To see the effect of damping treatment, production covers of figure 4a with and without a damping layer are compared in figure 5. Topology optimization of passive constrained layer damping with partial coverage on plate suffers form its high cost and complexity. Dynamic optimization of constrained layer damping structure. Constrained layer damping treatments with a thin damping polymer layer have long been used as a means to impart damping to a structure. These dampers are normally thin layers of a stiff material usually aluminium or steel laminated to a viscoelastic polymer which is. Decidamp cld was developed to meet market noise reduction requirements across automotive, marine, industrial and oem markets. Clds can lower vibration and noise levels as well as increase structural durability and fatigue life. These data can guide to specify the position of the constrained layer damping patch under pressure conditions. 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. Dynamic mechanical analysis tests are carried out, aiming at characterizing the rheological behavior of a vem compound. Effect of viscoelastic patch damping on casing cover dynamics. These dampers are normally thin layers of a stiff material usually aluminium or steel laminated to a viscoelastic polymer which is often self adhesive. We study the damping effects of a cantilever beam system consisting of a gun tube.
Dimensionless analysis of segmented constrained layer damping. Modeling of passive constrained layer damping as applied to a gun. 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. Ross, kerwin and unger rku model for passive viscoelastic damping has been used to predict damping effects in constrained layer sandwich cantilever beam. 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. Topology optimization of a constrained layer damping plate. A statistical characterization method for damping material. 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. In this case, the cover layer of pcld was replaced by piezoelectric material. In this paper, vibration control of an aero pipeline system using active constrained layer damping treatment has been investigated in terms of the vibration and stress distribution. Pdf some of the fundamental principles of constrained layer damping methodology are addressed and several mechanisms by which large. It is well known that constrained layer damping cld treatment is an effective means for suppressing the vibration of thinwalled structures and their noise radiation. Topology optimization for minimizing the resonant response of.
The damping contribution of the shunted piezoelectric intends to enhance the effective frequency range of the cld. Ross, kerwin and unger rku model for passive viscoelastic. Ris procite, reference manager, endnote, bibtex, medlars, refworks. Cld 14 consists of a bitumen mat with self adhesive and more. Validating the modeling of sandwich structures with. Keywords passive constrained layer damping, plate vibration. Thickness of the damping layer and constraining layer need to be. Composite sandwich structures have replaced homogenous dense solids in many applications due to their advantages of high stiffness to weight ratio, and. A comparative study on optimization of constrained layer. Ten years ago, constrained layer damping cld was the thing in highend audio. Since the damping layer is constrained on both sides, the vibration energy from the base layer is transformed into a shear deformation within the damping layer, which reduces the noise that is radiated by the system. Investigations of partial constrained layer damping. Passive viscoelastic constrained layer damping technology for. Constrained layer damping cld structure is proved to be effective in raising damping capacity for the thin plate and shell structures.
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. Threedimensional finite element models were developed for the constrained damping layer using the finite element package, abaqus. Most of the peak levels are attenuated by at least 10 db. The effect of the damping insertion due to viscoelastic material vem on the dynamic behavior of aluminum panels is assessed in this work. The first proposed configuration of this hybrid damping treatment was active constrainedlayer damping acld. 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. Constrained layer damping archives vibratec danska. Active constrained layer damping acld is an alternative form of cld that uses an active piezoelectric layer to replace the passive constraining layer in order to increase damping. Vibration control of plates with active constrained layer. The optimization of the constrained layer damping for strain energy minimization of vibrating pads depend on the position of the shape of the damping patch.
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. Article information, pdf download for augmented constrained layer damping in plates. Damping analysis of plates with multiple constrained layer. The purpose behind this study is to predict damping effects using method of passive viscoelastic constrained layer damping.
