考虑小载荷强化的汽车构件疲劳累积损伤试验研究

Experimental Investigation on Cumulative Fatigue Damage of Strengthening under Low Amplitude Loading for Automobile Structures

给出了材料和结构在累积损伤的同时还具有强化作用的S-N曲线方程,并建立了程序载荷谱下产生损伤的同时还具有强化作用的疲劳累计损伤模型。为了检验所建立模型的正确性和准确性,以某汽车前梁和车架为例,设计了两种不同载荷组合,进行了两级循环载荷疲劳试验。试验结果和所建模型估算结果表明,该模型不但能够估算疲劳极限以下载荷的强化和损伤,还能估算疲劳极限以上载荷的强化和损伤。

The S-N curve equation and the fatigue cumulative damage model of metallic material and structure considering the damage and coaxing effect were detailed herein. In order to validate the fatigue cumulative damage model the damage and coaxing effect of load under and over fatigue limit were considered in automobile structures, the two different fatigue tests of two step cycling load for automobile front axle and frame were designed. The results show that this fatigue cumulative damage model can well predict automobile structures fatigue life considering the load damage and coaxing under fatigue limit or over fatigue limit. It is concluded that the fatigue life of structures depends on both of damage and coaxing, not on fatigue damage alone.