Traditionally, design and optimisation of components for structural requirements and strength have been performed based on static load hypotheses. However, today products have to comply with a great number of specifications. One of the most important ones is the dynamic load strength and impact events analysis. The automotive industry is a clear example of this situation.
Designing components for impact presents a different concept when compared to static design. Generally speaking, the impact load supported by the system is unknown. It becomes the variable that needs to be determined by the analysis, whereas the load conditions are normally expressed in terms of displacement, velocity or acceleration (initial and boundary conditions).
Another special feature of impact design is the result of the high velocity load application, and this fact leads to two main consequences. First, the mass of the system plays an important role in dynamic equations and, consequently, inertia and wave propagation effects become crucial in the response. Also, material behaviour is strain-rate dependent, and generally speaking, when the velocity of deformation is increased, the materials become stiffer (higher stress level correspond to equivalent strain) and less ductile (ultimate strain is reduced).