, distribution calculation, reliability prediction, reliability evaluation and
other ways to input failure rate data. Here we choose [Reliability Prediction] to obtain
the reliability prediction data of module A that we have already done. As shown in the
following figure.
Figure 4-12 Failure Data Source Settings
Step 3:Click the Compute button. The reliability calculation results of the joint can
be obtained. As shown in Figure 4-13.
Step 4:Click on the Mission/system Reliability Display Box , Mission/system
reliability curves at different times can be viewed. As shown in Figure 4-13 below.
28
Figure 4-13 Reliability versus time curve
Step 5:After double-clicking on node 2, the same method is used to set the
parameters of cell node 2.The product associated with Unit 2 is Module B.
4.6 RBD calculation
After completing the configuration of node parameters, the whole RBD diagram
can be calculated (Note: If there are nodes without configuration parameters, the
software PosVim will prompt the lack of data, and marked with red).
The RBD calculation operation is as follows:
Step 1After setting the parameters of Unit Node 1 and Unit Node 2, click on the
toolbar Calculate reliability. At this point, the corresponding list of reliability
calculation results is displayed below. As shown in the following figure.
29
Figure 4-12 Reliability Calculations
4.7 RBD Failure Rate Parameter Settings
As mentioned above, when setting the failure rate parameters of nodes, we can
choose the way of directly inputting reliability, calculating according to distribution,
obtaining reliability prediction results, and obtaining reliability distribution results.
Direct Input Reliability: In the pop-up node parameter editing window, the data
source is selected as "reliability" and then input directly.
Figure 4-13 Direct Input Reliability
According to the distribution calculation: In the pop-up editing window of node
parameters, the data source chooses "Distribution Computation", then chooses the
distribution type, and inputs the distribution parameters. For example, select
exponential distribution and input failure rate. When choosing different distribution
types, the input parameters are different.
Figure 4-14 is calculated by distribution
Obtain reliability prediction data: The data of each module of PosVim is highly
integrated to ensure data consistency of each module and improve work efficiency.
RBD module can obtain reliability prediction and reliability allocation data. The
methods of obtaining reliability prediction data are as follows:
Reliability Result
30
(1) In the associated product input box, the corresponding nodes in the product
structure tree must be selected. Otherwise, reliability prediction data cannot be obtained.
For example, if you want to obtain the reliability prediction data of Module A as the
failure rate data of Unit Node 1, select Module A in the drop-down list of related
products.
(2) Select the "Reliability Prediction" option at the data source.
Figure 4-15 Obtaining Reliability Prediction Data
Obtain reliability allocation data: The method of obtaining reliability
distribution data is the same as that of obtaining reliability prediction data.
4.8 Creating Complex RBD
The previous RBD model is relatively simple, with only two nodes in series. This
part describes in detail how to create a complex RBD model. The RBD model includes
series group, parallel group, K-out-of-N, subgraph and so on.
Step 1: Select
associated Node
Step 2: Select
‘Reliability Prediction’
31
Step 1:click Icon, create a record named "Complex RBD" directly like section
4.3.2.The name of RBD is entered into "Complex RBD". The system belongs to "XXX
System". The name of mission is left blank (or mission 1 and mission 2 established
earlier) and the time of mission is input for 24 hours. Click save.
Figure 4-16 Creating RBD Records
Step 2: Add a series group (the same unit).This method can be applied to the
case of multiple units connected in series. From the list of RBD models on the right,
click on the model icon and drag it to the drawing area to create a series group. Double-
click on the serial group node, in the pop-up node attribute form, the associated product
selection module A, the node category selection "serial group", the total number of
devices input 2 (can input any natural number), and the reliability prediction of data
source selection. Click on the calculation to get the reliability results of this series group.
32
Figure 4-17 Setting Series Group Parameters
Step 3: Add a series group (different units).The previous addition is a series
group made up of the same units. Here we create a series group made up of different
units. Operation procedure are:
3A:From the RBD model library on the right of the RBD main Window, Click
Icons (note that the two colors are different) and drag them to the drawing
area. At this point, the number of windows in series will pop up the input prompt box,
input number 2.After clicking on the confirmation, the Window shown in Figure 4-19
is displayed, and two series nodes of Unit 3 and Unit 4 are added.
3b:Double-click on node 3 and node 4 respectively to configure node parameters.
The specific configuration method refers to Section 4.5.
Input Series Node Num
Default mission time
33
Figure 4-18 Setting the Number of Series
Figure 4-19 Drawing Window for Series Groups
Step 4: Create the K out of N (the same unit). K out of N is a commonly used
model in reliability modeling, such as radar equipment. Specific operation methods:
4A:From the RBD model library on the right of the RBD main Window, Click
Drag and drag the icon to the drawing area.
4b:Double-click K out of N, in the pop-up editing window of node attributes, select
"Module B" for the associated product, select "Redundant Group" for the node type,
and input 2 for the total number of devices required (2 out of 3 devices are required,
and the system works normally).Failure rate data source selection reliability prediction,
click calculation and save. As shown in the following figure.
