farzad mirshams, mechanical / thermal engineer

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

Air Velocity (LFPM) Measurement Results for Air Flow Through the Chassis Slots. Measurements Were Taken Using Hot Wire Anemometer Probe.

88

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

2/10/05 93

Thermal Analysis, Digeo Inc

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

Farzad Mirshams2/10/05

2/10/05 94

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

2/10/05 95

Fig-1: Two Proposed layouts for Chassis Assembly are Modeled, Isometric Views

2/10/05 96

Fig-2: Two Proposed Layouts Modeled, Side Views

2/10/05 97

Fig-3: Grille Areas, as Modeled

2/10/05 98

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

2/10/05 99

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

2/10/05 100

Fig-4: PCB assembly power dissipation, Top Side

2/10/05 101

Fig-5: PCB assembly power dissipation, Bottom Side

2/10/05 102

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:

2/10/05 103

2/10/05 104

2/10/05 105

2/10/05 106

2/10/05 107

2/16/05 110

Fig-1: Modified Chassis Assembly Model, Fan Orientation Changed, Top View

2/16/05 111

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

2/16/05 112

2/16/05 113

2/16/05 114

2/16/05 115

2/16/05 116

2/16/05 117

Fig-1: XCVRs Shelf Natural Frequency & Modes Of Vibration

Fig-2: XCVRs Shelf Static Deflection, and Von Mises Stress; Total Load: 97 lbs.

Fig-1: MicroCITE Chassis Front Cover(Door) Static Deflection

Fig-1: Bracket Stress Analysis

Fig-1: XCVR-PA Aluminum Casting FEA Thermal Analysis

Figure-1: Proposed 60K Load-Lock Chamber ModelFig-1: Load-Lock Vacuum Chamber Structural/FEA Analysis

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


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”


Fully Bonded Model Mesh


Non-Bonded Model Mesh


CAD Model: “50K assembly larger camlock cbores”


Fully Bonded Model





Max Gap = 0.019 inch


FEA Modeling of 25K Ceramic Assembly

• The FEA model is created per CAD file listed below:

• CAD file: “25K IPS Support Ceramics”

• Two possible loading configuration for the ceramic plates, by the Susceptor, were modeled:

• 1. Susceptor’s weight is supported evenly between the outer ceramic plates load pad areas

• 2. Susceptor’s weight is supported evenly by the outer ceramic plates load pad areas, and an Aluminum shim at the main ceramic plate’s center hole

• 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.

Ceramic assembly parts are made of COORSTEK / AD-96 with the following properties:

• Elastic Modulus = 44.0e+6 psi

• Poisson’s Ratio = 0.21

• Density = 0.135 lb/in**3

Center shim is made of Aluminum-6061 with the following properties:

• Elastic Modulus = 10.0e+6 psi

• Poisson’s Ratio = 0.33

• Density = 0.0981 lb/in**3

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

Model Description

Boundary Conditions, CAD Model: “25K IPS Support Ceramics”

Bonded Contact

Non-bonded Contact

Bonded Contact

Non-bonded Contact

No Center Shim With Center Shim

“With Center Shim” Model Mesh


CAD Model: “25K IPS Support Ceramics”


Deformation, No Center Shim

Deformation, With Center Shim


With Center Shim


farzad mirshams, mechanical / thermal engineer

Engineering