TY - JOUR TI - Nonsmooth impact mechanics of a free falling body DO - https://doi.org/doi:10.7282/T3NS0THK PY - 2011 AB - In this study, several models are developed for analyzing the oblique impact of a container dropped from a height above the impacting surface. The governing equations for impact of rigid bodies in the presence of friction are developed. A clear relationship for determining sliding behavior is presented. For both frictional regimes, the dependence of the energy loss on the initial parameters is analyzed. Several vibrational impact models are presented and analyzed. These models produce a transient description of the impact force and aid in the determination of the ratio of the cushion and cargo stiffness which produce the best impact outcome. The effect of aerodynamic drag prior to impact is also analyzed. The equations governing the aerodynamics form a set of coupled nonlinear differential equations. The numerical solution of these equations illustrates that there exists a point where the object’s velocity reaches a favorable minimum, which is substantially below the terminal velocity. An approximate solution, obtained by decoupling the aerodynamic equations, is presented and validated. Both the rigid body impact mechanics and the aerodynamics are combined in a simulation code capable of analyzing subsequent impact. The simulated tumbling distances for a container, which was designed for the U.S. Army, are compared to experimental drop test data. The results validate the use of the rigid body model for this type of container. KW - Mechanical and Aerospace Engineering KW - Nonlinear mechanics KW - Force and energy KW - Tribology KW - Contact mechanics LA - eng ER -