Analysis of thick section composite laminates
Abstract
Three-dimensional effective moduli are used in the analysis of thick laminates consisting of a large number of repeating identical sublaminates. Local stresses and strains in the laminae are recovered from the global average stresses and strains. A global-local method is developed in which the effective modulus theory is used to model the thick laminate except for the local region where accurate stresses are desired. A finite element code employing this global-local concept is used to analyze delamination cracks, interlaminar stresses and free edge stresses in thick laminates. The torsion problem of multilayer laminates is evaluated by three different approaches: the layer by layer local analysis, all global finite element method, and the derived analytical series solution. Numerical study shows that this analytical tool can achieve reliable results in conjunction with its superior efficiency. It also indicates that the torsion fracture of an edge cracked specimen is dominated by Mode III failure. An experimental configuration based on the torsion analysis of thick laminate is performed to measure the interlaminar Mode III fracture toughness of several angle ply composite systems. Test results show that the fracture toughness ranges from 460 N/m to 860 N/m for most interfaces.
Degree
Ph.D.
Advisors
Sun, Purdue University.
Subject Area
Mechanics|Aerospace materials
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