farzad mirshams, mechanical / thermal engineer, some project-samples

Some Samples of My Previous Design, Simulation & Test Projects, and Product Development Responsibilities

By: Farzad Mirshams, M.S.M.E.Professional Industry Experience: 25 Yrs

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M23-17inch-Rev01 HEAT LOADS

CPU Chip 48 W

GPU Chip 12 W

U3-Bridge Chip 10 W

Motherboard PCB Uniform Spread 45 W

DIMM 4 W

Display Panel 15 W

HDD 13 W

ODD 7 W

Power Supply 30 W

Fans 4W X 3 =12 W

TOTAL 196 W

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Thermal Analysis, Digeo Inc

Electronic Cooling Solutions Inc612 National Avenue, Mountain View, CA 94043 Phone: (650) 988-1155

Farzad Mirshams2/10/05

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Model Description

Physical Model

• Chassis Size (inside dimensions): 16.9 inch X 2.5 inch X 11.5 inch

• Chassis Material: 0.03 inch thick, cold rolled steel

• PCB Assembly: 0.063 inch thick FR4 / 8 layers. Effective (board averaged) in-plane, and normal to the plane conductivities modeled. Critical heat dissipating components are modeled as isothermal blocks with uniform volumetric heat generation

• Fan: Panasonic, Panaflo FBA06A12M1A, 60 X 60 X 25.5 mm / 16.6 CFM / 3.95 mmH2O / 28 dB-A / Hydro Wave Bearing. Fan curve modeled

• Hard Drive: modeled as hollow blocks with uniform heat generation inside a thin conductive outer shell, and in dry metal on metal contact with the chassis inside surface

• Power Supply: modeled as a porous “sponge” block with uniform volumetric heat generation. Flow impedance along the three axes is characterized using quadratic loss coefficients

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Fig-1: Chassis Assembly Model, Isometric View

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Fig-2: Model, Side View

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Fig-3: Grille Areas, as Modeled

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Model Description

Boundary Conditions

• Ambient Temperature: 40 C

• Chassis Top Surface: Natural convection & Radiation

• Chassis Bottom Surface: Radiation only

• Chassis Sides: Natural convection & Radiation

• Chassis Front Panel / Bezel: Insulated

• Chassis Rear Panel: Intake & Exhaust Grilles (65% open area ratio)

• Natural convection from external chassis surfaces are modeled using empirical film coefficients for horizontal, and vertical plates

• Radiation from external chassis surfaces are assumed to an infinite black body at the ambient temperature

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Model Description

Heat Loads / Power Dissipation

HD 12.5 W

PCB ASSEMBLY 70 W (Fig-4 & 5)

POWER SUPPLY 30 W

FAN <1.5 W (ignored)

TOTAL 112.5 W

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Fig-4: PCB assembly power dissipation, Top Side

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Fig-5: PCB assembly power dissipation, Bottom Side

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Model Results

• Total volumetric airflow thru the chassis: 12.1 CFM

• Mean processor heat sink's base temperature: 68.6 C

• Mean rear exhaust temperature: 52.4 C

• Temperature and air velocity plots are shown on the following slides:

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Fig-1: Chassis Assembly Model, Top View

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Model Results


• Mean exhaust temperature: 51.8 C

• Mean air temperature thru the fan: 45.6 C

• Mean processor heat sink’s base temperature: 69.0 C

• Mean HDD skin temperature: 53.9 C


• Mean exhaust temperature: 52.9 C

• Mean air temperature thru the fan: 48.4 C

• Mean processor heat sink’s base temperature: 76.8 C

• Mean HDD skin temperature: 54.9 C

Fan Blowing Air on the PCB:

Fan Pulling Air on the PCB

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Figure-1: Proposed 60K Load-Lock Chamber Model

F.Mirshams 4/28/2006

FEA Modeling of Proposed 60K Test Stand Load-Lock Chamber, Case Studies

Model Description

CASE #1:

Side Plates Thickness: 3.0 inch

Top/Bottom Plates Thickness: 3.5 inch

Lid-Cover Thickness: 3.5 inch

Lid-Cover Rib Design: NO RIBS

CASE #2:




Lid-Cover Rib Design: Open Web, 4 inch tall

CASE #3:





CASE #4:




Lid-Cover Rib Design: Closed Web, 4 inch tall

CASE #5:





The 60K load-lock model is shown in Figure-1. Five proposed design variations were modeled, as listed below:

F.Mirshams 4/28/06

• The assumed model boundary conditions are shown in Figure-2. Only 1/2 of the actual assembly was

modeled, taking advantage of symmetry in the geometry, and boundary conditions.

• The maintenance access opening’s bolted-in cover plate is not considered structurally significant,

thus it is not included in the model.

