DAMAGE AND FRACTURE PROCESS OF COMPOSITE LAMINATES IMPACTED BY PROJECTILE (Ⅱ)-DAMAGE AND FRACTURE CRITERIA

A model is developed to express the meso-damage,macro-damages(including debond,matrix crack and fiber break) and fracture process of composite laminates impacted by a projectile.It is assumed that the nonlinearity of composites is induced by the meso-damage produced in impact process,and is considered in constitutive equations.A maximum strain criterion is presented by the authors,and can be used to analyze the maoro-damages of composites.The process of the macro-damage is simulated by the nodal separate technique.