Optimization of a Military Vehicle Space Frame Subject to High Impact Loading

Abstract

Space frames are usually used to enhance structural strength of the vehicle while reducing its overall weight. These frames are comprised of beams connected together at joints. Recently, space frames are incorporated in military vehicles. However, space frames in this case are subjected to different types of loading than what is encountered in civilian vehicles such as, projectile and land mine attacks. In this paper, a finite element model for the upper half of the space frame of an armored vehicle is developed. The space frame is composed of hollow square cross-section bars and angle sections and is enclosed by uniform-thickness armor, except at the turret. The vehicle is subjected to high impact load that simulates an impact of a projectile. The model is parameterized to minimize the mass of the space frame and vehicle armor by varying the cross-sectional parameters of the beam members and joints, and the thickness of the armor plate, while maintaining the overall structural integrity of the space frame. This problem is solved using the Successive Heuristic Quadratic Approximation (SHQA). This algorithm combines successive quadratic approximation with an adaptive random search within varying search space. The entire optimization process is carried out within MATLAB environment. Results show significant reduction of the mass of the vehicle.