The Research On Damage Tolerance Of C80 Heavy-duty Train’s Bolster And Side Frame

Bolster and side frameare important parts of the bogie frame trucks, serving under dynamic loading, fatigue crack is the main failure mode. Based on the measured load spectrum of the bogie line of C80 heavy-duty train, this paper uses damage tolerance approach to study problems of crack growth and residual life. It is significant to ensure the railway transportation safety and save maintenance costs. The main contents are as followeds:(1)According to the steering frame load testing of C80, it makes one level 16 bad spectrum of center plate bad and side bearing and vertical side frame bad. It is a 1640km long spectrum of around trip from S he nmu North to Huanghua Port. It getsthe load characteristics by analysis.(2) Based on actual bad spectrum, it conducts finite element simulation on the swing bolster and side frame respectively. According to the analysis of calculation results, it gets the weak parts. The high-stress area of the swing bolster is mainly around the drain hole, the center hole of the center plate, the lower surface of area A and the wedge slot The high-stress area of side frame is mainly around the inside corners of guide chase, spring bearing seats and testing holes of the side frame. It also does the investigation and analysis of cracks in bolsters and side frames. Compared the results of simulation with investigation, we can find the agreement Choose the drain hole of the swing bolster and side frame inside corners to do crack analysis, which provides evidence to the crack growth law and extended life.(3) It introduces the influence factors of crack expansion, including initial crack size, fracture toughness, stress intensity factor threshold value, and crack safety sizes. Selecting shake piflow drainage hole and side guide frame inner bent angle to establish crack model, it respectively calculate the crack stress intensity factor, and analyze the crack characteristics of stress intensity factor. Also study the relationship between stress intensity factors and crack shape, bolster and side frame drainage holes in the corners, under the same crack depth and crackshape bigger, less stress intensity factor.(4) this paper, establishes fatigue crack propagation model by formula Paris. Combined with the existing crack tip stress intensity factor, It researches the changing of crack tip stress intensity factor and the crack growth rate with the changes of crack size and shape ratio and crack propagation rule da/dN-AK curve. Besides in this paper it calculates the remaining life of swing bolster and side frame. It provides the scientific basis for maintenance cycle of C80 heavy-duty train swing bolster and side frame.