Characterization of sandwich composite T-joints under different ageing conditions

High-tech demands of the aviation industry require a detailed knowledge of the mechanical and structural response of composite structures. This contribution presents experimental investigations on composite honeycomb sandwich T-joint connections. To understand the effect of loading and ageing on the adhesively bonded joints, quasistatic tension experiments have been performed with the original T-joints and with two sets of artificially aged specimen. The accelerated ageing was enforced by thermal cycling with temperatures in the range of -35 degrees C to 70 degrees C. The failure behavior of the original and the aged specimens are compared to provide primary data for analyzing the behavior of honeycomb sandwich T-joints in limit conditions. A fractographic analysis is performed to determine the failure modes. Additionally the provided data are verified with three-dimensional finite element analyses using a cohesive element technique. The achieved results provide not only new data for designers but can also be used for future computational models of sandwich structures.