Legetolex 1432 pressuresensitive constrainedlayer damper. Elproduktion power generation is one of vibratecs core areas were we supply vibration isolation, emission and noise solutions from small diesel emergency generation sets up to large gas turbines both onshore and offshore. The application of a viscoelastic layer between two thin face sheets gives rise to the concept of constrained layer damping which is an effective technique to. Three layer sandwich beams, made of two elastic outer layers and a viscoelastic layer sandwiched between them, are considered as damping structural elements. In this paper, two feasibility studies were conducted using microcellular foam.
Constrained optimisation design of aerodynamic shapes. Nowadays, it is a very common practice for automakers to add pcld patches to the structures. Cld in its simplest form consists of three layers as shown in. Smart constrained layer damping of functionally graded shells. These dampers are normally thin layers of a stiff material usually aluminium or steel laminated to a viscoelastic polymer which is often self adhesive. A fundamental tradeoff in the properties of a driver cone. A highly efficient damping glue for plywood, particle more. The tape is made from a soft polymeric damping material, which is also an adhesive and can be used to attach the tape, and a thick aluminum foil which constrains the polymeric material.
Effect of thickness of damping material on vibration. The acld consists of a viscoelastic damping layer sandwiched between two layers of piezoelectric sensor and actuator. Evolution of constrained layer damping using a cellular automaton algorithm c m chia, j a rongong, and k worden department of mechanical engineering, the university of shef. A highly efficient damping compound for structure borne more. Constrained layer damping is widely used in engineering practice for minimizing unwanted vibration. Conventional passive constrained layer damping pcld treatments with viscoelastic cores are provided with builtin sensing and actuation capabilities to actively control and enhance their vibration damping characteristics. Free vibration characteristics of circular cylindrical shell with passive constrained layer damping pcld are presented. Comparison of active constrained layer damping by using. The uk health and safety executive hse reccomend damping, and constrained layer dampers as one of theirtop 10 noise control techniques. Therefore, pcld treatment is more applicable than acld treatment in traditional industry. Constrainedlayer damping cld was employed through a sandwichtype structure constructed by attaching viscoelastic gel and thin metal sheets to the base.
Pdf an overview of constrainedlayer damping theory and. Active and passive vibration damping wiley online books. Higher damping in engineering applications is desirable to reduce structural vibrations. A total of eight materials were tested and analyzed using cyclic loading equipment to. The parameters examined include the total elastic and viscoelastic material fractions and the base beam thickness.
Dynamic stiffness and damping of the headstock, which is a critical component of precision horizontal machining center, are two main factors that influence machining accuracy and surface finish quality. Cutting both the constraining layer and the viscoelastic layer, which leads to segmentation, increases the damping efficiency. The loss factor and shear modulus of the viscoelastic material are as follows 0. This method of passive damping treatment is widely used for structural. Application of a constrained layer damping treatment to a. Traditionally, cld treatments are constructed of a very thin polymer layer constrained by a thicker metal layer. In this area we prefer to use our range of all metal mounts and our extensive. Constrainedlayer damping applied to dcj vibration isolation.
Baz a 1993b active constrained layer damping damping93 conf. A parametric study was carried out using modal strain energy method to explore interaction between. Decidamp cld was developed to meet market noise reduction requirements across automotive, marine, industrial and oem markets. Comparison of active constrained layer damping by using extension and shear mode piezoceramic actuators r. The fundamental work in this domain was pioneered by ross, kerwin and ungar rku 7, who used a three layer model to calculate damping in plates with constrained layer damping treatments. Because the adhesion of a thin polymer layer is very sensitive to surface finish, surfaces. The 7361d material is designed to offer the maximum amount of structural damping to panel structures by shearing. An acoustical topology optimization of a constrained layer damping cld plate coupled with a rigid acoustical cavity is presented to minimize the sound radiation power. Passive viscoelastic constrained layer damping technology for.
Cld may be described as a type of shearrelated energy dissipation achieved by interconnecting two or more structural materials using a relatively thin viscoelastic layer. The middle layer uses viscoelastic gel for damping and the outermost layers, or the restraint layers, are made of thin metal sheets to restrict the deformation of the gel. Typically a viscoelastic or other damping material, is sandwiched between two sheets of stiff materials that lack sufficient damping by themselves. Constrained layer damping cld was employed through a sandwichtype structure constructed by attaching viscoelastic gel and thin metal sheets to the base. The use of constrained layer damping in vibration control. The application of a viscoelastic layer between two thin face sheets gives rise to the concept of constrained layer damping which is an effective technique to achieve increased damping in engineering applications. Smart constrained layer damping of functionally graded. Evolution of constrained layer damping using a cellular. In the constrained layer damping technique the damping material is bonded to the structure similar to. Pdf this article deals with the optimal damping of beams constrained by viscoelastic layers when only one or several portions of the beam are covered find, read and cite all the research. Effect of thickness of damping material on vibration control. Topology optimization of passive constrained layer damping with partial coverage on plate suffers form its high cost and complexity.
