The mechanics of finite element analysis (FEA) regarding elastomers (or rubberlike materials) and foams apply to the FEA of glass, plastics, and biomaterials as well. The concepts are not only valuable to practitioners in the rubber and tire industries but also to those involved in:

• Glass, plastics, ceramic, and solid propellant industries
• Biomechanics and the medical/dental professions—implantable surgery devices, prostheses, orthopedics, orthodontics, dental implants, artificial limbs, artificial organs, wheelchairs and beds, monitoring equipment
• Highway and flight safety—seat belt design, impact analysis, seat and padding design, passenger protection
• The packaging industry
• Sports and consumer goods—helmet and shoe design, athletic protection gear, sports equipment safety.

Elastomers are used extensively in many industries because of their wide availability and low cost. They are also used because of their excellent damping and energy absorption characteristics, flexibility, resiliency, long service life, the ability to seal against moisture, heat, pressure, and non-toxic properties, moldability, and variable stiffness.

Rubber is very unique a material. During processing and shaping, it behaves mostly like a highly viscous fluid. After its polymer chains have been cross-linked by vulcanization (or by curing), rubber can undergo large reversible elastic deformations. Unless damage occurs, rubber will return to its original shape after removal of the load.

Proper analysis of rubber components requires special material modeling and nonlinear FEA tools that are quite different from those used for metallic parts. The unique properties of rubber are such that:

1. Rubber can undergo large deformations under load, sustaining strains of up to 500 percent in engineering applications,
2. Its load-extension behavior is markedly nonlinear,
3. Rubber is viscoelastic (time and temperature-dependent) similarly to glass and plastics, and exhibits significant damping properties, and
4. It is nearly incompressible, so its volume does not change much with stress: It cannot be compressed sig-nificantly under hydrostatic load.

For foamed rubber, the assumption of dense rubber near incompressibility is relaxed, as large volume change can be achieved by the application of relatively moderate loads.

Academic, research, and commercial nonlinear FEA programs, possess specially-formulated elements, material and friction models, and automated contact analysis procedures to model elastomers. Only a few proved capabilities and unique-ness in analyzing large, industry- scale problems. Efficient and realistic analyses for design of elastomeric products rely on several important concepts including: Nonlinear material behavior, automatic determination of material parameters from test data, failure, dynamics, modern automated contact analysis techniques, automated solution strategies, and automated remeshing and rezoning.

Select software offers a well-balanced combination of sophisticated analysis code integrated seamlessly with easy-to-use Graphical User Interface or GUI for the simulation of elastomeric products. They prove uniquely suitable for the simulation of complex physics of rubber, foam, plastics, and biomaterials.