## Structural Damping Examples

In structural dynamics the equilibrium of a vibrating system is usually described by a set of ordinary differential equations in the following form (see Clough, 1979, for example) M X"(t) + C X'(t) + K X(t) = F(t) (1. The stiffness proportional term contributes damping that is linearly proportional to. In such a case where. 016 Hz produced the spectrum shown as a dashed line in Figure 1. d : Damping ratio due to vibration control devices ÖNORM B4014 Teil 1, Code for Austria Wind (Actual Wind Load Code for Austria) 1st mode damping ratio ζ 1 (%) ζ 1 = ζ m + ζ c + ζ f ζ m: Structural damping ratio due to materials (%) 0. The estimation of structural damping is an in-exact science. For example, a damper consisting of a titanium flexure and viscoelastic damping material was designed for the rigid Hubble Space Telescope (HST) solar array, SA-3. Consequently, discomfort, damage, or outright structural failure caused by. 1 INTRODUCTION {XE "Viscous Damping" }In structural engineering, viscous velocity-dependent damping is very difficult to visualize for most real structural systems. 01 for steel, and. • Cast iron can have a damping factor of 0. 0 Introduction The race toward new heights has not been without its challenges. Results show that structural damping attenuates these waves and may modify the far-field acoustic pressure, mostly by reducing the scattered sound at structural resonances. Damping absorbs vibratory energy, converting it to heat. Structural Dynamics: Theory and Applications. Structural Damping Structural damping reduces both impact-generated and steady-state noises at their source. Thus, structural damping is suggested for models involving materials that exhibit frictional behavior or where local frictional effects are present throughout the model, such as dry rubbing of joints in a multi-link. Define damping ratio. Damping is an influence within or upon an oscillatory system that has the effect of reducing, restricting or preventing its oscillations. supplemental damping for velocity-dependent devices was proportioned based on the first mode of the structural motion. Francis Shangri-La Place, Mandaluyong City, Philippines. The higher the damping coefficient, the faster vibrations will be equalized, while lower damping coefficients would allow vibration to continue for a longer time. Damping, however, suppresses only resonant motion. TOPIC 6 Structural Dynamics III Structural Frequencies Rayleigh Proportional Damping (Example) 0. Hysteretic damping within the structural materials. This method is by far the simplest way to take care of vibrations in machinery. Ansys Structural nonlinear capabilities are needed to analyze for time-transient response of structural damping adhesives with accuracy. 15 Rayleigh Proportional Damping (Example) 5% Damping in Modes 1 & 2, 1 & 3, 1 & 4, or 1 & 5 0. One typical example is the assumption that the structures are proportionally damped. A major part of the book is devoted to damping of structures and many sources of damping are considered, as are the ways of changing damping using both active and passive methods. In mechanics, the internal friction may be one of the causes of such damping effect. Chapter 6 - Viscous & Viscoelastic Dampers CIE 626 - Structural Control Chapter 6 - Viscous-Viscoelastic Dampers 1. Normalized viscous and Coulomb friction resistance force, and displacement over one period. Experiments with these strips indicated that the bending modes die out in just a few cycles which are consistent with these damping estimates. An ANSYS user who is less experienced in utilizing material-dependent damping and the mode superposition method for transient dynamic analyses could end up with a structural model of zero damping. 72 (RC with cracks), 0. The damping factor. 6 is in fact equal to one half of the damping factor appropriate to the resonance frequency. Usually, the conversion between the damping ratio and loss factor damping is considered at a resonant frequency, and then \eta \approx 2 \zeta. Localized damping examples Figure 11. 1 percent can be assigned to steel. This paper investigates the consequence of using Rayleigh proportional damping in the analysis of inelastic structural systems. For example, soft viscoelastic Structural Damping Effects on Dynamic Instability of Subtangentially Loaded and Shear Deformable Beck's Columns. x(t) = sin. Three main types of damping are present in any mechanical system: • Internal damping • Structural damping • Fluid damping 1. A method to deal with general asymmetric systems is described in the appendix. Taking a different approach, Structural Damping: Applications in Seismic Response Modification considers the dynamic responses of structures with added damping devices as systems governed by the combined effect of the static stiffness, period, and damping―or "dynamic stiffness"―of the structure-device system. Structural dynamics is a type of structural analysis which covers the behavior of a structure subjected to dynamic (actions having high acceleration) loading. Damping, however, suppresses only resonant motion. Francis Shangri-La Place, Mandaluyong City, Philippines. KEYWORDS: effective damping ratio, damping coefficient, viscous damping, reinforced concrete, buildings. Knowledge of the level of damping in a dynamic system is important in the utilisation, analysis, and testing of the system. In structural systems, damping is more complex, appearing in several forms. Instructional Material Complementing FEMA 451, Design Examples SDOF Dynamics 3 - 11 Damping Damping Force Displacement Properties of Structural Damping (2) Damping vs displacement response is elliptical for linear viscous damper. set it in motion) we would observe the system oscillating as shown in Figure 1. The skillful application of the methods and analysis tools of structural dynamics is of paramount importance in the design of land, sea, air, and space vehicles. Download it once and read it on your Kindle device, PC, phones or tablets. Volume 5 contains examples of seismically isolated buildings and buildings with supplemental damping. The toolbox supports the proportional (Rayleigh) damping model and the modal damping model. Identification of Viscous Damping. Examples include viscous drag in mechanical systems, resistance in electronic oscillators, and absorption and scattering of light in optical oscillators. Modelling of damping is a very difficult issue because the level of damping in a structure can depend, for example, on the material damping that is dependent on the type of the. A static structural analysis determines the displacements, stresses, strains, and forces in structures or components caused by loads that do not induce significant inertia and damping effects. The fourth test evaluates the microspheres as a structural damping treatment in beams, measuring the beam bending stiffness loss factor. The utility of this passive damping technique is demonstrated experimentally, and examples showing the accuracy of the modal strain energy solution are presented. Defining linear uncoupled structural damping behavior. It dissipates vibrational energy in the structure before it can build up and radiate as sound. A curious effect of damping is that it results in increased amplitude at frequencies > 1. Dynamics of Undamped and Viscously Damped Systems. , slides on bearings) help to damp the system • To achieve more damping, a tuned mass damper or a shear damper should be used ζ ζ ζ ζ ζ 2 1 2 1 1 4 3 1 2 2 4. Damping comes in three main forms: hysteresis / structural damping, viscous damping, and Coulomb / dry-friction damping. For example, take a straight rectangular wing with no control surfaces. Structural Dynamics: Theory and Applications. 