Typically a viscoelastic or other damping material, is sandwiched between two sheets of stiff materials that lack sufficient damping by themselves. For this application, a thin sheet of 80 durometer, 0. Constrained layer damping cld treatments have been widely employed to reduce vibration and sound radiation of flexible structures. Constrained layer damping material, viscoelastic damping. Noise and vibration control with constrained layer damping. Kerwin was the first to present a theoretical approach of damped thin structures with a constrained viscoelastic layer. The use of constrained layer damping on the mechanism housings proved successful. The ending result is, any vibration made on either side of the constraining materials the two stiffer materials on the sides are trapped and. The 7361d material is designed to offer the maximum amount of structural damping to panel structures by shearing. A sandwich is formed by laminating a damping layer in between two structural constraining base layers. Decidamp cld is a constrained layer, viscoelastic damping material, designed to reduce structural vibration and sound transmission within light gauge materials. Constrained layer damping is a mechanical engineering technique for suppression of vibration. 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. Nowadays, it is a very common practice for automakers to add pcld patches to the structures.
The application of cld treatments to cast engine covers has been difficult due to the rough surface finish of the covers. Identification of the substancemixture and of the company 1. The topology optimization problem is formulated and the square of displacement resonant response in frequency domain at the specified point is considered as the objective function. The most important component in a cld is the viscoelastic damping material. In the constrained layer damping technique the damping material is bonded to the structure similar to. Vibration analysis of beams with multiple constrained layer. This method of passive damping treatment is widely used for structural. Constrained layer damping cld systems can be applied to control the resonant response of a variety of structures. The design optimization of vehicle interior noise through.
The constrainedlayer damping beam in this work consists of three layers. The design optimization of vehicle interior noise through structural modification and constrained layer damping treatment 2015010663 the design optimization of vehicle body structure is addressed to reduce interior noise and improve customer satisfaction in this paper. The hyperelastic and viscoelastic behaviour were considered to represent the material properties of the rubber layer. Topology optimization for minimizing frequency response. A highly efficient damping glue for plywood, particle more noisekiller black. Engineers and designers are often looking to reduce the weight of their components to increase performance and efficiency. Higher damping in engineering applications is desirable to reduce structural vibrations.
Augmented constrained layer damping in plates through the optimal. Due to the constrained condition, the viscoelastic core undergo transverse shear damped deformation which produce more energy dissipation than free layer damping treatment. Constrainedlayer damping cld is a specific method of treatment commonly used in the aerospace and military industries. Optimization of constrained layer damping for strain energy. Researcharticle dynamic optimization of constrained layer damping structure for the headstock of machine tools with modal strain energy method yakaixu,1 weiguogao,1.
Stiffening the body structure by adding a center divider plate, such. The 7361d damping material is produced as constrained layer or non constrained layer depending on the application. Baz a 1993b active constrained layer damping damping93 conf. Earlier works on cld are mainly on passive constrained layer damping pcld. Acld is quite effective in the low frequency range but is more expensive and more complex to implement than the passive cld.
This paper presents the layout optimization of passive constrained layer damping pcld treatment for vibration control of cylindrical shells under a broadband force excitation. Optimization of passive constrained layer damping treatments. In this area we prefer to use our range of all metal mounts and our extensive. Basically, it says that efficiency of a viscous damping layer can be increased by sandwiching it between 2 solid layers. Pdf passive viscoelastic constrained layer damping for. When the system flexes during vibration, shear strains develop in the damping layer and energy is lost through shear deformation of the material. This technique combines two surface damping methods, the shunted piezoelectricceramic damping with the viscoelastic constrained layer damping cld. An electromechanical surface damping emsd technique is proposed. Constrainedlayer damping applied to dcj vibration isolation. Application of a constrained layer damping treatment to a. The 03 vec layer comprises a rectangular array of the thin recta. Constrained layer damping archives vibratec engelska. In the past decades, there have been numerous papers published in the area. A highly efficient damping compound for structure borne.
This paper documents the effectiveness of such a treatment on a cast aluminum front cover for a v6 engine. Evolution of constrained layer damping using a cellular. Topology optimization for minimizing the resonant response. Cld was employed through a sandwichtype structure constructed by attaching viscoelastic gel and thin metal sheets to the base. The timetemperature superposition principle is applied and the vem compound master curve is. Constrained layer damping cld treatments have long provided a means to effectively impart damping to a structure. 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. With future design iterations, damping levels several times those seen in this document will be seen with a constrained treatment applied to a landing gear system. Constrained layer dampers heathcote industrial plastics.