Figure 4-20 Add N out of K nodes
34
Figure 4-21 Setting N for K-node parameters
Step 5: Create a subgraph. For complex RBD, in order to display RBD structure
better and understand RBD structure relationship better, sometimes we need to use
subgraph to display part of RBD model in subgraph. Or when RBD diagrams are
created by different people and departments, you can use the RBD diagrams created by
others as sub-diagrams and aggregate and embed them into the RBD diagrams you draw.
Specific operation methods:
5A:From the list of RBD models on the right side of the main RBD Window, drag
a unit node to the drawing area. Of course, in the actual use process, you can also change
a node in the drawing area to a subgraph. The way to change the subgraph is to double-
click the node, and then change the node into a subgraph in the pop-up form of node
attributes. See Section 4.9 for details.
5B:In the pop-up edit window for node attributes, the subgraph category selects
"direct subgraph". Then click Save. At this point, the node icon of the main Window
becomes an icon with a "+" number.
35
5C:Double-click the "+" number of the node icon, or select the node, right-click
the menu "Open Subgraph" and enter the modeling Window of the subgraph. Subgraph
modeling is the same as normal RBD modeling. Here, we create a series group in the
subgraph, connect the start node, the series group and the end point, and configure the
node parameters of the series group (see step 2).As shown in Figure 4-23.
5D:After creating the subgraph, Click Icon, go back to the top layer.
Figure 4-22 create subgraph
Fig. 4-23 subgraph rendering
Step 6:In the order shown in Figure 4-24 below, connect the previously created
series group, K out of N, and sub-graph nodes. Then click on the calculation to get the
calculation result of the complex RBD.
Select ‘create Subdiagram
directly’
36
Figure 4-24 RBD calculation
4.9 sub graph management
For complex systems, subgraphs are sometimes needed to better represent the
relationships among RBD modules. In addition, the RBD model of complex systems is
relatively large and complex, at this time, different people may be responsible for
different RBD model construction, and need to use subgraphs to aggregate different
people’s RBD diagrams.
Based on the above considerations, PosVim provides subgraph management
functions.
4.9.1 Direct subgraph
Direct subgraph is to add a subgraph directly in the current RBD model. By using
the function settings of subgraphs, the hierarchical construction of RBD diagrams can
be achieved.
Methods of operation:
Step 1: Verify that you have entered the reliability block diagram RBD
module.
Step 2:Create RBD record. See Section 4.3 for details. Suppose you create an RBD
record called Subgraph Test RBD.
Step 3:From the list of RBD models on the right side of the main RBD Window,
drag a unit node into the drawing area.
Step 4:Double-click the node. In the node property editing window, the node name
is changed to "Subgraph 01" and the subgraph category is changed to "Direct Subgraph".
At this point, the node icon of the main Window becomes an icon with a "+" number.
37
Figure 4-25 set the subgraph
Step 5:Double-click the "+" number of the node icon, or select the node, right-
click the menu "Open Subgraph" and enter the modeling Window of the subgraph.
Subgraph modeling is the same as normal RBD modeling. After building the subgraph,
Click Icon, go back to the top layer. At this point, the sub-graph settings are
completed.
4.9.2 Reference subgraph
Reference subgraphs are a very useful function. For example, when different
people are in charge of different subsystems and establish RBD diagrams of subsystems
respectively, the RBD diagrams of the whole product or system can be directly
referenced when the RBD diagrams of the whole product or system are established. Or
references to RBD diagrams between different projects. Specific operation mode:
38
Step 1:Assuming that through Section 4.3, two RBD subgraphs "RBD for Task 1"
and "RBD for Task 2" have been created. If not, you can refer to Section 4.3 steps for
creation.
Step 2: Make sure that the project name you open is "My first project" and
has entered the RBD modeling module.Create RBD record.See Section 4.3 for details.
Suppose that you create an RBD record called Reference Subgraph Test RBD.
Step 3:From the list of RBD models on the right side of the main RBD Window,
drag two nodes (node 1, node 2) into the drawing area.
Step 4:Double-click on cell node 1. In the pop-up node attribute form, the sub-
graph type chooses "Reference Subgraph" and the association subgraph chooses "RBD
of Task 1". Similarly, double-click on cell node 2 and select "RBD of Task 2" from the
association subgraph.
Step 5:When the configuration is completed and the above nodes are connected,
the calculation results can be obtained by clicking the calculation button.
Fig. 4-26 subgraph
39
4.10 Add Node Pictures
In order to display RBD graphical structure more vividly, PosVim supports setting
background pictures of each node when drawing RBD model. Operating mode is:
double-click the node that needs to configure the picture, in the pop-up editing Window
of node attributes, in the blank input box on the right side of the [node picture], right-
click, and then select "Call" to browse the picture you need to import.
Figure 4-27 Sets the Node Background Picture
4.11 Result Viewing and Output
After the RBD modeling and calculation are completed, the RBD calculation
results can be viewed.
Select any node in the RBD model and click on the one above the toolbar The
reliability parameters of the current node can be calculated.
Without selecting any nodes, in the case of the currently open RDB model, click
on the top of the toolbar In this way, the reliability parameters of the whole RBD
diagram can be calculated.
click The overall reliability calculation results of the currently open RBD model
can be viewed.
click RBD diagrams can be exported.
click The results of RBD calculation in EXCEL file format can be exported.
