Lightweight crash energy absorber design using composite materials

In an ongoing effort to increase the effectiveness of crash energy absorbers, thus improving the safety performance of cars, the interest in automotive industry in exploring lightweight alternatives to aluminum is deepening. In view of weight reduction, the research on composite materials has grown quickly because of their higher energy absorption-to-weight ratio. In the present work fiberglass composites with different shapes, types of fiber and stacking sequence are considered and analyzed by means of experiments and numerical simulations. At first, tension, compression, and shear properties of the materials are evaluated. Their dynamic properties are also investigated by drop testing according to ASTM D7136 standard. At a later stage, drop-tests are performed on cylindrical composite specimens in order to simulate the crash absorbers dynamic behaviour. Although the cylindrical specimens are not adhering to the standard, the drop tests allow to correlate the experimental data with the numerical simulations. Finally, in the light of the previous dynamic results, the stacking sequence of the composite crash absorbers is numerically optimized by means of design of experiments and optimization techniques for different geometrical shapes. Those considered are simple regular shapes, namely: circular, hexagonal, and octagonal.