3D Frame, 3-story 3-bayX 3-bayZ, Reinforced-Concrete Section & Steel W-Section. Structural Analysis IV Chapter 5 - Structural Dynamics 5 Dr. Structural Analysis IV Chapter 5 – Structural Dynamics 10 Dr. In other cases, we might be a member of the design-build team along with the fabricator and installer, reporting to the general contractor. It consists of two superposed beams (Fig. Structural damping is accounted for using complex structural stiffness defined by K* = K(1+ iβ) where β is the loss factor (In most literature it is written as 2β). 4 Structural Damping Look again at the frog in Figure 1. Damping depends on many factors, such as material, shape, environment, velocity, etc. Viscoelastic materials are materials which dissipate system energy when deformed in shear. Ken Shye and Mark Richardson. From the structural point of view, the main sources of damping in a wing are the friction in joints, viscous damping due to air flow and material damping. • Particularly true with small air gap = electrostatic gap of 3 µm. Hysteretic or Structural Damping In general, the damping materials are polymers (synthetic rubbers) which have been suitably formulated to yield high damping capacities in the frequency and temperature ranges of interest. 3 with the properties m = 10 kg and k = 100 N/m and if give the mass a deflection of 20 mm and then release it (i. This damping decreases with the span length. For example, 5% damping ( ξ = 0. The exact nature of damping is difficult to define; fortunately. Consequently, discomfort, damage, or outright structural failure caused by. Regards, Sandeep. Example sentences with "structural damping", translation memory patents-wipo The present invention is a conductive isolator including a damping structure , a conductive bridge component positioned within the damping structure , axial contact points between the damping structure and the conductive bridge component and radial contact points. Define damping coefficient. LINEAR VISCOUS DAMPING Linear Viscous Damping Is a Property of the Computational Model And is not a Property of a Real Structure 19. Shearing action of a rubber compound placed. 1a) where, M, C and K are constant coefficient matrices of mass, damping and stiffness, respectively. Examples include viscous drag in mechanical systems, resistance in electronic oscillators, and absorption and scattering of light in optical oscillators. response modulus, to estimate damping. With the advent of E. Simulation examples are provided to illustrate the proposed method. This force causes an energy dissipation that is known as fluid damping. In this type of damping, the damping force is proportional to the displacement rather than the velocity as in the other damping options. We'll also go over some specific examples. 2 of the elastic stress, where this fraction is called the hysteresivity, h, or, equivalently, the structural damping coefficient. accurate damping estimates in design, there is still no one technique for estimating these values (Kareem and Gurley, 1995). Use the abs and angle functions to obtain real-valued magnitude and phase, respectively. Ansys Structural nonlinear capabilities are needed to analyze for time-transient response of structural damping adhesives with accuracy. Therefore, this form of damping can be used only when the displacement and velocity are exactly 90° out of phase. Hence, the equivalent viscous damping constant for Coulomb friction is given by C c= 4F c ˇ!X (13) 2. For example, a damper consisting of a titanium flexure and viscoelastic damping material was designed for the rigid Hubble Space Telescope (HST) solar array, SA-3. 2 An Initial Numerical Example If we consider a spring-mass system as shown in Figure 1. Identification of Viscous Damping. AREA = ENERGY DISSIPATED The force-displacement relationship for a linear viscous damper is an ellipse. The damping, which belongs to the maximum stress amplitude is am =D J ⋅σam. 4 (RC without cracks, PSRC) ζ c: Structural damping ratio due to. Damping, however, suppresses only resonant motion. Structural joint damping occurs due to the frictional affects which accompany slipping. Use the abs and angle functions to obtain real-valued magnitude and phase, respectively. The seismic resistant frames, with dampers, were designed to remain elastic under a Design Basis Earthquake. Vibration is a repetitive motion of objects in alternately opposite directions from the equilibrium position when that equilibrium has been disturbed. set it in motion) we would observe the system oscillating as shown in Figure 1. For example, a damper consisting of a titanium flexure and viscoelastic damping material was designed for the rigid Hubble Space Telescope (HST) solar array, SA-3. Inherently, reinforced concrete structures have low damping value, in the order of 5-10% of critical damping. When the bell is struck, it. Damping, in physics, restraining of vibratory motion, such as mechanical oscillations, noise, and alternating electric currents, by dissipation of energy. equipment may also effect some improvement. For example, a constant damping value of 0. A common example of damping is shock absorbers on a vehicle. In doing so, damping reduces the maximum amplitude of the vibration at resonance and increases the width of the amplification zone (see Figure 2). Define a free damped oscillation. The parameters of the proportional damping model are the mass and stiffness proportional damping parameters. There is thus an ideal range of structural damping to reduce both plate vibration and. Structural damping enables you to incorporate hysteretic behavior due to internal material friction by specifying a coefficient on the stiffness matrix. 3D Frame, 3-story 3-bayX 3-bayZ, Reinforced-Concrete Section & Steel W-Section. In this type of damping, the damping force is proportional to the displacement rather than the velocity as in the other damping options. geometric damping - same as radiation damping. structuralDamping(structuralmodel,'Alpha',a,'Beta',b) specifies proportional (Rayleigh) damping parameters a and b for a structuralmodel object. Shock absorbers in automobiles and carpet pads are examples of damping devices. Damping characteristics of a structure could be improved by addition of additional damping devices, Dampers; at the strategic locations within the structure; which could be very. Viscoelastic materials are materials which dissipate system energy when deformed in shear. An example is the Taipei 101 (Figure 9) building (509 m) in. geometric damping - same as radiation damping. d : Damping ratio due to vibration control devices ÖNORM B4014 Teil 1, Code for Austria Wind (Actual Wind Load Code for Austria) 1st mode damping ratio ζ 1 (%) ζ 1 = ζ m + ζ c + ζ f ζ m: Structural damping ratio due to materials (%) 0. The book is written from a vibration theory standpoint, with numerous worked examples which are relevant across a wide range of mechanical, aerospace and structural engineering applications. xii Dynamic Analysis with Generalised Damping Models damping is detailed in Chapter 9. Structural Damping = "Energy Dissipation" Example 10 Q X= F o k m 2. TOPIC 6 Structural Dynamics III Analysis of Elastic MDOF Systems. Structural Frequencies Rayleigh Proportional Damping (Example) 5% Damping in Modes 1 & 2, 1. The design of supplemental damping for displacement dependent devices was based on the stiffness of the structure. x(t) = sin. In structural systems, damping is more complex, appearing in several forms. A curious effect of damping is that it results in increased amplitude at frequencies > 1. There is four percent damping. It was mounted in the base of the mast to achieve the School of Astronautics, Beihang University, Beijing, P. In recently published literature, there are many examples of structural damping being used in computational models with little or no experimental or theoretical justification. Structural Measurement Systems, Inc. Forced, nonreso-nant vibration is rarely attenuated. Despite their superior structural characteristics, lightweight structures exhibit poor vibrational and acoustic isolation levels. supplemental damping for velocity-dependent