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Increasing use of engineering thermoplastics in the applications such as load bearing automotive components necessitates accurate characterization and material modeling for predicting part performance using finite-element simulations. Uniaxial tensile test data on glass filled thermoplastic resins exhibit highly nonlinear deformation with no clear demarcation between elastic and plastic regions. Hence, the estimation of modulus and yield stress values, required for the finite element analysis, is invariably through the subjective interpretation of the CAE analyst, which may not be consistent and unique. Use of parameters such as tangent modulus, yield stress and the post yield data calculated at 0.2% strain for finite element computations does not yield good correlations with experimental values. This paper outlines an alternate approach for evaluating material parameters for short glass filled engineering thermoplastics.

This paper presents a new type of engineered structure that combines a pressure sequenced hydroform (PSH) tube over molded to an injection molded engineering thermoplastic (ETP) panel. A unique attachment feature is formed during the molding process. This eliminates separate mechanical fasteners that would otherwise be necessary to connect the tube to the plastic panel. This paper takes the reader through the process that was used to bring about a Hydroform – Plastic Structure (HPS). From the initial brainstorming approaches through the validation testing, each step will show how this technology was developed. Details accompany each step to illustrate the finer points of the application development with this structure. The application under investigation is an automotive front-end module. The front-end module serves as a structural member and vehicle hardware integrator at the front of the engine compartment.

As a result of the increased reliance on predictive engineering to reduce vehicle development resources, increasingly accurate predictive finite element models are important to help engineers meet cost and timing restrictions. For components made of engineering thermoplastics, accurate material modeling that helps predict part performance is essential. This material modeling accuracy is even more important where high speed and high loading conditions exist such as in airbag doors, knee bolsters and pillar trim. This paper addresses material modeling of engineering thermoplastics for finite element models that are subjected to high impact and high speed loading. Here, the basics of plastics behavior are introduced and a comparison of the accuracy of different material characterizations in an impact loading is presented. The material under analysis here is a polycarbonate - acrylonitrile butadiene styrene blend, PC-ABS.