Reliability analysis for the wing-fuselage joint of an aircraft

For implicit limit state equation, the standard finite element code is combined with advanced-mean-value-first-order (AMVFO) method, to analyze the stiffness reliability for the wing-fuselage joint of an aircraft. Under the required performance, the results indicate that the joint structure applied by the given load has a higher reliability when coefficient of variation in the applied load is 0.15 and those in elastic modulus and shear modulus are 0.05 respectively. Then the standard finite element code is combined with the iterative response surface method (RSM) to analyze stiffness reliability. The response limit state equation is assumed as a quadratic 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 actual implicit limit state equation of the joint structure at the most probable failure point. The calculation results of the RSM and the AMVFO are in good agreement. Finally based on elasticity-plasticity strain analysis, the reliability analysis for low cycle fatigue life is discussed. The fatigue reliability is obtained at the given life requirement. And the safety life is obtained at the given reliability requirement.