devices was proportioned based on the first mode of the structural motion. Damping is an influence within or upon an oscillatory system that has the effect of reducing, restricting or preventing its oscillations. return damping factors only at modal frequencies, thus obscuring the broadband characteristics of the material. The critical damping constant, Cc. Structural Element Stiﬀness, Mass, and Damping Matrices CEE 541. The structure will return to the zero condition in the fastest. Introduction to DampingIntroduction to Damping Impact, Mechanisms, and Measurements Structural Damping Example 10 Q X= F o k m 2. In addition to the. Dynamic loads include people, wind, waves, traffic, earthquakes, and blasts. Damping absorbs vibratory energy, converting it to heat. Simulation examples are provided to illustrate the proposed method. This is primarily due to the reality of variable loading on these types of systems. Therefore, this form of damping can be used only when the displacement and velocity are exactly 90° out of phase. Structural Damping - a measure of energy dissipation in a vibrating structure that results in bringing it to a quiescent state. One of the less attractive features of Rayleigh damping however is that the achieved damping ratio $\xi$ varies with response frequency. Knowledge of the level of damping in a dynamic system is important in the utilisation, analysis, and testing of the system. AREA = ENERGY DISSIPATED The force-displacement relationship for a linear viscous damper is an ellipse. Hysteretic damping within the structural materials. For a frequency response model with damping, the results are complex. Unless a child keeps pumping a swing, its motion dies down because of damping. Dynamics of Undamped and Viscously Damped Systems. Structural damping assumes that the damping forces are proportional to the forces caused by stressing of the structure and are opposed to the velocity. The fourth test evaluates the microspheres as a structural damping treatment in beams, measuring the beam bending stiffness loss factor. • Note: Resulting simulation involves coupling of electrical, structural, and fluidic. , slides on bearings) help to damp the system • To achieve more damping, a tuned mass damper or a shear damper should be used ζ ζ ζ ζ ζ 2 1 2 1 1 4 3 1 2 2 4. • Cast iron can have a damping factor of 0. The toolbox supports the proportional (Rayleigh) damping model and the modal damping model. The use of even small amounts of damping in computational models involving nonlinear plastic response can significantly influence the response calculations. Identification of Viscous Damping. The stiffness proportional term contributes damping that is linearly proportional to. Critical damping definition: the minimum amount of viscous damping that results in a displaced system returning to its | Meaning, pronunciation, translations and examples. An important form is structural damping, which is produced by rubbing friction: stick-and-slip contact or impact. Suppose the car drives at speed V over a road with sinusoidal roughness. In order to do so, guidelines on how to estimate this load is indicated in each local code provision. For example, a basketball has a low damping coefficient (a good bounce back). not clearly defined for the mode superposition transient analysis. 3 with the properties m = 10 kg and k = 100 N/m and if give the mass a deflection of 20 mm and then release it (i. Ken Shye and Mark Richardson. In NX NASTRAN the definition is via the structural damping coefficient GE. Damping devices include all pins, bolts, gusset plates, brace extensions, and other components required to connect damping devices to other elements of the structure. A fully worked example of ASCE 7-10 wind load calculations. Damping, in physics, restraining of vibratory motion, such as mechanical oscillations, noise, and alternating electric currents, by dissipation of energy. Concrete structures reveal a higher damping than do steel structures, not only because concrete exhibits a higher material damping, but also. Use the abs and angle functions to obtain real-valued magnitude and phase, respectively. Described are six methods of extracting damping from data: the half-power. Build model 2. Linear damping models for structural vibration are examined] _rst the familiar dissipation!matrix model\ then the general linear model[ In both cases\ an approximation of small damping is used to obtain simple expressions for damped natural frequencies\ complex mode shapes\ and transfer functions[ Results for transfer functions can be. We just put in our four percent critical damping and I'm going to drag that new damping level into the subcase and it overwrites the previous damping level. It dissipates vibrational energy in the structure before it can build up and radiate as sound. 3 Fluid damping When a material is immersed in a fluid and there is relative motion between the fluid and the material, as a result the latter is subjected to a drag force. Dynamic Behavior of a Structural Component:. Damping depends on many factors, such as material, shape, environment, velocity, etc. structuralDamping(structuralmodel,'Alpha',a,'Beta',b) specifies proportional (Rayleigh) damping parameters a and b for a structuralmodel object. This enhanced successor is far more comprehensive with more analytical discussion, further consideration of damping sources. In terms of accuracy, there is very little difference between using 1 spline to connect the aerodynamic and structural DOF, and dividing the wing into two regions (such as an outer wing and an inner wing section) and using two splines. These parameters consist of structural and damping indicators. Identification of Viscous Damping. Enhanced damping value protects the structural system. amplifying small structural motions make this type of damping system more viable for suppressing wind-induced motions. This damping decreases with the span length. Damping example. We have to double check structural damping's off, Rayleigh damping's not on. 1 This paper, however, reviews only the half power approach using the response modulus and how it relates to the structural response of a mechanical component. For example, a basketball has a low damping coefficient (a good bounce back). At first, a discrete model of the stay cable with an NSD attached perpendicularly near the support is established. Through this we will be able to see how the modal description relates to de- scriptions in the spatial, time and frequency domains. Obtain modal solution Block Lancos(missing mass) PCG Lancos(missing mass) Supernode 3. Analysis Techniques One-degree-of-freedom systems - Natural frequency and critical. The toolbox supports the proportional (Rayleigh) damping model and the modal damping model. The utility of this passive damping technique is demonstrated experimentally, and examples showing the accuracy of the modal strain energy solution are presented. • Note: Resulting simulation involves coupling of electrical, structural, and fluidic. The c viscous damping force is a cosine function, and the structural damping force is the product of the coulomb. (19) The structural damping can be calculated as = ⋅D D V ⋅α ⋅αs am k h, (20) where V is the volume of the structure, α k is the cross section. Note that these examples are for the same specific. To remedy this, a new generalized proportional damping model is proposed. Structural damping enables you to incorporate hysteretic behavior due to internal material friction by specifying a coefficient on the stiffness matrix. The discussion is presented theoretically, as well as by example through the analysis of a simple five-story structure. In some machines vibrations are deliberately excited as part of the process, for example,. Our example covers damped free vibration and the logarithmic decrement. radiation damping - energy radiation into the surrounding medium. The damping factor. The c viscous damping force is a cosine function, and the structural damping force is the product of the coulomb. US4527371A US06/466,382 US46638283A US4527371A US 4527371 A US4527371 A US 4527371A US 46638283 A US46638283 A US 46638283A US 4527371 A US4527371 A US 4527371A Authority US United States Prior art keywords body structure damping viscoelastic material viscoelastic Prior art date 1981-06-15 Legal status (The legal status is an assumption and is not a legal conclusion. A damping coefficient is a material property that indicates whether a material will bounce back or return energy to a system. Structural Analysis IV Chapter 5 – Structural Dynamics 10 Dr. (Remember, it is the term that goes to zero slowest term that controls the rate. However, their. Use the abs and angle functions to obtain real-valued magnitude and phase, respectively. Dynamic loads include people, wind, waves, traffic, earthquakes, and blasts. Knowledge of the level of damping in a dynamic system is important in the utilisation, analysis, and testing of the system. This paper investigates the consequence of using Rayleigh proportional damping in the analysis of inelastic structural systems. 