Passive Damping Concepts for Tubular Beams with Partial Rotational and Translational End Restraints (original) (raw)
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Experimental Passive Damping Concepts for Space Structures with Tubular Members
2016
Performance of potential passive damping concepts is investigated for a long tubular aluminum alloy member and a two-bar grillage structure. The members are restrained partially at the ends and are of the type being considered for possible use in the construction of future outer space stations. Four different passive damping concepts are studied under free and forced vibration and include nylon brush, wool swab, copper brush and silly-putty-inchamber dampers installed inside the hollow space of the tubular member(s). It is found that the silly-putty-inchamber and the wool swab dampers provide effective
Structural Vibration: Analysis and Damping_C. Beards
Structural Vibration: Analysis and Damping, 2006
Many structures suffer from unwanted vibrations and, although careful analysis at the design stage can minimise these, the vibration levels of many structures are excessive. In this book the entire range of methods of control, both by damping and by excitation, is described in a single volume. Clear and concise descriptions are given of the techniques for mathematically modelling real structures so that the equations which describe the motion of such structures can be derived. This approach leads to a comprehensive discussion of the analysis of typical models of vibrating structures excited by a range of periodic and random inputs. Careful consideration is also given to the sources of excitation, both internal and external, and the effects of isolation and transmissability. 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. The numerous worked examples liberally distributed throughout the text, amplify and clarify the theoretical analysis presented. Particular attention is paid to the meaning and interpretation of results, further enhancing the scope and applications of analysis. Over 80 problems are included with answers and worked solutions to most. This book provides engineering students, designers and professional engineers with a detailed insight into the principles involved in the analysis and damping of structural vibration while presenting a sound theoretical basis for further study. Suitable for students of engineering to first degree level and for designers and practising engineers Numerous worked examples Clear and easy to follow
Active Damping Of Tension Truss Structures
WIT Transactions on the Built Environment, 1970
This paper presents a strategy for active damping of cable structures. The control algorithm has guaranteed stability, including at the parametric resonance. The paper also describes an efficient modelling technique for cable structures; simple and powerful results are established, which allow to predict the closed loop poles with a root locus technique.
Damping analysis of beams submitted to passive and active control
Engineering Structures, 2009
In this paper an analytical method is proposed for damping analysis of sandwich beams with piezoelectric and viscoelastic layers. Based on the classical zig-zag model and some assumptions about the electric field, this method leads to an analytical expression of the modal loss factor and frequency. Considering two feedback control laws, the obtained hybrid damping of the sandwich beam is characterized. Numerical finite element applications are considered, in order to examine the efficiency and limitations of the presented method.
The need for new and better means of designing new structures and retrofitting existing ones from the damaging effects of severe environmental loadings has motivated civil engineers to develop innovative simple concepts of structural control to preserve the structural integrity of these buildings. One of the most effective concepts is the use of a tuned mass damper (TMD) to reduce the undesirable vibrations and enhance the response of the structure induced by wind or earthquake loads. The TMD is a passive energy absorbing device, consists of a mass, spring and a viscous damper attached to the structure. This system has proved to be significant in protecting environmental threats of large structures like towers, bridges and high rise buildings. Despite the fact that the TMD system has been successfully used for high-rise buildings, it needs a huge mass and a large room for installation at the top floor of the building, causing extra production cost and storage space problems. The present study aims to apply this concept for ordinary low-rise buildings making use of part of the building as the pendulum mass like water storage tanks located at top of the roof for these buildings. In this case the water tanks should be hung from the topmost story girder forming a pendulum. The damper of this type needs neither additional mass nor space because the building equipment is integrated into the damper. The study will develop a simple analytical technique which may be used by the designers to find out the optimum parameters of TMD that result in considerable reduction for the lateral vibrations.
Experimental research of dynamic damping of lateral vibrations of a rigid cantilever beam
Journal of Vibroengineering, 2013
This work considers passive dynamic absorber (without additional energy source) of the simplest type: a non-controlled spring with one degree of freedom. Object of vibration suppression is transversal vibrations of rigid cantilever beam. The inertial element is connected to the vibration protection object by means of elastic metal element - nonlinear conical coil spring. Experiments were performed on the universal vibration system TM 150.
ANALYSIS OF DAMPING EFFECT ON BEAM VIBRATION
The paper presents analysis of damping effect on beam vibration forced by impact. The air-related value of damping is researched. All the considerations are based on the assumption that the particular mount does not produce damping. Furthermore, they are true only for the researched range of the variability of the beam's geometry and the resultant resonance frequencies. Two applied methods of modelling produce results, which differ by one order of magnitude, but both of them are sufficiently small to be regarded as negligible.
Passive damping of beams with constrained viscoelastic material
1997
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An integrated approach to structural damping
Precision Engineering, 1996
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 method uses viscoelastic materials to dissipate energy in the manner of classic constrained-layer damping; however, the layers are embedded within the structure as opposed to being applied externally. This provides a robust means of incorporating damping without encountering several of the common disadvantages associated with external damping treatments. An analytical solution to the amount of damping in bending modes is presented using a modal strain energy approach. The utility of this passive damping technique is demonstrated experimentally, and examples showing the accuracy of the modal strain energy solution are presented.
Damped vibration of a non-prismatic beam with a rotational spring
Vibrations in Physical Systems, 2014
In this paper a problem pertaining to the damped lateral vibrations of a beam with different boundary conditions and with a rotational spring is formulated and solved. In the adopted model the vibration energy dissipation derives from the internal damping of the viscoelastic material (Kelvin–Voigt rheological model) of the beam and from the resistance motion in the supports. The rotational spring can be mounted at any chosen position along the beam length. The influence of step changes in the cross-section of the beam on its damped lateral vibrations is also investigated in the paper. The damped vibration frequency and the vibration amplitude decay level are calculated. Changes in the eigenvalues of the beam vibrations along with the changes in the damping ratio and the change in the model geometry observed on it are also presented. The considered beam was treated as EulerBernoulli beam.