QUASI-STATIC MODELING OF DELAMINATION CRACK-PROPAGATION IN LAMINATES SUBJECTED TO LOW-VELOCITY IMPACT

The quasi-static characteristics of impact responses and impact-induce d delamination crack propagation in [90(5)/0(5)/90(5)] graphite/epoxy laminates subjected to low-velocity heavy mass impact have been invest igated. A one-degree-of-freedom spring-mass model was used to predict the contact force history. The peak contact force was then used in con junction with a linear beam model to calculate the strain-energy relea se rate. The delamination size was obtained when the strain-energy rel ease rate reached interlaminar fracture toughness. The predicted delam ination size agreed very well with the experimental result.