15 Rayleigh Proportional Damping (Example) 5% Damping in Modes 1 & 2, 1 & 3, 1 & 4, or 1 & 5 0. x(t) = sin. Structural integrity and comfort are therefore compromised. A major part of the book is devoted to damping of structures and many sources of damping are considered, as are the ways of changing damping using both active and passive methods. For a frequency response model with damping, the results are complex. 15 Rayleigh Proportional Damping (Example) 5% Damping in Modes 1 & 2, 1 & 3, 1 & 4, or 1 & 5 0. For a frequency response model with damping, the results are complex. generic 2D Frame, N-story N-bay, Reinforced-Concrete Section & Steel W-Section 8 3D Structural Modeling & Analysis Examples 8. Suspension and cable stayed bridges typically exhibit a very low amount of structural damping. Structural Damping – a measure of energy dissipation in a vibrating structure that results in bringing it to a quiescent state. Again it can be divided into Structural as well as Material based on how the damping p. Structural damping enables you to incorporate hysteretic behavior due to internal material friction by specifying a coefficient on the stiffness matrix. Results show that structural damping attenuates these waves and may modify the far-field acoustic pressure, mostly by reducing the scattered sound at structural resonances. The structural damping of a tower can be increased by the application of a damping pad, as shown in Figure 3. Example sentences with "structural damping", translation memory patents-wipo The present invention is a conductive isolator including a damping structure , a conductive bridge component positioned within the damping structure , axial contact points between the damping structure and the conductive bridge component and radial contact points. Shock absorbers in automobiles and carpet pads are examples of damping devices. Define a free damped oscillation. Under this resonant condition, the structural amplification factor is a function of the structure's damping, as shown in Figure 1. Parametric Sensitivity of Damped Systems. Example 1: 750 HP fuel gas booster compressor. The damping, which belongs to the maximum stress amplitude is am =D J ⋅σam. If the bounce is caused by an unwanted vibration or shock, a high damping coefficient in the material will diminish the response. Example sentences with "structural damping", translation memory patents-wipo The present invention is a conductive isolator including a damping structure , a conductive bridge component positioned within the damping structure , axial contact points between the damping structure and the conductive bridge component and radial contact points. Thus, structural damping is suggested for models involving materials that exhibit frictional behavior or where local frictional effects are present throughout the model, such as dry rubbing of joints in a multi-link. dma = findStructuralDamping(structuralmodel. For example, a constant damping value of 0. Download it once and read it on your Kindle device, PC, phones or tablets. Structural Vibration: Analysis and Damping benefits from my earlier book Structural Vibration Analysis: Modelling, Analysis and Damping of Vibrating Structures which was published in 1983 but is now out of print. If you assume 10% critical damping, Eq. Parametric Sensitivity of Damped Systems. Define damping ratio. Modal testing has traditionally been used to confirm the validity of finite element models of structures. along with the structural damping ratio predicted for each. Derive formulae that describe damped vibrations. Because e−t goes to 0 more slowly than e−3t/2 it controls the rate at which x goes to 0. Damping absorbs vibratory energy, converting it to heat. An example is the Taipei 101 (Figure 9) building (509 m) in. Structural Dynamics D. This Technical Memorandum provides a quick reference for some of the more common approaches used in dynamics analysis. In mechanics, the internal friction may be one of the causes of such damping effect. In structural systems, damping is more complex, appearing in several forms. Damped Free Vibration Example 4 For a viscously damped system, free vibration trace measurements show a 60% reduction in vibration amplitude after 15 cycles. Critical damping definition: the minimum amount of viscous damping that results in a displaced system returning to its | Meaning, pronunciation, translations and examples. Structural damping with friction beams The double beam is an academic example which demonstrates the main features of a friction damped system. Viscoelastic materials are materials which dissipate system energy when deformed in shear. modal parameters and monitor the structural response under strong wind conditions. Because e−t goes to 0 more slowly than e−3t/2 it controls the rate at which x goes to 0. 2 of the elastic stress, where this fraction is called the hysteresivity, h, or, equivalently, the structural damping coefficient. Structural damping is a measure of energy dissipation in a vibrating structure that results in bringing the structure to a quiescent state. This is obviously not feasible, and so we make conservative assumptions based upon the resources we have available (see recommended damping values above). Example sentences with "structural damping", translation memory patents-wipo The present invention is a conductive isolator including a damping structure , a conductive bridge component positioned within the damping structure , axial contact points between the damping structure and the conductive bridge component and radial contact points. KEYWORDS: effective damping ratio, damping coefficient, viscous damping, reinforced concrete, buildings. 4 OpenSees Example 6. Forced, nonreso-nant vibration is rarely attenuated. radiation damping - energy radiation into the surrounding medium. Therefore, damping input shows an enhanced accuracy and a reduced calculation scale. Analysis Techniques One-degree-of-freedom systems - Natural frequency and critical. We first give a damping design method and interface whereby the user can set the damping properties so that motion aligned with each of a few chosen example deformations is damped by an independently prescribed amount, whereas the rest of the deformation space follows standard Rayleigh damping, or any viscous damping. Damping is basically reducing the oscillations (or magnitude of oscillations) through loss of energy. We have to double check structural damping's off, Rayleigh damping's not on. A wealth of empirical data supports the notion of structural damping in metallic structures26,27 that is proportional to dis-placement (strain) and in phase with velocity. damping definition: nounThe gradual reduction of excessive oscillation, vibration, or signal intensity, and therefore of instability in a mechanical or electrical device, by a substance or some aspect of the device. Another potential method of adding passive damping. 