JP2016020731A - Method for estimating sliding surface temperature, seismic isolator, and building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for estimating sliding surface temperature capable of easily estimating sliding surface temperature.SOLUTION: A method for estimating sliding surface temperature is provided with: a step S1 of performing an experiment by using a reduced model to calculate frictional heat Q to be generated on a sliding surface; a step S2 of performing finite element analysis of a sliding plate and a sliding bearing in one dimension along a cross section in a vertical direction to calculate an inflow ratio k; a step S3 of calculating contact ratios kof the respective points on the sliding surface; steps S4, 5 of calculating incident heat fluxes qbto be made incident on the respective points on the sliding surface, and performing the finite element analysis of the sliding plate in three dimensions by using the incident heat fluxes qbas a boundary condition to calculate temperature Tof sliding surfaces of the respective points on the sliding plate; and a step 6 of making temperature T of the sliding surface into a range larger than temperature Tmeasured by the experiment using the reduced model, and smaller than the temperature calculated by the step S5.SELECTED DRAWING: Figure 2

Description

  The present invention is, for example, a method for estimating a slip surface temperature of a slip plate of a seismic isolation device, and a seismic isolation device in which the material, size, and shape of the slip plate are determined by the slip surface temperature estimation method, and The present invention relates to a building equipped with this seismic isolation device.

  In a building having a seismic isolation structure, a seismic isolation device is provided on a foundation that is a lower structure, and the building that is an upper structure is supported through the seismic isolation device. This seismic isolation device includes, for example, a sliding plate provided on a foundation and a sliding bearing that slides on the sliding plate (see Patent Documents 1 and 2).

  In the above seismic isolation device, when the seismic force applied to the building is large during an earthquake, the sliding bearing slides on the sliding plate to reduce the seismic force.

  Here, the amount of movement of the sliding material provided on the sliding bearing in the horizontal direction with respect to the sliding plate is defined as the amount of sliding. This slip amount is affected by the friction of the sliding surface of the sliding plate, but it has been found that the friction coefficient decreases from that at normal temperature when the sliding surface becomes high temperature. Therefore, it is desirable to consider this reduction in the coefficient of friction when designing a building with a base isolation structure.

JP 2006-144346 A JP 2009-281559 A

The most accurate method for grasping the friction coefficient of the sliding surface is a full-scale experiment, that is, an experiment using a member having an actual size. However, there is a limit to the scale at which the experiment can be performed in terms of the performance of the test apparatus and the experimental cost, and only a reduced scale experiment may be performed.
In the reduction experiment, the material of the test specimen, the vertical dimension, the loaded load per unit area, and the like can be matched with each other relatively easily. On the other hand, it is difficult to match the horizontal dimension, that is, the diameter of the sliding bearing and the sliding amount to the actual size, and must be reduced.

When the dimension in the horizontal direction is reduced geometrically to the actual size, the ratio of the heat loss in the outer peripheral direction to the generated frictional heat increases, so that the temperature is lower than the actual size.
Therefore, it is necessary to correct the coefficient of friction by the reduction experiment using the actual and expected temperature.

  The slip surface temperature necessary for this correction needs to be estimated by heat conduction analysis based on the frictional heat obtained from the reduction experiment result. In this case, the slip plate and the slide support have a three-dimensional shape, slip direction, and heat transfer direction, so a three-dimensional heat conduction analysis is required. There was a problem that was big.

  It is an object of the present invention to provide a slip surface temperature estimation method, a seismic isolation device, and a building that can easily estimate the actual slip surface temperature.

