Research On Main Influence Factors Of Predicting Heavy Axle-load Freight Car Body’s Fatigue Life

ABSTRACT:Development of overloading is effective to improve the railway transportation capacity. Due to overloading, freight car’s fatigue strength becomes stricter. Security can be improved by predicting heavy axle-load freight car’s fatigue life accurately; production and maintenance cost can be decreased. Different S-N curve or fatigue load spectrum, fatigue life predicted will make a gigantic difference.Freight car of axle load40t gondola car (abbreviated as FMG ore gondola car) that is exported to Australia is the object in this paper. And how S-N curve or fatigue load spectrum influence on FMG ore gondola car body’s fatigue life was researched.The material of FMG ore gondola car body’s profiles is Q450NQR1, slippery plates, rough plates and welding joints specimens were make with the same material. Three groups of S-N curve were draw with fatigue text dates. And according to slippery plates or rough plates S-N curve and load spectrum of90.7t hopper car provided by AAR, FMG ore gondola car body’s fatigue life was evaluated, and effect of S-N curve on FMG ore gondola car body’s fatigue life was analyzed.The axle-load of FMG ore gondola is40t, its traction tonnage is38400t. Load spectrums provided by AAR were texted under lower axle-load and traction tonnage. When evaluating fatigue life, the damage under vertical load is converted according to the linear relationship of axle load, but for damage under longitudinal load, there isn’t related theory to describe the effect of load spectrum under different traction tonnage on predicting fatigue life. FMG ore gondola car body’s longitudinal damage were calculated according to coupler load spectrum under general line, coupler load spectrum under daqin line, FMG ore gondola car coupler load spectrum and90.7t hopper car coupler load spectrum provided by AAR. And effect of coupler load spectrum under different traction tonnage on FMG ore gondola car body’s longitudinal damage was analyzed.