Seminar "Sesam Present & Future" in Rio on Sept 2nd 2011, presented by Ole Jan Nekstad
TRANSCRIPT
Ole Jan Nekstad, Sesam Product Manager, DNV Software20 August 2011
1
SesamTM
40 years of success
New features in GeniE, DeepC and HydroDJune 2011
Presenter
Presentation Notes
Read the text: This presentation gives a brief outline of the new features in Sesam’s programs GeniE, DeepC and HydroD. It aims at documenting the benefits for our users and why you should upgrade to the new program versions. Notice: The presentation should be showed in “Slide Show” mode. You are requested to read the notes prior to presenting this power-point.
6. Wave load analysis including local shell models
7. Easier modelling of planar surfaces
8. More advanced use of cut plane
9. More features for making geometry
10. Faster updating of finite element models
11. Become more efficient by using scripting
DeepC v4.5
1. Regular wave condition
2. Direction dependent scatter diagram
3. Parallel execution
4. Cross-section and fatigue analysis of umbilicals
HydroD v4.5
1. Multibody additional damping
2. Compartment load retrieval independent of sub-model
3. User defined pressure reduction region
4. User defined reference point for calculation of results
5. Automatic proposal for the number of panels needed for an optimum analysis
Supporting Win XP, Win 7 and Win Vista
32bit as well as 64bit
Presenter
Presentation Notes
Read the text: What’s new in the Sesam June 2011 release The new versions of DeepC, GeniE and HydroD build on more than 40 years of history. This release focuses on providing more flexibility in performing design analyses and on giving our users more advanced analysis options to fine-tune the design. We have increased Sesam’s coverage to also include design of umbilicals. “The continuous investments in Sesam lead to new and improved products that help our customers become even more productive,” says Ole Jan Nekstad, Sesam Product Manager. The main reasons why you should upgrade and benefit from the new Sesam release is explained in the following. Please notice there are many other enhancements that also may be of importance to you. In case you want to switch from operating system Win XP to Win 7 you need to install the new versions.
GeniE v5.3 - BenefitsA major focus of this release has been to ease the work to do beam deflection reporting and to model complex surfaces.
Another main reason for the release has also been to allow for import of old frame models and results to do result presentation and code checking in GeniE - a typical example of such is the import of data from existing SRS (structural reanalysis systems).
Finally, we have made the code checking more flexible. To better support design requirements, users will now have the possibility of not strictly following the interpretations as given by the various statutory regulations, which can be over conservative.
1. GeniE – beam deflection reporting Easier to document compliance with
statutory requirements- Beams with one finite element- Cubic interpolation and local loads- Scanning many load cases- Check against AISC levels 180, 240 and 320
Presenter
Presentation Notes
Read the text: Beam deflection reporting is a requirement by for example the AISC code of practice. The new functionality related to beam deflection reporting significantly reduces the engineers’ amount of work. Instead of making many finite elements along a beam we now use one finite element per beam. Combined with cubic interpolation together with the effect of local loads GeniE derives the deflections and compare with the AISC pre-defined thresholds (typically a 180, 240 or 360 classified member). Furthermore, it is possible to do scanning operations meaning that GeniE automatically will make an envelope listing the maximum and minimum result over all load cases (or selected load cases). The pictures show an example of a member that is passing the 180 and 240 criteria, but not the 360 threshold. Start the video and use the text (duration 2 minutes and 14 seconds): 0 sec: This video shows in real time how to present beam deflections for a selected beam. The beam deflections are based on an analysis where each beam is modelled with one single finite element between each joint. 18 sec: To make a deflection report you select the member, right click and choose the option Beam Results Diagram. From here you select which components to present – for example total deflection and the 180, 240 and 360 AISC thresholds - and which load-cases to apply. In this case an envelope including two load combinations. 58 sec: You easily see that the member passes the 180 threshold, but not the 240 and 320 AISC limits. The actual deflection curves are exceed theses limits for the maximum envelope curves (the red curve). 1 min 16 sec: Presentation option cubic with loads is the default setting in GeniE since it gives the most accurate results. If you want you can use a pure linear option or cubic without loads but you should be aware that these results may be misleading. However, for early analysis you may want to use these options. 1 min 57 sec: If you want a very smooth deflection curve you can increase number of interpolation points per element from minimum 5 to maximum 25.