2 Damping treatment examples. The strategy to select the most suitable materials is based on the analysis of a set of parameters. A common example of damping is shock absorbers on a vehicle. Next Steps. Moreover, damping appears to be predominantly concentrated at joints. 2 An Initial Numerical Example If we consider a spring-mass system as shown in Figure 1. The damping discussion may indicate that all structures with damping require damped free vibration analysis. In hysteresis damping, some of the energy involved in the repetitive internal deformation and restoration to original shape is dissipated in the form of random vibrations of the crystal lattice in solids and random kinetic energy of the. Use the abs and angle functions to obtain real-valued magnitude and phase, respectively. 4 based on the experience achieved with the construction of the bridges of the Honshu-Shikoku. and therefore it is difficult to predict. This example shows how to include damping in the transient analysis of a simple cantilever beam. The parameters of the proportional damping model are the mass and stiffness proportional damping parameters. The effects of both spatial distribution and frequency content of excitations as well as structural dynamic characteristics on the evaluation of Rayleigh damping coefficients were investigated with a five-story building structure. Shock absorbers in automobiles and carpet pads are examples of damping devices. geometric damping - same as radiation damping. Therefore, this form of damping can be used only when the displacement and velocity are exactly 90° out of phase. The amplitude of the free vibration in this system will decay with the factor. AREA = ENERGY DISSIPATED The force-displacement relationship for a linear viscous damper is an ellipse. Martínez Analysis of Structural Damping Chapter 1. Thus, structural damping is suggested for models involving materials that exhibit frictional behavior or where local frictional effects are present throughout the model, such as dry rubbing of joints in a multi-link. When the bell is struck, it. We just put in our four percent critical damping and I'm going to drag that new damping level into the subcase and it overwrites the previous damping level. For example, a constant damping value of 0. accurate damping estimates in design, there is still no one technique for estimating these values (Kareem and Gurley, 1995). INTRODUCTION The response of buildings to earthquake ground shaking is a complex process. Let us begin with a review of how structural response can be represented in different domains. Thus, structural damping is suggested for models involving materials that exhibit frictional behavior or where local frictional effects are present throughout the model, such as dry rubbing of joints in a multi-link structure. We just put in our four percent critical damping and I'm going to drag that new damping level into the subcase and it. For example, we might work under contract with the developer as designer and owner's representative. Structural Dynamics Department of Civil and Environmental Engineering Duke University Henri P. 4, Read only 15. 4 (RC without cracks, PSRC) ζ c: Structural damping ratio due to. Underdamped Oscillator. Identification of Non-viscous Damping. The method is illustrated by some simple examples, also demonstrating the effect of damper characteristics on optimal tuning and on the amount of damping obtained in the structure. The behavior is shown for one-half and one-tenth of the critical damping factor. Introduction to Damping Models and Analysis Methods. ω 2π, with peak amplitude. In order to do so, guidelines on how to estimate this load is indicated in each local code provision. 1 OpenSees Example 7. 05 ) at the first natural frequency of the structure ( ω i = ω 1), and at ω j = 188. Structural damping can be defined only for mode-based steady-state dynamic and random response procedures. Thus, structural damping is suggested for models involving materials that exhibit frictional behavior or where local frictional effects are present throughout the model, such as dry rubbing of joints in a multi-link structure. …Three levels of damping are used,…and the responses are compared between them. In this case, the damping was estimated at 1. Parametric Sensitivity of Damped Systems. Introduction to DampingIntroduction to Damping Impact, Mechanisms, and Measurements Presented By Michael L. The damping discussion may indicate that all structures with damping require damped free vibration analysis. x(t) = sin. Structural Damping = "Energy Dissipation" Example 10 Q X= F o k m 2. response calculation. When the materials are deformed, energy is absorbed and dissipated by the material itself. Enhanced damping value protects the structural system. In doing so, damping reduces the maximum amplitude of the vibration at resonance and increases the width of the amplification zone (see Figure 2). To investigate the effect/difference of damping, I have assigned a constant damping value of very high 20% to all components of the brake model (4 pieces). 1a) where, M, C and K are constant coefficient matrices of mass, damping and stiffness, respectively. Another potential method of adding passive damping. 4 (RC without cracks, PSRC) ζ c: Structural damping ratio due to. Use the abs and angle functions to obtain real-valued magnitude and phase, respectively. The damping forces due to structural damping are intended to represent frictional effects (as distinct from viscous effects). The Damping Factor A third force, damping, is at work throughout the speed range. The second argument must be 'proportional'. Defining linear uncoupled structural damping behavior. Dynamic loads include people, wind, waves, traffic, earthquakes, and blasts. The damping model is basic viscous damping distributed uniformly through the volume of the beam. Rayleigh damping does afford certain mathematical conveniences and is widely used to model internal structural damping. An example of this calculation on an FRF is shown in Figure 1. Damping depends on many factors, such as material, shape, environment, velocity, etc. This reduction corresponds to increasing the basic structural damping by 4%. A major part of the book is devoted to damping of structures and many sources of damping are considered, as are the ways of changing damping using both active and passive methods. However, structural vibration caused by external excitation sources such as ground vibration, cross winds or turbulence from adjacent buildings can only be controlled by damping. 3 with the properties m = 10 kg and k = 100 N/m and if give the mass a deflection of 20 mm and then release it (i. In order for the motion to be periodic, the damping ratio must be limited to the range 0 \le \zeta < 1. Structural damping assumes that the damping forces are proportional to the forces caused by stressing of the structure and are opposed to the velocity. Structural Damping Structural damping reduces both impact-generated and steady-state noises at their source. Simulation examples are provided to illustrate the proposed method. Comparing the performance of the electromagnetic damper to that of viscous fluid dampers, the maximum damping density of electromagnetic dampers is, at best, equal to that of hydraulic dampers, but with a price at least five times higher. To investigate the effect/difference of damping, I have assigned a constant damping value of very high 20% to all components of the brake model (4 pieces). This is a good example of a paradox at work, that is, a structure that is stiff yet flexible when required to be so as to be able to provide structural damping against earthquakes. Because it's difficult to analytically calculate the exact amount of damping in most structural and mechanical systems, the. In NX NASTRAN