一种新的谱载荷寿命评估模型  

A NEW FATIGUE LIFE PREDICTION MODEL BY RANDOM LOAD SPECTRUM

作　　者：郑松林[1,2] 鞠方超 冯金芝[1,2] 

机构地区：[1]上海理工大学机械工程学院,上海200093 [2]机械工业汽车底盘机械零部件强度与可靠性评价重点实验室,上海200093

出　　处：《机械强度》2014年第2期261-266,共6页Journal of Mechanical Strength

基　　金：国家"十二五"863重大项目(2011AA11A265;2012AA110701);国家自然科学基金(50875173);上海市科委基础研究重点项目(10JC1411600;11140502000);上海汽车工业科技发展基金(1104)资助~~

摘　　要：基于零件的低载强化与损伤规律,提出了一种谱载荷下的寿命评估模型。汽车使用中遇到的随机载荷,80%是疲劳极限以下的小载荷,而传统的疲劳累积损伤理论在估算零件寿命时,很少或几乎不考虑使用过程中小载荷对结构造成的强度强化,只考虑大载荷对结构造成的损伤,使得估算结果与实际寿命存在很大差别。零件在小载荷作用下,随作用次数的增加,零件强度先增大后减小。该模型以此规律为基础,充分考虑了小载荷对的零件强度的影响,更加准确的反映了零件疲劳过程的客观现实。通过两种零件的寿命评估实例发现,该模型不仅计算简单,而且有更高的预测精度,为合理地进行汽车轻量化设计提供了理论和技术依据。Based on the strengthening and damaging properties of the structure strength, a new fatigue life prediction model for components and parts under random load spectrum is put forward. 80% of the random loads are low amplitude loads which are below the fatigue limit. This model overcomes the deficiency of the traditional methods, of which only the effect of damage is considered for high amplitude loads. The structure strength increases first and then decreases with the number of low amplitude loads increasing. Based on this law, the dual effect of strengthening and damaging under low amplitude loads has been fully considered. This model reflects the fatigue process of random loading accurately. According to two instances of different vehicle parts, the predicted life by the new model is more precise and more simple. This new fatigue life prediction model provides theoretical and technical basis for vehicle parts lightweight design based on the full utilization to the structure strength within the service period.

关 键 词：载荷谱 疲劳寿命预估 强化和损伤 试验验证 

分 类 号：U467.3[机械工程—车辆工程]