2. GeniE – more flexible code checking of beams User controlled options added to over-rule
defaults in code checking standards- Standards some times to conservative- User controlled options may lead to non-conservative
results
Run larger number of load cases for code check (AISC, EC, ISO)- Does not store all loads and code checking results- This is the default setting for a code check run
Code check updates- AISC: Exclude torsion effects when computing
vonMises stresses (Chapter G)- Eurocode: Include plastic moment of inertia in
formulae 6.2- API (WSD/LRFD), AISC (ASD/LRFD), ISO, Norsok:
user to decide max bending option (default) or local bending moment
Label code check buckling lengths
Use of default max bending moment
Use of local bending moment
Presenter
Presentation Notes
Read the text: The code checking in GeniE has been available for quite some time and we have learnt from user experiences that they want first of all to have more flexibility as compared to the most conservative interpretations of the standards, but also to do screening studies by running a larger number of load cases. This version of GeniE includes more flexibility whereby the user can decide options for using -Maximum or local buckling moments – this is relevant for compression buckling of members -Exclude torsion effects when computing vonMises stresses according to AISC -Include plastic moment of inertia in formulae 6.2 of Eurocode -Compute code check forces when needed and store the worst code check results only. This option will allow code checking of many more load cases as compared to previous GeniE releases The pictures show the results from a code checking of a segmented member in compression. Using the code check default according to the prescriptive rules will lead to a failure while using the local moment leads to a satisfactory result. With local moments the actual moment at the code checking position is used and not the maximum bending moment. Start the video and use the text (duration 1 minute and 53 seconds): 0 sec: This video shows in real time code checking of a segmented member with compression and lateral load at the end. We will show that the default maximum bending moment will lead to code check failure, while the option of using local bending moment satisfies the code check standard. 15 sec: The bending moment can be shown by using the Beam Results Diagram. Please also notice that the shape of the cross-section changes when the cursor passes the beam segmentation. 38 sec: There are two sections being used to model the segmented beam – a 457mm and 610mm pipe. 55 sec: The capacity check using the default maximum bending moment at the fixation of the beam for each code checking position will lead to a utilisation ration larger than 1.0. As can be seen the smallest pipe section fails with a value of 1.64. Furthermore you see that the utilisation factor is the same for all code checking positions since one and the same moment is being used. 1 min 10 sec: You select using the local bending moment from the property dialogue of the code checking run. You tick off the option under the member tab. There is also an explanation about the differences in the two methods. 1 min 39 sec: As you can see from the results, the segmented beam is now passing the code check standard and it is the largest pipe section closest to the fixation that has the highest utilisation factor.
3. GeniE – import old Sesam frame models Import old frame & planar plate models and retain finite element numbering system
- You may modify material & section properties, beam eccentricities as well as plate thicknesses
- Wajac load files automatically imported- File Import FEM file
Preframe model
Model imported in GeniE
Presenter
Presentation Notes
Read the text: There are many existing structural reanalysis systems also known as SRS based on previous generation of Sesam. To ease the upgrade to the present version of Sesam, GeniE now can import a finite element model (frame models) and keep the numbering system. This means that it is possible to import the model and use it in GeniE to create either a model for super element analysis or to do a direct analysis where the finite element numbering system is identical to the original base model. It is even possible to do minor modifications to the model like changing beam section and material properties, beam eccentricities and plate thicknesses. You should remember that if you delete or add structural components the finite element system will change. The pictures above show a finite element model that was created more than 22 years ago can be imported into GeniE and converted to a concept model with the same finite element numbers. Start the video and use the text (duration 3 minutes and 12 seconds): 0 sec: This video shows in real time how to import an old model, run analysis of it and look at some results. The import is found under File Import FEM file. By selecting the option Import mesh into analysis, GeniE will convert the old finite element model into a concept model with the same finite element numbering system. 34 sec: The concept model now behaves as any other concept model, except that you can not modify it if you want to retain the numbering system. Exceptions are changes of a property like for example sections or materials 1 min 30 sec: The mesh is identical as the old model and includes the same load-cases as were defined in the old model. 2 min 3 sec: To run a linear structural analysis you need to add such details to the analysis activity that was created during the import operation. Observe that the meshing activity is set to never regenerate meaning that it will not make a new finite element numbering system or include new details unless you specifically ask for it. 2 min 48 sec: After analysis you can look at results like before. In this case global displacements for load case 10. We will show that the default maximum bending moment will lead to code check failure, while the
4. GeniE – import old Sesam soil models Import old soil models and convert them to environment definitions
- Should be done prior to any modelling as a default environment with water depth 10 m is created
- File Import GENSOD file
Manual input format
Model imported in GeniE
Presenter
Presentation Notes
Read the text: In older versions of Sesam it was necessary to define the soil data by using a tool called Gensod. This required manual editing of an input file as illustrated above. To ease the work of reproducing the same soil data in GeniE it is now possible to import such soil data. This will reduce the amount of manual input and make the model less prone to user input errors. The picture to the right shows the same model, but imported to GeniE. Please remember that you should import such soil data before you define any other environment as it will set up a default environment. You can modify the environmental data after import. Start the video and use the text (duration 58 seconds): 0 sec: This video shows in real time how to import old soil data and that you can visualize the profiles and modify them. The import is found under File Import GENSOD file. 14 sec: When import is done you will see the profiles, in this case 24 different soil curves. You can easily do colour coding to see the extent and the name of each one. 39 sec: By selecting one you can see the properties of it and if you want you can modify it also. 50 sec: The import is complete and includes more than just the soil curves etcetera. Another property that is imported is the scour definition.
