考虑流体可压缩性的粘滞流体阻尼器理论与性能研究

发布时间：2018-12-27 09:29

【摘要】：双出杆孔隙式粘滞流体阻尼器是一种减振装置。结构振动时，，流体阻尼器产生阻尼力耗散能量，降低结构在共振频率附近的动态响应，减弱节点的局部受力和变形量，保护结构免受破坏。通常认为流体不可压缩，不考虑其刚度影响，但实际上流体是可压缩的，动态时会产生附加刚度，从而影响流体阻尼器的动态性能。尤其是当阻尼器内混入空气后其性能会有很大变化。故考虑流体可压缩的流体阻尼器设计和性能研究对安全合理使用流体阻尼器来说是非常紧迫的。本文在考虑流体可压缩性的基础上建立和完善的阻尼力理论，采用合理的方法步骤简化设计过程；性能研究主要是讨论不同工况下流体阻尼器表现出的性能变化规律。（1）针对目前国内流体阻尼器研究和使用存在的问题开展本文的研究，包括阻尼力产生机理和流体阻尼器动态特性的研究。（2）流体阻尼器按其结构可分为多种类型，根据各类型特点选择性能良好、使用范围广的双出杆孔隙式流体阻尼器进行研究。介绍了流体阻尼器中流体的粘度随剪切速率、温度、外界压力的变化规律。流体的压缩性是流体阻尼器产生动态附加刚度的主要原因。（3）流体阻尼器在动态激励下不仅表现出阻尼特性，而且还有刚度特性。但已有研究对附加刚度的影响大多基于试验数据，对混有空气的流体阻尼器性能的研究也不够深入。在非线性串联模型下，根据液压流体力学理论推导了层流流况下的阻尼力计算公式和串联液体弹簧的刚度。通过能量等效原则得到体现消耗能量效率的线性阻尼系数，可将其与设计阻尼系数比较是否符合要求。同样通过能量等效原则线性化了串联模型中的阻尼和刚度，并据此建立了一个线性并联模型，直观地反应力中弹性力和阻尼力的大小。（4）根据流体阻尼器试验的功能要求设计并制造了流体阻尼器试验台。（5）对不同流体介质、阻尼孔直径在不同频率下进行了简谐激励和动态激励试验。验证了本文阻尼力理论是正确的，并对一些影响阻尼器特性的因素进行了讨论。（6）介绍本文研究内容的工程应用价值。一是在设计理论和设计方法上的创新；二是对流体阻尼器模型的讨论，判断附加刚度的影响程度。
[Abstract]:The double-rod pore viscous fluid damper is a vibration absorber. When the structure vibrates, the fluid damper produces damping force dissipation energy, reduces the dynamic response of the structure near the resonance frequency, weakens the local force and deformation of the joints, and protects the structure from damage. It is generally considered that the fluid is incompressible and does not consider the influence of its stiffness, but in fact the fluid is compressible and will produce additional stiffness when it is dynamic, thus affecting the dynamic performance of the fluid damper. Especially when the damper is mixed with air, its performance will change greatly. Therefore, the design and performance study of fluid damper considering fluid compressibility is very urgent for the safe and reasonable use of fluid damper. In this paper, based on the consideration of compressibility of fluid, the damping force theory is established and perfected, and the design process is simplified by reasonable method. The performance research is mainly to discuss the performance variation law of fluid damper under different working conditions. The main contents are as follows: (1) this paper focuses on the problems existing in the research and application of fluid dampers, including the mechanism of damping force generation and the dynamic characteristics of fluid dampers. (2) fluid dampers can be divided into many types according to their structure. According to the characteristics of each type, the fluid dampers with good performance and wide range of use are selected for study. The variation of viscosity with shear rate, temperature and external pressure in fluid damper is introduced. The compressibility of the fluid is the main reason for the dynamic additional stiffness of the fluid damper. (3) the fluid damper exhibits not only damping characteristics but also stiffness characteristics under dynamic excitation. However, most of the studies on the effect of additional stiffness are based on experimental data, and the performance of air-mixed fluid dampers is not well studied. Based on the theory of hydraulic fluid mechanics, the formula of damping force in laminar flow and the stiffness of series liquid spring are derived under the nonlinear series model. According to the principle of energy equivalence, the linear damping coefficient, which reflects the energy efficiency, can be compared with the design damping coefficient. The damping and stiffness of the series model are linearized by the principle of energy equivalence, and a linear parallel model is established based on which the magnitude of the elastic force and the damping force in the force is intuitively reflected. (4) the fluid damper test rig is designed and manufactured according to the functional requirements of fluid damper test. (5) the harmonic and dynamic excitation tests of damping hole diameter in different fluid media are carried out at different frequencies. It is verified that the damping force theory is correct, and some factors affecting the dampers are discussed. (6) introduce the engineering application value of this paper. One is the innovation of design theory and design method, the other is the discussion of fluid damper model to judge the influence of additional stiffness.
【学位授予单位】：上海交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB535.1

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