Polymer damping material and damping structure

1 Damping Materials 1.1 Working Mechanism of Polymer Damping Materials When polymers are subjected to alternating stress such as vibration, it takes time to overcome the frictional resistance between chain segments due to the movement of chain macromolecules. therefore. Deformation 1 lags behind the factory stress changes. This kind of stagnation at a fixed temperature and frequency is very clear anvil deformation and stagnation means energy consumption. This just happens to reduce the kinetic energy of the vibrating body, and the qualitative analysis above the purpose of vibration reduction can not explain the development of polymer horny material material far enough. Therefore, many scholars tried to establish the relationship between the microscopic molecular structure and the viscoelastic properties. The relationship between the molecular structure and the damping properties was first discussed quantitatively, and it was suggested that the interpenetrating network polymer has a synergistic effect, which can make two polymers Inter-crosslinking limits the phase area and promotes molecular mixing, so that a broad damping peak 1018 systematically investigates how each molecular group in the polymer molecule structure absorbs energy, pointing out that each molecular group in the polymer The contribution to damping is not only related to its molecular structure, but also to the position 17 where the polymer is widely distributed, and then quantitatively proposes the base contribution molecular theory. 2 The analysis of these quantities can be regarded as a major progress in the study of the working mechanism of damping materials. , It promoted the development of new antimony materials to the molecular water and laid the foundation of 1.2 damping material modification methods; 1 The old village material is the most, the male reading crickets, the Huangying 1 transformation temperature, whether it is compatible with the use of the ambient temperature is The key to selecting a damping material is however the two most common high polymer rubbers and tanning materials. 7. The value is far lower than Shanghai's room temperature. These values ​​are much higher than room temperature, and the temperature of the operating environment is generally around the room temperature, so they are difficult to directly adapt to the use of temperature and ease of development. The viscoelastic material with a 7-value in the proper range becomes a target. In addition, the glass transition temperature range of the polymer is very narrow, and the temperature range that can produce effective damping is roughly in the upper and lower 2% 3 inverse, while the damping When the material is used, the wide transition temperature range becomes another problem that needs to be solved. For this reason, people are trying to blend the two polymer materials with 5 to form a polymer alloy. In general, if a material with a transformation temperature of 7 and a material with a transformation temperature of 2 co-occur, the 7 value of the blended material formed will be between 7 and 2, but care must be taken; Capacities and co-vulcanizates such as Cinnamon will receive propylene from 2001 to a mixture with a suitable 7-value, a wide range of conversion temperatures, and good damping properties and long life.

1 refers to a network polymer formed by the interpenetration of two or more crosslinked polymers, in which, the two interpenetrating networks are forcibly compatible and interfacially interpenetrate. Two-phase continuous. Its unique morphological structure emerges. That is, the heterogeneity of the microscopic phase has damping capacity in a wide range. Polyurethanes that are long-term researches such as Polyurethane Cool and Epoxy Tree Preparation 0145 are all in the conversion temperature range. The great improvement of this research field is attracting the attention of many scholars. The other methods are two transformation temperatures. The block copolymerization and graft copolymerization of the monomer of 7 and polymer materials. The overlap of 7 and 7 can significantly widen the conversion temperature range. Addition of fillers to the matrix can increase, broaden the transformation temperature range, and add plasticizers to reduce the value of 7. The addition of strontium and beryllium in the polymer Graphite and short fibers, etc., can effectively change the performance of the damping material, and can also reduce the cost, as to its mechanism. It is generally believed that the 2 damping structure caused by the slippage between the substrate and the filler interface has its structure 2, as can be seen from 2, similar to 1 but the middle foam is not a high-rigidity material but a soft polyurethane foam. The structure is comparable to a free damped structure.

More suitable for low frequency vibration.

Ffi N layer 1 When subjected to alternating stress Ordinary damping material Polyoxymethylene foam Basic damping body The traditional damping structure is mainly a free-damping structure constrained damping structure and a discrete damping structure, their structure is relatively single and the performance is difficult to meet the use Requirements Therefore, in recent years, many people have conducted research on changing the damping structure, and achieved a lot of results 789. Among them, the composite damping structure attracts people's attention. The essence of this kind of damping structure is to transform the existing simpler physical combination of various types of damping materials into a damping structure type that can meet various performance requirements. Practice has proved that using this method can be limited. A variety of damper structures with various properties are derived from a variety of damped village materials. The following describes several typical composite damping structures.

