振动阻尼系统如何工作？
Vibration damping systems encompass energy-absorbing devices which are installed into the building structure to dissipate a large portion of the induced energy.
这种能量吸收元件通常不是结构的主要承载成分。然而，结构变形或振动会导致这些设备移动，从而导致能量消散。这样，可以有效地减少动态响应和对主结构的损害。
Energy dissipation by fluid viscous dampers
Liquid viscous dampers work according to the principle of energy dissipation: The damper consists of a steel piston that is divided into two chambers by the piston head, a compressible hydraulic fluid (silicone oil), and a pressure accumulator to ensure smooth circulation of the fluid.
When the piston moves, the liquid flows through the orifice from one chamber into the other. The movement from the larger to the smaller area (orifice) and back from the smaller to the larger area (cylinder chamber) reduces energy due to pressure loss.
Fluid viscous dampers are able to work in ambient temperatures from -40°C to +70°C (Constantinou and Symans, 1992). Unlike other dampers – e.g. viscoelastic dampers – temperatures changes only have a minor effect on the performance of these devices (Constantinou and Symans, 1992).
A drawback, however, is that the seals of liquid viscous dampers require careful maintenance over extended operational periods to prevent the escape of oil (Sadek et al., 1996).
Hysteretic metallic dampers
To dissipate energy, metallic dampers use the property of plastic hysteretic deformation of a specific metal. Commonly used representatives of these damping systems include mild steel dampers, buckling-restrained braces (BRB), and lead dampers.
Hysteretic metallic dampers
There are several configurations of mild steel dampers, e.g. X-shaped steel plate dampers and triangular-shaped dampers. Such dampers are composed of several X-shaped steel plates or triangular steel plates, resp. The vibration energy is dissipated by the lateral bending yield of the steel plates to reduce the vibration response of the structure.
软钢阻尼器主要是机构发展rized by their stable hysteretic performance and good fatigue properties at low cycles as well as their high insensitivity to environmental influences.
Buckling-restrained braces and lead dampers
无论是在压缩下还是在张力下，屈曲弯曲的牙套都显示出相同的负载变形行为。此外，他们突出了更高的能量吸收能力，同时提供了刚度和强度的轻松调节性。如果发生明亮的地震，屈曲弯曲的牙套提高了建筑物的稳定性。在较大的地震期间，屈曲弯曲的支撑形成塑料滞后变形以耗散能量。
On the other side, lead dampers dissipate vibration energy by using the benefits of lead extrusion or shear-hysteretic deformation of lead. Like mild steel dampers, lead dampers have excellent stability and durability properties. In addition, they are insensitive to environmental influences. A disadvantage is, however, that the lead in the damper can pollute the environment.
Viscoelastic damper utilize shear-hysteretic deformation
粘弹性阻尼器（VE阻尼器）由通过硫化与钢板相连的粘弹性层组成。通过利用粘弹性材料的剪切滞后变形原理，这些抑制剂耗散结构振动能。
The hysteresis curve of viscoelastic dampers shows full ellipses. This indicates that they have an excellent energy dissipation capacity. Further advantages include that they are easy to design, produce, durable and low-priced.
Viscoelastic dampers can be used in new buildings, for seismic retrofits and for reconstruction after an earthquake. The drawback of these dampers is, however, that the viscoelastic material is sensitive to temperature fluctuations.
Tuned mass dampers reduce dynamic response
这种类型的阻尼器包括调谐质量阻尼器(TMD) and tuned liquid dampers (TLD). The energy of the main structure is transmitted to the dampers which are tuned to the frequency of the controlled main structure and thus attenuate dynamic responses.
The TMD system consists of a mass, springs and dampers which are usually mounted on top of the main structure. The mass, stiffness and damping can be adjusted in such a manner that the natural period is identical or similar to the natural period of the main structure. When the main structure starts to move, the TMD system generates a force in the opposite direction of the main structure. Dynamic responses of the main structure are effectively reduced. Mass dampers are easy to design and produce.
TMD systems offer outstanding damping performance
As TMD systems only have a minor effect on the function of the main structure, they are often used to reduce the dynamic response of a structure exposed to earthquake or wind forces.
TMD systems offer outstanding damping performance
If it is a narrow-band excitation, or if the vibration is controlled by the fundamental oscillation, the damping effect will be excellent – otherwise, the damping effect will be inferior. Consequently, the TMD system can only suppress dynamic responses of the main structure within a narrow range of the excitation frequency.
TLD systems use water for energy absorption
调谐的液体阻尼器是一种调谐的质量阻尼器，其中质量被水或其他液体代替。它使用与TMD系统相同的基本原理，将能量耗散。
Because of its practical application and cost-effectiveness, the system is popular and frequently employed. A very important aspect is the sloshing behavior of a free surface liquid contained in a tank. Even small movements of the container can create relatively strong fluid motions because high-pressure loads are generated when the liquid hits the walls of the container. To prevent damage and to reduce the adverse effects of sloshing, baffles or deflectors are often installed so that the original height of the liquid level is quickly restored after structural vibration has occurred.
通常，被动调节阻尼器易于安装和维护。它们不仅可以用于新建筑物，而且还可以用于现有建筑物以改善地震性能。
Ringfeder
blog.ringfeder.com
Filed Under:Coupling Tips
