10CrNiMo结构钢弹性模量在低周疲劳过程中的变化规律

Elastic Modulus Variation of 10CrNiMo Structural Steel in the Process of Low Cycle Fatigue

采用横截面为圆形的光滑试样,在六级轴向系列不同恒应变幅(0.3%~1.0%)控制下,研究10CrNiMo结构钢弹性模量在低周疲劳过程中的变化规律.结果显示:在不同级别应变幅控制下,随着应变幅值的增加,稳定循环下的弹性模量并不是恒量,而是以负幂指数函数规律减小,且最小与最大应变幅下的弹性模量相差超过15%;而在某一恒应变幅控制下的稳定循环区间内,弹性模量随着循环次数的增加而缓慢下降,但在疲劳失稳时,弹性模量迅速大幅降低.分析认为,出现上述现象的原因,与不同应变幅对材料造成不同程度的疲劳损伤及恒定应变幅控制下材料固有的持续疲劳抗力有关.

Elastic modulus variation of 10 CrNiMo structural steel in the process of low cycle fatigue was researched by smooth and rounded cross-section specimens, controlled by six series of different axial strain amplitudes ranging from 0.3% to 1.0%. The results displayed that elastic modulus under the stable cycles is changeable and decreases by power-function with a negative exponent with the strain amplitude increasing, and the elastic modulus has a deviation of over 15% between the biggest strainamplitude and the smallest one;controlled by a certain strain amplitude, elastic modulus drops slightly with the increasing cycles and decreases quickly at the failure point during stable cycles. Analysis shows that the phenomena are relative to different strain amplitudes resulting in different amount of fatigue damages and intrinsically durative resistance against fatigue of the tested materials under the control of constant strain amplitude.