航空发动机管路系统是发动机系统介质传输和能量传递的重要通道。航空发动机液压管路系统是保障发动机正常运行的重要外部附件系统，在所有管路系统中所占比例最大，主要用于实现进气调节、尾喷调节等重要功能，要求有极高的可靠性。在工程实际中，航空发动机液压管路系统的振动故障主要包括管体振动过大、管体之间及其与壁板碰撞、卡箍振松或振裂、管接头或焊接接头振裂等。据统计，管路故障占航空发动机总故障的30％以上。可见，航空液压管路系统的振动问题是目前迫切需要解决的工程难题。航空发动机管路系统的动力学与振动机理研究十分重要，系统振动情况复杂，振动形式多样，无法用统一的理论体系进行分析。尤其是管路与卡箍组成的系统具有典型的非线性振动特性。 航空液压管路系统的振动问题很多，归纳总结主要包括：(1)机匣振动传递与卡箍特性问题。一般航空发动机卡箍内衬带有柔性材料，起到减振作用，液压管路系统通过卡箍与机匣相对固定，机匣的振动通过卡箍传递给管路，使得管路与机匣之间的振动特性变的复杂。常见的故障包括卡箍的松脱等。(2)管路与管路之间振动问题，双联卡箍一般用于管路与管路之间和管路与附件之间的连接与固定，由于各个管路自身受到的强迫振动或自激振动，振动通过双联卡箍互相传递。常见的故障包括管路之间的撞击，管路的裂纹等。(3)高强压力对管路系统的振动激励问题，液压管路系统内部输送流体的流量、压力脉动对液压管路系统产生强迫振动，如果这种压力脉动频率与液压管路系统负载阻抗的谐振频率接近，将产生共振，高强压力脉动激励液压管路系统产生机械振动，常见的故障包括接头裂纹、管路振动疲劳等。 本文以单联直管-卡箍系统，单联弯管-卡箍系统和双联直管-卡箍系统为研究对象，考虑系统在卡箍松脱故障状态下和卡箍紧固正常状态下的工况，采用解析分析、数值计算和试验测试相结合的方法，开展了系统非线性动力学模型建立方法研究，进行了非线性解析理论的解析方法分析，以及在不同激励条件下，系统的振动测试试验研究，取得的主要研究成果如下： (1)自主开发了专用卡箍刚度测试系统，该系统可完成卡箍在不同工位装卡状态下的线刚度和扭转刚度的测定。通过对卡箍的单向压缩和卸载的试验测试，可将所得数据拟合为卡箍的单向压缩-卸载曲线。通过对曲线分析发现，卡箍内衬材料具有典型的滞回特性。提出了一套将卡箍单向压缩-卸载曲线拟合为动态滞回模型的分析方法。在卡箍紧固状态下，提出了一种建立含有动态滞回模型的管路-卡箍系统的非线性动力学模型的方法，通过数值计算与试验测试，验证了模型的正确性。通过解析与试验发现，材料非线性引起的系统非线性振动，具有软式非线性的性质，且属于弱非线性。 (2)提出了一套利用卡箍线性刚度曲线拟合为Duffing刚度模型的分析方法。针对卡箍松脱导致卡箍与管路之间有间隙的故障状态，提出了一种基于Duffing刚度的系统非线性动力学模型来描述卡箍松脱状态的建模方法，通过数值计算与试验测试，验证了模型的正确性，为管路-卡箍系统的工程实际故障分析提供有效方法。通过解析与试验发现，卡箍间隙引起的系统非线性振动，具有软式非线性的性质，且属于弱非线性。 (3)在单联弯管-卡箍系统的动力学建模与分析过程中，发现了弯管-卡箍系统在振动过程中存在等效质量效应，即系统的振动质量远大于管体的真实质量。另外，通过对泵源激励下的弯管系统振动测试发现，高压流体在管路弯曲处会产生水锤效应，在系统的等效质量效应及水锤效应的共同作用下，弯管系统振动剧烈。 (4)提出了一种建立双联直管-卡箍系统的垂直方向和水平方向的耦合动力学模型的方法，通过对模型简化与解耦计算，得到了在垂直方向上的二自由度系统的非线性动力学模型，通过数值计算与试验测试，证明了模型的正确性。 (5)搭建了一套采用泵源激励的航空发动机液压管路系统振动特性测试试验台，针对液压单联直管-卡箍系统，液压单联弯管-卡箍系统和液压双联直管-卡箍系统，分别在基频非共振区和主频近共振区的三种不同油压下，分析了卡箍在不同拧紧力矩时管路系统的非线性振动特性。通过试验测试，定性分析了系统的非线性振动特性，为后续深入研究泵源激励特性和管路-卡箍系统非线性振动特性等提供了测试方法与数据积累。 通过对航空发动机液压管路-卡箍系统的非线性振动特性研究，得到了卡箍的非线性特性，建立了描述卡箍松脱状态下的系统非线性动力学模型，建立了卡箍紧固状态下的系统非线性动力学模型，讨论了不同管型系统的非线性振动特性，得到了一些工程实用计算方法，定性分析了在泵源激励下的管路系统的非线性振动特性，以上为本文的主要研究成果，可作为航空发动机液压管路-卡箍系统振动分析与设计的理论支撑和技术参考。 关键词：航空发动机，液压管路-卡箍系统，非线性振动，振动分析，泵源激励

 Aero-engine pipeline system is an important channel for media transmission and energy transfer in engine systems. The aero-engine hydraulic pipeline system is an important external accessory system to ensure the normal operation of the aero-engine. It accounts for the largest proportion of all pipeline system, and is mainly used to realize important functions such as intake air regulation and tail spray adjustment, and it is required for extremely high reliability. In engineering practice, the vibration faults of aero-engine hydraulic pipeline system mainly include excessive vibration of pipe body, collision between pipeline body and wall plate, clamp loosening or vibration crack, pipe joint or welding joint vibration crack, etc. According to statistics, the pipeline fault accounts for more than 30% of the total fault of the aero-engine. It can be seen that the vibration problem of the aero-engine hydraulic pipeline system is an engineering problem that is urgently needed to be solved. Research on the dynamics and vibration mechanism of aero-engine pipeline systems is very important, and the pipeline system vibration is complex with diverse vibration forms, It is impossible to analyze vibration issues with a unified theoretical system. In particular, the pipeline-clamps system has typical nonlinear vibration characteristics. There are many vibration problems in aviation hydraulic pipeline systems, and the summary includes: (1) The problem of aircraft engine casing vibration transmission and clamp characteristics. General, aero-engine clamp lining is provided with a flexible material to reduce vibration, and the hydraulic pipeline system is fixed on the casing by the clamp, and the vibration of the casing is transmitted to the pipeline through the clamp, so that the vibration characteristics between the pipeline and the casing become complicated. Common faults include looseness of the clamp, etc. (2) The problem of the vibration between the pipelines. Duplex clamp is generally used for connection and fixing between pipelines and pipelines or between pipelines and accessories. Due to forced vibration or self-excited vibration of each pipeline itself, the vibration is transmitted to each other through the duplex clamp. Common faults include impacts between pipelines, cracks in pipelines, etc. (3) The vibration excitation problem of high pressure on pipeline system. The pressure pulsation of the fluid transported inside the hydraulic pipeline system generates forced vibration to the system. If this pressure pulsation frequency is close to the resonant frequency of the hydraulic pipeline system load impedance, resonance will occur. The mechanical vibration will be produced by high-pressure pulsation excitation. Common faults include joint cracks, pipeline vibration fatigue, etc. This paper takes