Mechanical Behaviour of a Metal-CFRP-Hybrid Structure and Its Components under Quasi-Static and Dynamic Load at Elevated Temperature

Abstract

Hybrid materials containing a light metal and CFRP are capable to make a relevant contribution in lightweight design and thereby in reducing greenhouse gases causing global warming. An aluminium CFRP-hybrid specimen with a thermoplastic interlayer that is suitable for application for the A-, B-, or C-pillar in a car is investigated in this work regarding the mechanical behaviour due to temperature variation. For this purpose, quasi-static as well as dynamic tensile tests are carried out not only for those hybrid specimens but also for their respective single-material components. Those are supported by various non-destructive testing (NDT) techniques such as thermography and CT-scans of X-ray tomography. The examination of the single materials as well as the hybrid specimens gives us the possibility to understand if a change in the damage process of the hybrid is caused by one of the single materials or the interaction of them. The use of the NDT techniques in combination with the mechanical experiments allows us to obtain a deeper look at the mechanisms causing the respective damage. It stands out that temperature changes affect the damage mechanisms in the hybrid significantly without having great influence on the single materials. In quasistatic testing, the maximum displacement of the hybrid specimens rises at elevated temperature, and in dynamic testing the initial stiffness and the sustained cycles decline significantly. It therefore can be concluded that the interfaces inside the hybrids are affected by temperature changes and play a major role concerning the damage mechanisms. The pure knowledge about the temperature behaviour of single materials is not sufficient for anticipating the behaviour of hybrid specimens under these restrictions.