JP2006194287A - Vibration-damping material using ferrous shape memory alloy and vibration-damping/vibration isolating device using the material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide vibration-damping material, vibration damping/vibration isolating device satisfying two different requirements to absorb earthquake energy and to have shape recovery function in vibration damping material design and vibration damping/vibration isolating device design. <P>SOLUTION: In ferrous vibration-damping structure material used for an earthquake-proof structure, ferrous shape memory alloy containing Fe-Mn-Si-based shape memory alloy containing NbC having anelasticity without strain hardening against strain vibration, strain deformation in a large strain amplitude zone in earthquake is used as vibration-damping material for earthquake-proof structure. Consequently, vibration-damping property and shape recovery property are given to the structure member. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  By using an iron-based shape memory alloy having pseudoelasticity without causing strain hardening in a large strain amplitude region due to earthquake motion, the present invention can impart vibration damping and shape restoration function to a structural member. The present invention relates to an iron alloy vibration damping material for earthquake-resistant structural members and a seismic isolation / damping device using at least this material. Specifically, the iron-based shape memory alloy having pseudoelasticity in the large amplitude region is an Fe-Mn-Si-based shape memory alloy containing NbC, and an iron alloy-based vibration damping material for an earthquake-resistant structural member. At least the seismic isolation / vibration control device used.

  More specifically, the Fe—Mn—Si based shape memory alloy containing NbC is Mn: 15-40 wt%, Si: 3-15 wt%, Cr: 0-20 wt%, Ni: 0-20 wt% Nb: 0.1 to 1.5% by weight, C: 0.01 to 0.2% by weight, and the balance Fe and inevitable impurities include Cu: 3% by weight or less, Mo: 2% by weight or less, A1 : 10% by weight or less, Co: 30% by weight or less, N: 5000ppm or less, and the atomic ratio of Nb to C (Nb / C) is 1.0 to 1.2. And a seismic isolation / vibration control device using at least this material.

  More specifically, the NbC-added Fe—Mn—Si based shape memory alloy is processed at a room temperature or 5 to 40% at a temperature range of 500 ° C. to 1100 ° C., and then at a temperature range of 400 ° C. to 1100 ° C. Moreover, an iron alloy damping material for earthquake-resistant structural members that has been subjected to aging heat treatment for 1 minute to 2 hours and memorized the shape by precipitating NbC carbide, and a seismic isolation / damping device using at least this material About.

  In recent years, earthquake disaster countermeasures have become a problem. In particular, since the Kobe earthquake, large-scale structures centering on urban infrastructure functions, seismic isolation design and vibration control design of buildings have been reviewed, and more effective measures based on stricter standards are required. Such a situation is being reviewed nationwide, and is urgently being developed, not to mention the Tokai area and metropolitan area where earthquakes are expected in recent years. In addition, not only large structures but also general houses are required to take measures.

  Under such circumstances, many various seismic isolation technologies and vibration control means have been actively proposed and developed so far. Examples of the seismic isolation / damping means for protecting the structure body from destruction include a damping damper and a damping brace. These are devices that absorb the vibrational energy when an earthquake occurs and prevent the vibration from reaching the structure body, but various proposals have been made for such dampers. Dampers roughly classified into viscous dampers (see Patent Document 1), viscoelastic dampers (see Patent Document 2), lead dampers (Patent Document 3), elasto-plastic dampers (Patent Document 4), etc. have been proposed and developed. Yes.

  Among them, elasto-plastic dampers using extremely mild steel have attracted particular attention in recent years because they are excellent in performance, cost, and maintainability. This elasto-plastic damper absorbs seismic energy by plastic deformation of the damper, thereby preventing and absorbing the energy so that the seismic energy does not directly reach the main body of the structure in the event of an earthquake. It is highly anticipated as an extremely promising seismic isolation / vibration control method.