5. GeniE – import of results from super element analysis Use results generated outside GeniE for post-processing and code checking
- Super element analysis, merge operations in Prepost- Old analysis together with import FEM and retain numbering system (e.g. SRS models)- Add yield data to material properties- File Import External Results SIN file
1. Import FEM 2. Import SIN Wave loads part of FEM import
Presenter
Presentation Notes
Read the text: It is also possible to import a result file meaning that the results from a super element analysis, a merge operation or even an old result file for a SRS can be imported into GeniE. GeniE also handles the import of a result file that has been converted from frequency domain (i.e. real and imaginary load cases) to deterministic domain (real load cases only). The obvious benefit is that results from complex or older analyses can be used as basis for result processing like beam deflection reporting and code checking of beams and plates using updated code check revisions. A normal working procedure will be to import a FEM file to ensure that that finite element numbering system is retained and then to import the result file also known as the SIN file. In case there is a wave load file it will be automatically imported. This is important with respect to local loads used in beam deflection reporting and code checking. The pictures above show an imported FEM file with super-element number 1 and the displacements of the same model based on an import of a result file from a super-element analysis where the top level was 21. The picture to the right shows the finite element model with wave loads. Please notice that results from an imported result file have a denotation of result cases and not load cases as for manually defined loads in GeniE. Start the video and use the text (duration 4 minutes and 24 seconds): 0 sec: This video shows in real time how to import an old model as well as a result file. It is also shown the steps on how to do a code check for such an import in GeniE. It is basically as before but you need to add yield data for the material properties. The first step is to import the FEM file and as can be seen it has two basic load cases as were defined on the FEM file. The names of the properties for sections and materials etc. are also identical to those on the FEM file for easy recognition purposes. 1 min: The result file is imported from File Import External Results SIN file. In this case the top level super element was 21. GeniE will automatically read in what is relevant for the old FEM model, in this case number 1. There are now 8 new result cases that were part of the structural analysis. 1 min 30 sec: The wave loads acting for each result case is also imported and can be visualized by looking at the mesh 1 min 40 sec: You can look at various results attributes like for example global displacements or deflections as if the model was modelled and analyzed on GeniE. 2 min 40 sec: prior to code checking you need to add yield data for the material properties as theses were not part of the FEM file before. In this case there is only one material where the yield is added as 2.35e08 Pascal. If you do not do this you will get code check results that are infinitive and obviously wrong. 3 min 6 sec: To do code checking of an imported model and result file is the same as any other model. The exception is that you select result cases and not load cases. This example shows one way of code checking based on the API WSD 2005 and includes all the result cases 1 to 8. Notice also that the new defaults on computing code checking loads only when needed and keeping the worst code checking results have been used. 3 min 55 sec: Please notice that the results in this case are artificial as the load combinations in the super-element assembly has been increased to give failure in the code checking
6. GeniE – wave load analysis including local shell models Run large wave load analysis with multiple local shell models
- Limitation of beam elements increased from 20.000 to 60.000 beams, hence possible to run large analysis models without the use of super element technique
- Number of time steps in wave load analysis increased from 8.192 to 262.144 time steps – it is now possible to run with much smaller time steps to capture peaks
- Boundaries for local shell model (loads and stiffness) automatically generated and updated- Load-cases for minimum shear and overturning moment in addition to maximum
Presenter
Presentation Notes
