飞机蓄压油箱的振动疲劳寿命分析

发布时间：2019-03-26 11:54

【摘要】：飞机蓄压油箱是飞机倒飞时的主要供油部件,且由于长期交变载荷的作用,可能会引起油箱的疲劳破坏,造成燃油泄漏,影响飞机的飞行安全。故设计完成后,都要对其进行地面耐振试验验证其疲劳强度,其中定频耐振试验是工程中常用方法。本文课题来源为某飞机工业(集团)有限公司,针对耐振试验某些频率下出现严重抖动的问题,对其进行动力学仿真分析,研究蓄压油箱的振动疲劳寿命。本文主要工作包括:1.利用有限元前处理软件详细建立振动试验系统的有限元模型,包括油箱支臂、绑带、油箱、底座、隔震橡胶等及其相互连接关系。同时采用声固耦合法考虑了液体燃油的影响,建立其声学流体模型。2.提取蓄压油箱的结构和流固耦合模态,通过对比说明液体对结构动力特性有重要的影响,进而对试验系统进行流固耦合模态分析,获得系统的动态特性,并与模态试验结果进行对比,验证有限元模型的准确性。3.依据试验载荷谱,对耦合系统进行谐响应分析,获得振动系统的应力分布,验证各零部件的耐振强度。同时找出蓄压油箱疲劳寿命的薄弱部位,为后续疲劳分析做准备。4.对蓄压油箱定频耐振试验13种载荷工况造成的损伤在频域内进行计算和累加,获得蓄压油箱一个试验循环的疲劳损伤,根据损伤等效原理预测蓄压油箱的实际使用寿命。本文的研究工作具有如下创新性:采用对所有节点的损伤进行累加计算的方法,对工程中常用的定频耐振试验的疲劳寿命进行了仿真分析,而目前关于定频振动疲劳的预测方法还未见报道。
[Abstract]:Aircraft pressure storage tank is the main fuel supply part of aircraft when flying upside down, and because of long-term alternating load, it may cause fatigue damage of fuel tank, cause fuel leakage and affect flight safety of aircraft. After the design is completed, the fatigue strength should be verified by the ground vibration test, and the constant frequency vibration test is a common method in engineering. The subject of this paper is an aircraft Industry (Group) Co., Ltd. The vibration fatigue life of the storage tank is studied by means of dynamic simulation and analysis, aiming at the problem of serious jitter at certain frequencies in the vibration test of a certain aircraft industry (group) Co., Ltd. The main work of this paper is as follows: 1. The finite element model of vibration test system is established by finite element pre-processing software, including fuel tank arm, strap, tank, base, isolation rubber and so on. At the same time, the influence of liquid fuel was considered by sound-solid coupling method, and its acoustic fluid model was established. 2. The structure and fluid-solid coupling modes of the storage tank are extracted, and the liquid has an important influence on the dynamic characteristics of the structure. Then the fluid-solid coupling mode analysis of the experimental system is carried out, and the dynamic characteristics of the system are obtained. The accuracy of the finite element model is verified by comparing with the modal test results. 3. According to the experimental load spectrum, the harmonic response analysis of the coupling system is carried out, the stress distribution of the vibration system is obtained, and the vibration resistance strength of each component is verified. At the same time, find out the weak parts of the fatigue life of the storage tank, and prepare for the subsequent fatigue analysis. 4. The damage caused by 13 load conditions is calculated and accumulated in frequency domain, and the fatigue damage of a test cycle of the storage tank is obtained. According to the principle of damage equivalence, the actual service life of the storage tank is predicted. The research work in this paper is innovative as follows: the fatigue life of the constant frequency vibration test is simulated and analyzed by using the method of cumulative calculation of the damage of all nodes in the engineering. At present, the prediction method of constant frequency vibration fatigue has not been reported.
【学位授予单位】：沈阳航空航天大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：V228.11

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