The slip surface temperature estimation method according to claim 1 is a sliding bearing (for example, an elastic sliding bearing 20 described later) on a sliding surface (for example, a sliding surface 11 described later) of a sliding plate (for example, a sliding plate 10 described later). Is a slip surface temperature estimation method for estimating the temperature of the slip surface for a seismic isolation device (for example, a seismic isolation device 1 to be described later), which produces a reduced model of the slip plate and the slide support, An experiment is performed using the reduced model, and a first step (for example, step S1 to be described later) for obtaining frictional heat (for example, frictional heat Q to be described later) generated on the sliding surface, the sliding plate and the sliding support are determined. along the vertical cross section by performing a finite element analysis in one dimension, the ratio of frictional heat generated in the sliding surface flows inside the sliding plate as the inflow rate (for example, the inflow rate k _{in below)} A second step (for example, step S2 to be described later) and, based on the diameter and amplitude of the sliding bearing, a time ratio at which each point on the sliding surface contacts the sliding bearing is determined as a contact rate (for example, A third step (for example, step S3 described later) to be obtained as a contact rate k _ct described later, and an incident heat flux incident on each point on the slip surface based on the frictional heat, the inflow rate, and the contact rate. (For example, an incident heat flux qb _XY described later) is obtained, and the sliding plate is subjected to three-dimensional finite element analysis using the incident heat flux as a boundary condition, and the temperature of the sliding surface at each point on the sliding plate ( For example, a fourth step (for example, steps S4 and S5 to be described later) for _obtaining a slip surface temperature T _fcal described later and a slip surface temperature (for example, a full-scale slip surface temperature T to be described later) are reduced. Use model The fifth step (for example, step S6 to be described later) is set to a range that is greater than the temperature measured in the previous experiment (for example, the temperature T _rexp of the sliding surface of the reduced model described later) and smaller than the temperature obtained in the fourth step. And.

According to the present invention, in the fourth step, only the slip plate is subjected to three-dimensional element analysis. Therefore, labor and calculation time required for the analysis can be greatly reduced, and the temperature of the slip surface can be easily estimated.
Further, in the fifth step, the temperature of the actual sliding surface can be obtained within a predetermined range. Therefore, when designing the sliding plate, the friction coefficient is calculated by appropriately using the minimum value or the maximum value of the predetermined range. If so, it can be easily considered on the safety side.

  Further, when performing finite element analysis on the sliding plate, it is necessary to set the ratio at which the frictional heat generated on the sliding surface is transmitted to the sliding bearing side and the sliding plate side. However, if this is to be set strictly, it is necessary to perform the calculation while switching the contact surface in consideration of the relative movement of the sliding bearing and the sliding plate, which increases the calculation burden.

  Therefore, in the present invention, without performing such a strict calculation, the phenomenon is simplified, and the time ratio at which each point on the sliding surface contacts the sliding bearing is defined as the contact ratio, and this contact ratio is used. Since the boundary conditions of the finite element analysis are calculated, the calculation burden can be further reduced.

  Since the sliding bearing reciprocates on the sliding surface, a certain point on the sliding surface actually repeats the state in contact with the sliding bearing and the state exposed to the ambient air periodically. Since it is cumbersome to calculate the presence or absence of contact with this sliding bearing over time, the coefficient representing the ratio of the contact time with the sliding bearing to the total excitation time is defined as the contact ratio. Boundary conditions for finite element analysis.

  The slip surface temperature estimation method according to claim 2 is characterized in that, in the second step, finite element analysis is performed on the assumption that the temperature at the boundary surface between the slip plate and the slide bearing is the same.

When performing finite element analysis, it is necessary to set the heat transfer coefficient of the sliding surface, but it is difficult to set accurately because it changes depending on the material of the sliding plate and the sliding bearing and the surface state of the sliding surface.
Therefore, in the present invention, the calculation burden can be further reduced by performing the finite element analysis on the assumption that the temperature at the boundary surface between the sliding bearing and the sliding plate is the same. Even in this case, the amount of heat transfer due to the temperature difference between the surface of the sliding bearing and the surface of the sliding plate is sufficiently smaller than the heat generated by friction, and the influence on the calculation result can be ignored.

  The seismic isolation device according to claim 3 is a seismic isolation device in which a sliding bearing slides on the sliding surface of the sliding plate, and the material, size, and shape of the sliding plate are the above-described slip surface temperature estimations. It is determined based on the temperature of the slip surface estimated by the method.

  A building according to claim 4 (for example, building 3 described later) is a building including a seismic isolation device in which a sliding bearing slides on a sliding surface of a sliding plate, and a friction coefficient (for example, described later) of the sliding surface. The friction coefficient M) is set on the basis of the slip surface temperature estimated by the slip surface temperature estimation method according to claim 1 or 2, and is designed based on the friction coefficient.

  According to the present invention, since only the slip plate is subjected to three-dimensional element analysis, labor and calculation time required for the analysis can be greatly reduced, and the temperature of the slip surface can be easily estimated.