Read the text: A unique feature in GeniE is the ability to easily include local shell models into a global frame model. This can be done in many ways and the GeniE SnackPack will help creating the shell models. The manual work is thus limited to trimming the surfaces, combining the shell and the beam model with rigid support links and finally add refined mesh parameters for the local shell model depending on type of analysis to be executed. A significant benefit of including a local model into a global model is that the boundaries as well as the loading conditions are automatically retrieved from the global model. To include the local shell model for the joint as shown above takes less than 10 minutes including analysis. A benefit as compared with before is that the wave load analysis can be executed with 60.000 beam elements and ignoring number of shell elements. This means that wave load analysis can be carried out with ease for jackets where a joint(s) has been modelled with shells for the purpose to carry out a stress analysis. Also important for jack-up analysis is the ability to find design wave load condition for minimum base shear or overturning moment (in addition to maximum base shear). In other words – it is now possible to determine the range between maximum and minimum values. For analysis where it is important to have small time steps close to peak values it is now possible to have up to 260.000 time steps which is an tremendous increase from the previous limitation of 8000 time steps. Start the video and use the text (this video should only be part of the webinar if there is ample time – it has a duration of 11 minutes and 4 seconds): 0 sec: This video shows real time modelling where a joint is converted to a shell model by using script functionality in the GeniE SnackPack. The video starts by showing the displacements from a wave load condition – this one will be compared with results from an analysis with one joint included as a shell model for the same wave load conditions. The main parts of the video show how to trim the surfaces, how to insert rigid support links and how to define some mesh parameters. At the end some typical shell results are presented based on a wave loads. At the end of the video the mesh density of the local shell model is modified from 0.25 m to 0.125 m and finally 0.0625 m – results are shown for each analysis. 30 sec: The GeniE SnackPack is used to convert beams to shells. The SnackPack is found at the dnvsoftware.com. In this case we are using the functionality tubes to shells for the conversion 1 min 20 sec: The beams in the selected joint are now converted to shells. The conversion includes orientation, eccentricities, thicknesses and materials 1 min 50 sec: The shells are created from start to end of a beam, and since the start position is inside the chord it may be necessary to remove all superfluous part inside the chord. The trimming of the shells are done using a combination of divide and delete functionality. The cut lines are automatically derived since GeniE has full control of the dynamic connectivity between objects. This is one of the unique features behind the concept modelling techniques developed by DNV Software. 3 min 30 sec: The mesh density for the shell elements is set to 0.25 meters and a test mesh is made based on other default mesh options. 4 min 5 sec: The mesh algorithm is changed to advancing front meshing also known as paver meshing. The new mesh clearly shows better finite element mesh along the connection lines between the chords. 5 min: Up to know the model consists of two disjoint parts and it is necessary to connect the shell model with the global beam model. This example shows how rigid support links can be used to do this. An independent point of the beam and a box option including all nodes are selected as well as which degrees of freedom to use. The local coordinate system of the rigid support link is found from the visual clipboard by copy and paste. This video is based on real time modelling and it shows that it is necessary to modify the box extent to match the local coordinate system. 7 min 55 sec: All rigid support links are in place and a mesh view shows that all slave nodes are connected to the master node. 8 min 25 sec: A complete analysis including waves and pile soil analysis is executed. Please notice that the video shows actual run time of the analysis with approximately twenty four thousand degrees of freedom 9 min 3 sec: The wave loads for a given load condition are shown and the maximum displacements are identical to the pure beam model analysis. 9 min 30 sec: The VonMises stresses are shown for the shell model. The significant change in stresses indicate that the mesh needs to be refined 9 min 53 sec. The mesh density is refined to 0.125 meters and the new VonMises stresses are shown. As can be seen there are now more finite elements between the chords and the stress gradients are more smooth. 10 min 30 sec: The mesh is now even more refined to 6.25 centimeters. This leads to even finer mesh distribution between the chords. It is easy and fast to modify the mesh densities down to the thickness of the shell which is required in a fatigue analysis. In such cases it is normal to work with partial meshing where each part has different mesh densities.
