Study Of New Child Restraint System Parameters Based On Three Crash Cases

With the increasing numbers of vehicle inventory, traffic accidents also occurfrequently. The child safety problem due to mismatch of the restraint system andoccupant size has aroused the wide attention of people. The traditional automotiverestraint device is developed based on adult body size, but it can’t reach the expectedprotection in the event of a vehicle collision, and may even cause some additionaldamage for smaller child occupant. Integrated child safety seat for use in vehicles, dueto the direct integration in the adult seat, and working with three point type adult seatbelt, therefore, it can avoid the misuse of the child seat effectively. The existingintegrated child safety seat has a widespread disadvantage of occupying adult seatposition and the cushion can not match different child occupant automatically.Based on the study of a new integrated child safety seat for automobile havingpassed the national patent application, and it had been certified to provide effectiveprotection for3~10child occupant. On the basis of the new integrated child safety seat,to achieve the best protection in crashes, with6years old child occupant as theresearch object, using a validated integrated child safety seat restraint system model,firstly the strength analysis for the seat cushion adjusting mechanism of the seat wascarried out, and then the Latin Hypercube, Orthogonal, Uniform test design andResponse Surface Model method were performed separately to optimize and design thenew child restraint system parameters of seat cushion height, depth and so on in threedifferent vehicle crash conditions of frontal collision, side collision and rear-endcollision, and the optimized results were verified and analyzed comparatively.The results showed that, the new integrated child restraint system could effectivelyimprove the protection performance of child restraint system in three typicalindependent collision conditions, and reduce child occupant injury in traffic accidents,and could provide the best protection for children. The optimization analysis ofsimulation results fixed the conditions of the optimal matching design in three cases.In frontal crash condition, that height of the seat cushion was0.145m and depth was0.129m was the best matching design, where the peak value of child head resultantacceleration decreased by15.52%, and the peak value of chest resultant accelerationdecreased by20.39%. In side crash condition, that cushion stiffness decreased by20%,cushion friction coefficient was0.3, upper fixed-point height of the safety belt was 0.325m, and the webbing stiffness reduced by20%, where the peak value of child headresultant acceleration decreased by13.40%. In rear-end crash condition, that headreststiffness increased by20%and seat cushion stiffness increased by20%was the bestmatching design, where the peak value of child head resultant acceleration decreasedby9.398%, and the peak value of chest resultant acceleration decreased by16.06%.The results of this study had certain reference significance on the study of childrenoccupant injury protection at home.