Modeling Net Capture of an Object in LS-DYNA

One way of capturing a moving object is by using a hanged cage-like net. The process is to be reliable under various impact velocities and orientations of the captured body. Thus, accurately modeling its dynamics is vital due to the need to account for multiple probable outcomes while including the complex net structure. The focus of the present work is on the modeling, characterization and calibration of the net and its motion. To best represent the geometric properties of the net, its initial state, motion, and body capturing procedure, the following stages were carried out. First, a beam-element-based model of the net was constructed in MATLAB® using a generative function, that allows simple generation of a multiple-parameter dependent net structure. This was due to the need for flexibility in dimensions, geometric properties, part allocation and base unit cell shape. Second, mechanical properties of the hyper-elastic unique net structure were characterized by a series of tensile experiments followed by properly choosing LS-DYNA elements and material formulations. Finally, two sets of finite element analyses (FEA) were conducted, where the first included folding the net to determine its initial state for the successive impact simulation. Both folding and impact procedures required careful consideration and examination of different aspects, such as contact types and formulations, mechanical forces and damping.