Stress Singularities in Laminated Composite Wedges.

This work primarily deals with the determination of stress singularities at the apex of both symmetric and antisymmetric N-layered composite laminate wedges, using classical lamination theory. The symmetric bending case is governed by a single differential equation, while the antisymmetric case, in which bending and inplane extension do not occur independently, involves three coupled differential equations. In each case, the governing differential equation(s) has(have) non-constant coefficients which depend on the polar coordinate (theta). Use of a finite difference scheme leads to (n + 2)-square, and (3n + 6)-square matrices for the symmetric and antisymmetric cases respectively, for the determination of the stress singularity parameter (lamda). Specializing to a seven-layered symmetric laminate and an eight-layered antisymmetric laminate, results are obtained (for graphite/epoxy T-300/5208) in both cases for various sector and ply angles, when the edges of the wedge are simply supported. In the last part of the work, a brief exploration of possible stress singularities at the apex of a two-layerd laminate, each layer being isotropic, using a more refined theory, is given.Ph.D.MechanicsUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/159439/1/8314340.pd