  However, the seismic isolation / damping means proposed and developed so far, including elasto-plastic dampers, are shock absorbers that prevent damage from earthquakes from reaching the main body of the structure. Can function effectively as a shock absorber, but there is no way to protect the vibration control device itself from an earthquake. That is, in any seismic isolation device and vibration control device, strain remains or deforms after the occurrence of the earthquake, and the device itself is not restored to its original state. Therefore, after a large earthquake, these devices need to be replaced with new parts and devices.

  These devices are usually mounted or embedded in structures, for example, pillars, walls, etc., which would be a hindrance when replacing them with new parts after an earthquake. It required a lot of labor, complicated work, and cost, such as removal of members such as walls, replacement of parts, and repair of walls. It would be extremely beneficial if it was freed from such complicated and costly repair work and could be easily restored to its original state in the situation. However, at present, such a device has not yet been developed. If a damping and seismic isolation device that can be easily restored to its original shape has been developed, its significance is immeasurable, and it can make a significant contribution to society as a whole. . In Japan, which has one of the world's leading economic powers, when a large-scale earthquake is damaged, the economic loss caused by this is immeasurable, and as a result it is expected to lead to global loss. The development and realization of is attracting worldwide attention and demand.

JP-A-5-263858 Japanese Patent Laid-Open No. 2001-146855 JP-A-5-106367 JP-A-5-26274

  The present invention is intended to meet the above requirements. In other words, in damping material design or seismic isolation / damping device design, the damping material, seismic isolation / damping device that can respond to two different requests that absorb the seismic energy and have shape recovery function Is to provide.

Therefore, as a result of diligent research in the inventors, a part of the inventors previously proposed and applied for a patent, exhibiting good shape memory characteristics even without training, and only after heating even after deformation. The iron-based shape memory alloy (see Patent Documents 1 to 4) that can be easily restored to its original shape with the above exhibits damping characteristics in a large amplitude region with a strain amplitude of ± 0.1% or more. I found out that It has never been known so far and is a new finding that an iron-based shape memory alloy having a low cost has such a damping function and can be expressed. The present invention has been made based on this finding, and the configuration thereof is as described in (1) to (11) below.
(1) In iron-based vibration-damping structural materials used for earthquake-resistant structures, an iron-based shape that has pseudoelasticity without strain hardening against strain vibration and strain deformation in the large strain amplitude region due to earthquake motion The use of a memory alloy as a vibration-damping material for a seismic structural member enables the structural member to be imparted with a vibration-damping property and a shape restoration property. Vibration material.
(2) Fe-Mn-Si based shape memory alloy containing NbC, an iron-based shape memory alloy having pseudoelasticity without strain hardening against strain vibration and strain deformation in a large strain amplitude region due to the earthquake motion The iron alloy damping material for earthquake-resistant structural members according to (1).
(3) Fe-Mn-Si based shape memory alloy containing NbC is Mn: 15-40 wt%, Si: 3-15 wt%, Cr: 0-20 wt%, Ni: 0-20 wt%, Nb: 0.1 to 1.5% by weight, C: 0.01 to 0.2% by weight, remaining Fe and inevitable impurities include Cu: 3% by weight or less, Mo: 2% by weight or less, A1: 10% by weight or less, Co: 30% by weight or less, N: 5000 ppm or less, and the atomic ratio of Nb to C (Nb / C) is 1.0 to 1.2. Iron alloy damping material for parts.
(4) The NbC-added Fe—Mn—Si based shape memory alloy is processed 5 to 40% at room temperature or in a temperature range of 500 ° C. to 1100 ° C., and then in a temperature range of 400 ° C. to 1100 ° C. and 1 The iron alloy vibration damping material for earthquake-resistant structural members according to (2) or (3), which is subjected to a shape memory treatment by precipitating NbC carbides by aging heat treatment for minutes to 2 hours.
(5) A vibration damping and seismic isolation device that absorbs vibration energy and protects structures against earthquake motion, and has pseudoelasticity without strain hardening against strain vibration and strain deformation in the large strain amplitude region due to earthquake motion. A vibration damping and seismic isolation device characterized in that it contains at least an iron-based shape memory alloy as a vibration damping material and absorbs vibration energy and imparts a shape recovery function to the vibration damping device.
(6) Fe-Mn-Si based shape memory alloy containing NbC, wherein the iron-based shape memory alloy having pseudoelasticity without strain hardening against strain vibration and strain deformation in the large strain amplitude region due to the earthquake motion The vibration control and seismic isolation device according to (5).
(7) Fe-Mn-Si based shape memory alloy containing NbC is Mn: 15-40 wt%, Si: 3-15 wt%, Cr: 0-20 wt%, Ni: 0-20 wt%, Nb: 0.1 to 1.5% by weight, C: 0.01 to 0.2% by weight, remaining Fe and inevitable impurities include Cu: 3% by weight or less, Mo: 2% by weight or less, A1: 10% by weight or less, Co: 30% by weight or less, N: 5000 ppm or less, and the atomic ratio of Nb to C (Nb / C) is 1.0 to 1.2. Seismic isolation device.
(8) The NbC-added Fe—Mn—Si based shape memory alloy is processed 5 to 40% at room temperature or in a temperature range of 500 ° C. to 1100 ° C., and then in a temperature range of 400 ° C. to 1100 ° C. and 1 The vibration damping device according to (6) or (7), wherein the shape memory treatment is performed by precipitating NbC carbides by aging heat treatment for minutes to 2 hours.
(9) The vibration damping / isolation device according to any one of (5) to (8), wherein the vibration damping / isolation device includes a vibration damper and a vibration brace.
(10) The vibration damping and seismic isolation device according to any one of (5) to (9), wherein the vibration damping and seismic isolation device includes heating means for restoring the shape in advance.
(11) The vibration damping and seismic isolation device according to (10), wherein the heating means for restoring the shape is an electrical heating means.

