Naval Research Laboratory has been developing measurement devices to study the dynamic response of the human body, commonly known as GelMan technologies in publications. This technology is currently being extended to upper extremity designs (GelMan-Upper Extremity, Figure 1a), consisting of upper arm and forearm with surrogate bones connected by a spherical joint and surrounded by generalized surrogate tissue. Computational low speed localized impact tests on the arm surrogate have been performed and compared to corresponding experiments. The outcome of this analysis can simulate the structural response of the arm, thus providing insight into preventing or mitigating injuries sustained from car accidents, sports and/ or battlefield injuries. A modal analysis and low speed impact transient analysis have also been performed on the arm surrogate constrained at the shoulder using the finite element program ABAQUS (Figure 1b). Linear elastic material properties from open literature are used for each arm component for the analysis using three dimensional, 8-noded hexahedral elements. Modes of vibration below 500 Hertz and strain-based frequency response have been obtained. A transient analysis of the arm is also being performed; von Mises stress contours, displacements and pressures inside the arm and total arm kinematics are extracted. These computational models have been validated with low speed, localized impact experiments using surrogate arm. Impacts of 10 N peak load are applied to upper arm and forearm of the surrogate model for 1 to 3 millisecond duration. Mode shapes of the arm are observed using a high speed camera and strain based frequency response curves are obtained. Experimental data (pressure and displacements) from transient test of the arm is compared to computational analysis. Agreement between the computational and experimental arm models provides a means for more advanced arm designs and loading situations.

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