Comsol Multiphysics Intro Models

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Introductory Models

Tutorials

Parallel plate capacitor

Thermal cube

Stresses in a wrench

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What you will learn

More experience with the interface

Sketching geometries in COMSOL

How to have a domain not active in the analysis

Tutorial 1: Parallel Plate Capacitor

More Practice with the User Interface

Adding a 2nd Physics

Adding Thermal Expansion

Tutorial 2: Thermal cube

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What you will learn

Hands on with the interface

The basic steps in all COMSOL models

How to show deformed plots

Tutorial 3: Stresses in a Wrench

Tutorial 4: Electrical Heating and

Thermal Stresses in a Busbar

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What you will learn

More experience with the interface

Sketching geometries in COMSOL

How to have a domain not active in the analysis

Tutorial 1: Parallel Plate Capacitor

Select 2D

AC / DC > Solid Mechanics

Stationary

Checkered flag to Finish

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Create Geometry

Open Model 1

Pick Geometry 1

Change Length Unit to cm

Draw Three Rectangles

Set Materials

Right Click on Materials

Choose Open Model Library

Pick Built-In Material Library

Select Air

Right Click on it, Add to Model

(This will assign it to all subdomains

but we will only use it in the air

domain: Electrodes will not be

included in the analysis)

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Electrostatics Active only in Air Domain

Pick Electrostatics in Model Builder

Clear all Selections (hit X )

Only Select Air Domain

Right-click to confirm

Set Boundary Condition Ground

Right-Click Electrostatics

Choose Ground

Choose Box Selection

Select Bottom Electrode

Confirm

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Set Boundary Cond Electric Potential

Right-Click Electrostatics

Choose Electric Potential

Set to 100 Volts

Choose Box Selection

Select Top Electrode

Mesh Free Triangular (Extra Fine)

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Solve

Pick Study 1

Hit =

More Practice with the User Interface

Adding a 2nd Physics

Adding Thermal Expansion

Tutorial 2: Thermal cube

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Choose Physics and Study

Choose File > New

Select 3D

Select Heat Transfer in Solids in Physics

Choose Stationary under Study

Draw Geometry

Right click on Geometry

Choose Block

Leave as 1 x 1 x 1 [m]

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Set Materials

Right click on Materials

Choose Open Material Library

Go to Built-in Section

Right Click on Aluminum 6063

Choose Add to Model

Assign it to the block

Set Boundary Conditions

Right Click on Heat Transfer

Select Convective Cooling

Choose All Boundaries

h = 1000 Text = 500

Right Click on Heat Transfer

Select Temperature

Choose bottom surface

Right click to confirm

Set Temperature as 300

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Mesh and Solve

Right Click on Mesh

Select Free Tetrahedral

Select Size

Choose Coarser mesh size

Right Click on Study

Select Compute

Add Structural Equations

Right Click on model 1 node

Choose Add Physics

Open Structural Mechanics

Pick Solid Mechanics

Choose the finish (checkered) flag

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Add Thermal Expansion

Open Structural Mechanics in Model Tree

Right Click on Linear Elastic Material Model

Choose Thermal Expansion

Change Temperature from user defined to Temperature (ht/solid1)

Leave Ref Temperature as 293 K

Constrain Bottom Surface + Solve

Right Click on Solid Mechanics

Choose Fixed Constraint

Select & Confirm bottom surface

Right Click on Study

Pick Compute

Open 3D Plot group 1

Right Click on Surface

Add Deformation

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What you will learn

Hands on with the interface

The basic steps in all COMSOL models

How to show deformed plots

Tutorial 3: Stresses in a Wrench

1) Set Dimensions, Physics & Study-Type

Select 3D

Structural Mechanics > Solid Mechanics

Stationary

Then the checkered flag to Finish

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2) Import Geometry

Right click on Geometry

Choose Import Then Browse

C:\COMSOL41\models\COMSOL_Multiphysics\Structural_Mechanics

Choose Wrench.mphbin

Import

3) Set Materials

In Model Builder:

Right Click on Materials

Open Model Library

Pick Built-In

Select High Strength Alloy Steel

Right Click, Add to Model

Select Steel AISI 4340

Right Click, Add to Model

Pick Bolt, right-click to add

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4 a) Constrain Bolt

In Model Builder:

Right Click on Solid Mechanics

Choose Fixed Constraint

In Graphics Window:

Pick the Bolt Cut End

Right Click to confirm

4 b) Add Load

In Model Builder:

Right click on Solid Mechanics

Choose Face Load

Pick end of the wrench

Enter F for Fz

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5) Mesh

In Model Tree:

Right Click on Mesh 1

Choose Add Tetrahedral

Pick Size

Change to Coarser

Right click Mesh 1

Pick Build All

6) Solve

In Model Builder:

Pick Study 1

Choose Compute

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Display Stress on Deformed Geometry

Open Results > 3D Plot Group 1

Pick Surface 1 > Replace Expression

Plot Von Mises Stress

Right click on Surface 1

Add Deformation

Tutorial 7: Electrical Heating

and Thermal Stresses in a Busbar

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Your first model

Exercises:

Electrical Heating in a Busbar

Bus bar made of copper.

Bolts made of titanium.

Direct current 10 mV from a transformer to an electric device.

Heat is produced due to the resistive losses--joule heating.

Calculate the thermal expansion.

Work though exercises, but not the appendix

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Your first training model: A Copper Busbar

A busbar is an electric current conductor typically found in high-

power applications.

You will investigate:

Joule Heating

Thermal Expansion

Flow with Cooling

for a certain busbar geometry

Boundary Conditions: Electric Currents

Electric Potential 10mV Ground

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Boundary Conditions: Heat Transfer

Cooling with a heat transfer coefficient

of 5 W/m^2/K and surrounding air

temperature at 293.15 K

The only difference between the hands-on and your problem is

Perhaps a few more physics

A bit more geometry

Some more loads & b.c.s

Go to it (!!!)

Now youre ready for your own simulations!

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Capture the ConceptTM

Questions & Answers