7. GeniE – easier modelling of planar surfaces Flat region modelling enables modelling of closed surfaces by single user
operations- No longer needed to split continuous lines to create plates- Saving up to 4-5 user operations per plate - Insert Plate Flat Region
Flat region tool sets up a temporary cut-plane
defined by user
The boundaries automatically
shown
Each plate can be created by clicking a
closed area
Presenter
Presentation Notes
Read the text: GeniE has been used for quite a while to model complex surfaces. Based on the feedback from users we have included new modelling capabilities that will speed up modelling. In some cases 3 to 5 user operations before is now replaced by 1 user operation. This will obviously help reducing modelling time. The new features include a much more powerful copy or move operation as a vector can be used directly together with a length specification. Another important new functionality is the flat-region tool that allows the user to easily insert plates between any surrounding structure or guide lines like for example inside the web-frames in a vessel. The example above shows a cut-plane inserted at a random position and the individual plates are inserted simply by graphic clicking. This used to be several user operations per plate before, while it now is reduced to how many plates need to be inserted. Start the top video and use the text (duration 52 seconds): 0 sec: This video shows how the flat region modelling functionality is used to define individual plates when there are continuous guide lines that are common for many plates. 15 sec: A temporarily flat region is defined for elevation z at 0 meters. When viewing this in 2D it is possible to generate a plate simply by clicking in the area defined by surrounding guide lines. Please notice that the guide lines as common for several areas. This was not possible before as it was necessary to split the guidelines so that they were unique per plate. Start the bottom video and use the text (duration 1 minute and 28 seconds): 0 sec: This video shows how the flat region modelling tool can be used when the boundaries are determined by existing structure or a mix between structure and guidelines. 10 sec: A temporarily cut plane is defined at elevation z equals minus 1 meter. When viewing in 2D we clearly see the guidelines as defined by the existing structure and two guide circles that were defined as guide curves. When clicking on the area the plate is defined. Please notice that GeniE keeps control of what is outside and inside the guide lines. Therefore in this case the area inside the circles is not included as part of the plate. 50 sec: By doing the same again, but at elevation z equals minus 2 meters we can define the plates inside the guide circles simply by clicking inside the circle area. 1 min 10 sec: Finally this example shows how to fill the entire web-frame if there are no guiding lines present. The elevation in this case is z equals minus 4 meters and the web-frame plate is inserted by clicking in the area as defined by the surrounding longitudinal structure.
8. GeniE – more advanced use of cut plane The Point/Vector and 3-Points cut plane makes dividing structural parts much easier
- Previously limited to global axis planes
The temporarily cut plane is perpendicular to axis
Point1 -> Point8
Presenter
Presentation Notes
Read the text: The new cut-plane option now includes a plane definition based on a point and a vector in addition to point and directions along global co-ordinate axis. This makes it much easier to cut structure as compared to before where the cut-planes were limited to global axis. In the example above a brace is divided normal to the brace orientation at a given point Point1. Such features are often used to divide structures for the purpose of making detailed stress model Start the top video and use the text (duration 1 minute and 26 seconds): 0 sec: This video shows how the two point copy operation works. In this case we want to copy the guide point at the toe of one of the braces half a meter towards the end of the brace. As you can see there are additional functionality by moving the mouse over the symbol at the end of the translation vector input field. Here you can use alternative translation methods like for example between two points. The direction is found by clicking at the start and stop point and the actual translation length is specifically given. 50 sec: The same operation is repeated on the opposite brace and again using a translation length of half a meter. This operation was only available from the script language. In other words this implementation makes it easier and more accessible for our users. Start the bottom video and use the text (this video should only be part of the webinar if there is ample time – it has a duration of 7 minutes and 55 seconds): 0 sec: This video shows how to use the temporarily cut plane for the purpose of making a refined mesh zone in the centre an overlapping tubular joint 10 sec: The divide function using the new option to define a cut plane based on a point and vector has been used for each brace. The divisions will form the boundaries of a local refined mesh zone. 1 min 10 sec: the face of the chord is divided using a cut plane in the global z-plane. 1 min 40 sec: The refined zone is grouped into a named set called “Detail” for later references. 2 min: The connectivity between objects is automatically maintained by GeniE. You can see them and use them by double clicking the actual surface. Please notice that a connectivity line will always form a mesh edge. 2 min 20 sec. The mesh density for the refined mesh zone is defined and applied to the named set “Detail”. The refined mesh is half the size of the surrounding mesh. 2 min 45 sec: For the global mesh a linear mesh growth rate of 1.05 is used. This will be used in linear edge meshing. 3 min: A mesh is created and it clearly shows that the mesh close to the joint should be refined if local stresses should be investigated. 3 min 25 sec: The refined mesh property is thus divided by 2 to 62.5 millimetres and a new mesh is generated. The mesh is now more tuned for looking at detailed results close to the intersections between chord and brace 4 min: The mesh transition zone between fine and coarse mesh can be improved by activating the linear distribution of the edge mesher. The new mesh is much better in the transition zone. 5 min: A new analysis is executed and the size is approximately 275000 degrees of freedom 5 min 20 sec: GeniE can now present various results for you and in this case VonMises stresses are shown both with and without deformations. The deformations are scaled for visualisation purposes. 6 min 30 sec: The refined mesh size is modified to 31.25 millimetres which is a factor of 8 as compared to the global surrounding mesh. This gives a finite element model with more than 800000 degrees of freedom. GeniE can easily analyse such model. The largest we are aware of comprised 6 million degrees of freedom. For this example we have shown the relative Jacobi determinant. As can be seen the mesh is very good also close to connections between braces and the chord. A further refinement of a factor of 2 will give a mesh that is representative for a fatigue analysis model.
