Numerical Simulation Of Hail Impacting Aluminum Alloy Plate Using Ls-Dyna

High speed hail can cause serious damage to the aircraft and other aviation vehicles, and threaten its flight safety, so it is of great significance to study the anti-hail impact of aviation mate-rials. The experimental study and numerical simulation of single hail impact are mainly studied in the present literature [4-9]. In this paper, a hail model considering the strain rate effect is used, and a numerical model which combines SPH method and FEM method is adopted. A numerical model of single hail impact AA2014T4 aluminum alloy plate is created by LS-DYNA software, the results obtained from the numerical simulation are consistent with the experimental results in reference [5]. The numerical simulation of multiple hail impact is fulfilled after the accuracy of simulation is va-lidated. Through numerical simulation, the following conclusions are obtained:1. The maximum central displacement of the target plate which obtained from the numerical simulation fits well with the data of reference[5].The failure strain of aluminum alloy can be deter-mined according to the failure impact velocities of reference [5],then the split and penetration of aluminum alloy under high velocity hail impact can be simulated. It can be concluded from the nu-merical simulation that the displacement and effective plastic strain of aluminum alloy plate in-creases with the increase of hail diameter and impact velocity, while decrease with the increase of plate thickness.2.Numerical simulation of two hail impact with different central distance were carried out and the result shows that the compound damage intensified with the decrease of central distance. Nu-merical model of multiple hail impact is built using MATLAB and LS-PREPOST, the outcome shows that multiple hail impact can cause much greater damage than single impact, especially in the position where the central distance of hails is very small. It can be concluded that the numerical si-mulation of multiple impact should be done to assess whether the thickness of aluminum alloy is safe for hail impact.