JP2008038950A - Energy absorbing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an elongation stress, a bending stress and a local stress from being concentrated, when energy absorber is deformed repeatedly, to obtain vibration absorbing performance of high durability and high stability, in an energy absorbing device for reducing vibrational energy, of an earthquake or the like, transmitted, for example, to a building or the like. <P>SOLUTION: This energy absorbing device is provided with a hollow part h penetrated along a vertical direction, in a layered body 3 formed by layering alternately a plurality of hard plates 1 such as a steel plate and elastomers 2 such as rubber in the vertical direction, and storage-arranged with the energy absorber 4 for absorbing the vibrational energy of the earthquake or the like, inside the hollow part h. The energy absorber is formed of a plurality of substantially same-diametric metal columns 4a-4c comprising metal prevented from being integrated each other by heat or the like generated in the vibration due to the earthquake or the like, and layered vertically as layers, and a height of each of the metal columns 4a-4c is less than a height of the layered body, and larger than two times of the sum of a thickness of the hard plate 1 and a thickness of the elastomer 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an energy absorbing device for reducing vibration energy transmitted to a building, a civil engineering structure, a precision instrument, or the like when an earthquake occurs. More specifically, the present invention relates to an energy absorbing device in which an energy absorber that absorbs vibration energy such as earthquake is provided in a laminate in which a plurality of hard plates such as steel plates and elastic bodies such as rubber are alternately laminated in the vertical direction. Is.

  Conventionally, in order to reduce vibration energy transmitted to a building, a civil engineering structure or the like when an earthquake occurs, for example, an energy absorbing device as in Patent Document 1 below has been proposed. FIG. 4 and FIG. 5 show an example of the energy absorbing device A as described above. A laminated body 3 in which a plurality of hard plates 1 such as steel plates and elastic bodies 2 such as rubber are alternately laminated in the vertical direction. Arranged between a pair of upper and lower substrates 5 and 5 and absorbs vibration energy such as an earthquake in a hollow portion (through hole) h penetrating in the vertical direction formed in the central portion of both the substrates 5 and 5 and the laminate 3. It is the structure which accommodated and arrange | positioned the energy absorber 4 which consists of elastic plastic bodies, such as lead. In the longitudinal cross-sectional view of FIG. 5, hatching (hatched lines) representing the cross sections of the hard plate 1, the elastic body 2, and the energy absorber 4 is omitted to avoid complication. The same applies to embodiments of the present invention described later.

  A mounting plate 6 is integrally attached to both the upper and lower ends of the laminate 3 and the energy absorber 4 via the substrate 5 with bolts 7 or the like, and bolts 8 or the like are attached to mounting holes 6a formed in the mounting plate 6. For example, in a building such as a building as shown in FIG. 6, an upper structure B of the building and a lower structure such as a base are installed. One or a plurality of the energy absorbing devices A are disposed between the upper and lower attachment plates 6 and C, and the upper and lower attachment plates 6 are attached to the structures B and C, respectively. For example, in a civil engineering structure such as a bridge as shown in FIG. 7, one or more energy absorbing devices A are arranged between an upper structure B such as a bridge girder and a lower structure C such as a bridge pier. Then, the upper and lower attachment plates 6 may be attached to the structures B and C in the same manner as described above.

  The energy absorbing device A arranged between the upper and lower structures B and C as described above is designed to reduce seismic energy by deforming in the horizontal direction when an earthquake occurs while stably supporting a building or the like. It functions as both a seismic isolation isolator and a seismic isolation damper. As a result, the installation space can be reduced and the workability can be improved as compared with the case where the isolator and the damper are separately arranged.

  By the way, in the above-mentioned Patent Document 1, when manufacturing the energy absorbing device as described above, a hydrostatic pressure equal to or higher than the shear yield stress is applied to a cylindrical energy absorber made of an elastic-plastic material such as lead. It has been proposed that the energy absorber is brought into close contact with the inner surface of the hollow portion of the laminated body by applying.

  However, when one columnar metal is used as the energy absorber, elongation or bending stress is generated in the energy absorber along with the shear deformation of the laminate, which may cause local stress concentration. Therefore, when the energy absorber is repeatedly deformed due to an earthquake or the like, the local stress concentration may cause performance deterioration.

