Constrained layer dampers heathcote industrial plastics. The design parameters and control gains of the resulting active constrained layer damping acld treatments are optimally selected, in this paper, for fullytreated beams using rational design procedures. The vibration control and damping design of passive and active. 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. Benefiting from the selfadaptive and selfmonitoring capabilities, active constrained layer damping acld has attracted much attention 11,12. Surface damping treatments are often effective at suppressing higher frequency. Cld was employed through a sandwichtype structure constructed by attaching viscoelastic gel and thin metal sheets to the base. The problem of optimizing the characteristics of shear damping at room and. The purpose behind this study is to predict damping effects using method of passive viscoelastic constrained layer damping.
Decidamp fdf should be incorporated into the grp structure at a stage where full thickness has been achieved. 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 global constrained layer damping cld market is anticipated to reach usd 1,160 million by 2026 according to a new study published by polaris market research. Concretebased constrained layer damping springerlink. Vibration control of plates with active constrained layer. Typically a viscoelastic or other damping material, is sandwiched between two sheets of stiff materials that lack sufficient damping by themselves. In this design of active constrained layer damping treatment in layerform, its active constrained layer damping necessary conformability with the curved host shellsurface is ensured by the use of a vertically reinforced piezoelectric composite pzc constraining layer, whereas the effective control of several modes of vibration of the. Constrained layer damping cld systems are used to increase damping in stiff structures.
Vibratec can offer several sorts of damping layers including visco elastic paint. In this thesis, the author presents a numerical and experimental study of the application of active constrained layer damping to a clampedclamped plate. Augmented constrained layer damping in plates through the optimal. A finite element model is used to describe the dynamic performances of the cld structure. Author links open overlay panel yang liu a b zhanqiang liu a b qinghua song a b. 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. Constrained layer treatments are surface treatments where the damping material is sandwiched between the base structure and a constraining layer david i.
In this paper, one kind of high damping material is. Constrained layer damping cld structure is proved to be effective in raising damping capacity for the thin plate and shell structures. Singh, vibration and damping characteristics of beams with active constrained layer treatments under parametric variations. Vibration control through passive constrained layer. Damping analysis of plates with multiple constrained layer.
Gopal, minglai lai, and pojen cheng constrained layer damping of a tennis racket, proc. To add damping to systems, viscoelastic materials vem are added to structures. Optimization of constrained layer damping for strain. Effect of free layer damping and constrained layer damping. Bending of the resulting plate structure mainly causes shear deformation in the viscoelastic layer which in theory leads to more efficient dissipation than damping due to pure strain deformation. When this constraining layer is an active element, the treatment is called active constrained layer damping acld. Concretebased constrained layer damping sciencedirect. Development of constrained layer damping toolholder to improve chatter stability in end milling. Pdf an overview of constrainedlayer damping theory and. The 7361d damping material is produced as constrained layer or non constrained layer depending on the application. Pdf the analysis and design of constrained layer damping.
Specific interests are on how the vem parameters will influence the passive damping ability and the active action transmissibility in an acl configuration. The 7361d material is designed to offer the maximum amount of structural damping to panel structures by shearing. 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. Each acld patch consists of a viscoelastic damping layer which is sandwiched between two piezoelectric layers. Design of constrained layer damping topologies asme. To circumvent the computationally expensive sensitivity analysis, an efficient. In order to enhance the damping effects of the vem, a constraining layer is attached, creating a passive constrained layer damping pcld treatment. Constrained layer damping sheet, decidamp fdf pyrotek. Passive viscoelastic constrained layer damping application. Constrained layer damping for vehicle rieter technologies. Heathcote specialise in the manufacture of constrained layer dampers clds one of the most effective and weight efficient forms of passive damper available. Bending vibration of flat plates is controlled using patches of active constrained layer damping acld treatments. This paper deals with an optimal layout design of the constrained layer damping cld treatment of vibrating structures subjected to stationary random excitation. Since energy dissipation arises only from the viscoelastic vem layer, the modulus of elasticity of.
Historically, constrained layer damping treatments have used a very thin adhesive layer as the damping material. The constrained version is a viscoelastic damping material, a constraining layer, and a protective release paper. The main objective is to model the viscoelastic sandwich beam for the modal analysis using the finite element method. Topology optimization of passive constrained layer damping with. Development of constrained layer damping toolholder to.
A highly efficient damping compound for structure borne more less noise in metal, plastic, wood etc. The analysed compressible constrained layer damping ccld object is configured as a three layered beam consisting of the load. We analyze the finite element modeling of constrained layer damping cld and. Very high damping of structureborne vibration can be achieved. Constrained layer damping material reduction of vibration in circuit boards and paneltype structures using a highly damped, constrained viscoelastic material attributes the epsg cldm material effectively and efficiently reduces the amount of vibration transmitted to a structure resulting in longer fatigue life of the structure or circuit board. The parameters examined include the total elastic and viscoelastic material fractions and the base beam thickness. Constrained layer damping is widely used in engineering practice for minimizing. This paper details the design of materials in such a con. Constrainedlayer damping cld systems are used to increase damping in stiff structures.