40
4.12 Other operations and instructions
RBD results show that:
Basic reliability:Basic Reliability means the probability that the product will
complete the specified function within the specified time and under the specified
conditions. It is recorded as R (t), also known as the reliability function. The basic
reliability is to treat the composition and structure of the product as a series connection,
and then calculate according to the above calculation formula.
Mission reliability: Different from the basic reliability, mission reliability is
calculated according to the logical relationship model of series-parallel fault of the
product and the formula.
MTBF:MTBF is the average value of product failure interval time. For example,
in the use of a product, N failures occur, and each failure is repaired and then continue
to work.MTBF is the average time between failures.
MTBCF:Average critical or fatal fault intervals.Unlike MTBF, the failures
considered here are only fatal or critical failures.MTBF is a failure whether it is fatal or
critical.Therefore, the calculated MTBCF value is larger than that of MTBF.
PDF:probability density function
Harzard graph:It is the ratio of failure rate to reliability. That is the value of
f(t)/R(t).
41
5 Reliability allocation
Reliability allocation is top-down method, and the top-level reliability index are
allocated to each subsystem and module layer by layer.
5.1 reliability allocation
Reliability allocation is easier to operate than reliability prediction and reliability
modeling RBD. Assuming that a project named "My First Project" has been created and
a product structure tree with the root node of "XXX System" has been established, the
reliability index of "XXX System" will now be assigned to module A and module B.
Operation procedure:
Step 1:To create a project, see Section 1.If created, skip and open the project
directly. Let’s assume that we have created the project "My First Project" according to
Section 1.Open the project directly.
Step 2:To create a product structure tree, see Section 2.If created, skip. Let’s
assume that we have created the product structure tree in accordance with Section 2,
and we don’t need to create any more.
Step 3:Confirm that you have opened "My First Project" and opened the reliability
allocation module. Select "XXX System" in the product structure tree on the left. As
shown in the following figure.
Figure 5-1 enters the reliability allocation Window
Step 4: Select the allocation method. According to the user’s requirements or the
requirements of the project itself, the specific reliability allocation method is
determined. For the detail information of various allocation methods, reference to the
corresponding books or standard materials. Here, suppose we choose the "AGREE
allocation method". At this point, the system reliability and reliability redundancy input
box on the right becomes editable.
42
Fig. 5-2 Allocation Method Selection
Step 5: Input allocation index. Because the selected allocation method is AGREE
allocation method, the reliability index that can be allocated is considered. Input
allocation of system reliability index (that is, input the index you need to allocate
downwards) 0.96, reliability redundancy input 0.1 (generally retain a certain reliability
allocation redundancy in engineering), or left blank. For the meaning of reliability
allocation redundancy, see section 5.5.
Figure 5-3 Setting of Allocation Index
Step 6: Input allocation parameters. Choosing different allocation methods
requires different allocation parameters to enter. The AGREE method is chosen here,
which requires input including mission time, number of components, and importance
factors. Enter the corresponding parameters as shown in the figure below.
Step 7: Allocation calculation. Click to complete the allocation calculation. The
results are shown in the following figure.
Figure 5-4 Allocation results
Step 8: Allocation adjustment. The allocation results need to consider
comprehensively the realizability. Therefore, the allocated results may need to be
adjusted. See Section 5.2 for the method of operation. It is assumed that the allocation
result of module B is adjusted to 0.98.
Figure 5-5 Allocation results adjustment
43
Step 9: The next level of allocation. Through steps 1-8, the allocation results of
module A and module B have been obtained. Suppose we need to continue allocating
now. Taking module B as an example, the allocation results of module B are further
allocated to the next layer. Specific operation steps:
9A:In the product structure tree on the left side of the main Window of reliability
allocation, select "Module B". At this time, the reliability allocation index of Module B
needs to show 0.98, indicating that the allocation results of the previous level have been
automatically obtained (of course, the data can be modified).
9b:According to steps 4-6, the allocation method selection, allocation index setting
(the result of the previous layer has been obtained by default) and allocation parameter
input are completed respectively.
9C:Click on the allocation calculation to get the result of the downward allocation
of module B index. As shown in the following figure.
Figure 5-6 Next Level (Module B) Allocation results
5.2 Adjustment of Allocation results
According to the previous selection of the appropriate allocation method to obtain
the reliability allocation indicators at all levels of the product, sometimes it is necessary
to adjust the allocation results of individual subsystems and modules, such as the
allocation of indicators to rectify processing, or research and development of high-risk
equipment needs to reduce the reliability index requirements. At this point, you need to
use the allocation result adjustment function.
Assume that the reliability index assignment of XXX system has been completed
according to Section 5.1. Now the allocation results need to be adjusted.
Step 1:In the column of "Adjusted Reliability", the results of reliability allocation
can be adjusted separately. For example, the reliability allocation result of module A is
adjusted from 0.966554 to 0.97, and that of module B from 0.980749 to 0.98.
Fig. 5-7 Reliability Allocation Result Adjustment
44
5.3 Allocation of Fixed Element Reliability
In reliability allocation, we often encounter the situation that the reliability index
of some components is known. At this time, when reliability allocation is carried out,
the reliability index of these components can be set to be fixed. Then the reliability
allocation is carried out.
