Study On Multi-objective Optimization Design Of Commercial Vehicle Cab Based On Crash Safety

The cab is an important part of commercial vehicles.National regulations on energy conservation and emission reduction are stricter.Meanwhile,with the increasing demands of consumers on cab safety and comfort,designing a new cab that is safe,comfortable,consuming less energy and having low pollution becomes a research hotspot in the industry.The traditional method focuses on the structural characteristics of the cab itself,less involved in the study of occupant safety and survival during a crash.This paper proposes an optimized design of the cab structure based on crash safety to provide a reference for solving related engineering problems.This paper took a commercial vehicle cab as an object and studied the cab quality,bending and torsional stiffness characteristics by establishing a cab body-in-white finite element model;on this basis,the crash simulation of the cab model was carried out according to ECE R29-03 regulations and the changing trend of the occupant’s living space were explored.Studies have shown that there is room for further optimization of the cab quality,and collision safety performance does not meet the requirements and needs to be improved.In order to accurately extract the key parameters that affect the performance of the cab,based on the random forest classification method,the influence mechanism of the thickness of the cab structural components on the crash safety performance index of the cab was discussed.The effectiveness of this method was verified by numerical examples and engineering application cases.Combined with the relative sensitivity and random forest algorithm,the key design variables of cab structure optimization were screened out to provide parameters for subsequent optimization calculations.In view of the complexity of the cab model,in order to improve the calculation efficiency and ensure the calculation results are accurate and effective,a parallel multi-point Kriging approximate model optimization method was proposed.This method is based on the global optimization method of the Kriging model,and it expands its optimization range by adding a search for the region of the maximum value of the predicted value,combined with the method of selecting multiple EI peak points as improvement points to increase its optimization speed.Three sets of numerical examples verified the feasibility of the method.Finally,based on the extracted cab variable parameters,the parallel multi-point Kriging method was used to build an approximate model,and the cab quality and the worst safety performance indicators were taken as the objectives,combined with the NSGA-Ⅱ multiobjective optimization algorithm,the cab was multi-objective optimized.The results of the study show that the crash safety performance of the cab has been effectively improved,the worst performance index has been increased by 63.45%,the quality of the cab has been reduced by 5.9%,and the lightweight effect is obvious.It shows that the optimized cab design method based on crash safety proposed in this paper is accurate and effective,and has important engineering application prospects.