摘要
针对换热器的疲劳失效分析,以概率论为基础,结合确定性的疲劳断裂力学估算方法,推导了换热器零部件的疲劳裂纹扩展寿命的计算公式。考虑到主要评定参数:初始裂纹尺寸、工况载荷、断裂韧性、机械强度、系数等的不确定性和随机性,应用蒙特卡罗模拟法对这些具有某种特定分布的随机变量进行了随机抽样计算。并利用数值积分法编制了计算机程序,求出在一定可靠度和置信度下的疲劳寿命,并与理论计算方法求得的疲劳寿命进行了比较。还比较了不同初始裂纹尺寸和断裂韧性对疲劳寿命的影响,并给出了算例。分析结果表明,蒙特卡罗模拟法真实地反映评定参数客观存在的不确定性,克服了确定性评定方法的缺点,具有良好的工程指导意义。
According to the fatigue failure analysis of heat exchanger, on the basis ot probability theory, combining the method of estimateof definite fatigue fracture mechanics, the formula to calculate the fatigue crack propagation life of heat exchanger＇s components was deduced. The uncertainty and randomness of main assessment parameters were considered; initial crack size, practical working load, fracture toughness, mechanical intensity and coefficients. The random variables having some certain distributions were calculated with random sample by Mote- Carlo simulation method. A computer program was developed by using numerical integration method, and the fatigue life under given reliability and credit degree was solved. The result was compared with the fatigue life gained by theory computation method, The fatigue life in different initial crack sizes and different fracture toughness was compared, and an example was given, Analysis resuh shows that Mote- Carlo simulation method can reflect objectively the uncertainty of assessment parameters and overcome the shortcomings of certainty assessment methods. So it plays a significant role in engineering application.
出处
《辽宁石油化工大学学报》
CAS
2006年第1期55-57,62,共4页
Journal of Liaoning Petrochemical University
关键词
换热器
蒙特卡罗模拟法
可靠度
疲劳寿命
Heat exchanger
Mote Carlo simulation method
Reliability
Fatigue life
