Structural and damping performance of the adhesively-bonded single lap joints with laminated composite adherends

Mechanical vibrations are serious problems threatening key electronics and components of aerial vehicles under mission. For controlling the vibrations, fibre reinforced polymer composites are promising materials that can provide high damping as well as high strength values depending on their fibre orientations and stack sequences. In this study, Single Lap Joints (SLJs) with glass fibre reinforced adherends were subjected to two different tests; first non-destructive vibrations to measure their damping values, and then quasi-static loadings to assess their structural performance. The objective was to design joints with high damping and high strength. For this purpose, the adherends with different fibre orientations and stacking sequencies were manufactured and bonded using a constant adhesive layer of 0.2 mm and an overlap length of 25 mm. It is found the plies with +/- 45 degrees fibre orientations that normally has a high energy absorption capability can contribute to the joint damping considerably depending on their stacking sequencies. The results show it is possible to get high values of damping as well as high the joint strength when using suitable parameters. For instance, Type3 joints achieved a 61% increase in damping with only a 14% reduction in strength compared to Type1. The joints were also analysed using finite element simulations that are consistent with experimental results.