Crashworthiness Research And Optimization Design Of TRB Hat-shaped Structure

In the 21 st century, energy conservation and environmental protection are the main challenges that the automotive industry suffers from. Fortunately, the vehicle lightweight technology can address these challenges effectively. Tailor Rolled Blank(TRB) is a effective lightweight technology, since it can decorate material reasonablely in term of the fact working condition and utilize the material more effectively. Furthermore, it also has the advantages such as low manufacturing cost, gently performance changes and high surface quality comparing with the widely used Tailor Welded Blanks(TWB). Therefore, it owns a huge latent force to apply in vehicle lightweight field. In order to promote the TRB application in vehicle body, the research about the crashworthiness of the TRB is urgent. In this thesis, the method combining numerical simulation and experimental validation is adopted. A series of works about crashworthiness of the TRB hat-shaped structure is conducted:(1) In order to probe the crashworthiness of the TRB hat-shaped structure, the equivalent mass’ specimens of common and TRB hat-shaped structure are designed and manufactured, respectively. The specimens are tested by quasi-static compressive experiment and dynamic axial impacting experiment. Based on the experimental results, in both loading cases, TRB can considerablely decrease the initial peak force under the premise of keeping energy absorption stable.(2) The material properties of TRB are studied by the uniaxial test. Then, based on the test data, the stress and strain field are constructed by interpolation method. The material parameters are identified by the field and used to construct the Finite Element model of TRB.(3) Based on the fact demension, thickness and material parameters of TRB hatshaped structure, the quasi-static compressive and dynamic loading Finite Element simualtion are implemented, respectively. Comparing the results from simulation and experiment, the accuracy and effectiveness of these FE simulation are verified.(4) The effects of each demension parameters on crashworthiness of TRB are studied by the effective FE models construsted before. In order to further improve the crashworthiness of TRB hat-shaped structure, the multi-objective optimizations for the quasi-static and dynamic loading case respectively are accomplished using surr ogates and NSGA-Ⅱ. In this study, the surrogates based on every single loading case are used in Multi-case optimization. In single case optimization, the optimized result is the best only for one case rather than all cases. Therefore, in real engineering problem, Multicase optimization can balance every cases and obtain a comparative optimized result for all cases.