Research On Composite Impact Attenuator Of FSAE Vehicle

In the field of racing, it will produce great impact energy when c ollision accidents of the racing cars with high speed happen. Therefore, it is required that specific buffering device should be installed at the front of racing car to absorb the impact energy and protect the safety of drivers. Composite materials own goo d energy absorption properties and high designability and can improve the safety performance of extreme sports car. Based on Formula SAE racing car which is targeted towards college students, the energy absorbing properties of composite impact attenuator are explored in this paper. FSAE composite buffering energy-absorbing lightweight structure are got by reasonable failure process optimization.To design and predict the energy absorption performance directly of composite structures under impact load has a certain difficulty, because under different failure modes the energy absorption efficiency are also different and the anisotropic characteristics of composite material is complex. Consequently, this paper starts from the composite thin-walled cylindrical shells which are set as the standard for composite energy absorption components. A complete comparative quasi-static compression tests are developed on simple composite tubes with varied lay-up, varied thickness and varied type of fiber. According to the ex perimental data of load-displacement, how the factors affect energy absorbing capacity are discussed and failure mechanism of the composites in the process of crushing are concluded. Based on the experiments, the influencing factors and variation are analyzed and the design principle of composite impact attenuator are given.According to the results of the quasi static experiments of the the composite cylindrical shells, the finite element models for typical lay-ups are established using the method of numerical analysis. Through the nonlinear dynamic finite element software ANSYS/LS-DYNA, the damage and the energy absorption of the composite structures under quasi-static compression, as well as dynamic impact condition, are simulated. Based on the comparison and analysis between these two conditions, the energy absorption characteristics are discussed for groundwork of the next design and optimization of the FSAE buffering structure.On the basis of energy absorption characteristics of composites, the requirements of the FSAE rules and the need of the whole vehicle’s arrangement, the preliminary design for the impact attenuator is first done. According to this preliminary design, optimization is divided into structural optimization and lay-up optimization. Through the optimization software LS-OPT, on the basis of the method of response surface analysis, the structure is optimized to get the composite impact attenuator model with the highest specific energy absorption(SEA). Then with the constraint of the maximum acceleration, energy absorbed and the average acceleration, the lay-up of model is further optimized to get the final lay-up with the minimum quality. Finally, the composite FSAE impact attenuator with high efficiency of energy absorbing, high specific energy absorption and light weight is achieved. Furthermore, process design is conducted and mold and product are also manufactured. At the same time, quasi static axial compression tests and the dynamic drop weight impact tests are conducted to verify the optimization design. The results of these two tests prove that the final composite impact attenuator satisfies the safety requirement of the FSAE car.