A multi-state progressive cohesive law for the prediction of unstable propagation and arrest of Mode-I delamination cracks in composite laminates

•Expression of toughness for crack initiation, propagation and arrest is derived.•A multi-state progressive cohesive law for dynamic crack propagation is proposed.•A quantitative characterization for unstable stick-slip fracture is conducted.•Ratio of initiation toughness to arrest has significant effects on fracture behavior.