High performance sandwich components have a great significance in aerospace applications. Particularly, lightweight sandwich structures made of honeycomb or foldcores show excellent load carrying capabilities. Both types of cores are usually made of aramid paper coated with phenolic resin. Therefore, the development of improved paper-like materials seems to be a promising approach to improve the mechanical performance of this kind of cores. An essential part of this development process is the evaluation of the new materials by the complete characterisation of the mechanical properties. This is still a challenging task, since the resulting papers are orthotropic and most of the existing testing procedures and devices are not suitable for very thin sheet materials. This is particularly true for investigating stiffness and strength properties under compressive and shear loading.
The paper presents a novel single-curved compression test device as well as an adapted shear-frame for the in-plane characterisation of very thin specimens. These devices have been applied in the development process of a new paper-like material that consists of three layers in order to increase the stiffness and strength of honeycomb- and foldcores. The performance of this material was evaluated by comparing relevant mechanical properties to that of state of the art paper materials. Based on the experimental results the benefits of the new paper-like material could be shown.