  Here, the iron-based shape memory alloy having the characteristic of absorbing vibration energy used in the present invention has been developed by a part of the present inventors and has already been filed for a patent earlier. These are based on the prior art iron-based shape memory alloys. That is, the shape memory alloy used as a damping material in the present invention is an inexpensive and high-performance shape memory alloy described in Patent Documents 5 to 8, specifically, an NbC-added Fe—Mn—Si based alloy. Itself is already known as a shape memory alloy.

  However, only the following paper (see Non-Patent Document 1) has been published regarding the tensile / compressive low cycle fatigue behavior of this Fe—Mn—Si based shape memory alloy. No mention is made of use as a damping material for structural members in the design of seismic structural members that require damping in the region of large strain amplitude caused by earthquakes. In addition, it has not been reported that NbC can be added to increase the strength, suppress work hardening to obtain a long-life vibration damping alloy, and restore the initial shape by using the shape memory effect together. The present invention is to actively use this iron-based memory alloy as a vibration damping material, and such an attempt is novel.

  In the configuration of the present invention, the Mn and Si concentration ranges defined in (3) or (7) indicate stress-induced martensitic transformation from the fcc structure to the hcp structure when the alloy system is deformed at room temperature. This is a condition necessary for the purpose, and is a condition for exhibiting good shape memory characteristics, and also a condition for exhibiting damping characteristics. The concentrations of Cr and Ni are for improving the corrosion resistance without impairing the shape memory characteristics and the vibration damping characteristics. In the above configuration, the matters relating to Nb and C defined in (3) and (7) and the heat treatment conditions defined in (4) and (8) are opposite to the stress-induced martensitic transformation by fine precipitation of NbC. It has the significance of reversibly causing transformation and improving shape memory characteristics, and when used as a damping alloy, it has the significance of suppressing strain hardening (work hardening) due to repeated deformation. ing. In addition, by installing a heating device in the vibration control / seismic isolation device or the structural member in advance (10 or 11), even if the earthquake is deformed due to strain after the occurrence of the earthquake, the wall must be removed one by one as in replacement work. No complicated operation such as removal is required, and the shape can be recovered by heating easily.

Japanese Patent No. 3542754 JP 2003-105438 A JP 2003-277827 A JP 2004-197161 A Gu, N .; J. et al. , C.I. X. Lin, et al. (2001). Reverse transformation and smart charactaristics of FeMnSiCrNi SMA. Shape Memory Materials and Its Applications. 394-3: 415-418.

