﻿ Deformation of Viscoelastic BarExamples | Product | Murata Software Co., Ltd.

# Example51Deformation of Viscoelastic Bar

General

• The model is a bar made of viscoelastic plastic, polystyrene. It is forced to bend.

• It is subjected to the temperature change below and over the glass transition temperature.

• Unless specified in the list below, the default conditions will be applied.

•

### Analysis Space

 Item Settings Analysis Space 3D Model unit mm

### Analysis Conditions

It is subjected to the temperature change below and over the glass transition temperature.

Select “Thermal load” and “Step analysis”

 Item Settings Solvers Mechanical Stress Analysis [Galileo] Analysis Type Static analysis Options Select Thermal load.

The Step/Thermal Load tab is set as follows.

Tab

Setting Item

Settings

Step/Thermal Load

Step Setting

Multi-step thermal load analysis

Time Setting

Set up

Reference temperature

25[deg]

Step/Reached Temperature Setting

 Step Time [s] Substeps Reached temperature [deg] 1 60 5 25 2 3540 5 25 3 3600 5 25 4 3660 5 120 5 3720 5 120 6 7200 5 120 7 7260 5 120

Options for the Multi-Step Analysis

Save the results of substeps : Select

The reference temperature (non-stress temperature) is 25[deg]

Select [Multi-step thermal analysis] for the Step Setting, [Set up] for the Time Setting.
Also, set up in the [Step/Reached Temperature Setting].

Each step below consists of 5 substeps.

Step 1 : 60[s] : The load is increased gradually for 1 minute.

Step 2 : 3540[s] : The load is sustained for almost 1 hour.

Step 3 : 3600[s] : The load is decreased gradually for 1 minute.

Step 4 : 3660[s] : The temperature is increased to 120[deg] in 1 minute.

Step 5 : 3720[s] : The load is increased gradually for 1 minute.

Step 6 : 7200[s] : The load is sustained for almost 1 hour.

Step 7 : 7260[s] : The load is decreased gradually for 1 minute.

Save results of substeps is selected by default to output all the results at substeps.

### Model

A rectangle polystyrene plate is 0.4[mm] thick.

### Body Attributes and Materials

 Body Number/Type Body Attribute Name Material Name 0/Solid Plate PS

The material properties for PS are set up as follows:

 Material Name Tab Properties PS Elasticity Material Type: Elastic/Isotropic Temperature Dependency: N/A Material Property: Young’s modulus: 1.39×10^9[Pa] Poisson’s ratio: 0.35 Viscoelasticity Defined by Prony series [coefficient input] Relaxation Component: Shear only Relaxation Table:   Temperature Dependency and Shift Function: WLF Reference temperature: 113[deg] C1: 8.86 C2: 101.6 Coefficient of Expansion 0x10^-6[1/deg]

### Boundary Conditions

 Boundary Condition Name/Topology Tab Boundary Condition Type Settings Fix_all/Face Mechanical Displacement Select all X/Y/Z components. UX=0, UY=0, UZ=0 Pz/Edge Mechanical Distributed edge load Select “Set the total load”. X=0, Y=0, Z=-1.0×10^-2   Select “Time dependency” and set “Weight function” as follows. This setting means the following. 60[s] : The load is increased gradually for 1 minute. 3540[s] : The load is sustained for almost 1 hour. 3600[s] : The load is decreased gradually for 1 minute. 3720[s] : The load is increased gradually for 1 minute. 7200[s] : The load is sustained for almost 1 hour. 7260[s] : The load is decreased gradually for 1 minute.

### Results

The deformations at 3540[sec] and 7200[sec] are shown below.

The contour indicates the displacement.

The contour diagram shows the displacement.

Deformation at 3540[s]. Temperature is 25[deg].

Deformation at 7200[s]. Temperature is 120[deg].

The deformation is larger at 120[deg], even though the mechanical load is the same as that of 25[deg].

The graph below shows the displacement of the plate tip.

The displacement is constant at 20[deg].

If unloaded, it returns to the original state.

The displacement increases at 120[deg] even though the load is constant.

If unloaded, it doesn’t return to the original state.

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