KR100337738B1 - Motion Damper for Large Structures - Google Patents

Abstract

The extrusion damper, which is sandwiched between the two members and absorbs the kinetic energy induced between the two members, has an outer jacket (1), a plastically deformable energy absorbing material (3) such as lead, In order to move through the outer jacket. It can be secured against the delivery outer jacket and the shaft has a portion that reduces the diameter moving through the lead. Alternatively, the lead may be fixed about the shaft and the outer jacket has an enlarged portion through the energy absorber. The energy absorbing material is preferably subjected to hydraulic pressure in excess of the shear yield stress of the energy absorbing material.

Description

Motion Damper for Large Structures

Hereinafter, the damper of the present invention will be described in detail with reference to the accompanying drawings.

1 is a longitudinal sectional perspective view of one embodiment of the damper of the present invention;

2 is a longitudinal sectional view of the damper of FIG. 1,

3 is a longitudinal sectional view of another form of the damper of the present invention, similar to the dampers of FIGS. 1 and 2,

4 is a longitudinal sectional view of another form of the damper of the present invention, similar to the dampers of FIGS. 1 and 2,

5 is a longitudinal sectional view of another form of the damper of the present invention, similar to the dampers of FIGS. 1 and 2,

6 is a longitudinal sectional view of another form of the damper of the present invention,

7 and 8 are views of Mohr original configuration cited in the description of the extrusion damper of the present invention,

9 is a graph showing the displacement of the axis over time illustrating the test applied to dampers of the type shown in FIGS.

10 is a graph showing the load resistance with respect to time of a damper of the type shown in FIGS. 1 to 5 in the displacement circulation of FIG.

FIG. 11 is a graph showing the load resistance seen during the test cycle of FIG. 9 against displacement, showing a continuous hysteresis loop over successive periods.

The present invention relates to dampers, commonly referred to as extrusion dampers, for reducing the effects of motion and displacement caused in various structures and equipment.

The dampers of the present invention are used in large structures such as bridges or buildings to reduce the effects of motion induced by earthquakes or strong winds. Dampers may also be used to dampen the motion of large or small moving objects. The damper may be used to attenuate a motion occurring in an industrial machine or an engine, for example, a motion generated in a home appliance such as a washing machine, or may be used in a field that needs to attenuate motion, vibration, and the like. Dampers may be used to dampen displacements caused by thermal expansion. The damper of the present invention can be applied in various ways.

[Field of Invention]

BACKGROUND ART Devices known as extrusion dampers are known which employ an elastic or plastic deformation of a particular material to absorb energy. U. S. Patent No. 3,833, 093 discloses an extrusion damper in the form of an energy absorbing material sandwiched between an elongated outer jacket of cylindrical shape and an axis that moves longitudinally within the jacket. Typically, the absorbent material is lead and the jacket and shaft are made of steel. Both ends of the jacket and shaft are connected between two members in the structure that are adapted to move relative to each other during an earthquake or other guided motion. "An Introduction to Seismic Isolation", R I Skinner, W H Robinson and G H McVerry, Wiley, 1993, describe these devices and related devices as a whole.

Lead is the preferred deformable energy absorber for a variety of reasons.

First, lead has a low shear stress of about 10.5 MPa at room temperature compared to other metals and corresponding plastic materials. Secondly, lead recovers its mechanical properties relatively quickly following yield deformation through recrystallization and related processes, which provides significant resistance to work hardening under periodic shearing at normal temperatures. Third, lead is readily available because it has the purity needed to exhibit these properties.

Indeed, such dampers are individually designed to protect the structure from damage by damping the movement exerted on a particular structure. Its behavior is almost similar to that of an ideal Coulomb damper that has a nearly square and actually ratio independent force-displacement hysteresis loop over a wide frequency range. Research is actively conducted to improve the performance of these devices.

[Summary of invention]

It is an object of the present invention to improve the performance of such dampers used in seismic isolation and other applications.