Composite Damping Structure 6 with Isolation Layer This composite damping structure is compared to a free damping structure. Its + adds a barrier layer between the elastic layer and the barrier layer. The barrier layer is characterized by the use of lightweight yet rigid materials such as rigid foamed paper honeycomb honeycombs etc. when the basic elastic layer generates bending vibrations. This isolation layer has a magnifying effect similar to that of a lever, and this hits Dao Town. In energy consumption, the damping structure of a complex damping structure with isolated damping and low-frequency vibration is separated by the energy dissipation of a person. The damping layer material of this person dissipates energy along with the stretching movement of the basic elastic layer, but if The basic elastic layer is used for low-frequency vibration. This method often fails to develop a 2 structure. In order to adapt to low-frequency vibrations, a foam layer is added. The foam is equivalent to root-soft ballast, and the normal muscle layer is equivalent. In a mass, it itself constitutes a quality rebound system, according to the vibration isolation theory, its effective frequency 1 natural frequency, can be obtained by the following formula foam layer stiffness, to foam layer is very soft, it means to fight The household is small.

The effective vibration isolation frequency is lower. By properly selecting the mass and elasticity, we can control the relationship between the loss factor and the frequency after the effective vibration isolation frequency range layers and their composite damping structures. It can be seen from 3 that the loss factor of the composite damping structure. In a wide range, to maintain a relatively large value, which applies to the wide (four) frequency range of glycosylated Kuni material slate damping material damping rubber asbestos or blew-poor 2.3 muffled composite damping structure absorbs the sound of the composite damping structure composed of Jl Low-frequency vibration of the composite damping structure phase. The hollow structure inside the fiber-type damping material is compounded by a material with a specific role of sound, and e is used for sound absorption. Because the sound waves enter these villages, the air and the fine fibers inside the hole vibrate and move toward the order of the pore walls. This friction and the empty viscous force cause the vibration energy to turn into heat energy and attenuate. Hard blood, light + strong acoustic reflection energy 9 Therefore, this type of composite resistance by them in a variety of combinations of similar structures and upper damping with less!

The nitrile screen pentene rubber forms a composite damping structure and the frequency range to which the damping structure is donated is also very wide and the strength is relatively low. Reason and the above several pairs of voices. Foam type it has a family, it will lead into the air and the intermolecular 1 has a better sound insulation material has a structure-like absorption sound absorption capacity = and the upper layer of ordinary damping rubber has a better sound insulation effect, the combination of Naturally has a good silencing effect.

Similar to the composite damping structure, in the middle of two layers of soft materials such as asbestos or foam, the damping rubber layer is sandwiched, and as long as the thickness of each layer is appropriate, it can play a good role in silencing. The fifth layer sandwiches a layer of damping material between the two layers of stone. The reflection of sound waves on the stone plate absorbs the absorption of the damping damping material, making this composite damping structure have good sound insulation performance. 14 The composite damping structure used to isolate earthquakes Seismic isolation from the seismic movement is the main condition for the support base to ensure that the building and its foundation are connected flexibly in the horizontal direction, and can provide sufficient support stiffness in the vertical direction, and the support seat absorbs vibration energy. Ability, 6 is its principle.

Multi-site bearing cushions High Kukuni rubber dampers Natural rubber sheet steel According to this principle, it was designed on the basis of a laminated rubber mat on which Qiao Shanglan is attached to buildings and foundations, and the core structure is a thin rubber sheet and sheet. Laminated steel sheets alternate with each other. The characteristic of this laminated rubber mat structure lies in that it maintains the inherent flexibility of the rubber in the shear direction, and at the same time, it can increase the compression stiffness in difficult directions. According to this design, the straight stiffness can exceed the horizontal stiffness by 16 times, so Laminated rubber mats provide flexibility in the horizontal direction required for seismic isolation while providing sufficient vertical stiffness to support the building site to isolate the other important function required, ie, to absorb vibrational energy. Its ability to eliminate the relative displacement between the building and the foundation has previously been achieved by placing the buffers side by side, and the types of buffers are hydraulic buffers that use metal plastic deformation to act as a buffer. In the upper part, the plastic buffer is used as a buffer, and it is directly placed in the laminating silicone heat 1!

The central part has reported that this type of seismic isolation composite damping structure works well and is being developed in the developed countries. It has also begun to be studied in China, and it should be known from the above that several ordinary damping materials undergo simple physical combination and change. A composite damping structure that satisfies a variety of different performance requirements, the technology is simple and effective and economic. Its development prospects are very bright. However, it should be pointed out that this kind of structural design is still in the 5th stage of trials. Some people have escaped from theoretical studies but have not yet formed a complete set of theories and methods that can guide such structural design. Based on feeling, a well-designed damping structure can only be verified by experimentation to verify its performance. Therefore, it is urgently needed to set up a complete design theory for this type of structure. Payne. The theory and practice of rubber application in engineering for a long time 1. Beijing Chemical Industry Press, 1985.

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