Multi-cavity pressure block force sensor and testing device

Abstract

The utility model discloses a multi-chamber pressure-bearing block force sensor and a testing device. The force sensor comprises a multi-chamber pressure-bearing block and a strain sensor. The multi-cavity pressure-bearing block comprises an outer cylinder and a nesting plate, a first detection mounting part is arranged on the nesting plate, a second detection mounting part is arranged on the outer wall of the outer cylinder in the length direction of the nesting plate, and a third detection mounting part is arranged on the inner wall and the outer wall of the outer cylinder in the preset rotation angle direction of the nesting plate. The first detection installation part, the second detection installation part and the third detection installation part are all provided with strain sensors. According to the utility model, the strain sensors are ingeniously designed on the outer cylinder body and the nesting plate, so that hardware support is provided for obtaining the pressure of the multi-cavity pressure-bearing block; in combination with a simulation test, the measurement of the total pressure by the multi-cavity pressure-bearing block force sensor is not influenced by a stress action position, the pressure borne by the support can be accurately measured, and good sensing stability is achieved; and the horizontal shearing force of the multi-cavity pressure-bearing shock insulation support can be further obtained.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of multi-chamber pressure block force sensor, testing device, belong to sensor circuit system and detection technical field. BACKGROUND

[0002] Building structure foundation isolation technology can greatly reduce the seismic response of structure by prolonging the natural period of structure and providing appropriate damping, effectively protect the safety of structure and improve the function recoverability of structure after earthquake. Isolation bearing is the core component to realize the isolation function of building, and it is of great significance to evaluate the state of isolation bearing to ensure the safety of isolation building.

[0003] During an earthquake, isolation bearings consume a large amount of energy and are key and weak points that are prone to damage. If the isolation bearing has been damaged before the earthquake and not detected in time, it will affect its isolation effect, and even lead to sudden failure of the entire structure. On the other hand, if the isolation bearing is in an abnormal working state, such as excessive axial pressure or shear deformation, it will also adversely affect its isolation effect: when the bearing axial pressure is too large, it will cause the bearing to be damaged prematurely under large deformation, and the pressure stress on the effective overlap area will exceed the allowable value, thereby failing to fully exert the isolation capacity; when the bearing shear deformation is too large, it will adversely affect its ultimate deformation capacity, making the bearing unable to meet the original design requirements, thereby causing the bearing to be damaged prematurely or the isolation layer displacement to exceed the limit. Therefore, it is necessary to monitor the axial pressure, shear deformation and damage of the bearing to effectively evaluate the actual state of the isolation bearing and ensure the safety of the isolation building.

[0004] During the long-term use of the bearing, even if it is a qualified product and meets the installation requirements, the bearing will still age, which is inevitable. This highlights the necessity and importance of monitoring the working state of the bearing. Currently, the common evaluation method for isolation bearings is to disassemble the bearing, and evaluate it based on appearance inspection and load test, which is time-consuming and labor-intensive, and cannot accurately evaluate the state of the bearing in the structure. Moreover, the bearing has certain concealment, making detection difficult and dangerous. If traditional manual detection methods are used, the workload is enormous, and the detection speed cannot meet the modern management requirements. SUMMARY

[0005] The utility model provides a kind of multi-chamber pressure block force sensor, testing device, by the way of making part of multi-chamber pressure body isolation bearing into sensing element, by Wheatstone bridge principle, the pressure acquisition of multi-chamber pressure block can be realized, and further the horizontal shear of multi-chamber pressure isolation bearing can be acquired.

[0006] The technical scheme of the utility model is:

[0007] According to the first aspect of the utility model, a kind of multi-chamber pressure block force sensor, including multi-chamber pressure block 1, strain sensor 2;The multi-chamber pressure block 1 includes outer cylinder 6 and nesting plate 7, the outer cylinder 6 is hollow cylinder, the nesting plate 7 extends from the hollow cylinder inner cavity along the radial direction one end to the other end and is connected with the hollow cylinder inner wall and forms multiple cavities;First detection mounting portion is equipped on the nesting plate 7, second detection mounting portion is equipped on the outer wall of outer cylinder 6 along the length direction of nesting plate 7, third detection mounting portion is equipped on the inner and outer wall of outer cylinder 6 along the rotation preset angle direction of nesting plate 7, the first detection mounting portion, second detection mounting portion, third detection mounting portion are evenly arranged strain sensor 2.