  Therefore, in order to prevent the above-described elongation and bending stress and local stress concentration due thereto, for example, the energy absorber may be divided into a plurality of layers in the stacking direction of the stack in advance. However, when lead is used as the energy absorber, lead may generate heat due to repeated deformation due to an earthquake or the like, and may be softened and integrated. For this reason, there are problems such as the elongation, bending stress, local stress concentration, and performance deterioration due to this.

  The following uniaxial fatigue test confirmed how easily lead is actually softened compared to other metals. That is, as shown in Table 1 below, as an example, it is confirmed whether tin, which is a metal having a melting point lower than that of lead, and stress change when lead is subjected to the same degree of fatigue, which is easier to soften.

  FIG. 8 shows the shape and dimensions of the specimen S for performing the uniaxial fatigue test. The unit of the dimension in the figure is mm. The parallel part (small diameter part) Sa of the test body S has a diameter φ = 10 mm and a length L = 15 mm. As the material of the test body S, lead and tin were used. Each test specimen S was held at 20 ° C. in a thermostatic chamber, and a strain (tensile and compression) of ± 1.0% of the length was applied 50 times in the length direction at a frequency of 1.0 Hz. The change of history characteristics was examined.

  As a result, hysteresis curves as shown in FIGS. 9 and 10 were obtained. FIG. 9 shows the first and 49th history curves when lead is used as the specimen S, and FIG. 10 shows the first and 49th history curves when tin is used. Both specimens are rigid plastic type. The secondary shape is extremely small.

  The average value of the first strain zero point stress of each test specimen is defined as the intercept stress, and the change due to 50 repetitions of the strain is shown in FIG. In general, the energy absorption amount is determined by stress × cross-sectional area × deformation amount. Therefore, the stress ratio is the energy absorption amount ratio in the same cross-sectional area and deformation amount. As can be seen from FIG. 11, it can be seen that tin absorbs 50% more energy than lead.

  FIG. 12 shows the relationship between the number of repetitions of the strain and the rate of change in stress for each number of repetitions based on the first stress. As is apparent from the figure, the stress of lead increased due to work hardening, and the 15th time increased by about 28% from the first time, but thereafter the stress tended to decrease. On the other hand, the stress of tin increased with repeated strain.

  The reason why the stress of lead is reduced as described above is considered to be due to the following reasons. That is, as shown in the thermophysical values of lead / tin in Table 1, since the specific heat and thermal conductivity of lead are lower than that of tin, the heat generated in the plastic deformation portion does not diffuse to the surroundings, and the temperature rises. This is thought to be due to softening. On the other hand, it is believed that tin is cheap because heat is diffused around and the temperature rise is small.

  From the above, it is considered that lead has a higher melting point than tin, but is more easily softened than tin, thereby reducing the stress. Moreover, since lead is easy to soften as described above, even if the energy absorber made of lead is divided into a plurality of pieces in order to prevent elongation, bending stress and local stress concentration as described above, an earthquake, etc. The lead may generate heat due to repeated deformation due to the above, and may be softened and integrated.

Japanese Patent No. 3360828

  The present invention has been proposed in view of the above-mentioned problems, and it can satisfactorily prevent elongation, bending stress and local stress concentration on the energy absorber due to shear deformation of the laminate due to vibration such as earthquake. An object of the present invention is to provide an energy absorbing device that can obtain vibration absorption performance with good durability and stability and can be manufactured easily and inexpensively.

  In order to achieve the above object, an energy absorbing device according to the present invention has the following configuration. That is, a hollow part that penetrates in the vertical direction is provided in a laminated body in which a hard plate such as a steel plate and an elastic body such as rubber are alternately laminated in the vertical direction, and vibration energy such as earthquake is absorbed in the hollow part A plurality of the energy absorbers made of metal that are not integrated with each other by heat generated at the time of vibration such as an earthquake and stacked in layers in the vertical direction. And the height of each of the metal cylinders is less than the height of the laminated body and larger than twice the sum of the thickness of the hard plate and the thickness of the elastic body. It is characterized by comprising.

