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侧架和摇枕的质量是根据它们的抗疲劳安全系数来评定的。在计算、评估该系数时,应该使用零件的持久极限,而持久极限则要采用疲劳试验的实验方法来确定。车辆轴重的提高、研制有发展前途的货车转向架以及零件在运行中断裂数量的增加,都要求对现行的疲劳试验方法的若干状况加以详细的研究。对高强度新结构零件的试验,必须要在加栽更高的最大循环载荷下进行。但是,最大载荷与最小载荷之比取决于常量的平均栽荷。这样就不能使用平常试验用的栽荷。同时,在高载荷下,有可能产生塑性变形和残余压缩应力,从而导致试验数据升高,或致使零件发生损坏。因此建议:第一,要在循环载荷不平衡的某个固定系数下进行试验;第二,在新一代(新制)零件不会发生断裂的前提条件下,按照标准的加栽循次数来评估每一种试验载荷结果。业已确定,在夏季和冬季,运行中发生零部件的断裂实际上是一样的。就此而言,其主要特征是疲劳裂纹缓慢发展,且区域面积不大。这证明这里存在着很高的作用应力。对摇枕在+20℃和-60℃温度下所进行的疲劳试验表明,温度在零度以下可稍稍提高零件的抗疲劳性,从而延缓了疲劳裂纹的萌发时间。但是这会明显降低裂纹的临界面积,即降低零件的生存能力。在试验台和运行中所获得的规律可以解释侧架大多在1年中寒冷季节发生断裂的原因,即形成了临界尺寸的裂纹,并极快地扩展,然后在2次计划检修期间断裂。
The mass of sideframes and bolsters are rated based on their anti-fatigue safety factor. When calculating and evaluating this factor, the endurance limit of the part should be used, and the endurance limit is determined using the experimental method of fatigue test. The increase of vehicle axle load, the development of a promising freight car bogie and the increase of the number of fractures in operation of parts require the detailed study on some conditions of the current fatigue test method. The test of high-strength new structural parts must be carried out under the higher maximum cycle load. However, the ratio of the maximum load to the minimum load depends on the average load of the constant. This will not allow you to use the usual test load. At the same time, under high loads, plastic deformation and residual compressive stress may occur, resulting in increased test data or damage to parts. Therefore, it is suggested that the test be carried out at a fixed coefficient of unbalanced cycle load. Second, under the condition of no breakage of the new generation (new system) parts, A test load result. It has been established that in summer and winter, breaks in operation of components are virtually identical. In this regard, the main feature is the slow development of fatigue cracks, and the area is not large. This proves that there is a high level of applied stress. Fatigue tests on the bolster at temperatures of + 20 ° C and -60 ° C show that the temperature below zero can slightly increase the fatigue resistance of the part and delay the germination time of the fatigue crack. However, this will significantly reduce the critical area of the crack, reducing the viability of the part. The patterns obtained during test rigs and operations explain why most of the sideframes are broken during the cold season over a period of one year, ie, cracks of critical dimensions are formed and propagate very rapidly, then fractured during the second scheduled overhaul.