9. GeniE – more features for making geometry Scaling and offsetting of curves and surfaces makes it easier to make regular as
well as complex geometrical shapes- Scaling around a point is often used to create similar shapes for the purpose of making
structure and controlling finite element mesh, Edit Copy- Offsetting will create similar shape (line or surface) in a given distance
Presenter
Presentation Notes
Read the text: Other important new functions are the ability to do both scaling and offsetting will help both quick modelling as well as better ways of controlling the mesh in critical parts. The scaling is available from the Edit Copy functionality, while the offset is accessed by right clicking the line or surface. Start the top video and use the text (duration 3 minutes and 20 seconds): 0 sec: This video shows how to do scaling of different shapes defined by guide curves and how this can be used to control the finite element mesh. 10 sec: The triangle is selected and a scaling factor of 1.5 is used. The reference point for the scaling is the bounding box center. This point is automatically found by GeniE. 35 sec: The quadrant is selected and a scaling factor of 2 is used. In this case a user defined point is used as the reference point 1 min 2 sec: The circle is selected and a scaling factor of 1.5 is used together with the bounding box as reference point. 1 min 30 sec: The two circles are used as boundaries for making a plate using the plate cover functionality 1 min 45 sec: The plate is divided into two to be able to insert feature edges for the purpose of controlling the mesh along the edges. The feature edges are inserted by referring to the connectivity lines. The connectivity lines are found when double clicking a plate. 2 min 25 sec: The same number of elements is used for all feature edges to ensure a regular mesh around the hole. In this case there are 16 elements with the same length along a feature edge. 3 min 5 sec: A regular mesh is now created using the other default mesh options in GeniE. As can be seen, the quality of the mesh is very good according to the relative Jacobi determinant. Start the bottom video and use the text (duration 1 minute): 0 sec: This video shows how tom offset two different curves and how to create plates based on a cover operation 5 sec: A curve or surface can be offset by right clicking and selecting the option Offset. In this case an offset of minus 1 meter is selected. Please notice that the offset is always perpendicular to the original line or surface. This means that a straight line cannot be offset since it is not possible for GeniE to determine the in-line plane. 22 sec: The scone curve is offset with a offset value of 1 meter. 40 sec: The original and offset curves are now used as boundaries when making plates using the cover curve functionality
10. GeniE – faster update of finite element mesh When properties are modified, but the topology is unchanged the creation of a finite
element mesh can be much faster. For large models, significant performance improvements are achieved when updating analysis models- Always Regenerate Mesh: Regenerates all, takes the longest time, same as before, default
option- Conditional Regenerate Mesh: GeniE detects what to do, regenerate all or just update
properties (materials, sections, thicknesses) or load intensities- Never Regenerate Mesh: Updating properties and load intensities- Edit Rules Meshing
Option: Never Regenerate Mesh
Presenter
Presentation Notes
Read the text: The creation of the finite element model (or analysis model) is fast for almost most of the cases. We have observed that in cases with large models it has taken to long time to recreate a new analysis model when the user has done minor changes like modifying section or material properties or even load intensities. The new mesh module in GeniE will detect if such minor changes have been performed and will only regenerate the modified parts of an analysis model. This option is called the conditional regenerate mesh. In other words, the meshing operation is greatly reduced. We have seen examples of saving up to 80-90% of the time depending on complexity of model and how many minor changes have been done. The settings for re-generation of the mesh are controlled from the activity monitor. Like previously explained the option called never regenerate mesh is used when importing finite element models. For safety reasons the always regenerate mesh is the program default settings to ensure that results are in accordance with the status of the model.
11. GeniE – become more efficient by using scripting The GeniE SnackPack gives you access to a number of script utilities that you can
use to improve your performance- Access from DNV Software web site under downloads (https://projects.dnv.com/sesam/Genie_utils/index.html)
- Learn from pre-defined scripts and make your own
Example: How to convert a beam model to a shell model?
