摘要
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.
关键词
统计分析法
疲劳极限
建筑材料
疲劳强度
statistical analysis method
fatigue limit
confidence
survival rate.