Stiffness Reliability Sensitivity Analysis Of Aircraft Connection Structure

The mechanical connection methods in the aircraft are primarily divided into bolted connections and rivet connections.Conventional aircraft connectors are connected to the force transmission components by bolts or rivets,because of the discontinuity of the structures and the complexity of the load transmitting methods,the combined structure is the key part of stiffness failure and fatigue failure.Therefore,whether or not the integrated structure is at normal operating condition which directly affects the safety performance of the aircraft.In this paper,three kinds of common tension joints of aircraft and multi-nail riveting are studied.The ANSYS parametic design language APDL is used to perform finite element modeling in classic ANSYS interface.The random characteristics of materials,sizes and loads of these kinds of research objects also are considered.The influence parameters of aircraft tension joints are the diameter of end,the fastener radius,the chamfer radius,the end thickness and the thickness of the bottom plate.The influence parameter of multi-nail riveting process are the rivet array pitch,rivet end distance,rivet margin and compressed length.The variation trends and influence degrees of the maximum strains of three aircraft tension joints and riveting process under different working conditions with the influenceing parameters are analyzed,obtaining the parameters which impact more under the same conditions by static analysis.It provides analysis basis for subsequent reliability sensitivity analysis.From the perspective of reliability,the limit state equations of aircraft tension joints and riveting process are established according to the stiffness failure theory.This article calculates the reliability sensitivity values of the random influencing parameters,combining with the reliability sensitivity analysis software NESSUS and using Latin hypercube sampling method which is improved by Monte Carlo method to survey a random sampling.The effects of the mean values and standard deviations of random parameters on the reliability of three common aircraft stretch joints and riveting processes were studied.Thus,it provides some theoretical references for accident prevention,structural size design and the optimized analysis of reliability of aircraft mechanical connection.