Evaluation of ballistic events using a moire fringe image processing methodology

摘要

Abstract: This paper describes a Moire fringe based image analysis system that was developed to determine the out-of-plane deformation of target plates impacted by high velocity projectiles. Due to the highly dynamic conditions that occur as the results of these impacts, such data are very difficult to acquire and analyze. Nevertheless, they are essential for the evaluation of armor materials designed to minimize behind- armor debris, and to study the fracture effects of very strong yet brittle advanced armor materials. Additionally, the data sought is required for fundamental verification of computational material models meant to simulate failure in ballistic experiments. The major goal for developing such a system was therefore to image and analyze the three- dimensional high-speed deformation, fracturing, and propagation of fractures that leads to the onset of fragmentation of targets during impact. The specific image processing methodologies discussed include noise reduction, automated and assisted Moire fringe finding, and the remapping of two-dimensional fringe patterns into three-dimensionally distorted surfaces. Results of applying the image processing system are also provided and methods for increasing system robustness in the presence of higher levels of noise are also discussed. !9