Stiffness Reduction Resulting from Transverse Cracking in Fiber-Reinforced Composite Laminates

摘要

Several damage modes, including fiber breakage, delamination, and transverse cracking, have been observed to contribute to the mechanical degradation of fiber-reinforced composite laminates. In this investigation, the effect of transverse cracking on laminate stiffness was studied. Four glass-epoxy laminates were evaluated. Two experimental test sequences were performed. In the first test sequence, longitudinal stiffness was measured at various stages of damage development. Damage development was monitored via edge replication. In the second test sequence, four laminate stiffnesses were measured in the undamaged and near-saturation damage states. Two analytical models were evaluated. A one dimensional shear lag model was used to predict longitudinal stiffness as a function of crack density. Correlation between theory and experiment was good. A modified laminate analysis was used to predict four laminate stiffnesses.