  As described above, the energy absorber is formed of a plurality of metal cylinders having substantially the same diameter that are laminated in layers in the vertical direction. It is possible to reduce the local stress concentration caused by. In addition, since the plurality of metal cylinders are formed of metals that are not integrated with each other due to heat generated during vibration such as an earthquake, the temperature of the plurality of metal cylinders is increased by repeatedly absorbing vibration. Even if they are slightly raised, they can maintain the desired vibration absorbing performance well without being integrated. Further, since the height of each metal cylinder is less than the height of the laminated body and larger than twice the sum of the height of the hard plate and the height of the elastic body, the metal cylinders are adjacent to each other when absorbing vibration. There is no fear that the vibration absorbing performance will be reduced by biting into the elastic body between the hard plates.

  Furthermore, it becomes possible to easily design an energy absorbing device having an arbitrary displacement history by changing the type, height, number of layers, etc. of the metal cylinder. In addition, at the time of manufacture, the metal cylinders can be inserted into the hollow portion of the laminate in a separated state, and can be easily and accurately loaded while checking the degree of closeness and the degree of adhesion of the metal cylinders. it can. As a result, it is possible to easily and inexpensively provide an energy absorbing device with high vibration absorption performance, durability, and reliability.

  Hereinafter, the present invention will be specifically described based on embodiments shown in the drawings. FIG. 1 is a longitudinal sectional view showing an embodiment of an energy absorbing device according to the present invention, and members having the same functions as those in the conventional example will be described with the same reference numerals.

  The energy absorbing device A of the present embodiment is a laminated body in which a hard plate 1 such as a steel plate and an elastic body 2 such as rubber are alternately laminated in the vertical direction and integrated with an adhesive or the like as in the conventional example. 3 is disposed between a pair of upper and lower substrates 5 and 5, and the energy absorber 4 is accommodated in a hollow portion (through hole) h formed in the center portion of both the substrates 5 and 5 and the laminated body 3 and penetrating in the vertical direction. The energy absorber 4 is formed by a plurality of metal cylinders 4a to 4c having substantially the same diameter stacked in layers in the vertical direction, and the height of each of the metal cylinders 4a to 4c is determined by their height. It is configured to be less than the height of the laminated body and larger than twice the sum of the thickness of the hard plate 1 and the thickness of the elastic body 2.

  The material of each of the metal cylinders 4a to 4c constituting the energy absorber 4 is appropriate, but at least a metal such as lead that does not integrate the metal cylinders by heat generated during vibration such as an earthquake. Specifically, for example, it is mainly composed of, for example, a single metal in a metal group consisting of silver, tin, copper, aluminum, and zinc, or any metal in the above metal group. In addition, an alloy in which one or two or more metals selected from the metal group other than the main metal or a metal other than the metal group are mixed can be used. In particular, an alloy mainly composed of tin having a purity of 99.9% or more and a mixture of one or more metals selected from bismuth, sulfur, cadmium, gold, silver, antimony, and zinc is suitable. . However, when the amount of the metal mixed with tin increases, the properties of tin such as rich ductility and recrystallization at room temperature are lost, so this alloy has 95% or more, preferably 99% or more, more preferably It is desirable to contain 99.5% or more of tin.

  As described above, the energy absorber is made of a metal that is not integrated with each other due to heat generated during vibration such as an earthquake, such as lead, and has a plurality of substantially the same diameter stacked in layers in the vertical direction. When the metal cylinders 4a to 4c are used, it becomes easy to load and adhere to the inner surface of the hollow portion h, and at the same time, the elongation and bending stress, and local stress concentration caused by the shear deformation of the laminate are reduced. It becomes possible to prevent.

  In the embodiment shown in FIG. 1, all the metal cylinders 4 a to 4 c of the energy absorber 4 have substantially the same height. However, as shown in FIG. The heights (thicknesses) of the metal cylinders 4a to 4c may be gradually decreased as they go, or the heights of the metal cylinders 4a to 4c are increased as they go to both ends rather than the central part in the vertical direction as shown in FIG. You may make it high. Further, if the height of each of the metal cylinders 4a to 4c is too low, the metal cylinders 4a to 4c may bite into the elastic body 2 made of rubber or the like around the hollow portion H. Therefore, at least the height of the hard plate 1 and the height of the elastic body 2 It is better to form it larger than twice the sum of.

