Co-authors​ :

 Tobias LORIMER (NEW ZEALAND), Tom ALLEN (NEW ZEALAND) 

Failure Criteria (FC) are commonly employed for the prediction of various forms of failure in Fibre Reinforced Polymers (FRP). However, they are usually extensions of criteria designed for isotropic materials and can struggle to accurately predict failure for FRP [1,2]. Numerable factors, such as stacking sequence, loading direction, material characterization and the definition of failure significantly affect the accuracy and therefore the reliability of most common FC [3,4].
A testing apparatus and a cruciform specimen are developed for experimental in-plane biaxial testing at a lab-scale. The new biaxial testing apparatus is used to assess the accuracy of five common FC in terms of their predictions of failure load and their suitability within the objective function of a coupled FEA-GA optimisation approach.
Each FC is used to design an optimal cruciform specimen by specifying the stacking sequence of a laminate such that the highest load is carried by the specimen when tested.
Preliminary analysis of the results indicate that the maximum-strain criteria most accurately predicts the first ply failure of the cruciform specimens and should be incorporated into the optimisation approach.