single straight pipeline-clamps system, single bend pipeline-clamps system and double straight pipeline-clamps system as research objects, considering the operating conditions that the clamp is loosed and the clamp is tightened, vibration characteristics of pipeline system is studied by combination of analytical analysis, numerical calculation and test. Take the research of establishing the nonlinear dynamic model of the system, the analytical analysis method of the nonlinear analytical theory has been used, and the vibration test of the system under different excitation conditions is studied. The main research results obtained are as follows: (1)A special clamp stiffness testing device has been developed independently. The system can test the line stiffness and torsion stiffness of the clamp in different position. The static stiffness curve of the unidirectional compression-unloading of the clamp was measured. It Is found that the clamp lining material has typical hysteresis characteristics. An analysis method for transforming the static stiffness curve of the clamp into the dynamic hysteresis force model of the clamp is designed. Based on the dynamic hysteresis force model of the clamp, the nonlinear model of the single straight pipeline-clamp system is established, and through numerical calculation and experimental tests, it is found that the nonlinearity caused by the material nonlinearity has softening characteristics, and it is the weak nonlinear (2)An analytical method for fitting the linear stiffness curve of clamps into Duffing stiffness model is presented. For the loosening condition of the clamp, an approach in which linear stiffness model of the clamp is fitted to the Duffing stiffness model is put up. A nonlinear model method based on Duffing stiffness is proposed to describe the looseness of the clamp is established. Through numerical calculation and experimental tests results have verified the correctness of the model. It provides an effective method for the engineering failure analysis of the pipeline-clamps system. It is found that the system nonlinear vibration caused by material gap has softening effect, and the nonlinearity is the weak nonlinear. (3)In the process of dynamic modeling and analysis, it is found that the equivalent mass effect exists in the vibration process of the bend pipeline-clamps system, that is, the vibration mass of the system is much larger than the real mass of the tube body. In addition, through the vibration response test of the bend pipeline-clamps system excited by the pump source, it is found that the pipeline with high pressure oil has water hammer effect. Under the combined action of the equivalent mass effect and water hammer effect of the system, the vibration of the bend pipeline-clamps system is violently. (4)A method to establish the coupling dynamic model of the vertical and horizontal of the double straight pipeline-clamps system has been presented, A two-degree-of-freedom vibration system model in the vertical direction is obtained by model simplified and decoupled, the correctness of the model is proved by numerical calculation and experimental test. (5) A test bed for vibration analysis of the hydraulic pipeline-clamps system of aero-engine excited by pump source is set up. Aiming at the hydraulic single pipeline-clamps system, the hydraulic bend pipeline-clamps system and the hydraulic double pipeline-clamps system, The vibration characteristics of the pipeline systems are analyzed under three different oil pressure of base frequency non-resonance region and main frequency near resonance region. Through the test, the nonlinear vibration characteristics of the system are analyzed, this has provided the test method and data accumulation for further study on the pump source excitation characteristics and the pipeline-clamps system characteristics. Through the study of the nonlinear vibration characteristics of the aero-engine hydraulic pipeline-clamps system, the nonlinear characteristics of the clamp is Obtained, and the nonlinear dynamic model of the system is established to describe the state of the clamp being loose, and the nonlinear dynamic model of the system under the tightening state of the clamp is established, and the nonlinear vibration characteristics of different pipeline systems are discussed, and some practical calculation methods for engineering is got, and the nonlinear vibration characteristics of the pipeline system under pump excitation is analyzed. The works of this paper can provide the theoretical support and the technical reference for the vibration analysis and the design of aero-engine hydraulic management system. Key words: Aero-engine, Hydraulic pipeline-clamps system, Nonlinear vibration, Vibration analysis, Pump source excitation