轮盘应变疲劳寿命可靠性分析方法

Reliability analysis method for the strain fatigue life of a disk

关键词:  涡轮盘  疲劳(力学)  可靠性分析  响应面法+  蒙特卡洛法

Key words:  Turbine wheel  Fatigue(mechanics)  Reliability analysis  Response surface method~+  Monte Carlo method

摘要:

为较准确评估应变疲劳寿命可靠性,通过引入两个相关随机变量对Coffin-Manson公式随机化,发展了一种轮盘应变疲劳寿命可靠性分析概率模型。对线性回归残差重新定义,使得到的回归参数不随坐标系的选取发生变化。采用响应面法和蒙特卡洛模拟相结合的方法获得轮盘危险点应变幅的分布,最后通过多次解非线性方程数值模拟得到轮盘危险点应变疲劳寿命分布及其可靠寿命。

Abstract:

A probabilistic model based on strain-life curve was developed to assess fatigue life reliability of a disk. By randomizing the Coffin-Monson equation with two related random variables. The square sum of residuals for linear regression of strain-life curve was redefined. In this way, the parameters obtained from regression will be unchanged when the coordinate system is changed. The strain amplitude distribution at a critical site of a disk was acquired through the combination of response surface method and Monte Carlo simulation. Finally, the distribution of strain failure life at the site can be achieved by numerical simulation. And then the reliable life or the reliability for any given life can be derived easily from the distribution.