Activepassive hybrid damping in beams with enhanced smart. The root mean square rms of random response is defined as the objective function as it can be used to represent the vibration level in practice. These thin layer cld treatments have yielded exceptional results in many applications. Kress, optimization of segmented constrained layer damping with mathematical programming using strain energy analysis and modal data. Experimental investigation of damping performance of. The novel design is highly flexible and economical while providing excellent damping for a wide range of structural shapes. Pdf some of the fundamental principles of constrained layer damping methodology are addressed and several mechanisms. Analysis and design of viscoelastic materials for active. Topology optimization of constrained layer damping. Control of active constrained layer damping article pdf available in journal of vibration and control 61. 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.
Constrained layer damping cld is a damping principle which utilizes a viscoelastic layer between two elastic covering layers. The 03 vec layer comprises a rectangular array of the thin recta. Topology optimization, passive constrained layer damping, modal loss factor. A design of active constrained layer damping treatment for vibration control of circular cylindrical shell structure 22 september 2016 journal of vibration and control, vol. Bending of the resulting plate structure mainly causes shear deformation in the viscoelastic layer which in theory leads to more efficient dissipation than damping due to. These are usually known as containment put it in a box, absorption usually foam, isolation usually rubber or hydraulic, passive damping and active damping. It is specifically designed to be used as a constrainedlayer damping sheet in glass reinforced plastic grp and fibreglassfoam sandwich constructions. Constrained og free layer 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. This paper is concerned with the investigations of viscoelastic material vem effects on active constrained layer acl based structures. Researcharticle dynamic optimization of constrained layer damping structure for the headstock of machine tools with modal strain energy method yakaixu,1 weiguogao,1. The analysis and design of constrained layer damping treatments. Pdf download for augmented constrained layer damping in plates through. 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. However, due to the surface roughness of this cover, a traditional thin layer cld was not feasible without a costly machining step.
When a ball strikes a racket with this damping system the vibration causes shearing strain in the viscoelastic material. Modelling of constrained layer damping for bending waves. Passive viscoelastic constrained layer damping technology. Identification of the substancemixture and of the company 1. Results show that significant improvements in damping performance, over 300% in some cases, are obtained by optimizing the constrained damping layer topology. Application of a constrained layer damping treatment to a. Passive viscoelastic constrained layer damping application for a small aircraft landing gear system by craig a.
Damping analysis of plates with multiple constrained layer damping treatments written by qingqing wu, minqing wang published on 20180720 download full article with reference data and citations. Ross, kerwin and unger rku model for passive viscoelastic damping has. Declaration this dissertation describes part of the research performed at the cambridge university engineering department between october 1997 and september 2000. 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. The use of constrained layer damping in vibration control. Finite element prediction of damping in structures with. Smart constrained layer damping of functionally graded. Optimum design and control of active constrained layer damping.
The main studies were conducted using a developed finite. Activepassive hybrid damping in beams with enhanced smart constrained layer treatment. Topology optimization of constrained layer damping on plates using. The damping system uses a viscoelastic material along with a stiff composite constraining layer which is molded on the inner surface of the tennis racket frame. Kochersberger mechanical engineering department abstract the main purpose of this report was to test several common viscoelastic polymers. Pdf download for constrained damping layer treatments. Higher damping in engineering applications is desirable to reduce structural vibrations. Smart constrained layer damping of functionally graded shells using verticallyobliquely reinforced piezocomposite under a thermal environment mcrayandrcbatra department of engineering science and mechanics, mc 0219, virginia polytechnic institute and state university, blacksburg, va 24061, usa received 19 january 2008, in. The invention relates to a vibration damper for application to a vehicle bottom plate 1, comprising an under floor panel 3 as a constraining layer and a damping layer 2 as a constrained layer, wherein the damping layer 2 has a lower modulus of elasticity than the under floor panel 3, and wherein the damping layer 2 is located between the vehicle bottom plate 1 and the under floor. 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. A design of active constrained layer damping treatment for. Constrained layer damping archives vibratec engelska.
This paper presents a topology optimization method to design the optimal layout of constrained layer damping cld material in structures subjected to harmonic excitations or stationary random excitations. Ten years ago, constrained layer damping cld was the thing in highend audio. Said damping material, characterized in that it is a bitumen. Effect of free layer damping and constrained layer damping on loss factor of aluminum structure written by jitender kumar published on 20180424 download full article with reference data and citations. Noisekiller black is a unique highly efficient damping compound developed for acoustic improvement of decks and bulkheads, vehicle chassis and other structures that are exposed to vibrations. Constrainedlayer damping cld is a specific method of treatment commonly used in the aerospace and military industries.
Noise and vibration control with constrained layer damping. Constrained layer damping material, viscoelastic damping. Optimal placement of constrainedlayer damping for reduction of interior noise related publications. Constrained layer damping archives vibratec danska. Constrainedlayer damping is a mechanical engineering technique for suppression of vibration. An overview of constrainedlayer damping theory and. Piezoelectric actuators with modal controllers are used to improve the performance of vibration suppression from the passive constrained layer damping treatment. Topology optimization for minimizing frequency response of. Modelbased control of plate vibrations using active. The damping is dependant on the composition of a damping material and increases with damping layer thickness. These data can guide to specify the position of the constrained layer damping patch under pressure conditions. Constrained and free layer damping vibratec engelska. The governing equation of motion of the plate is derived on the basis of energy approach.
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