After fabrication or in service, certain metal and ceramic matrix
laminates may exhibit extensive decohesion, such as debonding and sliding
at fiber-matrix interfaces. The evolution of the decohesion process, as
well as its effect on overall response and on redistribution of local
stress and deformation fields, is analyzed here with a modification of
the transformation field analysis method (Dvorak 1992). A finite element
analysis of a unit cell model of a fibrous ply is used to obtain the
decohesion-induced changes in the potential energy, needed in local
fracture criteria. Changes in the local stresses and overall strains
are found and converted into effective phase eigenstrains that produce
identical average fields in a perfectly bonded ply. Finally,
transformation strain analysis of a laminated plate is developed for
derivation of governing equations for incremental evaluation of the local
fields along a given overall loading path. Applications indicate that the
decohesion process may generate overall response similar to that of an
elastic-plastic laminate.
Last modified: Nov 4 2000