应变能—内应力干涉模型的多轴高周疲劳研究  

STRAIN ENERGY-INTERNAL STRESS INTERFERENCE MODEL OF MULTIAXIAL HIGH-CYCLE FATIGUE RESEARCH

作　　者：高超干 胡明敏[1] 徐昊[1] 

机构地区：[1]南京航空航天大学航空宇航学院,南京210016

出　　处：《机械强度》2014年第3期455-459,共5页Journal of Mechanical Strength

摘　　要：塑性应变能使材料微观组织结构发生不可逆变化而引起等效宏观应力,该应力随循环加载而增大。假定该应力的一种分布函数,将疲劳极限以上加载等效为塑性应变,建立了塑性应变与加载应力成线性关系的表达式,由此得到循环加载的塑性应变能。导出其最大应力与外加应力叠加达到材料本征断裂应力时的裂纹成核寿命,并由微裂纹引起上述两部分应力变化,得到继续加载直至宏观裂纹出现的疲劳寿命。所建立的多轴疲劳寿命公式由三个材料参数表达,并通过单轴疲劳试验数据确定。初步研究表明,该模型对所引用的多轴疲劳试验数据有很好的预测能力。The microscopic structure of material will be permanently changed and produces equivalent macroscopic stress due to plastic potential energy. The present muhiaxial fatigue model in high-cycle assumes that the plastic deformation is linear to applied fatigue loading above fatigue limit, and the plastic strain energy can be calculated. A distribution function of the stress is given to derive the crack nucleation life when the superposition of maximum equivalent macroscopic stress and applied loading stress achieves the material＇s intrinsic fracture stress. Considering the changes of the above two stresses caused by microcrack, we can work out the fatigue life of continue to loading until the macroscopic crack appears. The established multiaxial fatigue life prediction formula contains three material parameters, and is determined by uniaxial fatigue experiment data. Preliminary research indicates that the model can predict the referenced multiaxial fatigue test data well.

关 键 词：多轴疲劳 塑性应变能 寿命预测 高周疲劳 

分 类 号：TB115.2[理学—数学]