Constrainedlayer damping is a mechanical engineering technique for suppression of vibration. The use of weightless composite materials as constraining layers has been analyzed. Wave finite element method for modelling of constrained layer damping. The beam is made up of mild steel base layer and the ec2216 viscoelastic core layer constrained by cofe 2 o 4 magnetostrictive layer. Decidamp cld is a constrained layer, viscoelastic damping material, designed to reduce structural vibration and sound transmission within light gauge materials. A sustainable approach of damping treatment for aluminium. I would like to realize how does the damping work in the ansys transient dynamic analysis, will the program setting a model to calculate. Ansys simulations of vibration suppression using different damping materials that yielded results similar to the experimental results. Experimental investigation of damping performance of. Cld was employed through a sandwichtype structure constructed by attaching viscoelastic gel and thin metal sheets to the base. This presentation is given at santa clara ansys conference in 2014, where. The frequency response of the system is computed as the quotient between the translation of the mass and the rotation of the spindle. Topology optimization of passive constrained layer damping with.
Shearing mode constrained layer damping as seen in fig. Baruch is identified in chat paper as having suggested the shear damping mechanism, li the same year, a. Optimization design method for constrained damping layers. In this work a passive damping system used to reduce vibration is described. College of engineering, mathematics and physical sciences, university of exeter, exeter ex4 4qf, uk. Finite element analysis models were developed in ansys to compare the predicted frequency response functions with the. Ansys harmonic response analysis and damping ratio transient1 mechanical 1 aug 08 16. The uk health and safety executive hse reccomend damping, and constrained layer dampers as one of theirtop 10 noise control techniques. Wave finite element method for modelling of constrained layer.
The shear deformation occurring in the viscoelastic core is mainly responsible for the dissipation of energy. The harmonic load is a moment on the left end of the spindle. The results obtained from the numerical simulation are compared to that from theory to understand the range of applicability of the analytical solution. 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. 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. The purpose behind this study is to predict damping effects using method of passive viscoelastic constrained layer damping. Modeling of passive constrained layer damping as applied to a gun tube margaret z. Vibration control of beam with composite constrained layer treatment k. Constrained layer damping of a tennis racket constrained layer damping of a tennis racket harms, michael r cheng, pojen 19960501 00. Analytical modeling and damping optimization for a thin. Vibration control of beam with composite constrained layer. In this constrained layer damping treatment, the viscoelastic material was sandwiched between the surface of structure and thin facings of elastic metallic materials. Modeling technique of material damping properties in ansys.
In this mode, the two panels, one vibrating, the other constraining, are joined by. 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. The first term of the formula is the material damping, how to define this term and whats meaning of this term. A novel viscoelastic damping treatment for honeycomb. Vibration analysis of a beam with an active constraining. Traditionally, cld treatments are constructed of a very thin polymer layer constrained by a thicker metal layer. Finite element modeling of frequencydependent material. The model accounts for the geometrical and physical parameters of the slotted sol, the viscoelastic, layer the constraining layer, and the base structure.
Proceedings paper experimental and finite element analysis of standoff layer damping treatments for beams. Ansys mechanical has builtin topology optimization so engineers can easily determine where material can be removed for effective lightweighting of components. Constrained layer dampers cld are in widespread use for passive vibration damping, in. Constrained layer damping cld treatments have long provided a means to effectively impart damping to a structure. Development of constrained layer damping toolholder to. Thickness of the damping layer and constraining layer need to be. However, the performance of pcld treatments is achieved at the expense of adding considerable weight to the vibrating structures 1. Modeling of passive constrained layer damping as applied.
In this paper, a comprehensive finite element model of the standoff layer constrained damping treatment is developed. Constrained layer damping cld structure is proved to be effective in raising damping capacity for the thin plate and shell structures. The equations governing the vibration responses are derived using the energy approach and assumedmode method. Therefore, modeling of components covered with constrained layer damping is vital to optimize thicknesses of lower, middle and upper layers. Typically a viscoelastic or other damping material, is sandwiched between two sheets of stiff materials that lack sufficient damping by themselves. Ansys harmonic response analysis and damping ratio. Constrained layer dampers cld are in widespread use for passive vibration damping, in applications including aerospace structures.
Kress, optimization of segmented constrained layer damping with mathematical programming using strain energy analysis and modal data. Evolution of constrained layer damping using a cellular. The influence of viscoelastic core thickness and magnetostrictive layer thickness on the dynamic response. On the use of materialdependent damping in ansys for. Modeling viscoelasticdampingfordampeningadhesives 3,744 views. Passive constrained layer damping pcld treatments have been successfully used as effective means for damping out the vibration and noise of structures. Analysis of constrained layer treatment for damping in. Multiplelayer constrained viscoelastic damping structure, is hereby approved in. Based on the energy method and the assumed mode method, the analytical model was. Experimental and finite element analysis of standoff. Numerical simulation of the constrained damping treatment is done using ansys software.
