Elasticity/Hyperelasticity

Linear elasticity and hyperelasticity are two classes of constitutive models that are both easy to use and computationally efficient. Here, a constitutive model is considered to be easy to use if it requires little effort to calibrate and if it provides robust predictions for other loading conditions than what was used for the calibration. Both of these classes of models can provide useful predictions of the mechanical behavior of different polymers. The following sections discuss the theory behind these two classes of models, and how and when they can be applied to solve polymer mechanics problems. Note that although the hyperelastic models that are discussed in this chapter are most useful for rubber-like material, they are also a critical component/building block for both linear and non-linear viscoelastic and viscoplastic models that will be discussed in detail in the following chapters. Hence, the theory of hyperelasticity is of significant importance and will be discussed in detail in this chapter.