某型飞机翼身连接接头可靠性分析

首先将标准有限元程序与改进的均值法相结合，对某型飞机翼身连接接头处的刚度可靠性进行分析，结果表明，在所给载荷和允许应变情况下，该接头结构在外载变异系数为0.15，弹性模量和剪切模量为0.05时，仍具有较高的可靠度。然后，又将标准有限元分析程序与响应面法结合，在假设接头的响应极限状态方程为一不包括交叉项的二次多项式的基础上，利用有限元分析确定响应极限状态方程，通过迭代运算，保证响应极限状态方程在最有可能失效点处与接头结构真实的隐式极限状态方程有很好的近似程度。2种方法的计算结果具有较好的一致性。最后，基于弹塑性应变分析，给出了在大过载情况下的低周疲劳寿命可靠性分析结果，得到了在给定寿命要求下，结构可靠度随寿命变异系数变化的曲线，并给出了在要求寿命可靠度情况下，可靠寿命随寿命变异系数的变化曲线，从而，为该型飞机的设计定型提供了有力的依据和方法。

Reliability Analysis of a Wing-Fuselage Attachment Fitting

A stiffness reliability analysis of a wing-fuselage attachment fitting was conducted using an implicit limit state equation. First, the standard finite element program is combined with advanced mean value first order (AMVFO) method for the analysis.The results indicate that at applied load and allowed strain, the joint structure has a higher reliability when coefficient of variation in applied load is 0 15 and that in elastic modulus and shear modulus is 0 05. Second the standard finite element program is combined with the iterative response surface method (RSM) to analyze the stiffness reliability. The response limit state equation is assumed as a second-order polynomial with no cross terms. The finite element software is employed to obtain the response limit state equation. By iterative calculation, the response limit state equation is gradually convergent to the real implicit limit state equation of the fitting structure at the probable-most failure point. The calculation results from the RSM and AMVFO are in agreement. Finally,based on elasticity-plasticity strain analysis, the reliability analysis for low cycle fatigue life for high load factors is discussed.The fatigue reliability is obtained for a given life requirement. And the safety life is obtained for a given life reliability requirement.