Damage tolerance analysis of wading structures of amphibious aircraft based on Franc3D

基于Franc3D的水陆两栖飞机涉水结构损伤容限分析

¹ School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072, China
² AVIC GA Huanan Aircraft Industry Co., Ltd, Zhuhai 519090, China

Received: 18 September 2021

Abstract

Aiming at the combined action effect of the corrosive environment of amphibious aircraft wading structures and random loads including water surface take-off and landing impact, based on the standard load spectrum TWIST of transport aircraft, considering the load level and frequency corresponding to the hydrodynamic load, the simulated random load spectrum of the wading structure was first compiled; the Willenborg/Chang high-load hysteresis model was used to consider the hysteretic effect of hydrodynamic high-amplitude overload on structural crack propagation, and an engineering method for damage tolerance analysis of amphibious aircraft wading structures was established. Taking the common hole edge crack of a typical wading structure of a certain type of aircraft as an example, based on the Franc3D crack propagation analysis software, the crack propagation life under the combined action of corrosive environment and random load spectrum was analyzed, and the inspection threshold value and check interval for maintaining the airworthiness of the structure were determined by residual strength analysis. The method proposed in this study is simple and feasible, and provides a theoretical basis for the damage tolerance analysis and maintenance plan formulation of amphibious aircraft wading structures.

摘要

针对两栖飞机涉水结构服役的腐蚀环境及包含水面起降冲击的随机载荷共同作用, 在运输机TWIST标准载荷谱的基础上, 加入水动力载荷对应的载荷水平及频次, 编制了涉水结构的模拟随机载荷谱; 运用Willenborg/Chang超载迟滞模型考虑了水动力高幅超载对结构裂纹扩展的迟滞效应, 建立了水陆两栖飞机涉水结构损伤容限分析的工程方法。以某型飞机典型涉水结构的常见孔边裂纹为例, 利用Franc3D裂纹扩展分析软件分析了涉水结构在腐蚀环境、随机载荷谱共同作用下的裂纹扩展寿命, 并通过剩余强度分析确定了保持结构适航性的检查门槛值和检查间隔。文中提出方法简易可行, 为水陆两栖飞机涉水结构损伤容限分析及维修计划制定提供了理论依据。