Static structures (e.g. – buildings) – With synthetic resinous component – With nonresinous component
Patent
1983-02-14
1985-07-09
Murtagh, John E.
Static structures (e.g., buildings)
With synthetic resinous component
With nonresinous component
52731, 188378, 267136, E04C 100, F16F 710, E04B 198
Patent
active
045273715
DESCRIPTION:
BRIEF SUMMARY
The present invention refers to damping of structural vibrations and more particularly to such damping by the use of an adherent viscoelastic material and at least one counter body. The invention also refers to a damping apparatus utilizing the general principles of the invention.
As is well known in the art of vibration damping a viscoelastic material has the property to absorb vibration energy, i.e. to transform vibration energy into heat, when such a material is subjected to shearing between two covibrating parts, such as metal plates, between which the viscoelastic material is applied in a relatively thin layer adhering to both parts such that shearing is developed in the layer when the parts oscillate in a bending mode due to vibrations.
This technique and the theories behind it are described in e.g. "Noise and Vibration Control", edited by Leo L. Beranek and published by Mc Graw-Hill Book Company, New York, in 1971 (ISBN 07-004841-X).
Also, a great number of patents have been granted concerning various practical developments of the basic technique referred to above, such as U.S. Pat. Nos. 3,078,969; 3,078,971; 3,169,881; 3,215,225; 3,262,521; 3,828,504; 3,956,563; and 4,195,713, the three last mentioned patents having the inventor of the present invention as co-inventor.
In all applications of viscoelastic damping known to the Applicant only the energy dissipation in the viscoelastic material due to pure shearing--developed as discussed above--is utilized to damp structural vibrations. For example, a structure can be damped by applying an adhering layer of viscoelastic material to a plane surface of the structure and applying a separate, normally comparatively thin plate as a counter body onto the viscoelastic material. In such cases damping is achieved only by pure shearing in the viscoelastic material due to relative movements of the structure and the separate plate in any direction along the plane separating the structure and the plate.
Now, the inventor has made the astonishing discovery that if the counter body is so shaped and arranged that it may perform a lateral swinging or tilting motion relative to its longitudinal direction, a new and astonishing damping effect is added to the conventional damping caused by shearing in the viscoelastic layer. If, further, the length of the counter body is adapted to the longitudinal wave length in the material of the counter body also damping of longitudinal waves is obtained in a structure by shearing in the viscoelastic layer. A preferred shape of the counter body is one having a generally thread-like or rod-like configuration of circular or other cross-section.
The present invention, thus, is primarily characterized in that the counter body is generally thread- or rod-shaped and embedded in the viscoelastic material such that it has a possibility to oscillate in resonance relative to a structure under deformation of the viscoelastic material around portions of the counter body embedded therein when the viscoelastic material adheres to a vibrating structure.
The invention will now be described more in detail, reference being made to the accompanying drawings, wherein:
FIG. 1 is a perspective view showing a cut-out portion of a structure damped according to the invention;
FIGS. 2a and 2b show a section along line II--II of FIG. 1, FIG. 2a illustrating the structure at rest and FIG. 2b illustrating same in a strongly exaggerated transversal oscillation in vertical direction;
FIGS. 3a, b and c show a section along line III--III of FIG. 1, FIG. 3a illustrating the counter body in rest position while FIGS. 3b and 3c show same swinging leftwards and rightwards, respectively;
FIG. 4a shows from the above the structure of FIG. 1 set in strongly exaggerated transversal oscillation in horizontal direction;
FIG. 4b shows a section along line IVb--IVb of FIG. 4a;
FIG. 4c shows a section along line IVc--IVc of FIG. 4a;
FIGS. 5, 6, 7 and 8 show one example each of alternative counter bodies;
FIG. 9 shows a perspective view of several thread- or rod-shaped counter bod
REFERENCES:
patent: 1815558 (1931-07-01), Gammeter
patent: 3078969 (1963-02-01), Campbell et al.
patent: 3078971 (1963-02-01), Wallerstein, Jr.
patent: 3169881 (1965-02-01), Bodine, Jr.
patent: 3172800 (1965-03-01), Truesdell
patent: 3215225 (1965-11-01), Kirschner
patent: 3262521 (1966-07-01), Warnaka
patent: 3266966 (1966-08-01), Patchell
patent: 3402560 (1968-09-01), Alm
patent: 3448550 (1969-06-01), Herr et al.
patent: 3828504 (1974-08-01), Egerborg et al.
patent: 3956563 (1976-05-01), Spang et al.
patent: 4133157 (1979-01-01), Bschorr et al.
patent: 4278726 (1981-07-01), Wieme
patent: 4382587 (1983-05-01), Heinrich et al.
patent: 4425980 (1984-01-01), Miles
IFM-Akustikbyran AB
Murtagh John E.
Rudy Andrew Joseph
Wray James C.
LandOfFree
Structural damping does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Structural damping, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Structural damping will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-902457