According to the invention, a damper is inserted between two members to dampen the movement induced between the two members, the thinner outer jacket means being able to penetrate through the jacket means and move through the outer jacket during the induction motion. And a plastically deformable energy absorbing material filled in the space between the outer jacket and the shaft, wherein the energy absorbing material is fixed relative to the outer jacket and the shaft absorbs the energy absorbing material during the induction motion. A diameter reduced in force, and / or the energy absorbing material is fixed to the shaft, and the outer jacket includes an enlarged portion in which the energy absorbing material is forced during the induction motion. A damper is provided, characterized in that

The energy absorbing material is preferably subjected to hydrostatic pressure at least close to the shear yield stress of the material. The hydrostatic pressure applied to the energy absorbing material preferably exceeds the shear yield stress of the energy absorbing material. The hydrostatic pressure is preferably 5 MPa or more, most preferably 10-100 MPa.

The energy absorbing material is preferably lead, but other energy absorbing materials that may be used include lead alloys, aluminum, tin, zinc, brass, iron, superplastic alloys or materials with low work hardening ratios at high temperatures such as 200 ° C. Also included are densely packed granular materials such as rigid, glass beads, aluminum, silicon, silicon carbide or very hard granular materials.

The damper of the present invention is used in the earthquake-blocking field, to damp the motion caused by the earthquake in a large structure such as a bridge or building or to damp the shaking caused by the super wind. Dampers may also be used in applications where there is a need to dampen motion, vibrations and the like. For example, the damper of the present invention may be used to dampen the motion of an engine or other industrial machine. In the home, the damper of the present invention may be used in a washing machine, a hair dryer or a dishwasher to block vibration. The small damper of the present invention may be used as a "microisolator" of a sensitive electronic device such as a video recorder mechanism or in a similar field. Extrusion damper of the present invention can be used in a number of fields, the present invention is not limited to earthquake blocking damper.

Detailed Description of the Preferred Embodiments

The dampers shown in FIGS. 1 to 5 are each made of steel and, as shown, each comprise an outer jacket 1 which is cylindrical but can take other cross-sectional shapes, for example elliptical. . In each case, the shaft 2 can move longitudinally through the outer jacket 1 in the direction of arrow A. FIG. The shaft does not necessarily need to be located in the center of the outer jacket 1, but may be in a somewhat eccentric position. The shaft is also formed of steel.

The space between the outer jacket 1 and the shaft 2 is filled with a plastically deformable material such as lead, so that the shaft moves through the lead when in use.

The side 2 moves through an end cap 4 which also forms a support for supporting one end of the shaft and a support 5 provided on the other floating side. The tubular spacer 6 is provided between the end cap 7 and the floating support 5.

The central portion 2a of the shaft 2 is reduced in diameter, as shown. Figure 1 shows the damper's contour, while Figures 2 through 5 show the damper in the form of a longitudinal cross-section showing the variation of the configuration mentioned later.

In use, the outer jacket 1 of the damper is connected to one of the members of a building or other structure via a suitable mechanical coupling, and the shaft has an end 2b of the shaft, which can move relative to the member when movement is caused. Passing through, is connected to another member. In earthquake-blocking applications, when an earthquake-like motion occurs, the kinetic energy is plastically deformed, as the axis 2, especially the reduced diameter portion 2a, is forced through a deformable material 3 such as lead. Converted into energy and heat, and further converted into heat during recrystallization and other naturally occurring recovery processes, attenuating effects occur.

The energy absorbing material may optionally be subjected to prestress under hydrostatic pressure, at least close to or preferably above the shear yield stress of the energy absorbing material, such that the material is always in a compressed state. When the pressure of lead is 5 MPa or more, it has been found that typically 10 MPa to 30 MPa, but up to 100 MPa or more is effective.

The effect of the hydrostatic pressure will also be briefly described with reference to the mower circle configuration shown in FIGS. 7 and 8. According to the mower circle configuration, an appropriate tensor description of the stress can be expressed in two dimensions. The hydrostatic pressure applied to the energy absorbing material is defined as 1/3 of the sum of the three principal stresses applied thereto. In FIG. 7, the hydrostatic pressure is 0, and the magnitudes of the host stress δ _x , the main compressive stress δ _y and the maximum shear stress δ _xy are all the same. In FIG. 8, hydrostatic pressure p equal to the shear stress δ _xy was applied. The minimum tensile stress then becomes zero, so that the energy absorbing material is always in a compressed state. Thus, the energy absorbing material has tension.

