Numerical simulation and validation of distributed impact events

An underwater explosion (UNDEX) validation methodology was presented in O'Daniel et al. (2002, Int. J. Impact. Eng. 27, 919), describing a process where precision impact tests were used to generate a response equivalent to the underwater structural response of a flat panel subjected to a blast wave. A critical part of the methodology was to validate the code LS-DYNA3D (LSTC 936 (1995)) for the explicit finite element analyses of the short duration elastic responses of aluminum and composite panels subjected to low velocity, line and distributed impact loadings. A line impact was used as a base to perform preliminary tests of the precision impact test system, and the distributed impact configuration was necessary to generate a response similar to an underwater blast wave loading. Once validated for that range of structural response under impact loading conditions, LS-DYNA3D could then be used to predict impact tests to find responses that were equivalent to the UNDEX response of the target. This paper presents a detailed description of the precision impact events, and a comprehensive coverage of the validation of LS-DYNA3D for those impact events. O'Daniel et al. [1] provides an explanation of the equivalence between impact and UNDEX, as well as the overall methodology. A precision impact test machine was designed and fabricated, and low velocity impact tests were conducted to experimentally determine the panel responses for each impact configuration. Overall, the numerical predictions correlated well with the experimental results. However, better correlation may be achievable if more complex hyperelastic material models are used for the rubber materials in the composite and the impactor, a more detailed representation of the test frame-distributed impactor interface is included, and a static preload is numerically included in the panel-to-support interface. Details of the panel configurations, general impact solution methods, numerical simulations, precision impact equipment and impact tests, and comparisons between simulation and test results are presented. Published by Elsevier Ltd.