Assuming that Module B contains three components, the reliability requirement of
Module B is 0.98 (the result of upper level assignment), and the reliability index of M01
mechanical component is known to be 0.99. Then the operation steps of reliability
allocation of module B are as follows:
Step 1:Assuming that the reliability allocation is made according to step 1-8 of
Section 5.1, the reliability allocation result of Module B is obtained.
Step 2:In the product structure tree, module B is selected, and then the allocation
method is "AGREE allocation method", and the reliability allocation index is 0.98 (the
result from the allocation from the upper level).
Step 3:When input reliability allocation parameters, in the fixed reliability column
of M01 node, input 0.99.Then input the task time, number of components, importance
factor and other parameters of each component according to the figure below.
Step 4:Click on the button to get the reliability allocation results, as shown in the
following figure.
Fig. 5-7 Fixed Reliability Allocation
5.4 Settings do not participate in allocation
In the process of product development, some components and components are
mature products and generally do not participate in reliability allocation. At this time,
in the development of reliability allocation, only the corresponding components
involved in the allocation can be checked out.
Figure 5-8 Settings Do not Participate in Allocation
45
5.5 Other operations and instructions
Allocation method: Choosing different allocation methods, the reliability index
that can be allocated are different. When selecting the allocation method, system
reliability, MTBF and failure rate can be allocated; when AGREE method is selected,
system reliability can only be allocated. When selecting the allocation method and
grading allocation method, the system reliability, MTBF, failure rate and other
indicators can be allocated. You can input one of the index. Of course, you can also
enter multiple indicators.
System reliability:This column asks you to enter the reliability index you want to
allocate down. For example, the reliability requirement of the system is 0.9, which
requires that the index of 0.9 be allocated downwards. Then, enter 0.9 in the column of
system reliability.
Reliability redundancy: When carrying out reliability allocation in general
engineering, it is necessary to consider whether the target can be achieved in the later
development process, and some uncertain factors in the later development process may
affect the realization of the target. In order to ensure the success of product development,
there is a certain margin in general distribution. Therefore, when using PosVim to carry
out reliability allocation, if you don’t want to retain the margin, enter 0 in the column
of reliability margin (software default); if you want to retain the margin, enter 5%~15%.
The software will be allocated according to the system reliability input and the
corresponding reliability margin.
MTBF redundancy: It is similar to reliability redundancy.
Failure rate redundancy: It is similar to reliability redundancy.
Fixed reliability: When the reliability of the node is known or it is considered that
the node does not use the value assigned by the reliability allocation result, the
reliability value of the node is input directly.
Adjusted reliability: After selecting the reliability allocation method for
allocation, the distribution results of each node are obtained. When the general
distribution results are different from the actual distribution results with decimal points
or directly applying the distribution method, the adjusted values can be input in the
reliability column after adjustment. For example, the reliability of equipment A is
determined to be 0.9625 hours according to the grading allocation method. After
comprehensive consideration, it is considered that the implementation technology of
the equipment is relatively mature, and the reliability of the equipment can be increased
(0.97), while the reliability of other equipment can be reduced relatively, so the
reliability can be input 0.97 after adjustment. At this point, the allocation result will be
0.97 instead of 0.9625.
Fixed failure rate: It is similar to fixed reliability.
Adjusted failure rate: It is similar to the reliability after adjustment.
Fixed MTBF: It is similar to fixed reliability.
Adjusted MTBF: It is similar to the reliability after adjustment.
46
6 FMEA analysis
Failure Mode, Impact and Criticality Analysis (FMECA) is an engineering
technology for reliability and safety analysis. It is also an important work for
maintainability, supportability and testability design analysis. FMECA is an inductive
analysis method to analyze all possible failure modes and their possible impacts on the
system for each product/process in the system, and classify them according to the
severity of each failure mode, the difficulty of detection and the frequency of
occurrence. Using FMECA analysis method:
FMECA can be used for inspection and analysis of design drawings after the
completion of Engineering design.
Identify measures that can eliminate or reduce the chance of potential failure;
FMEA is generally required when new designs, new technologies, new
processes are adopted, or when existing designs or processes are modified, or
when existing designs or processes are used in new environments, sites or
applications.
6.1 Analytical method and standard predefinition
PosVim software supports FMEA standards such as GJB1391 and AIAG, and
supports function/hardware, process and software FMEA. PosVim software built-in
GJB1391, AIAG (automobile) industry FMEA standard template. It is assumed that
FMEA analysis is performed directly using the standard GJB1391 template built in
PosVim software.
6.2 FMEA analysis
6.2.1 Indenture levels selection
FMEA is a bottom-up reliability analysis method. In the process of FMEA analysis,
the choice of Indenture level and initial Indenture level will affect the depth of FMEA
analysis and the workload of FMEA analysis.
Suppose that the product structure tree of "XXX system" created in Section 2 (see
Section 2) is taken as an example, in which "XXX system" is chosen as the initial
Indenture level and the components of module A and module B as the lowest Indenture
level. FMEA analysis begins with the components of module A and module B.
Operation procedure:
Step 1:Make sure that you have open a project named "My First Project" and enter
the FMEA module. If the project and product structure tree are not created, they are
created in sections 1 and 2 respectively.
