철도 차량용 티어링 튜브의 충돌 에너지 흡수 능력 예측 기법

Abstract

This paper deals with the numerical prediction of energy absorbing capacity of a tearing tube, which can absorb the crash energy through expanding and axial splitting process. It is important to consider the dynamic material behavior and fracture characteristics of tube material in order to simulate accurately the deformation behavior of tearing tube. Therefore, uniaxial tensile tests are performed in order to obtain the flow stress curve and fracture strain of tube material according to strain rate. Quasi-static tensile tests were carried out in the range of strain rate from 0.001/sec to 0.01/sec using the static tensile testing machine. Dynamic tensile tests were conducted at the strain rate ranged from 0.1/sec to 300/sec using the high speed material testing machine. These dynamic material properties are applied to finite element analysis through user material subroutine of ABAQUS/Explicit. Especially, ductile fracture criterion is applied in order to describe the fracture characteristics of tube material during axial splitting process. Dynamic tearing cases are simulated and the reliability of the numerical results is verified by comparing with the experimental result in dynamic tearing test. The simulated results predict accurately the onset of fracture in axial splitting process and the energy absorption capacity has a good agreement with experimental result.