Homework, Quizzes, Simulation Examples — Hyperelasticity — Lesson 5

Simulation Example

Several simulation examples are provided here. Each of them comes with a description file, video instruction, and Ansys simulation file. All of the simulations are conducted using Ansys solutions.  Download the student version of the Ansys software here.

(1) Calibration of Hyperelastic Material

In this simulation, we will look at how to perform curve fittings of the experimental data to obtain Mooney-Rivlin material constants. These material constants are verified by simulating a rubber specimen under stretching and torsion. The moment vs. rotation curve is compared to the experiment to verify the accuracy. This example demonstrates a general way of obtaining and verifying material constants. Download the zip file and extract the contents. Go through the Readme file. Follow along with the provided How To Video file.

(2) Anterior Cruciate Ligament Simulation

The anterior cruciate ligament (ACL) is the ligament that stabilizes the knee joint. In sports, it is often subjected to large tension, moment and torsion due to sudden stops or changes of directions. This fact makes the ACL a common source of ligament injury. In this simulation, the ACL is simulated under various knee movement conditions. The hyperelastic and viscoelastic behavior of an ACL is considered. Download the zip file and extract the contents. Go through the Readme file. Follow along with the provided How To Video file.

(3) Cardio Stent Simulation

A viable stent-artery finite element model needs to reflect the nonlinear nature of the artery and its interaction with the stent. Biomaterials like artery are often accurately represented by hyperelastic material. Check this simulation and find out how the constitutive model of the artery is defined and how the interaction between the artery and stent is handled. Download the zip file and extract the contents. Go through the Readme file. Follow along with the provided How To Video file.

Homework

(1) Car Door Window Seal

Rubber materials can provide good sealing and are thus widely used in car door window sealing applications. In this homework, you are asked to first replicate a car door window simulation, then complete the following steps:

1.  Check the strain range of the deformed shape. How does it compare to the 0.2% yielding strain of steel?
2. Answer these questions: What is the benefit of using rubber in this case? What would be the quality control parameters one can obtain from the simulation?

Download the zip file and extract the contents. Go through the Readme file. Follow along with the provided How To Video file.

(2) Stretching a Rubber 

Rubber is a hyperelastic material and can undergo large deformations (> 100%) and still regain its shape, because the deformation is elastic in nature. This simulation compares rubber and metal stretching blocks of these materials into long strips and removing the displacement control.

1. Explain from the molecular point of view why rubber and metal behave the way they do.
2. Plot the stress vs. strain curve of the rubber material in this tensile simulation. Is Young's modulus constant?

Download the zip file and extract the contents. Go through the Readme file. Follow along with the provided How To Video file.