47
Step 2:Select the component "M01" under Module B.FMEA analysis begins with
components.
6.2.2 Failure Mode Information Setting
Step 3:Click on the top of the toolbar Add fault mode
Step 4:Enter product or function label in the "Product or Function Mark" column,
function description in the "Function" column, fault mode code in the "Identification
Number" column, fault mode directly in the "Mode" column, or select fault mode from
the drop-down selection box. As shown in the following figure.
Note: PosVim provides a fault mode library, which includes common mechanical
and electronic fault modes. You can choose the `Failure Mode of the `Basic Data Lib’
in the menu bar. Icon, click on, enter the maintenance and management of failure
mode.
Figure 6-1 Fault Mode Information Setting
6.2.3 Fault Affect Analysis
According to GJB1391 standard, fault affect includes three parts: local affect, high-
level affect and final affect.
Step 5:Input local affect and high level affect. Since the component M01 is the
object of current analysis and the upper layer is module B, the higher level affect refers
to the affect of module B. The final affect can only be selected at the initial Indenture
level "XXX System" level selected in section 6.2.1.This level does not belong to the
initial indenture level, so it cannot be input.
6.2.4 Qualitative analysis
According to GJB1391 standard, the information needed for qualitative analysis is
shown in the following figure. Other standards need to fill in different information,
according to specific standards.(Note: PosVim supports customize standards and
customize content and format requirements).
Figure 6-2 Qualitative Analysis
Select on Initial Indenture Level General five class
48
Step 6:Because the object of current analysis is component M01, which belongs to
the lowest indenture level, the severity class does not need to be filled in. The
corresponding information is filled in according to the actual situation in the probability
of failure mode, fault detection method, improvement measures and compensation
measures.
Note: PosVim will save these data as experience in the database every time it fills
in the fault detection method, improvement measures and compensation measures. The
next time it is used, it will automatically pop up the data items which contain the last
data, which can be selected for improving work efficiency.
6.2.5 Quantitative analysis
According to GJB1391 standard, the information needed to be filled in the
quantitative analysis column is shown in the following figure. Different standards need
to fill in different quantitative analysis content, can refer to the corresponding standards.
Figure 6-3 Quantitative Analysis
Step 7:In the quantitative analysis section, the following operations are performed:
7A:Firstly, data sources can be selected, such as reliability prediction, reliability
evaluation, reliability test and so on. By default, PosVim use the reliability predicted
failure rate data for the corresponding components.
7b:Then, the input frequency ratio is usually 0-1 in the section of "Failure Mode
Ratio";
7C: The affect probability can be filled according to empirical data or handbook.
7d:[Failure Rate] column is automatically acquired by default based on the
reliability predicted results, and you can also modify it manually.
7e:In the "Mission Time" column, fill in the mission time according to the actual
situation.
6.2.6 Affect Analysis of Intermediate level
Through the previous steps 1-7, the failure mode editing, qualitative analysis and
quantitative analysis of component M01 are completed. However, this is only to
complete the fault information editing and analysis of the lowest indenture level
component M01 itself, and further analysis of the affect of the fault mode on the upper
level and the higher level is needed until the initial indenture level "XXX system" is
reached. Methods of operation are:
Step 8:Click Module B in the "Product Structure Tree" list on the left of the
software main Window. At this time, you can see that in the failure mode, failure cause
column, the next layer node M01 information has been obtained.
49
Figure 6-4 Failure Information of Inheritance Module B
Fault affect analysis of module B is carried out according to the following methods
(including inherited M01 fault information and new fault mode information of module
B itself). Here, inherited M01 fault information is selected for analysis, and no new
fault mode information of module B is added):
8A:Fill in the corresponding information in the columns of Product or Function
Mark, Function and Identification Number respectively.
Figure 6-5 Fault Information Input of Module B
8b: According to the method of 6.2.3, 6.2.4 and 6.2.5 subsections, the fault affect
analysis information, qualitative analysis information and quantitative analysis
information are added respectively. As shown in the following figure.
Figure 6-6 Qualitative and Quantitative Analysis Input of Module B
6.2.7 Fault Analysis at Initial Indenture Level
Through step 8, the result of fault affect analysis of middle level module B is
obtained. The failure affect of module B will be regarded as the failure mode of the
initial indenture level "XXX system", and the failure mode of module B will be
regarded as the failure reason of the initial indenture level "XXX system".
Implement the operation steps of the fault affect analysis of the initial indenture
level "XXX system" are:
Step 9:In the "Product Structure Tree" list on the left of the software main Window,
click on "XXX System". At this time, the system automatically inherits the information
of the next level (module B).
9A:Fill in the corresponding information in the columns of Product or Function
Mark, Function and Identification Number respectively.
Figure 6-7 Fault Information Input at Initial Indenture Level 9b:When filling in the local affect, because the level is the highest level (initial
indenture level), only the information of the column is needed. The information of the
high level affect and final affect need not be filled in, and is not editable.
50
When filling in the information of qualitative analysis column, in addition to filling
in the corresponding information of failure mode probability class, fault detection
method and design improvement measures according to the filling method of section
6.2.4, be sure to choose the "severity category".
According to the method of 6.2.5, fill in the information of each column for
quantitative analysis.
