Finite Element Analysis for Impact Tests on Polycarbonate Safety Guards: Comparison With Experimental Data and Statistical Dispersion of Ballistic Limit

Design and testing of machine guards are provided by international standards in which the inadequacy/suitability of the tested materials for machine guards is obtained by the perforation/nonperforation of the guard in an experimental test at the maximum foreseeable speed of a standardized projectile. Uncertainties and limitations of this standardized test are known by researchers, but a better testing procedure is not already agreed on the standardization level. In this paper, finite element analysis of the impact of three different projectiles of a given mass on polycarbonate guards is presented and compared with experimental tests made using a standardized gas cannon. The good correlation found in terms of ballistic limit, energy absorbed, and residual velocity is presented trying to open the discussion to a “probability of perforation.” Moreover, a statistical analysis of experimental results, based on a nonlinear regression model, is briefly introduced. The penetration behavior is described by the well-known Recht and Ipson equation, and an evaluation of the statistical dispersion of the ballistic limit for each type of projectile is presented through the calculation of confidence intervals. This article is available in the ASME Digital Collection at https://doi.org/10.1115/1.4047464.