  The present invention is based on the above configuration, and can be restored to its original shape by a simple operation by heating.As a damping alloy that is required to absorb vibration energy exclusively, The vibration damping material is provided with a new property and a new function that have not been provided before, and the vibration damping device using this material is also the same. The present invention proposes a new vibration damping device. In particular, the alloy having the composition range defined in (3) and (7) having the above configuration has a shape recovery rate of 80% or more (preferably 98% or more) only by heating, and the damping device is deformed by an earthquake. Even if it comes, it can be easily restored to its original shape.

  In addition to the above, the damping material using the iron-based shape memory alloy used in the present invention and the damping device designed by this material are lower in cost than viscous dampers, viscoelastic dampers and lead dampers. No harmful substances are generated. Therefore, it is easy to handle, and using this material in the future will enable the development of new seismic isolation and damping devices, including damping dampers and damping braces. Compared to elastoplastic dampers with similar properties, the effects of work hardening are so small that they can be used repeatedly, and after being exposed to large-scale earthquakes due to the addition of the shape memory effect. The deformation and residual strain of the seismic isolation / damping device itself that occur can be easily removed by a simple process of heating.

  In addition, since the alloy itself has damping characteristics, there are numerous advantages such as realizing an inexpensive damping mechanism without the need to load complicated structures and systems. In the future, earthquake resistance of large structures in buildings and civil engineering will be realized. It is expected to be used greatly in design.

  Hereinafter, the present invention will be described based on the drawings and examples. However, these drawings and examples are specifically disclosed as an aid for facilitating the understanding of the present invention, and the present invention is not limited thereby.

The characteristics of the iron-based shape memory alloy of the present invention are shown by the low cycle fatigue test results shown in FIG. The alloy composition subjected to this test is an alloy represented by Fe-28Mn-6Si-5Cr-0.53Nb-0.06C (mass%), and is described in the examples described later. It is a shape memory alloy having a shape restoration function. This alloy was warm-rolled at 600 ° C. for 14% and then aged at 800 ° C. for 10 minutes and subjected to a low cycle fatigue test. Low cycle fatigue test carried out by the strain amplitude control of the sine waveform _{0.5H Z, ± 0.1%, 0.2} %, 0.4%, 0.6%, 0.8%, 1.0% of The test was carried out with one specimen while increasing the strain amplitude stepwise by 10 cycles at each strain amplitude. From the stress-strain curve with spindle-type strain history, it can be seen that this alloy has damping characteristics.

  Next, in order to quantitatively evaluate this damping characteristic, the vibration damping capacity (specific damping capacity (%), hereinafter referred to as SDC) of the shape memory alloy calculated from the strain hysteresis for each strain amplitude in FIG. FIG. 2 shows the SDC distortion amplitude dependence. According to FIG. 2, a significant vibration damping ability (SDC 10% or more) starts to be exhibited when the strain amplitude is 0.1% or more, and SDC reaches 80% or more when the strain amplitude is 0.4% or more. Also from this figure, it can be seen that the shape memory alloy has a significant damping characteristic.

  The damping alloy is also required to have stable characteristics when subjected to repeated deformation. For example, in the case of the conventional elasto-plastic damper, the plastic deformation of the alloy, that is, the movement of dislocation is used for energy absorption, but the alloy is processed by the interaction between moving dislocations and dislocations and other internal defects. As a result, the damping characteristics change. Such a phenomenon is a phenomenon commonly found in materials, but such a phenomenon must be avoided as much as possible in a metal material used as a structural material. For this reason, in order to use as an elastic-plastic damper, the technical device which reduces a work hardening degree is needed.

  On the other hand, the shape memory alloy according to the present invention, as shown in FIG. 1, shows that the increase in the generated stress due to work hardening when it is repeatedly deformed for 10 cycles at each strain amplitude is very small. . For example, when the strain amplitude is ± 1.0%, the maximum stress (526 MPa) at the 10th cycle is about 3% higher than the maximum stress (510 MPa) at the 1st cycle. It is understood that this alloy can be a material that can function satisfactorily as a damping material that absorbs vibration energy.

