Optimization of segmented constrained layer damping literature. 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. Constrained layer damping material, viscoelastic damping. 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. 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. Pdf an overview of constrainedlayer damping theory and. The use of constrained layer damping in vibration control. Constrained layer damping archives vibratec engelska. Constrained layer damping cld treatments have long provided a means to effectively impart damping to a structure. Cutting both the constraining layer and the viscoelastic layer, which leads to segmentation, increases the damping efficiency. Constrained layer damping sheet, decidamp fdf pyrotek.
Effect of thickness of damping material on vibration control. 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. The novel design is highly flexible and economical while providing excellent damping for a wide range of structural shapes. Nowadays, it is a very common practice for automakers to add pcld patches to the structures. Decidamp cld was developed to meet market noise reduction requirements across automotive, marine, industrial and oem markets. Effect of thickness of damping material on vibration. Passive viscoelastic constrained layer damping application. 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. Conventional passive constrained layer damping treatments with viscoelastic cores are provided with builtin sensing and actuation capabilities. 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. Charlottesville, va, usa, 1993 asmeamdvol 167, pp 6180. Passive viscoelastic constrained layer damping for structural application. Legetolex d300n pressuresensitive constrainedlayer damper.
Constrained layer damping how is constrained layer damping. The parameters examined include the total elastic and viscoelastic material fractions and the base beam thickness. 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. The acld consists of a viscoelastic damping layer sandwiched between two layers of piezoelectric sensor and actuator.
The constrained version is a viscoelastic damping material, a constraining layer, and a protective release paper. These dampers are normally thin layers of a stiff material usually aluminium or steel laminated to a viscoelastic polymer which is often self adhesive. Study of the effect of composite constrained layers in. Active and passive vibration damping wiley online books. Typically a viscoelastic or other damping material, is sandwiched between two sheets of stiff materials that lack sufficient damping by themselves.
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. In this paper, two feasibility studies were conducted using microcellular foam. Optimum design and control of active constrained layer damping. A parametric study was carried out using modal strain energy method to explore interaction between. Enhancing the results of damping efficiency of cld can be.
Topology optimization of passive constrained layer damping with partial coverage on plate suffers form its high cost and complexity. Application of a constrained layer damping treatment to a. It is specifically designed to be used as a constrainedlayer damping sheet in glass reinforced plastic grp and fibreglassfoam sandwich. Features superior adhesive properties to many substates aluminum foil constraining layer effective vibration damping over a wide temperature range. Baz a 1993b active constrained layer damping damping 93 conf. Acld treatments combine the best features of passive and active control of structural vibrations. May 14, 20 constrained layer damping cld is a specific method of treatment commonly used in the aerospace and military industries.
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 widely used in engineering practice for minimizing unwanted vibration. An overview of constrainedlayer damping theory and. Performance characteristics of active constrained layer damping. 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. 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. The problem of optimizing the characteristics of shear damping at room and elevated. 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. Constrained layer damping treatments promise to be an effective method to control vibration in flexible structures. In this paper, one kind of high damping material is. A mathematical model is developed to simulate the sound radiation based on the theories of the. Geng department of engineering science and mechanics, mjc 0219, virginia polytechnic institute and state university. Vibration damping of structures using active constrained layer damping pages. 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.
Cld was employed through a sandwichtype structure constructed by attaching viscoelastic gel and thin metal sheets to the base. 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. Constrained layer dampers heathcote industrial plastics. Preparation and properties of a kind of epoxy constrained. Constrained layer damping how is constrained layer. 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. An outline of the theoretical basis of constrained layer dampingcld in general, surface damping treatments fall into one of two categories. Comparison of active constrained layer damping by using.
In this area we prefer to use our range of all metal mounts and our extensive. Preparation and properties of a kind of epoxy constrained damping material author. Kerwin was the first to present a theoretical approach of damped thin. The youngs modulus of the sol 100 is set to be mpa and the loss factor is set to be 0. Cld in its simplest form consists of three layers as shown in. 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. Constrained layer damping archives vibratec danska. 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.
Topology optimization of a constrained layer damping plate. Vibration control of plates with active constrained layer. Each cld is composed of 1mmthick viscoelastic damping layer and 0. Damping of flexural waves by a constrained viscoelastic layer. Higher damping in engineering applications is desirable to reduce structural vibrations. A market leader in performance, this product is a lightweight pressuresensitive, constrained layer damper that is versatile for many applications. 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. Evolution of constrained layer damping using a cellular. 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.
Free vibration characteristics of circular cylindrical shell with passive constrained layer damping pcld are presented. A highly efficient damping glue for plywood, particle more noisekiller black. Comparison of active constrained layer damping by using extension and shear mode piezoceramic actuators r. The 7361d damping material is produced as constrained layer or non constrained layer depending on the application. The loss factor and shear modulus of the viscoelastic material are as follows 0. Dimensionless analysis of segmented constrained layer. 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.
