Blog Articles

Theory of the Yield Stress Dependence on Strain-Rate
Theory of how the constitutive elements influence the predicted yield stress dependence on strain rate

Best Material Model for Polycarbonate at High and Low Strain Rates
Review of how different material models can be used to predict the non-linear response of PC. Also covers how the yield stress depends on the strain rate.

Stress-Strain Cleanup using MCalibration
Video tutorial showing how to remove one load cycle from an experimental test.

The Math Behind Stress Relaxation and Creep of Polymers
Quick discussion about the math behind stress relaxation and creep in polymers.

Predicting the Long-Term Stress Relaxation Response of Rubbers
Discussion about how to extrapolate the stress relaxation response of rubbers to long times.

Predicting the Long-Term Stress Relaxation Response of Thermoplastics
Discussion about how to best estimate the long-term stress relaxation response of a thermoplastic based on short-term data.

Hytrel Material Modeling
Hytrel is a thermoplastic polyester elastomer. In this post I examine what material models can be used to predict the response of this class of materials.

Why Does Rubber Have Odd Temperature Dependence?
This article explains why some rubbers get softer with increasing temperature, and why some rubbers get stiffer.

PolyUMod Abaqus Hint: When to Set the ORIENT Flag for Anisotropic Materials
Tutorial on how and when to set the ORIENT flag with using Abaqus and an anisotropic material model from the PolyUMod material model.

PolyUMod with Abaqus/Standard: Make Your FE Simulation Faster
In this video I will show have to make most Abaqus/Standard simulations that use the PolyUMod library run faster (and with larger time increments). The key is to set an Abaqus time incrementation setting.

How to use a Parametric Study in MCalibration
Tutorial on how to use a Parametric Study in MCalibration to determine the influence of different material models.

Predicting Creep of Polycarbonate
Tutorial on how to predict the creep response of polycarbonate and other thermoplastics

Accurate FE Simulation of a PET Bottle using Ansys and the PolyUMod Library
Demonstration of how to accurately predict the deformation response of a soda bottle under internal pressure.

Stress Triaxiality and Thermoplastics
The applied stress triaxiality influences the mechanical response of thermoplastic materials in non-intuitive ways. In this article, I will explain how.

Shape Optimization using MCalibration and Abaqus
MCalibration can optimize both the specimen shape and material parameters at the same time. Here’s how!

How to Simulate a Teflon Seal using Ansys
Demo of how to simulate a Teflon seal using Ansys using a viscoplastic material model, without any experimental data.

Run COMSOL Multiphysics Using an Input File From a Command Prompt
How to run COMSOL Multiphysics using an input file and a command prompt. It is easy using the Java API.

Complete Guide to Using PolyUMod with COMSOL Multiphysics
Guide to using MCalibration and PolyUMod with COMSOL Multiphysics. A complete start-to-finish tutorial is presented.

What Material Model Can Predict Different Stiffnesses in Tension and Compression?
Soft polymer foams, and some other materials, often exhibit different stiffnesses in uniaxial tension and compression. Most material models cannot predict this type of behavior, but there are some excellent choices for this.

How to Force Drucker’s Stability in MCalibration
A material model is considered Drucker’s stable if an increase in strain results in an increase in stress. In some cases it can be important to enforce that a material model is Drucker’s stable. This article shows how you can easily achieve this in MCalibration.

How to Make Ansys find PolyUMod
Instructions for how to make sure Ansys Mechanical finds and uses a PolyUMod material model.

Material Modeling of Polymers
Here is a presentation about (non-linear) material modeling of polymers. I gave the presentation on 2021-06-24.

Plot Stress-Strain from Ansys Commands using MCalibration
Introduction In this article I will show how you can quickly convert any Ansys material model (in APDL format) into stress-strain predictions using MCalibration. That

Plot Stress-Strain from Abaqus Commands using MCalibration
It is easy to create stress-strain plots for any Abaqus material model using MCalibration. This article shows how.

MCalibration Material Model Templates
MCalibration supports not only a large selection of pre-defined material models, but you can also define your own material model using a Template.

FE Solvers and Templates in MCalibration
Demonstration of how to use different FE solvers and solver templates in MCalibration.

Extended Tube Model in Ansys Mechanical
The Extended Tube model is one of the most accurate hyperelastic material models available, but it can be difficult to use if you don’t understand how the material parameters influence the predicted stress-strain response. This article will demonstrate that by example.

Set Up MCalibration to Use Ansys
Short description of how to setup MCalibration so it can use Ansys as a solver.

Parametric Study of the Mullins Effect Model
The Ogden-Roxburgh Mullins effect model is highly non-linear. In this article I will graphically illustrate how the different parameters influence the predicted stress-strain response.

Calibrate a PolyUMod Material Model with Failure
Tutorial showing how to calibrate a PolyUMod TNV stress-strain and failure model to experimental data.

Calibrate Abaqus Johnson-Cook Model using MCalibration
Tutorial showing how to use MCalibration to calibrate the Abaqus Johnson-Cook model with failure to experimental data.

Introduction to MCalibration and PolyUMod for Altair Radioss
Introduction to how MCalibration and PolyUMod can be used with Altair Radioss. This is a great starting point if you are new to our software.

What is Resulting and what does it have to do with Material Modeling?
Resulting is a term used in the book “Thinking in Bets” to describe how not to make decisions when all you have is limited information. In this article I will describe how this relates to material modeling.

Practical Differences Between Linear and Non-Linear Viscoelasticity
Review of some practical differences between linear and non-linear viscoelasticity.

Strain Amplitude Sweeps in MCalibration
Quick demo of how to setup a strain amplitude sweep in MCalibration.

Set Up Altair Radioss™ to use PolyUMod
Succinct tutorial on how to setup Altair Radioss to use a PolyUMod material model.