摘要
基于改进的一次二阶矩法,利用线弹性随机有限元分析和局部应力应变法,考虑几何尺寸随机性进行转子叶片结构疲劳寿命可靠性的数值分析。根据榫头喉部关键尺寸的随机特性确定应力的统计特性,然后采用一种等概率方法,通过确定性数值计算得到叶片寿命的概率密度、均值和变异系数,讨论榫头喉部几何尺寸的随机性对危险点寿命可靠度的影响。
Based on the advanced first order second-moment method the fatigue reliability of rotor blades with random key dimension was investigated by stochastic finite element method （ SFEM ） and deterministic analysis. The widths of smaller sections of blade root are considered as the key dimensions. First, the statistic characteristic of linear elasticity stresses in a blade is computed by SFEM from the stochastic character of the key dimensions. Consequently, in a big enough region of elastic random stresses at each danger point a deterministic calculation of fatigue lives relative to the stresses is carried on using Neuber＇ s method and Manson-Coffin equation. In order to determine the probability density of fatigue life, an ＂equal probability＂ assumption is used, i. e. assume that the probability of elastic stresses in each small sub-region equals that of life in a corresponding sub-region. Then from the probability density curve, the average values and the variation coefficients of blade life as well as the fatigue reliabihty can easily be obtained. The proposed approach has been applied to study the effects of the randomness of key dimensions on the life reliability of the dangerous points. It is shown from the numerical results that the randomness of key dimension may enlarge dispersing of life and obviously decrease fatigue rehability.
出处
《机械强度》
EI
CAS
CSCD
北大核心
2007年第3期459-462,共4页
Journal of Mechanical Strength
基金
航空推进技术验证计划项目(APTD-0201-006)~~
关键词
转子叶片
寿命可靠性
随机有限元
几何尺寸
低周疲劳
等概率法
Blade
Life reliability
Stochastic finite element method
Geometry dimension
Strain fatigue
Equal probability method
