用统计分析法确定材料的最低疲劳强度

The minimum value determination of fatigue strength of materials using statistical analysis method

根据应力幅与材料疲劳寿命之间在双对数坐标上的线性关系，本文对４５号钢作了旋转弯曲疲劳试验，将静拉伸时的真实断裂应力σｆ及其寿命Ｎ＝ｌ／４作为理论点，与一个应力水平及其寿命得出的试验点连成直线，作此直线的延长线，并与ｌｏｇＮ０的纵线相交，得到σ－１的计算值，然后对一系列的σ－ｌ值作统计分析，可以获得在给定置信度和存活率下材料的最低疲劳强度．

In acoordance with the linear relation between stress amplitude and fatigue life in the double logarithmic coordinate, the rotating bending fatigue tests of steel No. 45 were made. The true rupture stress σf and its life N= 1/4 are regarded as a theoretical point, which is jointed to the test point of single-stress level and its life to form a line. Extrapolating this line and intersecting with the vertical line of logN0,σ-1 can be obtained. Then, using the statistical analysis to a series of values of σ-1, the minimum value of fatigue strength of material under the given confidence and survival rate can be determined.