Fig. 6-8 qualitative analysis
6.2.8 Other information added
The fault information input of module B has been completed. In order to better
understand the function of PosVim, the fault affect analysis of module A is also carried
out here.
Step 10:According to the method of 6.2.1 to 6.2.5, a fault mode analysis record is
added to the component "2CE52" of module A.
Figure 6-9 Component Fault Information Input of Module A
Step 11:According to the method of 6.2.6, a fault analysis record (information
inherited from component "2CE52" fault) is added to module A.
Figure 6-10 Fault Information Input of Module A
Step 12:In accordance with the 6.2.7 method, add a record to the initial contract
level "XXX system", as shown in the following figure.
Figure 6-11 Fault Information Input at Initial Indenture Level
6.2.9 Analysis and calculation
After completing the above steps 1-12, the calculation can be carried out.
Step 13:Click on the toolbar. Icon, calculate.
At this point, the software Window will go to the calculation results view Window.
As shown in the following figure. You can change between different results by clicking
on the list of results on the left.
51
Figure 6-12 FMEA analysis results
6.3 control plan &DVP
FMEA can be used to analyze and determine the impact level of different failure
modes, design improvement measures and coping methods. In order to implement these
improvement measures and coping methods, it is necessary to formulate corresponding
control plans, and carry out corresponding tests and verification. PosVim provides
control planning and DVP functions.
Methods of operation:
Step 1: Make sure you enter the project "My First Project" and the FMEA
analysis module.
Step 2:Click on the "Module B" node in the product structure tree on the left side
of the main Window, and then click on the one above the main Window. Icon,
you can pop up the control plan development window.
Step 3:In the control plan editing window, input the control plan information for
module B’s failure mode and cause, as shown in the following figure.
FMEA results list,
click to switch
52
Figure 6-13 Control Plan Editing
Step 4:When enterprises implement corresponding design improvements
according to the control plan, and carry out corresponding testing and testing, they need
to fill in the DVP form. Ensure that "Module B" is selected, click on the icon of the
toolbar, fill in the corresponding information in the pop-up Window as shown in the
following figure, and click save.
Figure 6-14 DVP editing
53
6.4 Convert to Fault Relation Diagram
In addition to checking the impact relationship of faults at all levels of the product
by listing, PosVim also provides the function of graphically viewing the impact
relationship of faults at all levels. This is more intuitive and easier to perform fault logic
analysis for complex and large-scale systems. Methods of operation:
Step 1: Confirm that you are currently in the FMEA analysis module of My
First Project.
Step 2:In the list of product structure trees on the left side of the software main
Window, click and switch to the level of the fault diagram you want to view. For
example, click on "XXX System".
Step 3:In the Fault Analysis Record List in the middle of the main Window, right-
click on any Fault Analysis Record to select "Fault Relation Diagram" or click on the
toolbar. The icon opens all relevant failure mode relation
diagrams that cause the failure to occur. For example, click on the "No Signal " record,
and then right-click on the "Failure Diagram" to open the Window shown in the
following figure.
Figure 6-15 Fault Relation Diagram View
6.5 Convert to Fault Tree
In addition to graphically viewing fault relationships at all levels, PosVim also
provides the ability to intelligently convert FMEA data to Fault Tree data. Fault Tree is
automatically drawn by software, which greatly improves work efficiency. It also
guarantees data consistency and validity of FMEA and FTA.
Operation procedure:
54
Step 1: Confirm that you are currently in the FMEA analysis module of My
First Project.
Step 2:In the list of product structure trees on the left side of the software main
Window, click and switch to the highest level you want to convert into a fault tree, that
is, the level at which the top event is located. For example, click on "XXX System".
Step 3:In the Fault Analysis Record List in the middle of the main Window, right-
click on any Fault Analysis Record to select "Convert to Fault Tree" or click on the
toolbar Icon, you can create the fault tree with the fault as the top
event. For example, by clicking on the "Signal Processing Function Failure" record,
and then right-clicking on "Turn to Fault Tree", a pop-up window is displayed to
indicate whether or not to convert to Fault Tree. Click to confirm, you can open the
Window shown in the following figure.
Figure 6-16 Converts to Fault Tree
6.5 Fault Mode Library Management
To carry out FMEA work, the maintenance of fault mode library is very important.
PosVim provides a common library of failure modes for mechanical and electronic
components. These fault mode libraries can be added, deleted, edited and modified.
Specific measures:
6.5.1 Add fault mode
The steps for adding failure modes are as follows:
55
Step 1:Click Basic Data on the menu bar, and then click Icon. It can enter the
fault mode library management Window. The Window is divided into two parts. On
the left is the fault mode, and on the right is the fault mode attribute.
Figure 6-17 Fault Mode Library Management
Step 2:Click on the icon of the list of failure modes on the left Then enter a
"fatigue failure" failure mode in the input field.
Figure 6-18 Adding Failure Mode
6.5.2 Setting Failure Mode Properties
After adding the fault mode, the attributes of the fault mode can be edited. By
editing the fault mode attributes, we can specify which categories of products the fault
mode is mainly used for, so that when FMEA analysis is carried out, the software can
automatically screen out the alternative fault modes.
