Hierarchical optimization of a novel vehicle door system under side impact based on integrated weighting method

Door system plays a very important role in the domain of automobile passive safety. In order to improve its side crashworthiness, some affiliated impact components are assembled. Conventional impact parts can make the door system possess enough stiffness and strength so as to ensure the integrity of car body when side collision occurs. But for occupant protection, the excessive rigidity may increase the risk of occupant injury. To address this problem, this work first introduces a kind of negative Poisson’s ratio (NPR) structure, and proposes a novel door system which is composed of NPR energy-absorbing block, NPR impact beam, inner panel, outer panel, and reinforcing plate. Next, parameter sensitivity analysis for each performance index is conducted to determine the corresponding variables when constructing the approximate model. Then, aiming at the disadvantages of the Technology for Order Preference by Similarity to Ideal Solution (TOPSIS) and the Mean Square Deviation Method (MSDM) in processing performance index data, a novel integrated weighting method is used to determine the weighting coefficient of each performance index. Finally, considering side structural crashworthiness, occupant protection, and lightweight, the hierarchical optimization for the novel door system is conducted to further enhance its overall performance. The result demonstrates that compared with the conventional door, the optimal door can improve the performance of occupant protection and ensure the side crashworthiness more effectively.