New results in finite element analysis of thermoforming

Various constitutive equations (Mooney-Rivlin, Ogden, G'Sell, Modified G'Sell and K-BKZ) for the description of extensional behavior of polymers are presented and their pros and cons are discussed. It is argued that accurate modeling of stress-strain behavior is needed for finite element simulation of thermoforming. The simulation of thermoforming of complex 3-D shapes requires also the combination of finite element solvers with powerful and robust mesh generators and pre- and post-processors. An example of complex thermoforming is given.