the definition is via the structural damping coefficient GE. Example 1: 750 HP fuel gas booster compressor. China Corresponding author:. Damping absorbs vibratory energy, converting it to heat. A static structural analysis determines the displacements, stresses, strains, and forces in structures or components caused by loads that do not induce significant inertia and damping effects. US4527371A US06/466,382 US46638283A US4527371A US 4527371 A US4527371 A US 4527371A US 46638283 A US46638283 A US 46638283A US 4527371 A US4527371 A US 4527371A Authority US United States Prior art keywords body structure damping viscoelastic material viscoelastic Prior art date 1981-06-15 Legal status (The legal status is an assumption and is not a legal conclusion. Identification of Non-viscous Damping. structuralDamping(structuralmodel,'Alpha',a,'Beta',b) specifies proportional (Rayleigh) damping parameters a and b for a structuralmodel object. This is a good example of a paradox at work, that is, a structure that is stiff yet flexible when required to be so as to be able to provide structural damping against earthquakes. Knowledge of the level of damping in a dynamic system is important in the utilisation, analysis, and testing of the system. This force causes an energy dissipation that is known as fluid damping. Addeddate 2015-09-02 21:19:26 Identifier StructuralVibrationAnalysisAndDampingC. 1 Physics 106 Lecture 12 Oscillations - II SJ 7th Ed. If you have. response modulus, to estimate damping. The structure will return to the zero condition in the fastest. Martínez Analysis of Structural Damping 1. 72 (RC with cracks), 0. Francis Shangri-La Place, Mandaluyong City, Philippines. For a frequency response model with damping, the results are complex. Chapter 12: Seismically Isolated Structures 12-3 isolators (and supplementary damping devices) could have been used equally well in the example. This essentially maximizes a combination of the aerodynamic damping and aeroe-. Instructional Material Complementing FEMA 451, Design Examples SDOF Dynamics 3 - 11 Damping Damping Force Displacement Properties of Structural Damping (2) Damping vs displacement response is elliptical for linear viscous damper. In recently published literature, there are many examples of structural damping being used in computational models with little or no experimental or theoretical justification. This is obviously not feasible, and so we make conservative assumptions based upon the resources we have available (see recommended damping values above). The numerous worked examples liberally distributed throughout the text, amplify and clarify the theoretical analysis presented. In doing so, damping reduces the maximum amplitude of the vibration at resonance and increases the width of the amplification zone (Figure 2). All systems will posses some fundamental damping property. If you want examples where the innate damping is useful against structural failure of the same component, yes I agree, that is rare. 2 of the elastic stress, where this fraction is called the hysteresivity, h, or, equivalently, the structural damping coefficient. Viscoelastic Damping System:In a system similar to a Viscous Damping system, the use of viscoelastic damping material, such as rubber, has been used for some applications. Chapter 6 - Viscous & Viscoelastic Dampers CIE 626 - Structural Control Chapter 6 - Viscous-Viscoelastic Dampers 1. The higher the damping coefficient, the faster vibrations will be equalized, while lower damping coefficients would allow vibration to continue for a longer time. ωt, and (8) v(t) =x (t) =ωcos ωt (9) The resulting coulomb damping force is obviously a square wave of period. In addition there is the possibility to assign damping values in the Engineering Data Materials in Ansys. accurate damping estimates in design, there is still no one technique for estimating these values (Kareem and Gurley, 1995). In structural design against dynamic loads, damping is perhaps the least understood aspect. Damping comes in three main forms: hysteresis / structural damping, viscous damping, and Coulomb / dry-friction damping. As our example, we will take the response of a bell, which is a lightly damped structure. The book is written from a vibration theory standpoint, with numerous worked examples which are relevant across a wide range of mechanical, aerospace and structural engineering applications. In structural dynamics the equilibrium of a vibrating system is usually described by a set of ordinary differential equations in the following form (see Clough, 1979, for example) M X"(t) + C X'(t) + K X(t) = F(t) (1. Otis' elevator and the introduction of structural steel, towers and skyscrapers have continued to soar. dma = findStructuralDamping(structuralmodel. Use the abs and angle functions to obtain real-valued magnitude and phase, respectively. We first give a damping design method and interface whereby the user can set the damping properties so that motion aligned with each of a few chosen example deformations is damped by an independently prescribed amount, whereas the rest of the deformation space follows standard Rayleigh damping, or any viscous damping. Damping systems are often implemented in order to solve this problem. In physics, damping is any effect that tends to reduce the amplitude of vibrations. For example, General Electric has investigated the potential of viscoelastic material for use in lightly damped space structures (Rogers et al 1988). For example, 5% damping ( ξ = 0. -3- For purely viscous damping, which is easy to analyse theoretically,. Addeddate 2015-09-02 21:19:26 Identifier StructuralVibrationAnalysisAndDampingC. The structural damping of a tower can be increased by the application of a damping pad, as shown in Figure 3. For example, a basketball has a low damping coefficient (a good bounce back). As an example, let's assume that the displacement is sinusoidal so. Although data of damping ratio for different types of bridges have been collected through such field vibration tests, there have not been many examples of newly constructed long-span bridges built in China. response calculation. Consequently, discomfort, damage, or outright structural failure caused by. external means, such as joint friction, air damping and absorbers (structural damping or system damping), or by intrinsic means, including the use of suitable high- damping materials (material damping). A wealth of empirical data supports the notion of structural damping in metallic structures26,27 that is proportional to dis-placement (strain) and in phase with velocity. AREA = ENERGY DISSIPATED The force-displacement relationship for a linear viscous damper is an ellipse. The proposed method requires only the measurements of natural frequencies and modal damping factors which can be obtained using a point measurement of the frequency response function (FRF). Lower-limit values of the structural damping ratio for suspension and cable stayed bridge vibration modes driven by the cables are systematized in Table 21. When the materials are deformed, energy is absorbed and dissipated by the material itself. The structure will return to the zero condition in the fastest. Structural Damping Structural damping reduces both impact-generated and steady-state noises at their source. We first give a damping design method and interface whereby the user can set the damping properties so that motion aligned with each of a few chosen example deformations is damped by an independently prescribed amount, whereas the rest of the deformation space follows standard Rayleigh damping, or any viscous damping. Damped Free Vibration Example 4 For a viscously damped system, free vibration trace measurements show a 60% reduction in vibration amplitude after 15 cycles. In this type of damping, the damping force is proportional to the displacement rather than the velocity as in the other damping options. 016 Hz produced the spectrum shown as a dashed line in Figure 1. 