Characterization of bi-stable pure and hybrid composite laminates - An experimental investigation of the static and dynamic responses

摘要

In this study, the static and dynamic responses of bi-stable hybrid composite laminates [0/AL/90](T) and [0(2)/AL/90(2)](T) were scrutinized, and their behavior was compared to bi-stable pure composite laminates including [0/90](T) and [0(2)/90(2)](T). The work consisted of an analytical study that was validated experimentally. An analytical method based on Hamilton's principle was developed to investigate the static and vibration characteristics of the laminates. Experimentally, curvatures and out-of plane-displacement, and snap-through load were measured using a quasi-static loading on a universal testing machine. Further experimental analysis was performed to characterize the damping viscous ratio, natural frequency, and critical base excitation that cause the snapping between the two different stable shapes. The results show that the hybridization of bi-stable pure composite laminates has the potential to increase the stable curvatures and enhance the static load-carrying capability up to five times when compared to a pure bi-stable composite laminate of the same thickness. It was also observed that the hybridization of bi-stable pure composite laminates may result in a dramatic change in the dynamic response. The natural frequencies of bi-stable hybrid composite laminates are increased in comparison with bi-stable pure composite laminates. The critical base excitation required for snapping has increased significantly for the hybrid composite laminate. The qualitative and quantitative comparisons between the analytical and experimental results were very promising and they agreed well.