摘要
用非平衡统计的概念和方法建立微观机理与宏观性能相结合的热疲劳理论 .给出了热疲劳微裂纹的演化方程 ,结合热应力公式和微裂纹演化的位错机理 ,求得了热疲劳微裂纹的长大速率和几率密度分布函数 .同时给出了与实验结果基本相符的微裂纹平均长度随热循环周数变化的表达式 ,进而由热疲劳断裂几率得到了热疲劳寿命的解析表达式 ,最终得出温度差。
A non equilibrium statistical theory of thermal fatigue which connects microscopic mechanism with macroscopic properties is established. A physical picture and a microcrack evolvement equation are given. With the help of a formula of thermal strain and dislocation mechanism of microcrack evolvement, a microcrack growth rate and a probability density distribution function are found. The formula of mean length varying according to the number of thermal circles, which is in agreement with the experiment result on the whole, is given also. Furthermore, a formula of thermal fatigue lifetime is got through the formula of thermal fracture. The impact of the temperature difference and Young's module on the thermal fatigue lifetime is made out finally.
出处
《北京理工大学学报》
EI
CAS
CSCD
北大核心
2001年第2期151-156,共6页
Transactions of Beijing Institute of Technology
基金
北京市自然科学基金资助项目!(2 982 0 11)
关键词
热疲劳
微裂纹演化方程
微裂纹长大速率
热疲劳寿命
thermal fatigue
micro crack evolvement equation
micro crack growth rate
thermal fatigue lifetime
