Plastic boss and screw fasteners are an economical means of securing automotive components, such as instrument or body panels. However, new materials and/or suboptimal design present chauenges to the boss/screw effectiveness. Thus, the goal of the research is to develop an FEA model to elucidate the thread forming process and permit subsequent optimization. The FEA must accommodate the nonlinear couplings, such as large strain and heat transfer. Heat generation is present in the forms of interfacial shear heating and plastic work associated with the large deformation of the interface between the boss and screw. Strain rate dependent materials are included using the Eyring theory for plastic flow of polymeric materials. Results of the model are pre-sented and compared to experimentally determined torque curves and temperatures.
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