铝合金缺口试样非对称循环疲劳极限的估算

THE ESTIMATION OF UNSYMMETRICAL CYCLE FATIGUE LIMITS FOR ALUMINIUM ALLOY NOTCHED SPECIMENS

提出了铝合金缺口试样非对称循环疲劳极限的估算公式，铝合金缺口试样等寿命曲线方程，以及用等寿命曲线方程绘制铝合金缺口试样非对称循环的Ｓ—Ｎ 曲线和等寿命图的新方法。只要测得材料在对称循环（ｒ＝ － １）下的Ｓ—Ｎ 曲线，就可以用等寿命曲线方程绘制材料非对称循环的Ｓ—Ｎ 曲线和等寿命图，为疲劳强度估算和寿命估算提供依据。用等寿命曲线方程绘制等寿命图与传统方法相比可减少６０％ ～７０％ 的疲劳试验量。

The estimating formulae of unsymmetrical cycle fatigue limits for aluminium alloy notched specimens are put forward. Also presented are the constant life fatigue curve equations for aluminium alloy notched specimens. Based on the proposed constant life fatigue curve equations of aluminium alloy notched specimens, a new method was presented in this paper by which unsymmetrical cycle S-N curves and constant life fatigue diagrams of aluminium alloy notched specimens can be drawn. The material's S-N curves under unsymmetrical cycle and its constant life fatigue diagrams can be drawn as long as the material's data of S-N curves under symmetrical cycle ( r =-1) are determined. This approach provides a basis for the estimation of fatigue strength and life. In comparison with the traditional approach, this method of drawing constant life fatigue diagrams by constant life fatigue curve equations can decrease the amount of fatigue experiments by 60%～70%.