Experimental Studies on Crushing Behaviour of Hexagonal Composite Tubes

Abstract

The theoretical results presented in the previous chapters are based on experimental investigations. Therefore, in this chapter, the experimental characterisation of the short fibre-reinforced composite is presented. The performed experiments increase in complexity, starting from uniaxial tensile tests at different strain rates up to multiaxial tests like true biaxial tests and the Nakajima test which introduce stress and strain states closer to applicational load cases. At least the results of the Nakajima tests can be regarded as verification experiments for the developed and implemented models. Effects like elasto-plasticity, damage and anisotropy are investigated in detail. The inhomogeneous strain states, which can be observed already in the uniaxial tests due to localisation phenomena in combination with damage, are evaluated using a three-dimensional optical strain measurement on the surface of the specimens. The underlying principles of digital image correlation are explained in detail.