Functionally graded materials (FGMs) are a new class of bio-inspired composite materials made from different material phases, in which their volume fraction changes gradually towards a particular direction. Accordingly, continuous changes in the composition, microstructure and porosity of the graded materials results in material properties gradients; for this reason, the material properties move smoothly and continuously from one surface to another, eliminating the interface problem. Hence, with appropriate design, FGMs can develop better properties than their homogeneous counterpart due to their better designability. One potential employment of FGMs is as damper or energy absorber in dynamic applications, in which optimization techniques such as the topology optimization method (TOM) can contribute to a better performance in relation to a non-optimized design. In this chapter, functionally graded structures are designed with and without the TOM in order to explore the advantages of the FGM concept in low-velocity impact condition, which is a special case in the world of dynamic analysis, and has interest for designing machinery parts and components.