Introduction

This example illustrates how to calibrate a hyperelastic-viscoelastic material's response curve using stress-strain test data for a sample of butyl rubber.

This page discusses:

Problem Description

Butyl rubber is a synthetic elastomer that is impermeable to air, and many industries use it for applications where an airtight rubber can be useful. These applications include rubber gloves, sealants, O-rings, and inner tubes. Like many other elastomers, butyl rubber exhibits a stress-strain response that changes as you increase the strain rate. You can calibrate a hyperelastic-viscoelastic material response that mimics this strain rate–dependent behavior.

To complete this example, you perform several actions in the app that were not included in the other Material Calibration example, Elastic and Plastic Material Calibration of Aluminum. These actions include:

  • Importing multiple test data sets
  • Adjusting the initial material parameters to improve the calibration
  • Selecting a calibration algorithm
  • Simplifying the calibration by adjusting optimization controls

Workflow

The workflow diagram below provides an overview of the example. The diagram shows the apps that you use as you perform the steps in sequence. Clicking a number in the diagram opens its corresponding step in the example.

Load the Test DataDefine the Rate-Dependent Material ModelInitialize the Material Model ParametersApply Weights to Emphasize the Importance of Selected Test Data SetsSpecify the Optimization AlgorithmSimplify the Optimization ProblemRun and Review the Material CalibrationExport Data to a Material Definition
Task Description
1 Load the Test Data Load the test data in the 3DEXPERIENCE platform.
2 Define the Rate-Dependent Material Model Define a hyperelastic-viscoelastic material model with neo-Hookean hyperelasticity and Yeoh viscoelasticity.
3 Initialize the Material Model Parameters Adjust the initial values of the hyperelastic and viscoelastic material parameters.
4 Apply Weights to Emphasize the Importance of Selected Test Data Sets Specify the weight of the test data sets, such that test data sets with lower strain rates have a greater influence over the resulting material model than the test data sets with higher strain rates.
5 Specify the Optimization Algorithm Select the algorithm for your material calibration.
6 Simplify the Optimization Problem Simplify the calibration problem by specifying the convergence criteria and solution bounds.
7 Run and Review the Material Calibration Run the calibration job, and then revisit the plot to assess how closely the material's response curve matches the test data.
8 Export Data to a Material Definition Export the hyperelastic and viscoelastic material parameters to a material definition for use in simulations.

Complete the workflow steps in the order listed. Deviation from the instructions associated with each step might cause errors that prevent a successful material calibration.