Experimental investigation on the buckling and post-buckling behavior of variable stiffness laminates

On the basis of adequate considering the process constraints and defect control methods of tow curve placement, two types of variable stiffness laminates were designed and manufactured. A comprehensive experiment has been carried out through the 3D digital image correlation system, strain gauges, and displacement meters. The measured results show that the buckling and failure loads of variable stiffness specimens are improved by at least 40% and 70%, respectively. The FEA results of out-of-plane displacement and strain agree well with the experimental results. Furthermore, the reason for the higher buckling and failure loads of the variable stiffness specimens was elucidated by numerical results.