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. 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. The uk health and safety executive hse reccomend damping, and constrained layer dampers as one of theirtop 10 noise control techniques. Its material properties are provided in the standard reduced temperature format in 52.
Electromechanical surface damping combining constrained. These layers constrain the movement of a damping layer in such a way that unwanted energy is disposed through shear rather than bending. Topology optimization for minimizing frequency response of constrained layer damping plates zhanpeng fang1, ling zheng2 state key laboratory of mechanical transmission, chongqing university, chongqing, p. To compute structural responses of the constrainedlayer damping beam, a 10dof finite element is used. Passive viscoelastic constrained layer damping application. 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. Constrainedlayer damping cld systems are used to increase damping in stiff structures. Two versions of the production plate are evaluated. Because the adhesion of a thin polymer layer is very sensitive to surface finish, surfaces. This can then be transformed into a format that is compatible with the.
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. San francisco, ca, usa 1993 baz a and ro j 1993a partial treatment of flexible beams with active constrained layer damping conf. A topology optimization method is proposed to minimize the resonant response of plates with constrained layer damping cld treatment under specified broadband harmonic excitations. Pdf the analysis and design of constrained layer damping. Cutting both the constraining layer and the viscoelastic layer, which leads to. Passive damping is an important mechanism for reducing noise and vibration and improving fatigue and impact resistance of structures. The basic concept was mentioned by plump and hubbard in 1986, but it was the publications by baz in. Optimization of segmented constrained layer damping literature. A mathematical model is developed to simulate the sound radiation based on the theories of the. Novel constrained layer damping design based on expanding concrete. Further, the advent of finite element modeling has enabled closer looks at strain relationships for viscoelastic materials in vibrating situations. The equations governing the vibration responses are derived using the. Charlottesville, va, usa, 1993 asmeamdvol 167, pp 6180. The feadesigned cabinet with its constrained layer damping bracing and precision engineered curved baffle, the uniq driver and the elliptical flexible port all work in concert to prevent cabinet vibration and resonances that produce unwanted sound coloration putting you that much closer to how your favorite music.
Constrained layer damping cld systems can be applied to control the. Constrained and free layer damping vibratec engelska. 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. W kung and r singh acoustics and dynamics laboratory\ department of mechanical engineering\ the ohio state university\ columbus\ ohio 32109. 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. The constrained version is a viscoelastic damping material, a constraining layer, and a protective release paper. Multiobjective optimization for vibration reduction in. The eigenvalue problem of the constrainedlayer damping beam problem is defined as. Constrainedlayer damping is a mechanical engineering technique for suppression of vibration. Passive viscoelastic constrained layer damping technology. They are also looking to increase the life and durability of their products to reduce the need for maintenance and repair. Pdf vibration control of an aero pipeline system with.
Pdf an overview of constrainedlayer damping theory and. In this paper, one kind of high damping material is. A hierarchical optimization strategy for position and thickness. A fundamental tradeoff in the properties of a driver cone is mechanical stiffness versus mechanical damping. Topology optimization of passive constrained layer damping. Material damping can be easily incorporated into laminated structures in the form of viscoelastic layers and constrained layer damping cld is one of the most commonly employed methods to suppress. Passive viscoelastic constrained layer damping for structural application. The equations governing the vibration responses are derived using the energy approach and assumedmode method. Therefore, pcld treatment is more applicable than acld treatment in traditional industry. Optimization of active constrained layer damping of beam. Optimization of constrained layer damping for strain. A constrained layer damping pair usually consists of a viscoelastic damping material layer and a constraining layer. It the past decades, there have been numerous papers published in the area of cld treatment.
The first proposed configuration of this hybrid damping treatment was active constrained layer damping acld. 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. Principles of rapid machine design university of utah. Optimization design method for constrained damping layers. Typically a viscoelastic or other damping material is sandwiched between two sheets of stiff materials that lack sufficient damping by themselves. An overview of constrainedlayer damping theory and.
Vibration analysis of beams with multiple constrained. Earlier works on cld are mainly contributed to the passive constrained layer damping pcld. 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. Traditionally, cld treatments are constructed of a very thin polymer layer constrained by a thicker metal layer. Smart constrained layer damping of functionally graded shells.