SHEAR-LAG ANALYSIS ABOUT AN INTERNALLY-DROPPED PLY

The region around a terminated ply is modeled as several elastic layer s separated by shear regions. A shear-lag analysis is then performed a llowing for the thickness of the elastic and shear layers to vary. Bou ndary conditions, away from the ply drop, are based on the deflections determined by a finite element model. The interlaminar stresses are c ompared against those generated by the finite element model for tapere d laminates under pure extension, pure bending, and extension-bending coupling. The shear-lag analysis predicts the interlaminar shear at an d near the ply drop for pure extension and in cases involving bending if the deflections due to bending are removed. The interlaminar shear stress and force equilibrium are used to determine the interlaminar no rmal stress. The trends in the interlaminar normal stress shown by the finite element model are partially captured by the shear-lag analysis . This simple analysis indicates that the mechanism for load transfer about a ply drop is primarily due to shear transfer through the resin- rich areas.