Presenter
Presentation Notes
Read the text: Many of our users are already using the scripting functionality in GeniE to make parametric models, customized reporting or other user operations. To make these possibilities more known among all users, we have made a GeniE SnackPack with many examples to learn from. You can find it on our download services at DNV.com/software. Start the video and use the text (duration 2 minutes and 15 seconds): 0 sec: The Snack pack is available from DNV Software’s web site. It is located under downloads and there is free access to it. For each of the categories there are both script files as well as a reference model case that will help you to regenerate the results as well as to learn from it to customize to your own need. If you have scripts you want to share with other Sesam users, please contact us. 25 sec: The start page explains more about the purpose of the SnackPack 34 sec: The section related to hull forms has several parametric models and the offshore vessel is shown in detail here 52 sec: The tab including reporting lists many options of making your reports more advanced in addition to the reporting functionality as part of the GeniE user interface. The ability to include illustrations in the report is shown here 1 min 16 sec: The importing lines part shows how you can do it and gives you also some hints on what to remember. 1 min 37 sec: The part for loads and mass explains how you can manipulate these properties. Typically how to automatically convert line loads to point masses in case you want to do a dynamic analysis. 1 min 55 sec: This tab explains how you can work with script files that will convert typically beam elements to shell elements. Also described is how to easily generate a shell cone that is typical for wind turbine supporting structures. This video show more in detail how you can convert a module from frame structure to shell structure.
GeniE v6.0 – BenefitsFull support of 64 bit technology will give our users access to “unlimited amount” of memory. This will in particular help out when modelling very large models, but also during code checking of models with a significant number of load cases.
Furthermore, it can import additional Sacs data and the code checking has been made even more flexible for the ISO standard.
Scheduled for release September 2011. It is not part of the Sesam 2011 August DVD, but can be downloaded from our Customer Portal
Main new features version 6.0-** True 32 and 64 bit applications – “unlimited access to data memory”
Enhanced import of Sacs data – load combinations, improved handling of beam line and point loads, and support for additional profile libraries
Beam code check updates- ISO standard: Check of critical joints where factor Ub can be computed by GeniE based on
member code check. Users can also specify minimum allowed value of Ub- ISO standard: Added an alternative formula for X-joints in tension (OMAE2008-57650(8))- Perform code check of very large models by saving results on a new format (file and not
database) – significantly reduced risk of running out of virtual memory
Reporting: Save report to CSV format in addition to txt, html, Word(xml), Excel(xml)
Much faster display of plates and beams, both structure and mesh view, possibly up to an order of magnitude for large models
Change properties for existing support points and point masses without the need to always regenerate the finite element mesh
Combine imported result cases for use in result presentations and code checking
DeepC v4.5 – BenefitsA major update of this release is the possibility to use regular waves in addition to irregular waves for fatigue analyses. Compared with irregular wave fatigue used for detailed fatigue analysis, the new regular wave fatigue functionality let the user get the fatigue results much quicker in the initial design process. Other important benefits are the handling of direction dependent scatter diagrams and parallel execution to run an arbitrary number of analyses at the same time.
DeepC also supports cross-section drawings, cross-section analysis (capacity curves) and fatigue analysis of helix elements in umbilicals and flexible risers. DeepC has thus become a complete solution for all slender structures like risers, mooring lines and umbilicals.
Main benefit: Regular in addition to irregular wave conditions
A typical regular wave fatigue analysis approach is similar to irregular wave fatigue analysis, which normally includes:- Creating multiple regular waves and multiple regular time conditions based on a height/time
scatter diagram- Specifying a number of periods (typically 10) based on a predefined analysis template- Running all the analyses and making a fatigue analysis. During the analysis, an explicit time
interval may also be given
Regular wave conditions can also be used in a coupled analysis.
1. DeepC – include regular wave condition
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Regular wave shown
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Presentation Notes
A typical example is the validation of model test. Nowadays, regular wave (sometimes white noise) conditions are normally included in a model test to get RAOs of floaters including mooring and riser systems. Traditional frequency domain analysis (de-coupled method) only includes slender structure effects which can be a significant simplification for deep water conditions. DeepC offers an efficient way of calculating the response under regular waves while considering coupling effects at the same time.
3. DeepC – parallel execution Possible to run an arbitrary number of analyses in parallel.
- This will lead to reduction in analysis elapsed time
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User can choose from 1 to maximum 64 parallel analyses or use ‘Maximum -1’ to keep one for other work. Pay attention that extra SIMO/Riflex licenses may be needed when using this function.