It is a longitudinal cross-sectional view of the seismic isolation apparatus to which the slip surface temperature estimation method which concerns on one Embodiment of this invention was applied. It is a flowchart of the procedure which estimates the temperature of the slip surface of the slip board of a seismic isolation apparatus using the slip surface temperature estimation method which concerns on the said embodiment. In the slip surface temperature estimation method according to the embodiment, it is a schematic diagram of a reduction experiment for calculating frictional heat generated on the slip surface. It is a figure which shows the time-dependent change of the frictional heat calculated | required by the reduction experiment in the slip surface temperature estimation method which concerns on the said embodiment. FIG. 5 is a schematic plan view for explaining a procedure for measuring a temperature on a slip surface in the slip surface temperature estimation method according to the embodiment. It is the schematic diagram which modeled the vertical direction cross section of the slip board and the slide support in the slip surface temperature estimation method which concerns on the said embodiment. It is a figure which shows the specific example of the time-dependent change of an inflow rate in the slip surface temperature estimation method which concerns on the said embodiment. It is a figure which shows the specific example of distribution of a contact rate in the slip surface temperature estimation method which concerns on the said embodiment. In the slip surface temperature estimation method according to the embodiment, it is a schematic plan view of a slip plate for explaining the distribution of contact ratio. It is a figure which shows the specific example of the result of a three-dimensional finite element analysis in the slip surface temperature estimation method which concerns on the said embodiment. In the slip surface temperature estimation method according to the embodiment, it is a schematic plan view of a slip plate for explaining the result of three-dimensional finite element analysis. In the slip surface temperature estimation method according to the embodiment, it is a diagram showing a change with time in the temperature of the slip surface obtained by prediction and the temperature of the slip surface measured by an experiment using a reduced model.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a side view of a seismic isolation device 1 to which a slip surface temperature estimation method according to an embodiment of the present invention is applied.
The seismic isolation device 1 is provided on a foundation 2 that is a lower structure and supports a building 3 that is an upper structure.

A reinforced concrete lower seismic isolation base 4 is constructed on the upper surface of the foundation 2, and a reinforced concrete upper seismic isolation foundation 5 is constructed on the lower surface of the building 3.
The seismic isolation device 1 includes a sliding plate 10 fixed to the upper surface of the lower seismic isolation base 4 and an elastic sliding bearing 20 provided on the sliding surface 11 of the sliding plate 10 so as to be slidable in the horizontal direction. Prepare.
The elastic sliding bearing 20 includes a sliding member 21 provided on the sliding plate 10, a lower steel plate 22 provided on the sliding member 21, a laminated rubber 23 provided on the lower steel plate 22, and a laminated material. And an upper steel plate 24 provided on the rubber 23.

The above seismic isolation device 1 holds the state in which the building 3 can move in the horizontal direction with respect to the foundation 2 while supporting the building 3 from below by taking a reaction force on the foundation 2.
In the event of an earthquake, when a small seismic force applied to the building 3 is applied, the laminated rubber 23 of the elastic sliding bearing 20 is deformed to relieve the seismic force, and when a large seismic force is applied, it is elastic. The sliding support 20 slides on the sliding plate 10 to reduce the seismic force.

The temperature of the sliding surface of the sliding plate 10 of the seismic isolation device 1 is estimated, the friction coefficient M on the sliding surface 11 is set based on the estimated temperature, and the building 3 is designed based on the friction coefficient M. Yes.
Hereinafter, the procedure for designing the building 3 will be described with reference to the flowchart of FIG.

In step S1, the frictional heat Q generated on the sliding surface is calculated using the reduced model, and the temperature T _repp at the measurement point on the sliding surface is measured.
That is, as shown in FIG. 3, a reduced model of the seismic isolation device is manufactured, and the sliding support of the reduced model is actually vibrated on the reduced model sliding plate. In this reduction experiment, the size / material in the vertical direction, the surface pressure, and the amount of slip per unit time are made to coincide with each other.

For example, a reduction experiment was performed under the following experimental conditions. The outer diameter of the test body is set to 300 mm, and biaxial loading is performed in which a sine wave having a period of 4 seconds is vibrated horizontally with a constant vertical axial force. The reference surface pressure was 20 N / mm ² and 250 consecutive vibrations were applied.

  In this reduction experiment, the horizontal force H acting on the sliding bearing is measured. When the sliding amount of the sliding bearing is D, the frictional heat Q per unit area generated on the sliding surface is obtained by the following equation (1).