Acld treatments combine the best features of passive and active control of structural vibrations. Preparation and properties of a kind of epoxy constrained. Enhancing the results of damping efficiency of cld can be. Constrained layer dampers heathcote industrial plastics. Theseversatile materials can be adapted to a wide variety of applications including constrained layer dampers, multi layer laminates using metal or polymeric films, free layer dampers, suspension dampers, shock and vibration isolators, panel, pipe and wing dampers and more. Constrained layer damping treatments promise to be an effective method to control vibration in flexible structures. The complex stiffness method of damping for constrained damping structure with a standoff layer wenjun zhang1, dagang sun2, bijuan yan3, zhanlong li4 the standoff layer can add the distance between the base layer and the damping layer and can increase the deformation of damping layer which enables the. A mathematical model is developed to simulate the sound radiation based on the theories of the. The fundamental work in this domain was pioneered by ross, kerwin and ungar rku 7, who used a threelayer model to calculate damping in plates with constrained layer damping treatments. We saw cld turntable plinths, cld shelves, cld racks, cld aftermarket feet, cld audio cables i am sure if i looked hard enough i would have found cld remote controls and power cables. Noise and vibration control with constrained layer damping. The constrained version is a viscoelastic damping material, a constraining layer, and a protective release paper. Concretebased constrained layer damping sciencedirect.
Wave propagation approach rather than finite element method, transfer matrix method, and rayleighritz method is used to solve the problem of vibration of pcld circular cylindrical shell under a simply supported boundary condition at two ends. The youngs modulus of the sol 100 is set to be mpa and the loss factor is set to be 0. Baz a 1993b active constrained layer damping damping 93 conf. An overview of constrainedlayer damping theory and. Passive viscoelastic constrained layer damping application. However, if deformations of the constraining layer are appropriately controlled to enhance the transverse shear deformations of the constrained viscoelastic layer, the damping of the structure is improved and the structure is said to undergo active constrained layer damping. Virginia polytechnic institute and state university.
However, if deformations of the constraining layer are appropriately controlled to enhance the transverse shear deformations of the constrained viscoelastic layer, the damping of the structure is improved and the structure is. Features superior adhesive properties to many substates aluminum foil constraining layer effective vibration damping over a wide temperature range. Constrained layer damping how is constrained layer. Optimum design and control of active constrained layer damping. The applied viscoelastic damping treatment to the gear was of a constrained layer type, promoting increased shear deformation over free surface treatments, and therefore enhanced energy dissipation within the viscoelastic layer. Constrainedlayer damping is a mechanical engineering technique for suppression of vibration. Optimization of segmented constrained layer damping literature. The damping treatments with viscoelastic layers can be applied on the surface of the vibrating structure, with or without a constraining layer, or integrated in the structure constituting a sandwich material, fig. Design of constrained layer damping topologies asme.
The damping method is a constrained layer damping cld design where the layers are replicated in place using expanding concrete inside of viscoelastic damping inserts. The 7361d damping material is produced as constrained layer or non constrained layer depending on the application. In this project we will focus on partial constrained layer damping treatment and full constrained layer damping treatment. Study of the effect of composite constrained layers in. Preparation and properties of a kind of epoxy constrained damping material author. Constrained layer damping cld treatments have long provided a means to effectively impart damping to a structure. Geng department of engineering science and mechanics, mjc 0219, virginia polytechnic institute and state university. Constrained layer damping archives vibratec engelska.
A market leader in performance, this product is a lightweight pressuresensitive, constrained layer damper that is versatile for many applications. Performance characteristics of active constrained layer damping. Constrained layer damping cld treatment is a widely used surface damping treatment for vibration and noise control. Kerwin was the first to present a theoretical approach of damped thin. A highly efficient damping glue for plywood, particle more noisekiller black. Conventional passive constrained layer damping treatments with viscoelastic cores are provided with builtin sensing and actuation capabilities. Constrained layer damping how is constrained layer damping. Free layer damping fld is simply a surface layer added bonded to the structure of interest 1, 2. Dimensionless analysis of segmented constrained layer damping. Dimensionless analysis of segmented constrained layer. Decidamp cld is a constrained layer, viscoelastic damping material, designed to reduce structural vibration and sound transmission within light gauge materials. This paper describes an application to an outlet guide vane whereby damping treatments are considered in terms of external constrained layers and internal fillers. Constrained layer damping is a mechanical engineering technique for suppression of vibration. Constrained layer damping cld is a driver cone technology from atc that represents another advance in driver performance one that transfers directly to system performance and the reproduction of music.
