# Category: Theory

### Full Finite Element Solver in 100 Lines of Python

Tutorial on how to write a full FE solver in 100 lines of Python. This is part one of this tutorial series.

### Introduction to Anisotropic Hyperelasticity

Did you know that there are 3 different ways to formulate an anisotropic hyperelastic model? This article explains how.

### Calibrating the Mooney-Rivlin Model

The Mooney-Rivlin model be calibrated to monotonic uniaxial tension data, but in most cases it is better to use more experimental data.

### 4 Things You Didn’t Know About the Ogden Model

Summary of 4 things that are important to know about the Ogden model. It is a very powerful model, but it can be difficult to use correctly.

### All About the Arruda-Boyce Hyperelastic Model

The Arruda-Boyce Eight-Chain model is a micromechanism-inspired hyperelastic model that works very well. This article explains the theory.

### Permanent Set Using Viscoelasticity

Did you know that it is possible to predict permanent set using a viscoelastic material model? This article explains how.

### What is Time-Temperature-Superposition (TTS)?

Time-Temperature Superposition (TSS) is an excellent tool when a material is thermorheologically simple. This article explains how.

### Calibrate the BB-Model using a Single Experiment

It is possible to calibrate a two-network visco-plastic material model to experimental data from a single experiment. This article explains how to do it.

### Which Ansys Creep Model is Best?

Review of different creep models that are available in Ansys Mechanical. In the article I will recommend which to use and which to avoid.

### Which Abaqus Creep Model Should You Use?

Tutorial on Abaqus creep laws, which 2 you should not use, and which are the best. I also discuss how creep models work for polymers.