Failure of materials subjected to torsional and axial cyclic loading is studied by applying the principles of thermodynamics of dissipative processes. Extensive experimental tests are conducted using stainless steel (SS) 304 and SS316 materials to gain insight into both torsional and tension–compression fatigue life. It is shown that the higher magnitude of dissipated energy in torsional loading, as reported in many studies, is due to the anelastic deformation in the material and its associated internal friction. It is further shown that proper assessment of the damaging dissipation energy requires one to exclude the non-damaging internal friction from the total amount of energy dissipation. Accumulation of thermodynamic entropy generation as an index parameter using the modified dissipated energy is estimated to predict the fatigue life. The experimental results are found to be in good agreement with the proposed fatigue life prediction.

通过应用耗散过程的热力学原理，研究了材料在扭转和轴向循环载荷作用下的失效。使用不锈钢（SS）304和SS316材料进行了广泛的实验测试，以洞察扭转和拉伸压缩疲劳寿命。结果表明，如许多研究报道的那样，扭转载荷下的耗散能量较高，是由于材料的弹性变形及其相关的内部摩擦引起的。进一步表明，对破坏性耗散能量的正确评估需要从能量耗散总量中排除无损内部摩擦。估计使用修正的耗散能量将热力学熵的产生作为指标参数进行累积，以预测疲劳寿命。