Mechanical design of injection moulded parts made of short-fibre reinforced thermoplastics by means of integrative simulation

 

Ernst Schmachtenberg, Marcel Brandt

 

Institute of Plastics Processing (IKV) at RWTH Aachen University

Pontstraße 49, 52062 Aachen, Germany

 

Abstract

 

      For a precise mechanical design of injection moulded parts made of short-fibre reinforced thermoplastics by means of FEA, the local fibre orientation in the part has to be considered. Therefore an integrative CAE-based simulation concept is presented that includes the calculation of the fibre orientation in the actual moulded part, the determination of the anisotropic material properties of the fibre/matrix-composite and finally a mechanical structural analysis using these data. In comparison to the results of stiffness calculations including isotropic substitute properties a marked increase in design quality is obtained. In the field of strength analysis for anisotropic materials, only the use of the developed routines based on adequate failure criteria provides meaningful results. Furthermore, by applying the fracture hypothesis of Puck it is possible for the first time to differentiate between failure parallel to the direction of main orientation or perpendicular to it also for short-fibre reinforced plastics.