  Further, the shape memory alloy having the above composition is repeatedly subjected to tensile deformation load and unloading, and the dependence of the pseudoelastic behavior appearing on the cycle number and deformation rate is shown in FIG. The shape memory alloy having this composition hardly depends on the number of cycles and the deformation rate, and shows that it is stable at any cycle and deformation rate.

  FIG. 4 shows the relationship between the shape recovery rate of the shape memory alloy having the above composition and the heating temperature. From this figure, it can be seen that the shape of this alloy is almost completely restored to its original shape of about 80% when heated to 200 ° C., and further about 98% when heated to 300 ° C. That is, the shape memory alloy can be used not only for the purpose of absorbing vibration energy, but also can remove deformation remaining after functioning as a damping alloy by heating at a low temperature of about 200 to 300 ° C. This indicates that the damping alloy has performance that is impossible.

  FIG. 5 shows the results of a shear strength test conducted using a cylindrical test piece having a diameter of 17.6 mmΦ in the shape memory alloy having the above composition. The fracture occurs at a shear displacement of 2 mm, and the load at that time is 260 kN. As a result, it has been found that the alloy exhibits a shear strength of 1,100 MPa that can be used as a structural material body. This result suggests that the present alloy can also be used as a structural material itself having damping characteristics.

  An Fe-28Mn-6Si-5Cr-0.53Nb-0.06C alloy (the numerical value is mass%) obtained by adding NbC was melted to produce an NbC-added Fe-Mn-Si based alloy. The produced alloy was subjected to a uniform heat treatment at 1200 ° C. for 10 hours, followed by warm rolling at 600 ° C. with a reduction rate of 14%, and further an aging treatment at 800 ° C. for 10 minutes. This alloy is an NbC-added Fe—Mn—Si based shape memory alloy according to the inventors' invention described in Patent Documents 1 to 4, and the deformation of about 5% is approximately caused by heating at 600 ° C. It has been confirmed that the original shape recovers to 95%. The alloy was subjected to various tests below to clarify its properties. The results are as shown in FIG. 1 to FIG. 4, but will be further supplemented below.

First, the vibration absorption performance of the shape memory alloy produced above was evaluated by a low cycle fatigue test in a strain amplitude region of strain amplitude of 0.1% to 1.0%.
A test specimen of the above-prepared alloy was prepared. The specimen is a standard dumbbell-type tensile specimen having a gauge part size of Φ8.0 mm × 15 mm ^L. Sinusoidal strain stress due to the control of the vibration frequency 0.5H _Z in this specimen was loaded, and measure the response. There are 6 types of strain amplitude: ± 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, and each strain amplitude is 10 cycles at a time. The test was carried out with one specimen while increasing the number. As a result, a stress-strain curve with a spindle-type strain history shown in FIG. 1 was obtained. From this figure, this alloy has extremely small work hardening with an increase in the number of cycles. For example, when the strain amplitude is ± 1.0%, the maximum stress at the 10th cycle (526 MPa) is the maximum stress at the first cycle (526 MPa). It was about 3% increase from 510 MPa).

  FIG. 2 is a vibration damping capacity SDC (Specific Damping Capacity) calculated from a strain history drawn by a stress-strain curve at each strain amplitude. It is said that a significant damping effect appears when the SDC is 10% or more. When the strain amplitude exceeds 0.1%, the SDC increases to 10% or more. Further, the SDC increases rapidly as the strain amplitude increases. After reaching about 80% when the strain amplitude is 0.4%, it gradually increases. Continue. From the above, it was confirmed that this iron-based shape memory alloy exhibits good vibration damping characteristics with extremely little deterioration due to work hardening in a strain amplitude region of 0.1%. In the case of an M8 class earthquake, the instantaneous maximum strain amplitude must be assumed to be about 1%, but the damping characteristics of the alloy hardly deteriorate even with such a large strain amplitude.

