Research And Optimization Design Of Whipping Performance Of Front Row Driver Seat Of A Commercial Vehicle

With the increase in the number of cars,various types of traffic accidents occur frequently.Some of them are rear end collisions,which are mostly low-speed collisions.Although the mortality rate is low,the injury rate is high,and it is easy to cause whiplash injuries to the human neck.The series of personal and social losses generated should not be underestimated.The experimental method for studying the mechanism of human neck injury has low efficiency and high cost.The development and progress of numerical simulation technology provide a new way to reduce costs and increase efficiency for the study of whiplash injuries.A company conducted a whip test on the front driver seat of a commercial vehicle and obtained a CNCAP score of 3.358,where the dummy neck injury value NIC and the dummy upper neck torque M＿The individual score ofis 0.812 and0.944.The enterprise design requires that the product seat whip test score be above 4points,so it is necessary to optimize the seat.This article uses Hyper Mesh software to preprocess the seat model,and OASYS Primer software to construct the dummy and seat belt finite element model.The dummy state and posture in the finite element model are set according to the C-NCAP2021 whip test procedure to maintain consistency with the actual test of the seat.After obtaining simulation results through LS-DYNA software,the reliability and feasibility of the simulation model were verified from four aspects:static size measurement,dummy motion posture,evaluation index time history curve,and whip score.The finite element model of the seat was used to analyze the reasons for the loss of points and explore the influencing factors.Six research factors were selected:headrest clearance,head height,headrest rod stiffness,headrest stiffness,seat back stiffness,and seat back rotation stiffness.Through multiple sets of simulation experiments,the influence of various factors on the score of the whip test was studied.The head back gap and head height have a significant impact on neck injury,and appropriately reducing the head back gap and head height will reduce the neck injury value;The wall thickness of the headrest rod affects the stiffness of the headrest rod,and using a headrest rod with a larger wall thickness can help improve seat performance;By adjusting the stiffness of the headrest,seat backrest,and angle adjuster,the results of the influence of each parameter on neck injury were obtained.Based on the analysis results and combined with a large amount of engineering practice experience,a total of nine design variables were selected.The optimal Latin square was used to conduct 100 sets of sampling within the variable value range.The polynomial response surface method was further used to construct an approximate model for the seven evaluation indicators required for output,and R2Verify the accuracy of the established approximate model.The NSGA-II algorithm was used to perform multi-objective optimization on the seat based on the optimal Latin square experimental design and response surface approximation model.After iterative calculation,the optimal solution of the design variables was obtained.Ultimately,the C-NCAP whip test score for the seat was raised to 4.15 points,improving the whip performance of the seat and meeting the requirements of the enterprise product design.