Overall configuration of designed constrained layer damping toolholder the dimensions are in mm. Nafems parametric fem for dynamic response modeling of. For 5layer constrained damping plate, 5 layouts can be obtained depending on attaching constrained layers and damping layers onto one side single side or two sides double sides of the host layer and on whether the thicknesses of the 2 constrained layers and 2 damping layers are equal or not. A computational optimal control approach to the design of. Constrained layer damping cld systems can be applied to control the. Recently, febased commercial codes, such as ansys, abaqus, nastran. Topology optimization of passive constrained layer damping with partial coverage on plate.
In the second kind of damping treatments, the viscoelastic damping layer is constrained by the piezoelectric layer, whose longitudinal strain can be controlled in response to the structural. The damping plays a vital role in structural dynamic and acoustic performance of aluminium honeycomb sandwich structures. Finite element modeling techniques for constrained layer damping. The buckling, free vibration and damping of magnetic constrained layer damping mcld beam is analyzed. 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. The treatment is similar to the unconstrained layer type, except the viscoelastic material is constrained by another layer. Sasikumar department of mechanical engineering,kongu engineering college, perundurai, erode52, tamil nadu, india,pin638052. 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. Moreira r a and rodrigues j d 2004 constrained damping layer treatments. Get contact details, compile quote requests, browse product pictures and make contact.
Constrained layer damping cld is recognized as an effective means for. Ross, kerwin and unger rku model for passive viscoelastic damping has. Lowering mechanical noise floor in speakers pt 2 audioholics. Find 1 constrained layer damping uk company on businessmagnet. 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. The beam rotates in a vertical plane under the gravitational effect with variable angular velocity and carries an end mass. 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. Decidamp cld was developed to meet market noise reduction requirements across automotive, marine, industrial and oem markets.
Constrained layer damping has been extensively used since many years to damp flexural vibrations. Vibroacoustical analysis and design of a multiplelayer constrained. The viscoelastic damping treatment of skins is most common. A novel viscoelastic damping treatment for honeycomb sandwich structures. Study of the effect of composite constrained layers in. Mohammad gharaibeh sunybinghamton on jan 1, 20, at 1. The treatment is similar to the unconstrainedlayer type, except the viscoelastic material is constrained by another layer. 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.
This paper analyzes the damping effect of the constraining layer on plate type structures numerically using the fem software ansys. For this model i am doing a full harmonic analysis with material damping for the spindle. Cld efficiency became worst than the freelayer or extensional damping. Finding the best coating location with the fixed shape of the hard coating is an urgent need for the engineering application of the hardcoating damping. A very a common hybrid activepassive damping method for controlling vibration and noise of flexible structures is the socalled active constrained layer damping acld treatment, which typically. Full harmonic analysis with material damping ansys. The other is called active constraining layer damping acld treatment, where the elastic constraining layer in pcld is replaced by a piezoelectric layer. Hence, the regenerative chatter can be suppressed in the constrained layer damping toolholder. Passive standoff layer psol and slotted standoff layer ssol damping treatments are presently being implemented in many commercial and defense designs. Experiments are conducted to validate the analytical results. Influence of various arrangement on the vibration characteristics of constrained damping plate. Optimization of segmented constrained layer damping with. Noise and vibration control with constrained layer damping. Kerwin entitled damping of flexural waves by a constrained viscoelastic layer, dr.
These dampers are normally thin layers of a stiff material usually aluminium or steel laminated to a viscoelastic polymer which is often self adhesive. In this paper, a computational approach is adopted to solve the optimal control and optimal parameter selection problems of a rotating flexible beam fully covered with active constrained layer damping acld treatment. Effect of viscoelastic material thickness of damping treatment. Constrained layer dampers heathcote industrial plastics. Vibration and damping characteristics of cylindrical.
In this study, dynamic response of plates partially covered with constrained layer damping treatment is studied using ansys parametric design language apdl. Pdf topology optimization of passive constrained layer. However, this efficiency is balanced by greater complication in analysis and application. Singh, vibration and damping characteristics of beams with active constrained layer treatments under parametric variations. An alternative, the use of sustainable cork inserts to improve the damping of cores and the whole assembly is investigated in this study. The tools within ansys mechanical for topology optimization are fast, easy to use and included with all current licenses of the ansys mechanical product family. Vibration control of beams using standoff layer damping. A new method for enhancement of damping capabilities of segmented constrained layer damping material is proposed. When a ball strikes a racket with this damping system the vibration causes shearing strain in the viscoelastic material. Constrained layer damping cld is a type of passive damping treatment commonly used in. Are the alpha damping and beta damping related to frequency or independently. In a psol damping treatment, a standoff or spacer layer is added to a conventional passive constrained layer damping treatment.
Recently, febased commercial codes, such as ansys, ab a qus, n. In this paper, a study on optimal placement of hardcoating damping treatment for vibration reduction in the cantilever plate was presented. Constrained layer damping material, viscoelastic damping. From table 2 and table 3, it can be seen that for the same material in different position, damping effect of btdc is better than that of bdtc, which means the transition layer located between base layer and damping layer can increase shear deformation of the damping layer more than that of located between damping layer and constrained layer. Vibration and damping analysis of a multilayered composite.
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