Characteristics of windshield cracking upon low-speed impact: Numerical simulation based on the extended finite element method

Windshield glass crack characteristics are of great interest to vehicle manufacturers, safety engineers, and accident investigators, because they contain important information on energy mitigation, pedestrian protection, and accident reconstruction. We use the extended finite element method (XFEM) to analyze the model problem of low-speed head impact on a windshield plate. Both the radial crack and circumferential crack propagations are characterized. A parametric study is carried out to investigate the effects of impact speed, head mass, initial material flaw, material fracture criterion, etc., and correlate them with the crack direction and length. It is found that the critical accident information, such as the impact speed or damage stress, can be deduced from the crack pattern characteristics. A qualitative bridge can be established between numerical simulation result and real-world accident via the crack growth mechanism. Our study shows that XFEM is a useful tool for simulating several types of cracks that appear during quasi-static indentation or low-speed impact of foreign objects on windshield materials. (C) 2010 Elsevier B.V. All rights reserved.