2 to 5 show a number of devices for applying hydrostatic pressure to the lead 3 (or other energy absorbing material). In FIG. 2, a block composed of a layer of elastic material 8 such as rubber and rigid material 9 such as steel is provided between the tubular spacer 6 and the end cap 7. In FIG. 3, pads 10 made of an elastic material such as rubber are provided at both ends of the absorbent material 3. In both cases, the spacer 5 is of a length such that a predetermined hydrostatic pressure can be applied to the lead 3 when the end cap 4 is screwed. In FIG. 4, the outside of the absorbent material 3 is surrounded by a sleeve made of elastic material such as rubber or reinforced rubber or other elastic material. In FIG. 5, the absorbent material is completely filled in the elastic material layer 12. As shown in FIG.

In each case, the energy absorbing material 3 may be placed directly at a predetermined position in the outer jacket 1 around the axis 2. In the embodiment of FIGS. 4 and 5, the rubber sleeve or casing may be stretched around the lead mass after being placed around the shaft 2, after which the shaft and lead are press fit into the outer casing. Otherwise, lead may be cast as a plug with a constant diameter hole through the lead. The lead plug is inserted into the outer casing, after which the shaft is pressed into a central hole through the lead. For example, by fitting the end cap 4 or a corresponding member, pressure is applied to the lead, whereby the lead is compressed to move around the portion 2a where the diameter of the shaft is reduced.

As noted above, the overall cross-sectional shape of the damper may be cylindrical, otherwise elliptical, square, rectangular or other desired shape.

The shaft and other portions of the damper may optionally be coated with Teflon, porcelain, titanium nitride, hardened ceramic material, glass, and the like.

In assembling the damper, the components are preferably coated with hot / high pressure grease or other lubricant.

6 shows another form of damper of the present invention. The damper preferably consists of a cylinder but includes an outer jacket 21 of steel that can take on a different cross-sectional shape. A part of the outer jacket 21 had a portion 21a of enlarged diameter as shown. The axis extended at both ends 22a penetrates through the outer jacket 21. The end 22a of the shaft forms a plunger in the outer jacket 21. In order to seal the plunger portion 22a of the shaft with respect to the inner hole of the outer jacket, a sealing member 26 such as a Chevron sealing member may be provided. The plunger portion 22a of the shaft is shown in cross section. At least one end of the shaft extends out of the outer jacket beyond what is shown in the drawings, so that the shaft can be connected to a predetermined position when in use. The shaft has a central portion 22b with a reduced diameter. In the figure, the shaft is shown as a three-part shaft with a small diameter central portion 22a which is screwed into the large diameter portion 22b of the shaft at both ends, as shown at 22c.

Lead 23 or other energy absorbing material is secured around the reduced portion 22b of the shaft 2. The lead receives hydrostatic pressure by plunging the plunger portion 22a onto the center portion 22b of the shaft and applies a predetermined pressure to the lead filled in the outer jacket 1. A different configuration can be taken.

In use, the outer jacket 21 is connected to either a member of a building or other structure and one or both ends of the shaft is connected to another member that can move relative to the member when movement is caused. In earthquake-blocking applications, when an earthquake-like movement occurs, the shaft moves relative to the outer jacket 21 such that lead is passed through the interior of the outer jacket 21 including the increased portion 21a in the outer jacket. 23), the kinetic energy is converted to plastic strain energy and heat, and further converted to heat during recrystallization and other naturally occurring recovery processes, resulting in a damping effect.

The interior of the shaft and outer jacket may be coated with Teflon, porcelain, titanium nitride, or the like, and the components of the damper may be covered with hot grease during assembly, as described above.

The following shows the test results of the damper of the present invention.

