Experimental investigation and numerical modelling of composite-honeycomb materials used in Formula 1 crash structures
This thesis has investigated composite-honeycomb sandwich materials commonly used in Formula 1 nosecone structures. Experimental work has investigated their failure behaviour under static and dynamic crash loading, from which new constitutive failure laws for implementation in the explicit Finite Element code PAM-CRASHTM have been proposed. An investigation using an improved Arcan apparatus has been conducted to establish the mixed shear-compression properties of the honeycomb. An investigation has also been performed to establish relationships between in-plane deformation and out-ofplane compression properties. These relationships have been identified and successfully implemented into a honeycomb solid element material model available in PAMCRASHTM. A further investigation to represent honeycomb using geometrically accurate shell representation of the honeycomb has also been presented. This model was shown to reproduce trends observed during testing. The composite skin material has also been experimentally investigated and presented. This investigation made use of digital image correlation to examine the onset of intralaminar shear failure mechanisms, from which a non-linear damage progression law was identified. This law was successfully implemented into the Ladevéze damage model in PAM-CRASHTM for composite material modelling and has been shown to improve the representation of in-plane shear damage progression and failure. A series of experimental investigations to examine the energy absorbing properties of the sandwich have been conducted and presented. These investigations include three point bend flexural testing and edgewise impact loading. Failure mechanisms in the skin and core have been identified for each loading case. Experimental findings were used to assess the capability of PAM-CRASHTM for sandwich material modelling. This investigation has highlighted deficiencies in the material models when representing the sandwich, specifically with the existing composite skin and honeycomb models. Improvements introduced to the core and skin material models have shown some improvement when representing sandwich structures.