拉压负载下各种碳钢的疲劳寿命简便预测方法研究

A STUDY OF A CONVENIENT PREDICTION METHOD OF FATIGUE LIFE FOR KINDS OF CARBON STEELS UNDER LOADING OF PUSH PULL

对多种碳素钢在拉伸压缩和旋转弯曲负载下的微小裂纹扩展速率进行了研究。这些材料在两种负载条件下裂纹扩展速率可以用ｄｌ／ｄＮ＝Ｃ′εｎ′ｐｌ统一地表示，同时讨论了裂纹扩展速率表达式中常数Ｃ′、ｎ′与材料静抗拉强度σｂ间的相关性。运用这些研究结果，提出仅用材料静抗拉强度σｂ值在拉压负载条件下就可以预测相应材料疲劳寿命的简单方法。最后与日本金属材料研究所公布的多种碳素钢疲劳试验结果和国内一些疲劳试验结果进行了比较，两者吻合良好。

A study has been done over the small crack growth rate for kinds of carbon steels under push pull and rotating bending.The small crack growth rates in the two types of loading can be expressed by the same small crack growth law based on the plastic strain amplitude ε p,d l /d N = C′ε n′ p l for these materials.Meantime,the relationship between C′,n′ and ultimate tensile strength σ b are discussed.Based on these results,a convenient prediction method of fatigue life is proposed for these steels by just using σ b.The fatigue lives were compared between the predicting value and the fatigue test data published by national research institute for metals in Japan.The results have shown to be in good agreement.