• Load-Lock chamber and lid-cover are made of Aluminum 6061-T6, with the following properties:

– Elastic Modulus = 10.0e+6 psi

– Poisson’s Ratio = 0.33

– Density = 0.0981 lb/in**3

• The computed deformation plots, and deformation animation movies are displayed in the follow up

slides.

FEA Modeling of Proposed 60K Test Stand Load-Lock Chamber, Case Studies

Figure-2: Assumed Boundary Conditions for the proposed 60K Load-Lock FEA Model

Bolted Fixed Frame Support Areas are shown in teal color

Surface Pressure Areas are shown in blue color

Surface Pressure Areas are shown in blue color

Figure-3: A Typical FEA Mesh for the proposed 60K Load-Lock Model

ANSYS Element Types Used:1. SOLID 187 / 10 Nodes Tetrahedral / Quadratic Displacement Function2. CONTA174 & TARGE170 / Surface to Surface Contact Pair (Frictionless Non-

Bonded Contact Option)

# of Nodes: 367,956

# of Elements: 233,188

Figure-4: A Typical FEA Mesh for the proposed 60K Load-Lock Model

ANSYS Element Types Used:1. SOLID 187 / 10 Nodes Tetrahedral / Quadratic Displacement Function2. CONTA174 & TARGE170 / Surface to Surface Contact Pair (Frictionless Non-

Bonded Contact Option)

# of Nodes: 392,225

# of Elements: 248,743

CASE #3:





Figure-13: Deformation

CASE #2:




Lid-Cover Rib Design: Open Web, 4 inch tall Figure-12: Von-Mises Stress

CASE #2:





Figure-8: Deformation in the Y-Direction

CASE #4:





Figure-15: Deformation in the Y-Direction

CASE #5:





Figure-22: Deformation in the X-Direction

F.Mirshams 4/16/2006

FEA Modeling of 60K/50K Ceramic Assemblies / Camlock CB Hole Size Study

• Two proposed design variations were modeled, per CAD files listed below:

• 1. CAD file: “60K 125 taper 17 shaft 8 cbored camlocks”• 2. CAD file: “50K assembly larger camlock cbores”

• Two levels of structural modeling were performed for each assembly, as follows:

• 1. The ceramic assembly was modeled as fully-bonded parts composing a single ceramic piece. Thus no possible gapping or slippage between assembly parts were allowed in the model.

• 2. The ceramic assembly was modeled as separate piece parts in non-bonded frictionless contact, using ANSYS surface to surface contact elements. Thus assembly parts could flex individually causing gaps to form.

• The assumed model boundary conditions are shown in the follow up slides. Only ¼ of the actual assembly was modeled, taking advantage of symmetry in the geometry, and boundary conditions.

• Locating pins & camlock fasteners are not considered structurally significant, thus they were not included in the model.

• Assembly parts are made of COORSTEK / AD-96 Ceramic material with the following properties:• Elastic Modulus = 44.0e+6 psi• Poisson’s Ratio = 0.21• Density = 0.135 lb/in**3

• The computed Maximum Principal stress plots are displayed in the follow up slides.

Model Description

Boundary Conditions, CAD Model: “60K 125 taper 17 shaft 8 cbored camlocks”

ANSYS Element Types Used:1. SOLID 187 / 10 Nodes Tetrahedral / Quadratic Displacement Function2. CONTA174 & TARGE170 / Surface to Surface Contact Pair (Frictionless Non-Bonded Contact Option)

Fully Bonded Model Mesh

# of Nodes: 42,689# of Elements: 24,900

Non-Bonded Model Mesh


CAD Model: “60K 125 taper 17 shaft 8 cbored camlocks”

Max Deformation = 0.095 inch


C/Bore size: 1.0” Diameter, 0.125” Round

Fully Bonded Model




Non-Bonded Model, “Gaps Allowed”


Max Gap = 0.013 inch


CAD Model: Modified “60K 125 taper 17 shaft 8 cbored camlocks”




C/Bore size: 1.0” Diameter, 0.125” Round, Location Change C/Bore size: 1.5” Diameter, 0.25” Round, Location change

0.25” Round0.125” Round

Boundary Conditions, CAD Model: “50K assembly larger camlock cbores”

ANSYS Element Types Used:1. SOLID 187 / 10 Nodes Tetrahedral / Quadratic Displacement Function2. CONTA174 & TARGE170 / Surface to Surface Contact Pair (Frictionless Non-Bonded Contact Option)

Fully Bonded Model Mesh


Non-Bonded Model Mesh


CAD Model: “50K assembly larger camlock cbores”


Fully Bonded Model





Max Gap = 0.019 inch

farzad mirshams, mechanical / thermal engineer, some project-samples

Engineering

w dimm

w fans

w total

w power supply

w pcb assembly

chassis assembly model

w gpu chip

w display panel