A highly efficient damping glue for plywood, particle more. Concretebased constrained layer damping springerlink. This method of passive damping treatment is widely used for structural. Conventional passive constrained layer damping pcld treatments with viscoelastic cores are provided with builtin sensing and actuation capabilities to actively control and. In this project we will focus on partial constrained layer damping treatment and full constrained layer damping treatment. Dynamic optimization of constrained layer damping structure. Constrained optimisation design of aerodynamic shapes. Free layer damping fld is simply a surface layer added bonded to the structure of interest 1, 2. Constrainedlayer damping is a mechanical engineering technique for suppression of vibration. Study of partial constrained layer damping treatment. Constrainedlayer damping applied to dcj vibration isolation.
Investigations of partial constrained layer damping treatment. Analysis of active constrained layer damping in composite. Investigations of partial constrained layer damping. 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. Constrained layer damping cld treatment is a widely used surface damping treatment for vibration and noise control. 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. Legetolex 1432 pressuresensitive constrainedlayer damper. Hybrid activepassive models with frequency dependent damping. Traditionally, cld treatments are constructed of a very thin polymer layer constrained by a thicker metal layer. 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.
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. Researcharticle dynamic optimization of constrained layer damping structure for the headstock of machine tools with modal strain energy method yakaixu,1 weiguogao,1. A total of eight materials were tested and analyzed using cyclic loading equipment to. Constrained layer damping cld structure is proved to be effective in raising damping capacity for the thin plate and shell structures.
Hence to achieve maximum damping in the vibrating structure, the thickness ratio of constrained layer damping material to constraining layer cl should be. 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. A highly efficient damping compound for structure borne more. A highly efficient damping compound for structure borne. Ten years ago, constrained layer damping cld was the thing in highend audio. Measurements are performed on sandwich beam structure.
Typically a viscoelastic or other damping material is sandwiched between two sheets of stiff materials that lack sufficient damping by themselves. Therefore, pcld treatment is more applicable than acld treatment in traditional industry. Three layer sandwich beams, made of two elastic outer layers and a viscoelastic layer sandwiched between them, are considered as damping structural elements. Vibration control of plates with active constrained layer damping. Cld 14 consists of a bitumen mat with self adhesive and more. Passive viscoelastic constrained layer damping technology for. 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. Abstractconstrained layer damping has extensively used since many years to damp. 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.
Constrainedlayer damping cld was employed through a sandwichtype structure constructed by attaching viscoelastic gel and thin metal sheets to the base. Topology optimization of passive constrained layer damping. Smart constrained layer damping of functionally graded shells. Decidamp cld is a constrained layer, viscoelastic damping material, designed to reduce structural vibration and sound transmission within light gauge materials. Kerwin was the first to present a theoretical approach of damped thin structures with a constrained viscoelastic layer. In the constrained layer damping technique the damping material is bonded to the structure similar to. Pdf passive viscoelastic constrained layer damping for. Concretebased constrained layer damping sciencedirect. Because the adhesion of a thin polymer layer is very sensitive to surface finish, surfaces. Virginia polytechnic institute and state university. A market leader in performance, this product is a lightweight pressuresensitive, constrainedlayer damper that is versatile for many applications. 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. Dimensionless analysis of segmented constrained layer damping. Passive viscoelastic constrained layer damping technology.
Identification of the substancemixture and of the company 1. Baz a 1993b active constrained layer damping damping93 conf. Ross, kerwin and unger rku model for passive viscoelastic damping has. Constrainedlayer damping cld is a specific method of treatment commonly used in the aerospace and military industries.
The uk health and safety executive hse reccomend damping, and constrained layer dampers as one of theirtop 10 noise control techniques. The 7361d material is designed to offer the maximum amount of structural damping to panel structures by shearing. Smart constrained layer damping of functionally graded. The paper also gives an insight into the fundamentals governing the dynamics and activepassive control of smart composite sandwiched plate structures to use as the potential basic building block of structures where effective vibration damping is essential to their successful operation. This paper presents the effect of thickness of constrained damping material on modal loss factor of vibrating structures. Design of constrained layer damping topologies asme. Pdf an overview of constrained layer damping theory and. Ross, kerwin and unger rku model for passive viscoelastic damping has been used to predict damping effects in constrained layer sandwich cantilever beam.
The purpose behind this study is to predict damping effects using method of passive viscoelastic constrained layer damping. A fundamental tradeoff in the properties of a driver cone. Noise and vibration control with constrained layer damping. A fundamental tradeoff in the properties of a driver cone is mechanical stiffness versus mechanical damping. Pdf some of the fundamental principles of constrained layer damping methodology are addressed and several mechanisms by which large. 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. Constrained layer damping is a mechanical engineering technique for suppression of vibration. Constrained layer damping cld was employed through a sandwichtype structure constructed by attaching viscoelastic gel and thin metal sheets to the base. Damping analysis of plates with multiple constrained layer. San francisco, ca, usa 1993 baz a and ro j 1993a partial treatment of flexible beams with active constrained layer damping conf. Pdf the analysis and design of constrained layer damping.
1266 1121 28 583 1104 1269 1030 616 737 566 1164 1561 533 1526 1287 764 1531 69 1275 55 840 439 534 536 822 440 254 313 966 26 1482 1372 197 900 7 13 283 1050