基于低幅锻炼载荷的累积强化效果模型

Cumulative Strengthening Effect Model Based on the Low-amplitude Training Load

根据汽车结构件在车辆运行过程中的受载特点,以汽车传动轴为对象,研究其在低幅锻炼载荷作用下的强度演变规律。通过对汽车传动轴光滑试样的低载强化效果试验,确定传动轴材料40Cr的低载强化应力区间,重点分析锻炼载荷幅值和加载次数对结构件剩余疲劳强度的影响,结果表明结构强度在一定条件下存在最佳的强化效果;并通过试验数据的正交分析与处理,拟合出强化或损伤效果与等效对称应力、加载次数的关系模型。进而以这一模型为基础,结合汽车传动轴工作的随机载荷谱,通过多级低幅载荷循环下强化和损伤强度的积分,建立传动轴在实际工作过程中的疲劳累积强化效果模型;并根据设计应力区间和最佳强化效果的应力区间的匹配,提出以低幅锻炼载荷的累积强化效果为目标的轻量化设计思路,为汽车结构件的轻量化设计提供理论基础。

According to the load characteristics of vehicle structural parts during operation,the drive shaft strength evolution under low-amplitude training loads is studied.Through coaxing effect experiment of smooth specimens,the coaxing stress range of shaft material 40Cr stress is determined.The influences of load amplitude and load times on the residual fatigue strength of structural parts are analyzed.The results show that the best coaxing effect of structural strength exists under certain conditions.By orthogonal analysis and processing of test data,the relation model of strengthening or damage effect and equivalent symmetrical stress and load times is fitted.Furthermore,based on this model and the work load spectrum of auto drive shaft,a fatigue cumulative strengthen model in work process is built through the integration of strengthening and damage effect.In accordance with matching the design stress range with the best coaxing effect,a new method of lightweight design is proposed with the aim of cumulative strengthening effect of low amplitude loading,so as to provide a theoretical basis for auto structural parts lightweight design.