Finite Element Investigation of a Composite Cylindrical Shell Under Transverse Load with through Thickness Shear and Snapping.

摘要

The static response of a circular cylindrical open shell (curved panel) constructed of an orthotropic graphite/epoxy laminate is numerically investigated in this thesis. The shell is subjected to an inward point load, centered on and normal to the shell surface, which maintains its original orientation through deformation (i.e. dead load). The shell displacement response is seen to vary widely with shell geometry and boundary conditions, not only in magnitude of deformation but also in the nature and progression of the collapse under critical load. The finite element analysis is conducted with a quasi-two dimensional thin shell element which incorporates parabolic transverse shear stress through the thickness. The element can be formulated with either large displacement/rotation kinematics or the simpler Donnell relations. To enable tracking through critical load and displacement points and investigation of the post-critical regime, a solution algorithm other than the popular Newton-Raphson technique with displacement control or load control is required. The algorithm employed here uses a modified Riks/Wempner technique. It allows continuous tracing of the load - deflection response through critical load and critical displacement points. Step size is automatically scaled to follow the solution path closely in the areas of large load or displacement changes which surround critical points. (KR)