Fatigue life assessment of a Short Fibre Reinforced Thermoplastic at high temperature using a Through Process Modelling in a viscoelastic framework

A Through Process Modelling (TPM) fatigue life assessment methodology – previously validated in an elastic framework for Short Fibre Reinforced Thermoplastics at room temperature – was extended to high temperature. The viscoelasticity of the matrix was taken into account to estimate the local effective mechanical properties at any point, from the knowledge of local fibre orientation provided by the simulation of injection-moulding. Lifetime estimation was obtained from an energetic fatigue criterion applied in the stationary regime. The approach was validated from uniaxial fatigue tests conducted at 110 °C in tension, on PA66GF30 samples cut out from injected plates with three different orientations to the injection direction, at two stress ratios (0.1 and −1).