대차프레임 구조취약부 균열평가를 위한 응력확대계수 계산

초록

In this paper, we propose a stress intensity factor, SIF calculation method on a cracked railway bogie frame. For this purpose, we built a 3D FE model of railway bogie frame with shell elements and performed structure analyses to find structurally vulnerable points, following UIC code. The hot spots were compared with physical crack locations, found at the railway bogies which had over 20 years commercial line operation history. Base on the structure analyses results, we modelled a three dimensional crack on the railway bogie frame to calculate the SIF. Also, we suggested a sub-modelling method to calculate SIF by using the FE model for structure analysis. And the sub-modeling method was verified by comparing the analyses results from full FE model which was meshed from the geometry model of bogie frame. The proposed sub-modelling method shows reasonable correlation. Base on the calculated SIF, the integrity of railway bogie frame was analyzed. We found that the calculated SIF was low compared to the fracture toughness of bogie frame material. Therefore, we can expect that catastrophic failure due to crack propagation is hard to occur in given operation condition.