4. DeepC – cross-section and fatigue analysis of umbilicals Sesam extends its portfolio by providing tools for cross-section analysis and efficient
fatigue analysis of helix elements in umbilicals and flexible risers- UmbiliCAD makes an engineer’s produce cross-section drawings and linear cross
section analysis within hours increasing the precision level in the bidding process as well as in the detailed engineering phase.
- Helica performs the non-linear cross section analysis and fatigue analysis faster than other systems without the need for a detailed finite element model. The input for short term fatigue comes from a DeepC time domain analysis (environmental data) while the cross section details comes from UmbiliCAD.
The purpose of short-term fatigue analysis is to assess the fatigue damage in a stationary short-term environmental condition considering fatigue loading in terms of time-series of simultaneous bi-axial curvature and effective tension produced by global dynamic response analysis (DeepC). Long-term fatigue analysis can also be done by accumulation of all short-term conditions.
HydroD v4.5 – BenefitsWhen sub-modelling techniques are used we have now made the sub-model independent of the compartment – this means that it is now possible to retrieve loads from the compartments even though only parts of the compartment is part of a sub-model. Hydro-dynamic results like RAO’s can be calculated based on user defined reference points in addition to the still water line.
Flexibility in user specification of simulating pressure loading in a zone around the mean free surface has also been introduced. And for those who do hydrodynamic analysis of multi bodies it is now possible to define an additional coupled damping matrix for the bodies. Finally, much larger time domain analysis can be carried out since the computational engine supports 64bit application technology.
- The definition of acceleration and zero pressure reference points allows that a submodel may be independent of a compartment
- In other words, a sub-model may contain partial compartments also for load transfer- Flexibility in modelling compartment model and sub-models
Compartments global model Sub-model at
node Load retrieval from compartments to sub-
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Presentation Notes
A strong benefit of the Sesam system is the ability to make a sub-model and analyse it independently of the global model. To make this even more flexible we have introduced the definition of acceleration and zero pressure reference points for compartments. This means that the submodel is independent of the compartment; in earlier versions the sub-model had to include the complete compartment(s) for a proper load transfer. This applies to analysis both in frequency and time domain.
3. HydroD – user defined pressure reduction region Apply a user defined pressure reduction region on a selected part of the vessel
- The the method is only recommended on the part of the vessel which is wall-sided and should thus be controlled by the user
- Benefit: User defined in addition to supporting the DNV rules- This option is available for both frequency and time domain analysis
User defined wall-sided part
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Presentation Notes
HydroD has supported DNV rules on how to simulate pressure loading in a region around the mean free surface in a frequency domain analysis. In addition, the program now allows the user to apply this functionality on a selected part of the vessel, since the method is only recommended on the part of the vessel which is wall-sided. This option is available for both Wadam (v8.2-02) and Wasim (v4.5-04) analysis.
4. HydroD – user defined reference point User defined reference point for calculation
of results- More flexibility as the reference point can be
used for calculation of hydrodynamic results like e.g. motions, forces and RAO’s
- Applicable for results from both frequency and time domain analysis
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When deriving hydrodynamic results such as RAO (Response Amplitude Operators) these were previously relative to the still water line. The new HydroD is much more flexible since the user can define reference points for calculation of results both from Wadam and Wasim. The pictures above shows the effect on the surge (0 degrees wave) and sway (90 degrees wave) on the barge by using two different reference points. The blue lines are based on a reference point at the keel of the barge, while the red lines stem from a reference point at the barge deck level.
5. HydroD – optimum panel definitions Automatic proposal for the number of panels needed for an optimum analysis
- When creating a panel model from a section model- Based on the model dimensions and mesh criteria
Different panels proposed for different model dimensions
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Presentation Notes
To help users creating the hydro model from a section model, typically for a Wasim analysis (also known as the “pln file”), HydroD will set up an automatic proposal for the number of panels needed for an optimum analysis. This is based on the dimensions of the model and some mesh criteria
Based on feedback from our customers during Sesam development, we are confident that the new possibilities will help engineers be more productive within the design and operation of fixed and floating structures. At the same time new functionality in Sesam allows engineers to do riser design (traditional or based on coupled analysis results) as well as umbilical drafting and design (capacity curves and fatigue). Some of the new improvements are already part of our user courses – see our training schedule on DNV.com/software for more details. “We will continue our strong effort to enhance Sesam,” says Ole Jan Nekstad, Sesam Product Manager. “In the time to come, the main focus will be on faster and editable meshing, making complex jacket analysis easier, enabling free surface effects in hydrodynamic analysis and automated air-gap analysis for coupled analysis,” he says.