Constrained layer damping archives vibratec danska. The damping of vibrations at high frequencies by the method of constrained layers is done best when the thickness of viscoelastic layer is half the thickness of constraining layer cl. Cld 14 consists of a bitumen mat with self adhesive and more. Constrained layer damping material, viscoelastic damping. Analysis of active constrained layer damping in composite. Passive viscoelastic constrained layer damping technology. The ending result is, any vibration made on either side of the constraining materials the two stiffer materials on the sides are trapped and evidently. Ross, kerwin and unger rku model for passive viscoelastic damping has been used to predict damping effects in constrained layer sandwich cantilever beam. This paper presents the effect of thickness of constrained damping material on modal loss factor of vibrating structures. Dynamic optimization of constrained layer damping structure. Passive viscoelastic constrained layer damping for structural application. Topology optimization of a constrained layer damping plate. Abstractconstrained layer damping has extensively used since many years to damp.
An outline of the theoretical basis of constrained layer dampingcld in general, surface damping treatments fall into one of two categories. A highly efficient damping compound for structure borne. Ten years ago, constrained layer damping cld was the thing in highend audio. The novel design is highly flexible and economical while providing excellent damping for a wide range of structural shapes. Vibration control of plates with active constrained layer. Damping analysis of plates with multiple constrained layer. Vibration control of plates with active constrained layer damping. Constrained layer damping sheet, decidamp fdf pyrotek.
The cldm material is designed to offer the maximum amount of structural damping to circuit boards and panel structures by shearing the highly damped viscoelastic layer. In this paper, one kind of high damping material is. San francisco, ca, usa 1993 baz a and ro j 1993a partial treatment of flexible beams with active constrained layer damping conf. It is specifically designed to be used as a constrainedlayer damping sheet in glass reinforced plastic grp and fibreglassfoam sandwich. Researcharticle dynamic optimization of constrained layer damping structure for the headstock of machine tools with modal strain energy method yakaixu,1 weiguogao,1. Identification of the substancemixture and of the company 1. Cld was employed through a sandwichtype structure constructed by attaching viscoelastic gel and thin metal sheets to the base. Hybrid activepassive models with frequency dependent damping. Vibration damping of structures using active constrained layer damping pages. Pdf passive viscoelastic constrained layer damping for. Constrained layer damping cld structure is proved to be effective in raising damping capacity for the thin plate and shell structures. This paper prepare a kind of epoxy constrained damping material, and studied the modulus, damping layer, constrained layer of different material selection for the damping properties of system, obtained when the damping layer modulus is small, the damping. A market leader in performance, this product is a lightweight pressuresensitive, constrainedlayer damper that is versatile for many applications.
Legetolex d300n pressuresensitive constrainedlayer damper. Constrainedlayer damping cld is a specific method of treatment commonly used in the aerospace and military industries. The purpose behind this study is to predict damping effects using method of passive viscoelastic constrained layer damping. Each cld is composed of 1mmthick viscoelastic damping layer and 0. Concretebased constrained layer damping springerlink. Pdf the analysis and design of constrained layer damping. Study of partial constrained layer damping treatment. Researcharticle dynamic optimization of constrained layer damping structure for the headstock of machine tools with modal strain energy method yakaixu,1 weiguogao,1 yuhanyu,2 daweizhang,1 xiangsongzhao,1. Pdf an overview of constrained layer damping theory and. The problem of optimizing the characteristics of shear damping at room and elevated. Investigations of partial constrained layer damping treatment. Hence to achieve maximum damping in the vibrating structure, the thickness ratio of constrained layer damping material to constraining layer cl should be. Charlottesville, va, usa, 1993 asmeamdvol 167, pp 6180. Conventional passive constrained layer damping pcld treatments with viscoelastic cores are provided with builtin sensing and actuation capabilities to actively control and.
371 689 785 1320 1087 311 480 405 1394 389 1627 1176 1083 483 1330 304 665 1331 1433 453 1441 1136 1447 1014 35 596 345 263 173 1035 1158 246 1392 23 1155 1416 203 1119 92 759 792 825