Mean stress effects in pressurized steel blocks were examined under constant amplitude fatigue loading. The tests were performed to provide experimental data needed to study the effect of mean stress on fatigue lives of subject specimen, and to substantiate the use of analytical expressions to account for the mean stress. The mean stress was the result of subjecting the specimens to an autofrettage pressure which induced compressive residual stresses at the crossbore intersection of the specimens. Fatigue tests were carried out under both tensile and compressive mean stress levels. Test results were compared to several mean stress accounting relationships such as the Smith-Watson Topper, Bergmann and Seeger, modified Goodman, Gerber and Soderberg. Test results indicated that the modified Goodman equation is favorable in accounting for the effect of both tensile and compressive mean stresses on fatigue life (up to a compressive mean stress to ultimate stress ratio of −0.2). The behavior under compressive mean stress to ultimate stress ratio of less than −0.2 indicated that a linear correction relationship was required.

在恒定振幅疲劳载荷下检查加压钢块中的平均应力效应。进行这些测试是为了提供研究平均应力对受试试样疲劳寿命的影响所需的实验数据，并证实使用解析表达式来解释平均应力。平均应力是使试样承受自应力压力的结果，该压力在试样的交叉孔交叉处引起压缩残余应力。疲劳测试在拉伸和压缩平均应力水平下进行。测试结果与几种平均压力核算关系进行了比较，例如 Smith-Watson Topper、Bergmann 和 Seeger、修正的 Goodman、Gerber 和 Soderberg。测试结果表明，修正的古德曼方程有利于考虑拉伸和压缩平均应力对疲劳寿命的影响（压缩平均应力与极限应力比为 -0.2）。压缩平均应力与极限应力比小于 -0.2 时的行为表明需要线性校正关系。