机身壁板内压载荷试验研究

Test Research on Fuselage Panel Subjected to Internal Pressure Load

内压载荷是一种非常重要的重复性载荷,对机身结构疲劳和损伤容限特性产生很大影响。承受内压载荷机身壁板边界模拟困难,边界模拟的优劣决定试验件过渡区范围的大小,甚至影响试验区的应力分布和大小。为了获得承受内压载荷机身壁板更加真实的应力响应,给出一种机身壁板内压载荷试验新方法,该方法采用"D"型夹具模拟机身筒段直边结构,采用"弓"型夹具模拟机身筒段曲边结构,采用气密端板模拟机身筒段的端部结构;按照边界模拟要求,设计制造试验装置和试验件,并完成内压载荷试验。结果表明:试验件试验区蒙皮的周向应力、纵向应力明显高于过渡区蒙皮周向应力、纵向应力;试验区蒙皮周向应力、纵向应力和法向位移与理论计算结果吻合,该试验方法满足工程精度要求;该研究可为民机机身壁板内压载荷结构选型试验提供参考。

Internal pressure is a severe cyclic load for fuselage structure,and it is important to investigate the fatigue and damage tolerance characters of fuselage panel under internal pressure.Boundary condition simulation of fuselage panel subjected to internal pressure load is challenging,and the quality of the simulation influences the range of transition area and even the stress distribution size in examining area.To investigate the stress distribution of fuselage panel subjected to internal pressure,a new test method is proposed."D"jig is utilized to simulate the longitudinal boundary conditions of fuselage panel,and "Arch"connectors are utilized to simulate the circumferential boundary conditions.Airtight end-plate is utilized to simulate the end of the fuselage barrel.Test fixture and fuselage panel specimen are designed and manufactured according to the boundary simulation requirements.Tests are conducted based on the proposed method.The test results show that hoop stress and axial stress in transition area are much more lower than in the test area.Hoop stress,axial stress and normal displacement in the test area are consistent with theoretic results.The proposed test method settle for engineering precision requirements and provides reference for configuration-selection tests of fuselage panel subjected to internal pressure load.