Dynamic And Static Performances Anaysis Of A BIW Based On Non-Probability Reliability Method

The bend stiffness, torsion stiffness and the mode performance of the BIW are important mechanical indexes of the minibus, which are relevant to the safety, the ride comfort and the handling stability of the vehicle. They should satisfy certain standard during the design process. But as a fact, uncertainty widely exists in the practical engineering problems, which makes the real performance of the minibus unstable. As a result, some may not satisfy the standard and lead to a failure. Accordingly, it is significant to introduce the reliability analysis method into the design of the minibus.This dissertation conducts a relevant research for the reliability analysis, and aims at contributing an efficient way to evaluate the design target of the minibus. Accordingly, the following studies are carried out in this dissertation:(1)In this dissertation, the testified finite-element model of the minibus was established. Firstly, we introduced the main procedure of the finite-element modeling, and then an approach of estimating the scale of the FE model was constructed. The size of the element is determined with respect of the efficiency and the accuracy. Secondly, the principle of processing the special features of the structure is stated, such as the hole, the boss and the ribs. Finally, we compared calculation of the bending stiffness, torsion stiffness, the mode frequency of the minibus through FE method with the data of the relevant experiments. It is showed that the FE model possess high accuracy.(2)Combined with the latest progress of the reliability theory, non-probability reliability method was proposed to analyze the stiffness and mode performance of the Body-in-White (BIW). Then the reliability of the stiffness and the mode performance of the minibus were calculated. Firstly, the thicknesses of the plates which greatly affect the stiffness and mode performance of the minibus were chosen as the uncertain parameters, and then their fluctuation ranges were determined by the National Standard. Secondly, the Latin Hypercube method was employed to generate samples and the stiffness and mode performance of each sample is calculated. Thirdly, three second-order respond surfaces were established describing the stiffness and mode performance respectively, and then the reliability of each performance is calculated. Finally, the reliability results were analyzed.In this dissertation, the non-probability reliability method was applied to analyze the stiffness and mode performance of the minibus. The influences of the uncertain parameters were evaluated, and instructions were delieverd to make sure the performance of the minibus more stable.