FIG. 3 shows pseudoelastic behavior that appears when a tensile deformation load and unloading are repeated on a sample produced under the same composition and the same heat treatment conditions as described above. A tensile strain was accurately measured by attaching a micro strain gauge having a base width of 1.4 mm to a tensile test piece having a rectangular gauge portion having a size of 0.4 mm ^T × 2.0 mm ^W × 15 mm ^L. After measuring three times with a crosshead speed of 0.1 mm / min, once at each deformation speed of 0.2 mm / min, 0.4 mm / min, 0.5 mm / min, and 0.25 mm / min The stress-strain characteristics up to a maximum load strain of 0.2% were measured using one test piece. Although a slight residual strain of about 0.003% appears only at the first measurement at a deformation rate of 0.1 mm / min, the second and subsequent measurements showed reversible deformation without residual strain with a strain history. The curve shape and hysteresis are almost constant without depending on the number of cycles and the deformation rate, and it was found that the pseudoelasticity and damping characteristics of this alloy do not depend on the deformation rate (vibration frequency).

FIG. 4 shows the evaluation of shrinkage (recovery of shape) due to heating by measuring the change in distance between the gauge points after applying about 2.2% tensile deformation to this alloy. It was confirmed that the deformation was recovered 80% by heating up to 200 ° C. As the heating temperature was raised to 200 ° C. or higher, further shape recovery progressed gradually, and at 300 ° C., the shape recovery rate was approximately 98%, which almost completely recovered to the original shape.
FIG. 5 shows a shear strength test result of the alloy having the same composition and heat treatment as described above. The test piece has a cylindrical shape, and the diameter of the cross section of the portion subjected to shear deformation is 17.6 mmΦ.

  From the above, the damping alloy used in the present invention is an Fe-Mn-Si based shape memory alloy previously filed by the present inventors, having both damping characteristics and shape recovery performance, and deforming the shape. Even if this occurs, it has been clarified that the shape can be restored to its original shape simply by heating, and can be used as a seismic isolation / damping material having a shape recovery function. This makes it possible to design a seismic isolation / damping device having a shape recovery function, and it is expected that it will be greatly used in the design of seismic isolation / damping systems for large structures such as civil engineering and architecture.

  In this example, the NbC-added Fe-Mn-Si-based shape memory alloy was explained based on a specific component composition, thereby indicating that it has both vibration damping characteristics and a shape recovery function. However, the shape memory alloy that can be used as a base isolation material in the present invention is not limited to this composition example. That is, the iron-based shape memory alloy in the region disclosed in the invention according to the previous patent application or the iron-based shape memory alloy that has been subjected to the aging heat treatment is included.

  When the iron-based memory alloy of the present invention is used as a vibration damping material, the alloy may be used alone or in combination with other materials, and the present invention may include any of the embodiments. Moreover, since the alloy itself has damping characteristics, an inexpensive damping mechanism is realized without the need for a complicated structure or system. Of course, it can include devices such as vibration dampers, vibration braces, etc. Therefore, not only as a device such as a damper, but also a mode in which the structure itself is designed by this new damping alloy is possible and may be included.

  The fatigue cycle behavior of the Fe-Mn-Si based shape memory alloy used as a damping material in the present invention is as described above, and this has not been positively positioned as a damping alloy, rather It has been considered inferior as a vibration damping material. One of the reasons is a problem related to the measurement condition of the vibration damping characteristics, and another reason is a problem related to the presence or absence of superelastic characteristics in the alloy system.

That is, among alloys showing the same kind of martensitic transformation, what is known as a damping alloy is an Fe-Mn binary alloy, and even if any third element is added thereto, the damping characteristics are usually descend. However, this discussion is based on the fact that conventional research on damping characteristics has been progressed mainly in the context of historical research on metal wear, and has targeted a small strain amplitude region of 10 ⁻³ or less. The damping characteristics of the alloy system show significant strain amplitude dependence, and research from a new viewpoint is necessary in a large strain amplitude region of 10 ⁻³ or more.