Operational steps (follow step 2 above):
Step 3:After adding the "Fatigue Failure" fault mode (remember to make the fault
mode input box non-editing state, otherwise it will remain in the state of input fault
mode, unable to add attributes. The method of operation is: click on any blank to switch
the input state, click on the toolbar above the list of fault mode attributes on the right,
and pop up the window to add fault mode attributes. The meanings and settings of each
column are shown in the following figure. Among them, "Product Category" column
56
refers to the category of products that want to classify the failure mode into, "Predicted
Category" refers to the category of products that want to classify the failure mode into
the classification method in the prediction standard. The causes of failure, design
improvement, compensation measures and detection methods refer to the
corresponding causes and improvement measures of the failure mode. After setting up,
the software will fill in the information by default, without manual filling. If the
"Default" column is checked, the previous settings will take effect, otherwise they will
not take effect.
6.6 Computing configuration
The qualitative and quantitative analysis of FMEA involves many problems such
as the inheritance of fault information at different levels and the processing of different
fault information belonging to the same component. PosVim provides intelligent
functions to deal with these problems, such as ratio normalization, fault affect
inheritance and so on. Method of setting FMEA configuration information are:
Step 1:Click on the icon of the toolbar, pop-up in the qualitative analysis,
quantitative analysis, normalization processing Window, according to the need to
configure. As shown in figure 6-19~21.
Set use this
FM default
Set use this Cause
default
Set use this
Corrective default
57
Figure 6-19 Qualitative Analysis Settings
Figure 6-20 Quantitative Analysis Settings
58
Figure 6-21 Frequency Ratio Settings
6.7 Detection Method Library Management
PosVim provide the function of management common detection methods library.
The operation is:
Select "Basic Data Lib" from the menu bar and click Icon. Enter the detection
method library management Window.
click Add detection record.
6.8 Management of Fault Correction Action Lib
Through the management function of PosVim’s fault correction action library, we
can management the common fault correction action within the unit. The operation is:
Select "Basic Data Lib" in the menu bar and click on the icon 。Enter the
detection method library management Window.
click Add detection record.
59
7 Fault tree analysis
7.1 create fault tree
Fault tree is an important and commonly used technical in the process of reliability
and safety analysis.
7.1.1 Creating Fault Tree Records
A project can create multiple fault trees. Project and fault tree are one-to-many
relationships. Therefore, we first need to create a fault tree analysis record. Operation
procedure:
Step 1: Make sure that you currently open a project called My First Project
and enter the Fault Tree Module(Click on the design analysis section of the menu
bar, and then click Icon.
Step 2:In the pop-up Fault Tree Management Window, Click Icon, new
fault tree record, name input "XXX system cannot work properly". As shown in the
following figure. Then click Open Fault Tree.
Figure 7-1 Fault Tree Record Creation
60
7.1.2 Drawing Fault Tree Model
After opening the fault tree record, it enters the main Window of fault tree analysis.
The left Window is the product structure tree, followed by the fault tree structure list
(according to the fault tree drawing in the middle, real-time display of the structure
information of the fault tree), the middle is the main Window of the fault tree drawing,
and the right is the fault tree model library. As shown in the following figure.
Figure 7-2 Fault Tree Drawing Window
Assuming that the top event we have created is "XXX system cannot work
properly", the intermediate event that causes XXX system to not work properly is
module A failure or module B failure. The bottom event that causes module A failure
is each component failure, and the bottom event that causes module B failure is the
component simultaneous failure of module B. That is to say, the fault tree we want to
create includes three layers. The first layer is the top event "XXX system cannot work
properly", the middle layer is the failure of module A and module B, and the third layer
is the bottom event, that is, the failure of each component.
The steps to create the fault tree are as follows:
Step 3 (follow step 2 above)From the fault tree model library on the right, drag
and drop one and one or more doors to the drawing area, respectively. And double-click
on the new and door, or door, modify the door described as "A module function failure",
"B module function failure".
FTA structure
list
FTA Draw
Panel
Product
Structure tree FTA Model Lib
61
Figure 7-3 Add and Gate, or Gate
Step 4: Drag three basic events from the model library and place them under the
"A module function failure" OR gate; similarly, drag three basic events under the "B
module function failure" AND gate. Double-click on the added basic events and modify
the names of each event according to the naming method shown in the figure below.
Figure 7-4 Adding Basic Events
62
Figure 7-5 Modify Node Name
7.1.3 Calculating the probability of bottom/basic event
To obtain the probability of top events, it is necessary to set the probability of all
basic events/bottom events. The probability of occurrence of the underlying event/basic
event is as follows:
Step 5 (following step 4 above):Double-click the node named "2CW52" to pop
up the property box of the node. PosVim provides a variety of settings for event
occurrence probability, including direct input occurrence probability, distribution
calculation, etc. Distribution calculation mode is selected here. Exponential distribution
is selected for distribution type. Exposure time (or task time) is input for 24 hours, and
failure rate is input for 0.5.Click save. Similarly, other nodes are set in the same way.
So far, the fault tree has been constructed. It can be transferred to calculation.
63
7.2 Fault Tree Computation and Analysis
7.2.1 Top event calculation
Step 1:Click on the icon on the toolbar to calculate the probability of the top event.
