충돌 조건에서 경충돌안전장치용 인장볼트의 하중 측정

Abstract

The tension bolts are adopted as mechanical fuses in crash condition of the light collision safety devices. The tension bolts sustains the initial crash load from the coupler, frontal equipment of the light collision safety devices, After the energy absorption of the coupler ends, the tension bolts fails at designed fracture load and the main energy absorption mechanism of the light collision safety devices starts finally. The maximum load of single tension bolt is designed as 375 kN at the crash condition. Therefore the crash tests of the tension bolts are performed at 9.5 m/sec(34.2 ㎞/h), i.e. about the targeting speed of the light collision safety devices. The load measurement of the tension bolts was a challenging issue because of the load ringing phenomena caused by heavy mass and extremely short test duration the crash test. Load signal is measured from strain gauges attached directly on the tension bolts to eliminate the load ringing. Experimental result demonstrates that the load measuring system using strain gauges diminishes the load ringing dramatically. Measured fracture load of tension bolts was about 410 kN consistently for six tension bolts. Numerical analysis of crash tests was also carried out with dynamic material properties of SCM440H, The results of the numerical simulation showed close coincidence with the experimental results, which are maximum load, duration and energy absorption.