  Furthermore, although each said embodiment formed the energy absorber 4 with the five metal cylinders 4a-4c, the number is appropriate, for example, you may make it provide 4 or less or 6 or more. Further, the contact surfaces of the metal cylinders, that is, the contact surfaces of the metal cylinders adjacent to each other in the upper and lower sides and, in some cases, the contact surfaces of the metal cylinder and the substrate, are provided with uneven portions that engage with each other as necessary. You may make it provide. As the concavo-convex portion, for example, a concave portion such as a hole or a groove and a convex portion such as a protrusion or a ridge that engages with it by fitting or meshing are provided on the contact surface, or the contact surface is roughened. Etc., and other appropriate methods.

  As described above, the energy absorbing device according to the present invention forms the energy absorber 4 with the plurality of metal cylinders 4a to 4c that are not integrated by heat generated during vibration such as an earthquake. Even when the body is subjected to shear deformation, elongation, bending stress, and local stress concentration due to the elongation do not occur in the cylinder, and the metal cylinder can be easily placed on the inner surface of the hollow part h in the hollow part h of the laminate 3 during production. It can be loaded in a well-adhered state. As a result, it is possible to easily and inexpensively provide an energy absorbing device that exhibits stable performance during shear deformation of the laminate. In addition, by changing the type, height, number of layers, etc. of the metal cylinder, it becomes possible to easily design an energy absorbing device having an arbitrary displacement history, which can greatly increase industrial applicability. .

The longitudinal cross-sectional view which shows one Embodiment of the energy absorption apparatus by this invention. The longitudinal cross-sectional view which shows other embodiment of the energy absorption apparatus by this invention. The longitudinal cross-sectional view which shows other embodiment of the energy absorption apparatus by this invention. The perspective view which shows an example of the conventional energy absorption apparatus. The longitudinal cross-sectional view of the said conventional energy absorption apparatus. Explanatory drawing of the example which constructed the said conventional energy absorption apparatus in the building. Explanatory drawing of the example which constructed the said conventional energy absorption apparatus to the civil engineering structure. The structure explanatory view of the specimen of a uniaxial fatigue test. The graph which shows the hysteresis curve of lead by a uniaxial fatigue test. The graph which shows the hysteresis curve of tin by a uniaxial fatigue test. The graph which shows the relationship between the repetition frequency by a uniaxial fatigue test, and an average stress. The graph which shows the relationship between the repetition frequency by a uniaxial fatigue test, and an average stress ratio.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hard board 2 Elastic body 3 Laminated body 4 Energy absorber 5 Board | substrate 6 Mounting plate 7, 8 Bolt A Energy absorber B Upper structure C Lower structure h Hollow part

Claims (3)

Energy that absorbs vibration energy such as earthquakes in a hollow part that penetrates in the vertical direction in a laminated body in which multiple hard plates such as steel plates and elastic bodies such as rubber are alternately laminated in the vertical direction In the energy absorption device that houses and arranges the absorber,
The energy absorber is formed of a plurality of metal cylinders having substantially the same diameter, which are made of metals that are not integrated with each other by heat generated at the time of vibration such as an earthquake, and stacked in layers in the vertical direction. An energy absorbing device, characterized in that the height of each metal cylinder is less than the height of the laminated body and greater than twice the sum of the thickness of the hard plate and the thickness of the elastic body.   The metal cylinder is mainly composed of any one metal element in the metal group consisting of silver, tin, copper, aluminum, and zinc, or any metal in the metal group, and the metal that is the main element. 2. The energy absorbing device according to claim 1, wherein the energy absorbing device is made of an alloy obtained by mixing one or more metals selected from the metal group other than the above or a metal other than the metal group.   The energy absorbing device according to claim 1 or 2, characterized in that uneven portions that engage with each other to prevent slipping are provided on contact surfaces of a plurality of metal cylinders constituting the energy absorber.

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