Numerical investigation, experimental validation and macroscopic yield criterion of Al5056 honeycombs under mixed shear-compression loading

- Yield behaviour of Al5056 aluminium alloy honeycombs is investigated under mixed shear-compression.
- Numerical simulations allow to overcome a limitation of the experimental measurements.
- Numerical and experimental investigations allow to investigate the normal and shear behaviours separately.
- A macroscopic yield criterion expressed as a function of the impact velocity, the loading angle Ψ and the in-plane orientation angle β.

Numerical simulations of honeycomb behaviour under mixed shear-compression loading are performed to overcome a limitation of the experimental measurements and to investigate the normal and the shear honeycomb behaviours separately. A detailed FE model allowing to simulate the mixed shear-compression honeycomb behaviour is presented. A validation between numerical and experimental results in terms of crushing responses and collapse mechanisms allows to dissociate the normal and shear forces components. They are used to identify the parameters of a macroscopic yield criterion expressed as a function of the impact velocity, the loading angle and the in-plane orientation angle. A well known dynamic enhancement phenomenon is confirmed by this macroscopic yield criterion. However, as a new result, this dynamic enhancement is reversed when the loading angle reaches a critical value. An analysis of the collapse mechanisms is carried out under both quasi-static and dynamic loading conditions in order to explain this inversion.