Special hybrid stress element for stress analyses around circular cutouts in laminate composites

摘要

a 3-Dimensionlal hybrid stress element with a traction-free Cylindrical surface based on a modified complementary energy principle has been derived for efficient and accurate analysis of stress concentration around circular cutouts in thin to thick laminated composites. New expressions of six stress components are developed by using three stress-functions in cylindrical co-ordinates, so that the homogeneous equilibrium equations, the interlayer surface transverse-stresses and the traction-free boundary condition on the cylindrical surface are satisfied exactly, while the interelement traction conti- nuity has been relaxed via the Lagrange multiplier method.