【作者】 李大鹏；

【导师】 仇原鹰；

【作者基本信息】 西安电子科技大学 ， 机械电子工程， 2015， 硕士

【摘要】 飞机液压管路系统是飞机系统的重要组成部分,而振动疲劳引发的飞机液压管路的强度问题,一直困扰着飞机液压系统设计师和事故分析人员。随着飞机的液压系统朝着高压化、大功率、重量轻等方向发展,这一问题变得更加突出。而这些问题可能导致飞机液压管路的疲劳破坏甚至断裂,造成巨大的经济损失和人员伤亡。这必然对飞机液压系统的设计提出了更高的要求。因此研究飞机液压系统的振动特性和共振疲劳试验,并改进管路系统的设计方法,提高管路结构的安全性和疲劳可靠性,具有重要的理论意义和巨大的工程应用价值。前人对管路系统振动的理论计算和有限元仿真技术的研究已经获得了很多进展。然而国内对于飞机液压管路系统振动方面的研究主要集中在对简单管路数学模型的推导和简单管路的有限元仿真,距离实际工程应用还有一定的差距。因此,基于实际的工程项目,对典型飞机液压管路流固耦合振动进行系统的有限元仿真。本文通过研究液压管路的流固耦合振动的有限元仿真技术,并据此重点对典型飞机液压管路进行了振动特性分析。主要研究内容如下:首先,阐述了流固耦合的基本理论和方法,基于有限元方法基本理论,分别建立简单管路的流固耦合模型,并对模型进行了模态分析,结果与已有结论相符合,验证了本文有限元仿真分析的正确性与合理性,为飞机液压管路的动力学分析建立了仿真基础。其次,完全按照某型飞机液压管路进行了一比一建模,在三种不同状态下,对整个管系进行采用流固耦合法模态分析,讨论了不同状态结果对飞机液压管路的影响,给管路设计人员在设计和修改模型时提供一定的参考。同时介绍了一种管路流固耦合模态的实验方法,并与软件计算结果进行了相互验证,结果表明,相互验证了软件方法和试验方法的正确性为后文的下一步分析奠定了基础。再次,对管路模型施加发动机的随机激励谱进行随机振动分析,来模拟管路在发动机干扰下的振动情况。针对飞机液压管路的模型,做了简要且合理的简化,进行了随机仿真分析,对结果进行了分析对比,验证了随机分析方法可信分析结果可靠。最后,利用ANSYS Mechanical对某飞机液压管路进行基于流固耦合的动力学分析,对比了分析结果和试验数据,验证了响应结果基本与实际情况相符,并对最大范氏应力处的螺柱进行了疲劳校核。更多还原

【Abstract】 The aircraft hydraulic pipeline system is an important part of aircraft system, while its strength problems caused by vibration fatigue are always puzzling the hydraulic system designers and accident analysis personnels. With the development of the aircraft hydraulic system, these problems become more and more prominent. These problems may lead to fatigue destructions of the aircraft hydraulic pipelines, even huge economic losses or life casualties, which have certainly put foward a high request for the aircraft hydraulic system design. So it is essential in theoretic and engineering to study vibration characteristics and resonance fatigue testing of aircraft hydraulic system, improve design approach for safety and fatigue reliability.Previous researches on theoretic calculation and finite element simulation technology of pipeline system vibration have achieved great progress. However, the research on vibration of aircraft hydraulic pipe system in our country is mainly focus on the derivation of pipeline mathematical model and the finite element simulation of simple pipelines, so there are still certain gaps from the engineering application. Therefore, based on the practical project, it can provide an important theoretic guidance for vibration fatigue test to carry out finite element simulation on vibration caused by fluid-structure interaction for a typical aircraft hydraulic pipeline.In this paper, numerical analysis and finite element simulation on the fluid-structure interaction of hydraulic pipeline systerm are studied. Moreover, the vibration characteristics analysis of the typical aircraft hydraulic pipeline are studied. The main works can be described as follows:Firstly, the fluid turbulent model and piping model are established respectively. The fluid structure interaction is simulated using both one-way and two-way coupled techniques. The results indicate that it is feasible and reasonable to simulate and analyze the hydraulic pipes using one-way coupled technique in certain condition.Secondly, the FSI vibration of a straight pipe is researched. The simulation examples show that different pipe lengths, fluid flow speeds and fluid pressures impact the pipeline vibration greatly. The calculated results can provide some reference for designers to design and modify their CAD model of hydraulic pipes.Thirdly,the random excitation spectrum of the random vibration analysis has been done on the model, to simulate the vibration condition of pipeline in engine interference. In view of the hydraulic circuit model of aircraft, a briefly and reasonably has been simplified, the random simulation analysis. the results are analyzed and compared with the result of before, The results show that analysis method is reasonable analysis result is reliable.Finally, the dynamics analysis of the aircraft hydraulic pipes based on FSI is carried out using ANSYS-Mechanical. The results show that the response coincides with the actual conditions by comparing with the experimental data. Furthermore, the fatigue analysis of the screw bolt where the maximum von Mises stress exists is done, which demonstrates the screw bolt meets the fatigue strength criterion.更多还原