Impact Fracture Simulations of Automotive Laminated Glass: The Two Extrinsic Cohesive Models

As one of the important component of an automobile, the investigation of impact fracture characteristics of the automotive windshield glass contributes to the pedestrian safety protection, traffic accident reconstruction and the design of the windshield glass. Currently, the impact fracture mechanism of laminated glass is investigated by means of theoretical analyses, experimental investigations and numerical simulations. In view of the advantages of numerical simulations, in this work, we focus on the development of cohesive zone-based numerical algorithms for the application of interest here. The purpose of this work is to numerically investigate initiation and propagation of crack in the framework of cohesive zone modelling (CZM). Based on the cohesive theory, we develop two cohesive elements for brick and shell elements respectively. Different from the predefined approach adopted in the commercial codes, such as LS-DYNA, the cohesive elements are inserted adaptively during calculation. We improve node-to-surface and single surface contact algorithms to correspond to the adaptive generation of contact pairs, and propose edge-edge algorithm to describe crack closure. Two laminated glass models are proposed, among which brick elements are adopted to discretize glass in one model, and shell elements are adopted in the other. The main fracture patterns including radial and circular cracks are captured, the impact force history is obtained during calculation. The simulation results compare well with the corresponding experimental outcomes in terms of the fracture patterns and impact force, which demonstrates the capacity of the proposed method to simulate the impact fracture behaviors of laminated glass. Both the two cohesive elements, used in brick and shell element respectively, are certainly accurate and computational efficient for the simulation of material failure.