The calculation results are shown in the following figure. Including the calculation
results of top event occurrence probability, minimum cut set, event importance, number
statistics of cut sets of each order, probability statistics of occurrence of each order, etc.
Figure 7-6 Fault Tree Calculations (Top Events)
7.2.2 Computation of any other nodes
PosVim can not only calculate the occurrence probability of top events, but also
select any node of the fault tree to calculate the occurrence probability of events and
other indicators. Assuming that the probability of module A function failure is to be
calculated, the method of operation is as follows:
Return to the FTA draw window, select Node ‘Module A Function failure’ and
click Icon, we can calculate the probability of module A occurrence, and the
corresponding cut set, importance and other indicators.
Figure 7-7 Fault Tree Computation Results (Functional Failure Node of Module A)
64
7.2.3 Set Cutset order
For complex fault trees, there are many cut sets, which can reach hundreds of
thousands or even tens of millions. At this point, if you want to filter out some higher-
order cutsets, you can use the toolbar’s Option, input the maximum order of
cut set, you can filter the higher order cut set.
7.3 Multifunctional/Common Cause Analysis
PosVim supports not only general fault analysis, but also fault tree analysis of
multi-functional nodes (special common cause) and common mode faults. It is assumed
that the RJ4501-1 fault event under the "module A function failure" gate event belongs
to the same component as the RJ4501 event under the "module B function failure" gate
event, that is, the component can complete the function of module A and module B. To
carry out multi-functional node fault analysis, the specific operations are as follows:
Step 1:Considering that the probability of occurrence of the three events under
module B is small, and it is with the gate, the result is very small. In order to better
compare the analysis results of whether multi-functional is set, the type of "module B
function failure" door is changed to "OR gate". The modification method is to double-
click the gate and then change the type to or gate.
Step 2:Click to calculate the probability of top events without multi-functional
nodes.
Figure 7-8 Computational results without multi-function nodes
Step 3: Return to the fault tree drawing Window, double-click the "RJ4501-1 fault"
event under the "module A function failure" gate event, in the pop-up property editing
box, Click Icon, pop-up multi-functional settings Window.
Step 4: Enter the name of the multifunctional group "RJ4501 Multifunction", then
double-click "RJ4501 Failure" under "Module B Function Failure" in the optional event
list. As shown in the following figure. Click save.
65
Figure 7-9 Setting up Multifunctional Groups
At this time, you can see that the border of "RJ4501-1 Fault" and "RJ4501 Fault"
in the Fault Tree Drawing Window becomes red, indicating that the multi-function
setup is successful.
Figure 7-10 Fault Tree with Multifunctional Nodes
Step 5: click Icon for top event calculation. The probability of top
event occurrence is 3.31194E-05 (4.15191E-05 when no multi-function is set).
66
Figure 7-11 Fault Tree Calculations with Multifunctional Nodes
7.4 Other operations and instructions
(1) PosVim fault tree analysis module can output fault tree graphics and various
calculation results.
(2) PosVim fault tree analysis module supports more than 10 types of events, such
as basic events and room events.
(3) PosVim fault tree analysis module supports more than 10 Boolean logic models
such as AND gate, OR gate, XOR gate.
(4) Support paging display, support loose layout and compact layout.
(5) All operations provide right-click menu operations.
The above functions can be experienced according to actual needs.
67
8 Derating Analysis
8.1 Derating Standard Selection
PosVim supports GJB/Z 35, ECSS-Q-30-11-A, AS-4613 and other derating
standards, and can customize the derating criteria. The setting of the customized
derating criteria can be seen in section 8.5.
Suppose that GJB/Z 35 level II derating criterion is selected for module A
component derating design.
Step 1:Confirm that you have entered the project named "My First Project" and
entered the derating analysis module. Click Module A of the Product Structure Tree on
the left of the main Window.
Step 2:Click on the toolbar Select the level
II derating criterion of PosVim’s built-in GJB/Z 35 standard.
8.2 Setting of Derating Parameters
Step 3 (following the preceding steps):Select any component node in the middle
list of the main Window for derating design, such as the "2CW52" diode.
Step 4:Click on the top of the toolbar, or double-click on the "2CW52" diode node,
and pop up the parameter setting Window below the Window.
Step 5:Select the subclass "general diode" and then set the derating value of the
input current, voltage and other parameters as shown in the following figure.
Figure 8-1 Derating Parameter Setting Window
Step 6:Similar to other devices, the derating parameters are set one by one.
68
8.3 Conformity Check of Derating
After setting the derating parameters of the components one by one, Click to get
the results of the conformity check of the derating. As shown in the following figure.
Figure 8-2 Conformity Check
8.4 report output
Click on the icon to output the derating design and inspection results.
8.5 Custom derating Criteria
In addition to PosVim’s built-in derating criteria, you can customize the derating
criteria.
Step 1:Click on the icon to pop up the custom guideline Window. Click on the
Custom Criteria Window Then enter "My Criteria" in the criteria name.
Step 2:It can input the required values of each criterion directly, or copy the
required values of GJB35 criterion directly, and then modify the parameters of each
criterion.
After modification, click the save icon.
69
Figure 8-3 Custom Derating Criteria