摘要
采用概率断裂力学方法研究了船用柴油机机身球墨铸铁材料(QT400-18)的裂纹扩展寿命可靠性。基于QT400-18的裂纹扩展试验,考虑了裂纹扩展速率的分散性,采用统计分析获得了Paris公式参数的分布特征,建立了QT400-18裂纹扩展速率的随机概率模型。反推得到了da/d N≤10-7mm/cycle时材料的疲劳启裂门槛值。进一步建立了剩余寿命预测模型,通过数值抽样仿真,得到了不同初始裂纹长度下的裂纹扩展剩余寿命及其分布,并建立了剩余寿命与可靠度关系图谱。
This paper investigated the reliability evaluation process of crack propagation life of marine diesel engine body material QT400-18 with probabilistic fracture mechanics method. Based on the crack propagation experiments of QT400-18 and considering the dispersion of crack propagation rate,we obtain the Paris formula parameters with statistical analysis,and establish a random probability model of crack propagation rate of QT400-18. Furthermore,a residual life reliability prediction model is also built. Through the numerical sampling simulation,the residual life and its distribution in different initial crack length are achieved and the correlation curve of reliability with residual life is drawn. In the condition of,the threshold of fatigue crack growth is obtained with an inversion approach.
出处
《机械科学与技术》
CSCD
北大核心
2015年第6期940-944,共5页
Mechanical Science and Technology for Aerospace Engineering
基金
国家自然科学基金项目(51305350)
陕西省自然科学基础研究计划项目(2013JM6011)资助
关键词
球墨铸铁
裂纹扩展速率
概率模型
寿命可靠性
crack initiation
crack propagation rate
crack tips
diesel engines
fatigue crack propagation
forecasting
fracture mechanics
mathematical models
nodular cast irom
nodular irom
normal distribution
probability density function
probability model
probability
reliability analysis
residual life reliability
stochastic models
