Analysis of Accelerations in a Dynamically Loaded Tactical Shelter.

摘要

A finite element model used for performing static analyses of a two-for-one tactical shelter was modified so that it could be used for dynamic analyses. Discussions on the construction of the mass matrix and the choice of a proportional damping matrix are given. Low frequency undamped free body vibration mode shapes are determined. Dynamic loads for use in an analysis of an end drop are determined by analyzing a rigid shelter impacting a continuous series of springs at an angle. A time difference between the peak acceleration response at the impact end and at the center of the floor was found both numerically and experimentally. Computed floor stresses for both soft and hard impact surfaces are presented. Data from a Belgian block test is presented. The Belgian block test is numerically simulated by enforcing a pitching and rolling motion of the ISO fittings (attachment points to the mobilizers). All transient calculations were made by integrating the equations of motion by the Newmark methods using the COSMIC* NASTRAN program. (Author)