Impulsive responses of functionally graded material bars due to collision

We investigated the ability of functionally graded materials (FGMs) to absorb impact energy by mathematically analyzing the impulsive responses of functionally graded (FG) bars colliding with a homogeneous bar on the basis of Laplace transformation and calculated by using numerical transformation and its inversion. Young’s modulus in the FG bar was assumed to be proportional to the square of its density, which was similar to foam materials. Results showed that maximum impact loads were not strongly dependent on the distribution of material property in the FG bar. In the FG bar with increasing modulus from the impact end to the fixed end, much larger compressive stress and even large tensile stress occurred near the fixed end compared with the ones in the homogeneous bar. In the FG bar with decreasing modulus from the impact end, the compressive stress was approximately the same as the one in the homogeneous bar, and the history of the stress varied regularly.