Electronic Thesis and Dissertation Repository


Master of Engineering Science


Mechanical and Materials Engineering


Liying Jiang

2nd Supervisor

Samuel Asokanthan



The nature of elastomers has been extensively studied ever since the vulcanization of rubber in the 19th century. Elastomers have been heavily employed in various fields, such as automobile, aerospace, robotics, biomimetics, dynamics and energy harvesting. Due to their molecular nature, these materials display hyperelastic and viscous response when deformed. Their response has been studied in a number of works, which tend to explain their nature through the theory of polymer dynamics or using rheological models. As elastomers are designed as actuators, generators or artificial tissues with complex geometries, the need for finite element analysis to study their response is becoming more essential. The purpose of this study is to develop user defined subroutines (UMATs) to capture the viscoelastic and hyperelastic response of elastomeric materials in ABAQUS CAE. Two UMATs have been formulated based on the existing theory of linear viscoelasticity and hyperelasticity. The developed UMATs are then tested using ABAQUS CAE software on their accuracy, robustness and versatility. The UMAT for predicting the linear response of elastomers can capture the time and rate-dependent response of material. However, it showed some offset from experimental results since the material is nonlinear in nature. The UMAT for predicting the nonlinear behavior of elastomers quite accurately capture the hyperelastic response of the material.