  Q = H × D (1)

  FIG. 4 is a diagram showing a change with time of frictional heat obtained by a reduction experiment. As can be seen from FIG. 4, the frictional heat Q decreases with time.

Further, when this reduction experiment is performed, as shown in FIG. 5, measurement points are set in a grid pattern on the slip surface of the slip plate, and the temperature T _rexp at each measurement point is measured.

In step S2, calculating the flow rate k _in the finite element analysis of a one-dimensional.
As shown in FIG. 6, the sliding plate and the sliding bearing are modeled along a vertical section. Then, each element becomes one-dimensional in a line in the vertical direction. Performing a finite element analysis with respect to this model, determine the rate of flow into the frictional heat Q is sliding plate as inflow rate k _in.
In this finite element analysis, the temperature at the boundary surface (slip surface) between the slide bearing and the slide plate is set to be the same.
FIG. 7 is a diagram illustrating a specific example of the change over time of the inflow rate k _in .

In step S3, the contact ratio _kct is calculated for the actual size.
It is assumed that the sliding bearing vibrates on the sliding surface of the sliding plate with a predetermined amplitude and a predetermined cycle. Then, based on the diameter and amplitude of the sliding bearing, a time ratio at which each point on the sliding surface comes into contact with the sliding bearing is obtained as a contact ratio _kct .

FIG. 8 is a diagram illustrating a specific example of the distribution of the contact ratio _kct , and FIG. 9 is a schematic plan view of the sliding plate.
FIG. 8 shows a part (shaded portion) of the sliding plate shown in FIG. 9, and the contact ratio k _ct when the sliding support is vibrated in the direction of the white arrow in FIG. 8 on the sliding plate of FIG. Distribution.
As shown in FIG. 8, the closer to the center of the sliding plate, the longer it takes for the sliding support to contact the sliding surface, so the contact rate _kct is higher.

In step S4, the incident heat flux qb _XY is calculated for the actual size.
When the sliding bearing vibrates on the sliding surface, the incident heat flux qb _XY incident on each point on the sliding surface based on the frictional heat Q, the inflow rate k _in , and the contact rate k _ct is expressed by the following equation ( Obtain according to 2).

_{qb XY = k ct k in Q} + h (1-k ct) (T a -T XY) ... (2)
h: Sogo heat transfer coefficient T _xy: temperature T _a of each measurement point xy any sliding plate surface at a calculated point: ambient temperature

In the right side of the above equation (2), the first term calculates the heat from the sliding surface toward the sliding plate. That is, it is the product of the frictional heat Q, the inflow rate k _in , and the contact rate k _ct that are the calculation results of steps S1 to S3.
On the other hand, the second term on the right side calculates the heat released from the sliding surface to the outside. That is, each point of the slip surface is air-cooled by the surrounding air in a state where the slide support is not in contact, and thus the heat radiated by this air-cooling is obtained.

In step S5, the temperature T _fcal of the slip surface at each measurement point on the slip plate is obtained by three-dimensional finite element analysis.
Using the incident heat flux qb _XY obtained in step S4 as a boundary condition, the sliding plate is subjected to three-dimensional finite element analysis to obtain the temperature T _fcal of the sliding surface at each measurement point on the sliding plate.

FIG. 10 is a diagram showing a specific example of the result of the three-dimensional finite element analysis, and FIG. 11 is a schematic plan view of the sliding plate.
FIG. 10 shows a part (shaded portion) of the sliding plate shown in FIG. 11, and a three-dimensional finite element analysis in the case where the sliding support is vibrated on the sliding plate of FIG. Is the result of

In step S6, the temperature of the _actual sliding surface is set as T, and the range of T _fcal >T> T _rexp is set.
The temperature T of the _actual sliding surface is higher than the temperature T _rexp of the sliding surface of the reduced model. The reason is that the actual size is smaller in the rate at which the generated frictional heat is lost in the outer circumferential direction than the reduced model.

In step S7, the friction coefficient M on the slip surface 11 is set based on the estimated actual temperature T of the slip surface.
In step S8, the building 3 is designed based on the set friction coefficient M.

