Optimized Design Of Automobile Tailor Rolled Blank Based On Hybrid Cellular Automata

With the development of the automotive industry,the requirements for designing lightweight and crashworthiness of the vehicle body are increasing.Tailor rolled blank(TRB)is an advanced manufacturing process,by which,it can rationally distribute the thickness to realize the design of lightweight automotive body structure and the crashworthiness according to the stress conditions of the structure.The TRB B-pillar is a typical body’s key collision force-transmitting structure and energy-absorbing component,which is composed of several constant thickness zones and thickness transition zones.However,the conventional numerical optimization algorithm cannot be used to deal with this multi-dimensional variable and non-linear problem,while the quantities and location of constant thickness zo snes in the tailor rolled blank as well as the thickness transition zones are unknown.The hybrid cellular automata(HCA)method is an effective way to solve the above problems.In this paper,a series of research work has been carried out on the thickness distribution optimization of TRB structure under bending loads based on the HCA method and the structural characteristics of TRB.The research work and innovative results of this paper are mainly reflected in:(1)The basic theory of the HCA method is studied which converted the design problem of maximizing the structural stiffness to the design problem of averaged strain energy density based on the equal strain energy density criterion.A finite element model of the square thin plate structure is established.The HCA method is used to design the structure with the element thickness as the design variable and the effectiveness of the HCA method is verified.(2)The quasi-static three-point bending test of hat-type beams is carried out and the finite element models of equal-thickness hat thin-wall structure and TRB hat thin-wall structure were established.The simulation results’ accuracy is verified and can be used to further optimization study.A one-dimensional cellular automata(ODHCA)method is proposed for optimizing the thickness distribution of TRB hat thin-wall structure under three-point bending conditions.It inherits the advantage that HCA does not have gradients while ensuring that the TRB structure meets the rolling process and successfully solves the problem of low efficiency of the conventional size optimization method.The thickness distribution of the TRB hat thin-wall structure is optimized by using the HCA method,the ODHCA method and the optimization method of the surrogate model.The results show that the specific energy of the optimal solution of HCA method and ODHCA method is higher than that of the optimal solution of the optimization method of the surrogate model.The optimized thickness distribution of the ODHCA method satisfies the flexible rolling process compared with the HCA method.The ODHCA method has obvious advantages in terms of computational efficiency compared with the optimization method of the surrogate model.(3)An improved ODHCA method is proposed in order to apply the TRB structure to the design of automotive B-pillars.The thickness distribution of the TRB B-pillar reinforcing plate was optimized based on the improved ODHCA method.Then,the lightweight and crashworthiness design of the B-pillar was achieved.The ODHCA method has a good guiding effect on the application of TRB B-pillars on the body-in-white,while it has theoretical and practical value.