Modeling Impact Damage in Laminated Composite Plates

The simulation of impact damage in laminated composite plates presents many challengesto modelers. Local failure takes the form of various fracture processes. For compositesthis is further complicated because the various modes can strongly interact with each other.Another modeling challenge particular to composite materials is that it is often necessaryto simulate the structural behavior simultaneously on different length scales. This makes itdifficult to create a model that is computationally efficient.Cohesive zone models (CZMs) have been developed to model crack growth in a ma-terial or debonding between two different materials and have alleviated many of the nu-merical problems inherent in crack modeling. However, significant errors can emerge infinite element models if the element are much larger than the crack process zone. Theseerrors are often large enough to cause the solver to fail to converge except for very smallstructures.In this thesis, an improved numerical integration algorithm is presented that solves theinterface convergence problem. A Multiple Length Scale Finite Element Method (MLS-FEM) is also presented as a means of modeling both large-scale structural behavior as wellas small-scale damage progression. The application of these models is with impact on lam-inated composite plates. Both of these models, however, can be applied to a wide varietyof problems in composite structural analysis. Thesis Supervisor: S. Mark SpearingTitle: Associate Professor