Glossaries -- Motivation and Outline -- Injection Moulded Short Fibre Reinforced Thermoplastics -- Polymeric Matrix Materials -- Reinforcement Fibres -- Composite Properties -- Injection Moulding -- Determination of Fibre Distributions -- State of the Art of SFRP Material Modelling -- Mechanical Basics -- Kinematics -- Stress -- Linear Elasticity -- Yield Condition and Plastic Potential -- Limit Criteria -- Damage -- Rate Dependency -- Material Characterisation -- Choice of Material -- Coordinate System Definition -- Experimental Set-up -- Experimental Results -- Discussion of Temperature Effects -- Material Modelling -- Overview -- Modelling of Linear Elasticity -- Modelling of Plastic Behaviour -- Modelling of Damage and Failure -- Numerical Implementation -- Verification -- Verification of Linear Elastic Response -- Verification of Plastic Response -- Numerical Verification of the Material Model -- Considerations for Engineering Practice 1857 -- Determination of the Elastic Stiffness Matrix -- Determination of the Limit of Linear Deformation -- Determination of Plastic Deformation -- Consideration of Damage and Failure -- Summary and Outlook.

This work introduces a material modelling approach for explicit finite element simulations of injection moulded short fibre reinforced thermoplastics. The material model considers linear-elastic behaviour and non-linear orthotropic stress-state dependent viscoplastic deformation for arbitrary fibre distributions. Regarding elasticity and the initial yield surface, a micro-mechanical Mori-Tanaka based approach is applied. On the matrix level an isotropic quadratic yield surface is introduced which is transferred into a Tsai-Wu yield surface on the composite level. An analytical expression for non-linear hardening and a simplified consideration of strain rate dependency is presented. The constitutive equations were verified with the experiments of a self-compounded PPGF30 material regarding regarding tension, compression and shear at different orientation distributions.