[exam]

The damper consisted of a cylindrical outer jacket of steel with an internal diameter of 40 mm. The shaft was a 19 mm diameter cylindrical shaft with a 20 mm long center portion where the diameter of the shaft was reduced smoothly to at least 12 mm and again increased to the top diameter of the shaft. In order to enclose the shaft in the outer jacket, lead of 99.9% purity was filled between the outer jacket and the centrally located shaft. The length of lead mass fixed in the casing and surrounding the shaft was 130 mm. Before filling the lead in the desired position, the shaft was covered with high pressure lubricant. When the end cap of the outer jacket was fixed to the body by bolts, the lead was placed at a hydrostatic pressure of about 20 MPa. By means of an instron tester the damper was placed in a displacement cycle of the axis of ± 195 mm with a maximum crosshead speed of 200 mm / min and a maximum force of 250 kN. Results were recorded by the data logger on a chart recorder directly connected to Instron. 9 shows the displacement of the axis with respect to time. 10 shows the load resistance exhibited by the damper over time. Figure 11 shows the load resistance exhibited by the damper against displacement, showing a continuous hysteresis loop for successive periods. After an extended test, the damping force and absorbed energy per cycle were still within 20% of the initial value. When the extended test was completed, the damper was removed from the test ring and removed. Lead was visually inspected and found to be in good condition.

As described above, the present invention has been described based on various preferred embodiments. As will be apparent to those skilled in the art, variations and modifications to the present invention are within the scope of the invention, unless the claims depart therefrom.

Claims (10)

A damper inserted between two members to dampen the movement induced between the two members, the damper having an elongated outer jacket, an axis forced through the outer jacket to move through the outer jacket during the induction motion; Consisting of an energy absorbing material which is actually completely filled in the space between the outer jacket and the shaft, wherein the energy absorbing material is fixed relative to the outer jacket, the shaft having a maximum diameter inside the outer jacket and decreasing relative to the maximum diameter An arcuate wall having a radius of curvature greater than the maximum diameter is formed, and the energy absorbing material is non-flexible and normally solid, but the central portion of the shaft during the induction motion occurs. Energy when energized to move through an energy absorbing material The plastic deformation and recrystallization of the water material causes the damping motion of the shaft through the energy absorbing material, or the energy absorbing material is fixed to the shaft, and the outer jacket is formed by the diameter of the outer jacket on one side of the operating part of the outer jacket. The energy absorbing material is configured to receive force through the operating portion of the outer jacket during the induction movement, and is non-flexible and normally solid while the induction movement occurs. Damper, characterized in that the damping movement is made by plastic deformation and recrystallization of the energy absorbing material when the shaft and the energy absorbing material fixed thereto is forced to move through the operating portion of the outer jacket. The damper according to claim 1, wherein the energy absorbing material is subjected to hydrostatic pressure at least close to the shear yield stress of the energy absorbing material. The damper according to claim 1, wherein the energy absorbing material is subjected to hydrostatic pressure at least exceeding the shear yield stress of the energy absorbing material. The damper according to claim 1, wherein the energy absorbing material is subjected to hydrostatic pressure of 10 MPa or more. The damper of claim 1, wherein the energy absorbing material is subjected to hydrostatic pressure in excess of 20 MPa. 4. The damper according to claim 3, wherein the energy absorbing material is lead. 2. The damper of claim 1, wherein the interior of the shaft and outer jacket is coated with Teflon, titanium nitride or other ceramic material or glass. The damper as claimed in claim 1, wherein the shaft or the inside of the outer jacket is coated with Teflon, titanium nitride or other ceramic material or glass. A damper inserted between two members to dampen the movement induced between the two members, the damper having an elongated outer jacket, an axis forced through the outer jacket to move through the outer jacket during the induction motion; It consists of an energy absorbing material which is actually completely filled in the space between the outer jacket and the shaft, wherein the shaft is secured to the outer jacket and the shaft is at the inside of the outer jacket except for a single actuated portion having a reduced diameter Or a fixed diameter, or the energy absorbing material is fixed to the shaft, the outer jacket comprises an operating portion having an enlarged diameter relative to the diameter of the outer jacket on one side of the operating portion of the outer jacket Damper. 10. The damper according to claim 9, wherein said single actuating portion having a reduced diameter consists of an arcuate wall.