08 (Steel) 0. For example, soft viscoelastic Structural Damping Effects on Dynamic Instability of Subtangentially Loaded and Shear Deformable Beck's Columns. If you have. Introduction to Structural Dynamics 1 Examples of dynamics in structures are: is the damping ratio which is the ratio of the damping coefficient, c, to the critical value of the damping coefficient ccr; we will see what these terms physically mean. Although there are three distinct damping cases, only the underdamped case (ζ< 1) is important for structural dynamics applications. Let's just double check it's worked properly. Important ex-ceptions to the structural damping model are found in viscoelastic. An example of this calculation on an FRF is shown in Figure 1. Structural Damping - a measure of energy dissipation in a vibrating structure that results in bringing it to a quiescent state. For low values of damping (<2%), the structural amplification is over 25x, which indicates that even a low level of crowd force may cause a large acceleration response. Introduction to Damping Models and Analysis Methods. Obtaining the correct data for the materials and components in a structure is, however, often challenging. To investigate the effect/difference of damping, I have assigned a constant damping value of very high 20% to all components of the brake model (4 pieces). reducing structural vibration. In structural dynamics the equilibrium of a vibrating system is usually described by a set of ordinary differential equations in the following form (see Clough, 1979, for example) M X"(t) + C X'(t) + K X(t) = F(t) (1. Analysis Techniques One-degree-of-freedom systems - Natural frequency and critical. x(t) = sin. A static structural analysis determines the displacements, stresses, strains, and forces in structures or components caused by loads that do not induce significant inertia and damping effects. ω 2π, with peak amplitude. The discussion is presented theoretically, as well as by example through the analysis of a simple five-story structure. In hysteresis damping, some of the energy involved in the repetitive internal deformation and restoration to original shape is dissipated in the form of random vibrations of the crystal lattice in solids and random kinetic energy of the. The c viscous damping force is a cosine function, and the structural damping force is the product of the coulomb. Structural damping is accounted for using complex structural stiffness defined by K* = K(1+ iβ) where β is the loss factor (In most literature it is written as 2β). Unless a child keeps pumping a swing, its motion dies down because of damping. detailed examples of the application of auxiliary damping devices in Australia, Canada, China, Japan, and the United States. Another form of external damping is fluid damping. generic 2D Frame, N-story N-bay, Reinforced-Concrete Section & Steel W-Section 8 3D Structural Modeling & Analysis Examples 8. Because damping in typical structures is small, approximations have been made to facilitate the design process with negligible effects. A common example of damping is shock absorbers on a vehicle. Damping, in physics, restraining of vibratory motion, such as mechanical oscillations, noise, and alternating electric currents, by dissipation of energy. In addition to the Standard and the Provisions, the following documents are either referenced directly,. 2 of the elastic stress, where this fraction is called the hysteresivity, h, or, equivalently, the structural damping coefficient. In addition there is the possibility to assign damping values in the Engineering Data Materials in Ansys. This book is a result of last 15 years of research and teaching in the area of damped vibration problems. - [Instructor] This video shows setting up…and running a Transient Response Analysis. Hysteretic damping within the structural materials. response modulus, to estimate damping. In physics, damping is any effect that tends to reduce the amplitude of vibrations. The utility of this passive damping technique is demonstrated experimentally, and examples showing the accuracy of the modal strain energy solution are presented. Suppose the car drives at speed V over a road with sinusoidal roughness. 2 An Initial Numerical Example If we consider a spring-mass system as shown in Figure 1. The 2012 IBC Structural/Seismic Design Manual provides a step-by-step approach to applying the structural provisions of the 2012 International Building Code® and referenced standards. Damping absorbs vibratory energy, converting it to heat. The same data (bandwidth) can be obtained from phase angle information employing a modal circle. The estimation of structural damping is an in-exact science. 1 INTRODUCTION {XE "Viscous Damping" }In structural engineering, viscous velocity-dependent damping is very difficult to visualize for most real structural systems. AREA = ENERGY DISSIPATED The force-displacement relationship for a linear viscous damper is an ellipse. The numerous worked examples liberally distributed throughout the text, amplify and clarify the theoretical analysis presented. In physical systems, damping is produced by processes that dissipate the energy stored in the oscillation. For example, take a straight rectangular wing with no control surfaces. accurate damping estimates in design, there is still no one technique for estimating these values (Kareem and Gurley, 1995). Therefore, damping input shows an enhanced accuracy and a reduced calculation scale. The chapter defines a damping device as: "A flexible structural element of the damping system that dissipates energy due to relative motion of each end of the device. Each of these mechanisms is analyzed to em-phasize the factors important in the utilization of damping as an engineering property. A static structural analysis determines the displacements, stresses, strains, and forces in structures or components caused by loads that do not induce significant inertia and damping effects. The damping, which belongs to the maximum stress amplitude is am =D J ⋅σam. Structural damping assumes that the damping forces are proportional to the forces caused by stressing of the structure and are opposed to the velocity. 10 for rubber The inclusion of damping has the greatest effect in the vicinity of resonance, decreasing the vibration amplitude. SUPPLEMENTARY DAMPING SYSTEMS Contractual Arrangements We can work in various roles within a project. Underdamped Oscillator. The numerous worked examples liberally distributed throughout the text, amplify and clarify the theoretical analysis presented. Obtain spectrum solution. The damping discussion may indicate that all structures with damping require damped free vibration analysis. This force causes an energy dissipation that is known as fluid damping. …The file is plate_1_begin. From the structural point of view, the main sources of damping in a wing are the friction in joints, viscous damping due to air flow and material damping. In hysteresis damping, some of the energy involved in the repetitive internal deformation and restoration to original shape is dissipated in the form of random vibrations of the crystal lattice in solids and random kinetic energy of the. ω 2π, with peak amplitude. It consist of two components: one is a damping washer or pad between the anchor bolt and the chair plate; and the other is a large pad that fits between the base plate and leveling, or shim, plate on top of the concrete foundation. The concrete mass block is about. 4 OpenSees Example 6. AB - This paper considers a passive damping method that can be applied to a wide range of structural geometries including machine tool bases and components. The use of even small amounts of damping in computational models involving nonlinear plastic response can significantly influence the response calculations. LINEAR VISCOUS DAMPING Linear Viscous Damping Is a Property of the Computational Model And is not a Property of a Real Structure 19. 