ANALYSIS OF INSTABILITY-RELATED DELAMINATION GROWTH USING A CRACK-TIPELEMENT

One-dimensional delamination buckling and growth is analyzed using clo sed form cylindrical buckling and crack tip element analyses. A cylind rical buckling analysis is used to determine the strains, curvatures, deflections, forces, and moments in a buckled region bounded by the la minate free surface and a near-surface delamination. These results are used as input into a linear crack tip element analysis to obtain the total energy release rate and individual mode I and mode II components . Geometric nonlinearities are accounted for through the loading on th e crack tip element. Total energy release mte and fracture mode ratio as found by this new technique are shown to agree with nonlinear finit e element results.