In a large strain amplitude region of 10 ⁻³ or more, metal usually undergoes plastic deformation. However, in recent years, various damping alloys that are actively engaged in product development by building manufacturers and steel manufacturers use this plastic deformation rather. It absorbs the energy of the earthquake. On the other hand, the NbC-added Fe-Mn-Si based alloy of the present invention exhibits damping characteristics by a kind of pseudoelastic reversible deformation involving stress-induced martensitic transformation instead of causing slip deformation in the large strain amplitude region. Became clear. Therefore, by specifying the application target as a damping material for damping of seismic motion and evaluating the performance in the large strain amplitude region, the possibility of using the alloy system as a damping alloy is opened. In addition, it is expected to be used as a damping alloy superior to the Fe-Mn binary alloy by comprehensively utilizing added values such as strength, corrosion resistance, and shape memory characteristics.

Furthermore, another reason that the Fe—Mn—Si based shape memory alloy has not attracted attention as a vibration damping alloy is that the alloy is considered not to exhibit superelasticity. Superelasticity is manifested by stress-induced martensitic transformation caused by deformation above the _Af point and reverse transformation by unloading. However, the Fe-Mn-Si-based shape memory alloy has a remarkably large phase transformation temperature hysteresis (about 300 K), and if it is deformed at the Af point or higher, it causes slip deformation rather than stress-induced martensitic transformation. In addition, the general view is that the alloy system does not exhibit superelasticity because the properties differ from the conventional shape memory alloy called thermoelastic type in various respects.

  If the superelasticity is not exhibited, it has been said that the vibration damping characteristics as in the Ni—Ti alloy cannot be expected. However, as a result of earnest researches by the present inventors, the NbC added Fe—Mn—Si group As for the alloy, it was discovered and revealed that it exhibits pseudoelasticity, which is a mechanism different from normal superelasticity. In addition, various strengthening methods such as NbC precipitation strengthening and work strengthening can increase the yield strength against slip deformation, and it is also clarified that super-elasticity can be exhibited if the martensitic transformation temperature is appropriately designed. . The present invention is based on the results of such basic research, and is based on the principle and principle of damping material design. In any case, we proposed a vibration damping material that has a shape recovery function not found in conventional vibration damping alloys and that can be easily achieved at low cost, and is technically superior and sufficiently practical. Is expected.

  Although mentioned in the beginning of this article, the vibration control and seismic isolation technology for building structures is a highly demanding theme. In recent years, various metal dampers have been commercialized, and are now becoming major development targets in the fields of architecture, civil engineering, and steel materials. Among them, elasto-plastic deformation type dampers such as ultra-soft steel, which are designed with coarse crystal grains and a low yield point, are hit products. The present invention has invested a great deal of effort in such industry trends, and has found a material with a function exceeding this elastic-plastic deformation type damper, and its significance is extremely large. In the future, it will be actively used as a damping material and damping device, and is expected to be greatly adopted for seismic design of various structures.

  The present invention uses an inexpensive, high-performance iron-based shape memory alloy as a seismic isolation / damping material. By using this material, the seismic isolation / damping device absorbs seismic energy. However, even if distortion or deformation occurs, it can be easily restored to its original shape simply by performing an operation by heating. In the past, this type of seismic isolation / vibration control device was to once tear the column material, wall, etc. to which it was attached and replace it with a new member or device. It can be restored to its original shape, and it has a great significance not only in the industry but also in society. In the future, not only large structures such as architecture and civil engineering, but also large houses are expected to be used and spread.