In addition, the _actual sliding surface temperature T is lower than the sliding surface temperature T _fcal obtained in step S5. The reason is as follows.
That is, even if the amount of movement of the sliding bearing is the same, the friction coefficient decreases and the frictional heat per unit area also decreases as the sliding surface temperature increases. As described above, since the temperature T _rexp of the sliding surface of the reduced model is lower than the temperature T of the _actual sliding surface, the frictional heat Q in the reduced model is higher than the actual frictional heat. In step S5, the slip surface temperature T _fcal is obtained using the frictional heat Q higher than the _actual size obtained in the reduction experiment. Therefore, the slip surface temperature T _fcal obtained in step S5 is the _actual slip surface. The temperature T becomes higher.

Figure 12 is a diagram showing the temperature T _fcal of the sliding surface obtained by the prediction, and the temperature T _rexp the measured sliding surface Experiments using miniature, the time course of. In FIG. 12, the temperature T of the _actual sliding surface is a region surrounded by T _fcal and T _rexp .

According to this embodiment, there are the following effects.
In step S5, since only the slip plate is subjected to three-dimensional element analysis, labor and calculation time required for the analysis can be greatly reduced, and the slip surface temperature can be easily estimated.
Further, since the temperature T of the _actual sliding surface is obtained in the range of T _fcal >T> T _rexp , when designing the sliding plate, the minimum value (T _rexp ) or the maximum value (T _fcal ) of this predetermined range. If the coefficient of friction is calculated appropriately, it can be easily considered on the safety side.

To simplify the event, the time proportions in contact with bearing slip each point on the sliding surface and contact ratio k _ct, incident heat flux qb _XY is a boundary condition of the finite element analysis using the contact ratio k _ct The calculation burden can be further reduced.

  In step S2, assuming that the temperature at the boundary surface between the sliding bearing and the sliding plate is the same, the calculation burden can be further reduced by performing the one-dimensional finite element analysis.

  It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.

DESCRIPTION OF SYMBOLS 1 ... Base isolation device 2 ... Foundation 3 ... Building 4 ... Lower base isolation base 5 ... Upper base isolation base 10 ... Sliding board 11 ... Sliding surface 20 ... Elastic sliding bearing 21 ... Sliding material 22 ... Lower steel plate 23 ... Laminated rubber 24 ... Upper steel plate D ... Slip amount H ... Horizontal force M ... Friction coefficient Q ... Frictional heat T ... _Full- scale slip surface temperature T _fcal ... Slip surface temperature T _rex ... Reduced model slide surface temperature k _ct ... Contact Rate k _in ... inflow rate qb _XY ... incident heat flux

Claims (4)

For a seismic isolation device in which a sliding bearing slides on a sliding surface of a sliding plate, a slip surface temperature estimating method for estimating the temperature of the sliding surface,
Producing a reduced model of the sliding plate and the sliding support, performing an experiment using the reduced model, and determining a frictional heat generated on the sliding surface;
A second step of performing a one-dimensional finite element analysis of the sliding plate and the sliding bearing along a vertical cross-section and obtaining a rate at which the frictional heat generated on the sliding surface flows into the sliding plate as an inflow rate When,
A third step of determining, as a contact ratio, a time ratio at which each point on the sliding surface contacts the sliding bearing based on the diameter and amplitude of the sliding bearing;
Based on the frictional heat, the inflow rate, and the contact rate, an incident heat flux incident on each point on the slip surface is obtained, and the slip plate is defined as a three-dimensional finite element using the incident heat flux as a boundary condition. A fourth step of performing an analysis to determine the temperature of the sliding surface of each point on the sliding plate;
A slip surface temperature, characterized in that the slip surface temperature includes a fifth step in which the temperature of the slip surface is larger than the temperature measured in the experiment using the reduced model and smaller than the temperature obtained in the fourth step. Estimation method.   2. The slip surface temperature estimation method according to claim 1, wherein in the second step, finite element analysis is performed on the assumption that the temperature at the boundary surface between the slip plate and the slide support is the same. A seismic isolation device in which the sliding bearing slides on the sliding surface of the sliding plate,
The seismic isolation device according to claim 1, wherein a material, a size, and a shape of the slip plate are determined based on a slip surface temperature estimated by the slip surface temperature estimation method according to claim 1. A building having a seismic isolation device in which the sliding bearing slides on the sliding surface of the sliding plate,
The building according to claim 1, wherein the friction coefficient of the slip surface is set based on the temperature of the slip surface estimated by the slip surface temperature estimation method according to claim 1, and is designed based on the friction coefficient.

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