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Various analyses of an Elbow Bracket using the Structural

Mechanics Module

General information on structural analysis within the COMSOL

environment

Structural Analysis Introductory Tutorial



Structural Analysis in the COMSOL

Environment

Analysis types available in COMSOL Multiphysics: ± Static

± Transient

± Frequency-response

± Eigenfrequency (modal analysis)

± Damped eigenfrequency

± Elastoplastic

± Thermal stress

± Viscoelastic

± Creep

± Hyperelastic

± Poroelastic

± Contact

± and more including Multiphysics analysis: Flow, Electromagnetics, Heat, Piezo



CAD Interoperability

Bidirectional Associative Parametric Interfaces with SolidWorks®

and Autodesk® Inventor®



CAD Interoperability

Import of CAD Files* from: ± SolidWorks®

± Autodesk® Inventor®

± STEP

± IGES

± X_T (Parasolid®)

± SAT® (ACIS®)

± Pro/E®

± CATIA®

± Inventor®

± NX (Unigraphics)

± Solid Edge®

± VDA-FS

* Trademarks of respective holders



CAD Repair and Defeaturing Tools

Parasolid-based CAD Geometry Repair and Defeaturing tools ease

meshing of large CAD parts and assemblies



CAD Repair Tools ± for easier meshing

CAD repair

Repair CAD model and prepare for FEA analysis: remove small

surfaces, fill in gaps, etc.



CAD Repair Tools ± for easier meshing

Remove small faces

Before

After



CAD Defeaturing ± for easier meshing

Remove holes

Before

After



CAD Defeaturing ± for easier meshing

Remove fillets (rounded corners)

Before

After



Material Library

Data for more than 2500 materials.

A given material entry store data for up to 24 different properties by

default ± can be extended upon by user.

Focus on elastic and thermal properties. Each of these materialproperties is described as a function of some variable, typically

temperature T.

In all, the Material Library contains a total of almost 20,000

property functions (material curves).

Search Feature: look for materials by name, UNS number, or DINnumber.



Material Library

More than 2500

materials



Material Library

Search function



Material Library Example: Elasticity (E) vs.

Temperature (T) of Ti-Ni shape memory alloy



Material Library

Detailed references



Create your Own Material and Material

Functions



Some Structural Analysis Examples(Available as Step-by-step Tutorials in the Structural Mechanics Module Documentation)



Modal Analysis of a Crank Shaft

(here with mesh imported from NASTRAN)



Contact Analysis of Cell-Phone Screen

Assembly



Large Deformation Contact Analysis of Snap-

Hook Fastener



Viscoelastic Analysis Including Transient

Hysteresis



Fatigue Analysis of a Wheel Rim



Hyperelastic Analysis of a Boot Seal



Viscoplastic Creep of Solder Joints



Elastoacoustic Waves ± Nondestructive Testing

with Structural Nonlinearities (Murnaghan

Material)



Piezoelectric Examples

Radially polarized disc Shear bender beam Ultrasonic Transducer

Piezo-Dielectric

Heating

Distributed Mode

Actuator

Piezo-Acoustic

Transducer

Piezo-Actuators

SAW Sensor



Multiphysics Analysis: Fluid-Structure-Heat

Interaction in Aluminum Extrusion



Elbow Bracket Tutorial

Analysis types demonstrated by this tutorial:

± Static

± Transient

± Frequency-response ± Eigenfrequency (modal analysis)

± Damped eigenfrequency

± Elastoplastic

± Thermal stress

Full step-by-step PDF available in the product manual



Static Analysis: Setup

Finds the deflection at static equilibrium

Most straightforward analysis type

´Glued´ at one end: fixed displacement

A distributed load at an angle at the other end: ± Fx=3.0 MPa

± Fy=0.0 MPa

± Fz=3.0 MPa

Fixed

Distributed load



Static Analysis: Setup

Default Mesh: ± 66765 degrees of freedom (nodes)

± 13339 quadratic elements



Static Analysis: Results

von Mises effective stress maximum at 190 MPa

Compare with yield stress

350 MPa: 54 % utilization



Modal/Eigenfrequency Analysis: Setup

Default settings finds the 6lowest vibrational modes andfrequencies

Deformations for modalanalysis are normalized andmesh dependent ± Deformation values not important

for modal analysis

Important quantities:

± Frequency ± Overall mode shape

Fixed



Modal/Eigenfrequency Analysis: Results

Mode shape at 416 Hz



Modal/Eigenfrequency Analysis: Results

416 Hz 570 Hz 1926 Hz

2454 Hz 3110 Hz 3931 Hz



Transient Analysis: Setup

Transient sinusoidal load

A distributed load in the x-

direction

Rayleigh dampingparameters: ± alpha = 300

± beta = 3.2e-5



Transient Analysis: Results

x-displacement

at this point



Frequency-response Analysis: Setup

Response to sinusoidal loads of varying frequencies

´Glued´ at one end: fixed displacement

A sinusoidal distributed load at an angle at the other end:

± Fx=3.0cos(2f·t) MPa ± Fy=0.0 MPa

± Fz=3.0*cos(2 f·t) MPa

Sweep from 350 Hz to 650 Hz

Fixed

Distributed load



Frequency-response Analysis: Results

Response from 350 Hz to 650

Hz at a point on the loaded

surface

Resonance peaks asindicated by earlier mode

analysis at 416 Hz and 570

Hz

x-displacement amplitude

z-displacement amplitude

y-displacement amplitude



Parametric Analysis: Setup

Perform a parametric sweep over the angle of the distributed

load

± Fx=3·106 · cos( · /180) N/m2

± Fz=3·106

· sin( · /180) N/m2



Parametric Analysis: Results

-45º

-45º

-20º

-0º



Transient Thermal-Stress Analysis: Setup

Combined Thermal and Structural Analysis

Quasi-static approach: transient thermal analysis combined with

static structural analysis

Ends held at fixed temperature Applied mechanical load and temperature load

T = 20º C

T = 500º C Mechanical load



Transient Thermal-Stress Analysis: Setup

Heat Transfer

Thermal load from

heat transfer application

Solid, Stress-Strain



Transient Thermal-Stress Analysis: Results

Temperature and deformation

at t=1000 s

von Mises stress at t=1000 s



Transient Thermal-Stress Analysis: Results

Total displacement

at this point



Elasto-Plastic Analysis: Setup

3D elbow bracket

Elasto-plastic constitutive model

Isotropic hardening

Hardening function: experimental stress-strain curve

Fixed

Distributed load




Function interpolated from experimental stress strain data




Apply the elasto-plastic

material data

Apply boundary conditions

Solve the problem by stepping

up the distributed load with

the parametric solver



Elasto-Plastic Analysis: Results

Plastic region at the final load step

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