Part I of this paper describes the computations of the quasistatic nonlinear
moment-slope relation for an edge-cracked beam element with a strictly linear softening
cohesive zone ahead of the crack tip. A static plane stress linear elastic boundary
element analysis is used in which the cohesive nonlinearity appears in the crack plane
boundary conditions only. An iterative solution scheme is used to determine the
unknown cohesive zone length, the cohesive displacement jumps, and the bending mode
-integral.
Interpreting the moment-slope relation as a generalized load-displacement relation the
bending compliance (and slope) at a given applied moment are calculated from computed
-integral
values over a grid of applied moment and crack-length values. The dependence of the
moment-slope relation on the cohesive law parameters is studied and the various
computed moment-slope relations are then used in Part II to model the dynamic
effect of the cohesive zone and law on the free-vibration of an edge-cracked
simply-supported beam.
Keywords
cohesive zone, linear softening, compliance, $J$-integral,
nonlinear load-displacement