2 of the elastic stress, where this fraction is called the hysteresivity, h, or, equivalently, the structural damping coefficient. The c viscous damping force is a cosine function, and the structural damping force is the product of the coulomb. Other damping mechanisms besides coulomb and structural damping undoubtedly exist, particularly for high velocity airfoils, or if hydraulic or iron core magnetic sub-systems are included in the. with structural damping terms HironoriMichihisa∗ Department of Mathematics, Graduate School of Science, Hiroshima University Higashi-Hiroshima 739-8526, Japan Abstract After GGH model was proposed in [2], Ikehata-Iyota [12] showed decay estimates for the total energy of solutions to GGH equations uniformly in the initial data. Obtaining the correct data for the materials and components in a structure is, however, often challenging. On completion of this tutorial you should be able to do the following. ωt, and (8) v(t) =x (t) =ωcos ωt (9) The resulting coulomb damping force is obviously a square wave of period. The numerous worked examples liberally distributed throughout the text, amplify and clarify the theoretical analysis presented. The Damping Factor A third force, damping, is at work throughout the speed range. o A major form of structural damping is the slip damping that results from energy. It consists of two superposed beams (Fig. • Of course, damping is present in the form of air damping. A common example of damping is shock absorbers on a vehicle. Knowledge of the level of damping in a dynamic system is important in the utilisation, analysis, and testing of the system. 3 with the properties m = 10 kg and k = 100 N/m and if give the mass a deflection of 20 mm and then release it (i. Simulation examples are provided to illustrate the proposed method. It was mounted in the base of the mast to achieve the School of Astronautics, Beihang University, Beijing, P. TOPIC 6 Structural Dynamics III Analysis of Elastic MDOF Systems. Structural Damping – a measure of energy dissipation in a vibrating structure that results in bringing it to a quiescent state. Use the abs and angle functions to obtain real-valued magnitude and phase, respectively. The use of even small amounts of damping in computational models involving nonlinear plastic response can significantly influence the response calculations. Caprani Contents 1. detailed examples of the application of auxiliary damping devices in Australia, Canada, China, Japan, and the United States. As our example, we will take the response of a bell, which is a lightly damped structure. We have to double check structural damping's off, Rayleigh damping's not on. The book is written from a vibration theory standpoint, with numerous worked examples which are relevant across a wide range of mechanical, aerospace and structural engineering applications. Damping characteristics of a structure could be improved by addition of additional damping devices, Dampers; at the strategic locations within the structure; which could be very. In lung tissues, for example, the frictional stress is almost invariably between 0. We also use viscoelastic rubbers, more specifically polyurethane, for damping in our model. Usually, the conversion between the damping ratio and loss factor damping is considered at a resonant frequency, and then \eta \approx 2 \zeta. Dynamic loads include people, wind, waves, traffic, earthquakes, and blasts. The method is illustrated by some simple examples, also demonstrating the effect of damper characteristics on optimal tuning and on the amount of damping obtained in the structure. Drake for Brush Beryllium & Composites. For this reason a major part of the book is devoted to the damping of structural vibrations. COMSOL Multiphysics provides you with a broad range of options for describing damping. Under this resonant condition, the structural amplification factor is a function of the structure's damping, as shown in Figure 1. not clearly defined for the mode superposition transient analysis. Chapter 6 - Viscous & Viscoelastic Dampers CIE 626 - Structural Control Chapter 6 - Viscous-Viscoelastic Dampers 1. Structural Vibration: Analysis and Damping benefits from my earlier book Structural Vibration Analysis: Modelling, Analysis and Damping of Vibrating Structures which was published in 1983 but is now out of print. TOPIC 6 Structural Dynamics III Structural Frequencies Rayleigh Proportional Damping (Example) 0. Moreover, damping appears to be predominantly concentrated at joints. Chapter 6 - Viscous & Viscoelastic Dampers CIE 626 - Structural Control Chapter 6 - Viscous-Viscoelastic Dampers 1. 08 (Steel) 0. Any structure can be subjected to dynamic loading. Derive formulae that describe damped vibrations. Build model 2. The 2012 IBC Structural/Seismic Design Manual provides a step-by-step approach to applying the structural provisions of the 2012 International Building Code® and referenced standards. ; Example 3: Brownfield project involving the installation of new. In this type of damping, the damping force is proportional to the displacement rather than the velocity as in the other damping options. It consist of two components: one is a damping washer or pad between the anchor bolt and the chair plate; and the other is a large pad that fits between the base plate and leveling, or shim, plate on top of the concrete foundation. 4 based on the experience achieved with the construction of the bridges of the Honshu-Shikoku. • Note: Resulting simulation involves coupling of electrical, structural, and fluidic. This enhanced successor is far more comprehensive with more analytical discussion, further consideration of damping sources. [7] minimized the structural state vector of the ﬁnal time steps of an initially ﬂuttering airfoil. -3- For purely viscous damping, which is easy to analyse theoretically,. Parametric Sensitivity of Damped Systems. For low values of damping (<2%), the structural amplification is over 25x, which indicates that even a low level of crowd force may cause a large acceleration response. In this type of damping, the damping force is proportional to the displacement rather than the velocity as in the other damping options. Damping depends on many factors, such as material, shape, environment, velocity, etc. Structural Engineering and the Edexcel HNC/D module Mechanical Science. Let us begin with a review of how structural response can be represented in different domains. Structural joint damping occurs due to the frictional affects which accompany slipping. To really know the damping you would have to build the stack, erect it, and then do measurements on the stack to measure the damping. The effect of wind on structures during typhoon is one of the critical loads that a Structural Engineer should anticipate. Taking a different approach, Structural Damping: Applications in Seismic Response Modification considers the dynamic responses of structures with added damping devices as systems governed by the combined effect of the static stiffness, period, and damping—or "dynamic stiffness"—of the structure-device system. Structural damping with friction beams The double beam is an academic example which demonstrates the main features of a friction damped system. A major part of the book is devoted to damping of structures and many sources of damping are considered, as are the ways of changing damping using both active and passive methods. 1 This paper, however, reviews only the half power approach using the response modulus and how it relates to the structural response of a mechanical component. In addition there is the possibility to assign damping values in the Engineering Data Materials in Ansys. o A major form of structural damping is the slip damping that results from energy. The Damping Factor A third force, damping, is at work throughout the speed range. For a frequency response model with damping, the results are complex.