Finite Element Analysis and Material Modeling of Elastomeric Components and Assemblies: Some Practical Considerations 2007-26-041

Elastomers are used extensively in many industries like automotive, aerospace and heavy industries because of their wide availability and low cost. They are also commonly used because of their excellent damping and energy absorption characteristics. They are often used to seal against moisture, heat, and pressure. Flexibility, resilience, nontoxic properties, moldability, and variable stiffness attributes are added benefits. Elastomeric materials behave like a highly viscous fluid during initial processing and manufacturing. During final processing, the polymer chains are cross-linked by vulcanization (or by curing), and the elastomeric material is then no longer highly viscous and the material can then undergo large reversible elastic deformations. In view of the above complex properties, the behavior of elastomeric materials is not adequately characterized by conventional elastic or elasto-plastic material models. Since the usage of elastomers in the auto industry is exponentially increasing and the design requirements are increasingly demanding it is of utmost importance to characterize elastomeric materials accurately with math models. Accurate analysis of elastomeric components requires special material model definitions and the material models are quite different than those commonly used for metallic or plastic parts. This paper attempts to characterize elastomeric materials with hyperelastic material models and also describes how to apply such math models into commercially available CAE tools. These studies will act as a useful guideline or best practice for engineers working with elastomeric components. A standard seal configuration has been studied to demonstrate a step-by-step procedure undertaken to develop an accurate material model for a seal material. The scope of this study goes beyond just analytical simulation. Consideration and the details for material testing have also been included. Some difficulties in obtaining and using material data for elastomers with finite element analysis have been highlighted and some methods of overcoming these problems have been suggested. Several standard mathematical models for elastomeric material have been reviewed. Problems associated with analysis of contact have been highlighted with particular reference to hyperelastic materials