Mechanism of Energy Absorption via Sensitivity Analysis for Crashworthy Design ofComposite Structures

摘要

The objectives of the current research are accurate analysis of compositestructures under compressive loading and development of efficient analytical sensitivity analysis procedure for application to crashworthy design of composites. A new higher order theory has been developed to study the delamination buckling, postbuckling and growth problem in composite plates and shells. Experimental investigation was performed on delamination buckling and postbuckling of composites with built-in delaminations to evaluate critical load and postbuckling characteristics. The result is a comprehensive data base. Elasticity approach, which accurately models transverse shear and transverse normal deformation, has also been developed. The experimental data base and the elasticity solutions have been used to validate the developed new higher order theory. The research provides a comprehensive investigation on modeling of delaminated composites and an accurate evaluation of limitations of the classical laminate and other improved shear deformation theories. An analytical design sensitivity procedure and a hybrid optimization technique have also been developed for application to improved energy absorption in composites. The procedure is computationally efficient. The hybrid optimization technique allows the simultaneous inclusion of continuous and discrete design variables and is applicable to a wide variety of design problems. The procedure has been used to maximize the energy absorption of composite plates subject to compressive loading and shows significant improvements.