STUDY ON THE KEY TECHNOLOGIES OF CONTROLLING METHODS FOR DECELERATION CURVES OF CHILD RESTRAINT SYSTEM'S DYNAMIC TEST

• 1、China Certification Centre for Automotive Products,China Academy of Machinery Science&Technology,Beijing 100044
• 2、China Certification Centre for Automotive Products,China Academy of Machinery Science&Technology,Beijing 100044

Abstract：The purpose of the study was, by simple and effective means, to ascertain the influencing factors for the deceleration curves of child restraint system's dynamic test, and find a solution to generate the required deceleration curves conveniently, thus optimizing test impulses by adjusting part or all of the according factors, with the fewest tests and the lowest cost. The study was based upon Proe-Ansys-Lsdyna modelling and solving technique, and tests were carried out to verify the reliability of the simulation scheme. After the verification, part or all of the factors affecting the deceleration curves in dynamic tests underwent proper adjustments, and they could include the steel pipes' thickness, slope, heat treatment process, the trolley's weight, velocity, and the size of sliding block's hole, etc. When all the factors influencing deceleration curves in tests were ascertained, a method which could conveniently and effectively produce deceleration curves for the deceleration-type trolley which is generally cheaper and therefore more popular with laboratories and factories of small scale, was then recommended to optimize the required curves in child restraint system's dynamic test by comparison between influences of the factors upon the curves in simulation. Furthermore, the feasibility of other similar energy-absorbing methods was explored. However, the study depended to some extent upon simulations which were adopted to minimize the number of dynamic tests and to reduce the test cost, with tests of limited number for verification. Although the tendencies of curves in simulations and tests resemble each other, the ideal type of simulations would unavoidably be affected by the complexity of test conditions, i.e., simulation results could not be identical to test ones because of even tiny changes in test conditions. Meanwhile, the method to generate deceleration curves was limited to deceleration-type trolley only. Nevertheless, steel pipes with different slopes, thicknesses and yield stresses, together with other parameters concerned such as trolley's velocity, weight and the size of sliding block's rectangular hole could be combined to control the shape of deceleration curves easily, thus fulfilling the according requirements of deceleration-type trolley. Finally, deceleration curves required by child restraint system's dynamic test can be generated successfully by means of changing the parameters of pipes and trolley, and the adjustment is simple and effective.

Keywords： transportation safety engineering child restraint system dynamic test deceleration trolley steel pipe