The figure which showed the low cycle fatigue test result of the iron-type shape memory alloy shown in the Example. The figure which showed the strain amplitude dependence of the vibration damping ability calculated | required from the strain hysteresis of the low cycle fatigue test of the iron-type shape memory alloy shown in the Example. The figure which shows the cycle number and deformation rate dependence of the pseudoelastic behavior which appears by repetition of the tensile deformation load and unloading of the iron-type shape memory alloy shown in the Example. The figure which shows the relationship between the shape recovery rate of the iron-type shape memory alloy shown in the Example, and heating temperature. The figure which shows the shear strength test result of the iron-type shape memory alloy shown in the Example

Claims (11)

  An iron-based shape memory alloy that has pseudoelasticity without being hardened against strain vibration and strain deformation in a large strain amplitude region caused by ground motion in an iron-based vibration-damping structural material used for earthquake-resistant structures. An iron alloy-based vibration damping material for earthquake-resistant structural members, characterized in that the structural member can be provided with damping properties and shape restoration properties by being used as a vibration-damping material for earthquake-resistant structural members.   The iron-based shape memory alloy having pseudoelasticity without strain hardening against strain vibration in the large strain amplitude region due to the earthquake motion and strain deformation is a Fe-Mn-Si based shape memory alloy containing NbC. The iron alloy damping material for earthquake-resistant structural members according to claim 1.   The Fe—Mn—Si based shape memory alloy containing NbC is Mn: 15 to 40 wt%, Si: 3 to 15 wt%, Cr: 0 to 20 wt%, Ni: 0 to 20 wt%, Nb: 0 0.1 to 1.5% by weight, C: 0.01 to 0.2% by weight, remaining Fe and unavoidable impurities: Cu: 3% by weight or less, Mo: 2% by weight or less, A1: 10% by weight The iron for earthquake-resistant structural members according to claim 2, comprising Co: 30% by weight or less, N: 5000ppm or less, and an atomic ratio of Nb to C (Nb / C) of 1.0 to 1.2. Alloy-based damping material.   The NbC-added Fe—Mn—Si based shape memory alloy is processed 5% to 40% at room temperature or in a temperature range of 500 ° C. to 1100 ° C., and then in a temperature range of 400 ° C. to 1100 ° C. and 1 minute to 2 The iron alloy vibration-damping material for an earthquake-resistant structural member according to claim 2 or 3, wherein the shape memory treatment is performed by precipitating NbC carbides by time-aging heat treatment.   Absorbs vibration energy against seismic motion and protects structures. Damping and seismic isolation devices have pseudoelasticity without strain hardening in the large strain amplitude region due to seismic motion and strain deformation. A vibration damping and seismic isolation device characterized by including an iron-based shape memory alloy as a vibration damping material and using it to absorb vibration energy and to give the vibration damping device a shape recovery function.   The iron-based shape memory alloy having pseudoelasticity without strain hardening against strain vibration in the large strain amplitude region due to the earthquake motion and strain deformation is a Fe-Mn-Si based shape memory alloy containing NbC. 6. A vibration damping and seismic isolation device according to claim 5.   The Fe—Mn—Si based shape memory alloy containing NbC is Mn: 15 to 40 wt%, Si: 3 to 15 wt%, Cr: 0 to 20 wt%, Ni: 0 to 20 wt%, Nb: 0 0.1 to 1.5% by weight, C: 0.01 to 0.2% by weight, remaining Fe and unavoidable impurities: Cu: 3% by weight or less, Mo: 2% by weight or less, A1: 10% by weight The vibration damping and seismic isolation device according to claim 6, comprising Co: 30 wt% or less, N: 5000 ppm or less, and an atomic ratio of Nb to C (Nb / C) of 1.0 to 1.2. .   The NbC-added Fe—Mn—Si based shape memory alloy is processed 5% to 40% at room temperature or in a temperature range of 500 ° C. to 1100 ° C., and then in a temperature range of 400 ° C. to 1100 ° C. and 1 minute to 2 The vibration damping device according to claim 6 or 7, wherein the shape memory treatment is performed by precipitating NbC carbide by a time aging heat treatment.   The vibration damping / isolation device according to any one of claims 5 to 8, wherein the vibration damping / isolation device includes a vibration damper and a vibration brace.   The vibration damping / isolation device according to any one of claims 5 to 9, wherein a heating means for restoring the shape is previously incorporated in the vibration damping / isolation device.   The vibration damping and seismic isolation device according to claim 10, wherein the heating means for recovering the shape is an electrical heating means.

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