[0008] Further, the first detection mounting portion, second detection mounting portion, third detection mounting portion are located at 1 / 2 height of the multi-chamber pressure block 1.

[0009] Further, the nesting plate 7 adopts cross type nesting plate, and one first detection mounting portion is distributed at the center of the side surface of each branch plate of the cross type nesting plate.For the side of the first detection mounting portion provided on any two adjacent branch plates, the side is the side of the two adjacent branch plates away from each other;Each first detection mounting portion is fixed with one strain sensor in longitudinal direction, and the four strain sensors are strain gauges 1-strain gauges 4.

[0010] Further, the outer wall of outer cylinder 6 is distributed with four second detection mounting portions along the length direction of nesting plate 7, and each second detection mounting portion is fixed with one strain sensor in longitudinal direction, and the four strain sensors are strain gauges 5, strain gauges 7, strain gauges 9 and strain gauges 11;Wherein, strain gauges 5 and strain gauges 9 are located on the outer wall of outer cylinder 6 along the first length direction of nesting plate 7, and strain gauges 7 and strain gauges 11 are located on the outer wall of outer cylinder 6 along the second length direction of nesting plate 7;The inner and outer wall of outer cylinder 6 is distributed with four pairs of third detection mounting portions along the rotation preset angle direction of nesting plate 7, and the four pairs of third detection mounting portions are arranged at equal intervals, and each third detection mounting portion is fixed with one strain sensor in longitudinal direction, i.e. including first pair of strain gauges, second pair of strain gauges, third pair of strain gauges and fourth pair of strain gauges located on the inner and outer wall of outer cylinder 6.

[0011] According to the second aspect of the utility model, a kind of multi-chamber pressure block force sensor testing device, the multi-chamber pressure block force sensor testing device includes the multi-chamber pressure block force sensor of any one of the above, data processing module 5;The information collected by strain sensor 2 in the multi-chamber pressure block force sensor is transmitted to data processing module 5.

[0012] The utility model discloses a beneficial effect is: the utility model discloses a clever design strain sensor on the outer cylinder of multi -chamber pressure -bearing block, nested board provides hardware support for the acquisition of multi -chamber pressure -bearing block pressure, based on the test method of multi -chamber pressure -bearing block force sensor and combines simulation test, and multi -chamber pressure -bearing block force sensor total pressure measurement is not affected by the position of force, can be more accurate pressure measurement support, has good sensing stability, and further can obtain the horizontal shear of multi -chamber pressure -bearing isolation bearing, compared with artificial measurement mode, greatly reduce the workload, improve the detection efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 It is multi -chamber pressure -bearing block force sensor test device schematic drawing;

[0014] Figure 2 It is multi -chamber pressure -bearing block sectional view;

[0015] Figure 3 It is cross type pressure -bearing block patch plan view;

[0016] Figure 4 It is whole isolation bearing structure diagram;

[0017] Figure 5 It is vertical pressure -bearing body finite element model diagram;

[0018] Figure 6 It is multi -chamber pressure -bearing block detection installation part detection point schematic drawing;

[0019] Figure 7 It is finite element simulation strain result diagram;

[0020] Figure 8 It is cross type pressure -bearing block wheatstone bridge 4 strain gage series bridge circuit diagram;

[0021] Figure 9 It is cross type pressure -bearing block wheatstone bridge 2 strain gage series bridge circuit diagram;

[0022] Figure 10 It is multi -chamber pressure -bearing body support force sensor accuracy test loading device;

[0023] Figure 11 It is the μ-N correlation fitting curve when loading frequency 0.01Hz;

[0024] Figure 12 It is the μ-N correlation fitting curve when loading frequency 0.05Hz;

[0025] Figure 1 、 Figure 2 、 Figure 4The components are labeled as follows: 1. Multi-chamber pressure-bearing block; 2. Strain gauge sensor; 3. Acquisition module; 4. Transmission module; 5. Data processing module; 6. Outer cylinder; 7. Nesting plate; 8. PTFE pad; 9. Cover plate; 10. Sliding friction surface; 11. Upper connecting plate; 12. Lower connecting plate; 13. Rubber connecting plate; 14. Rubber; 15. Middle connecting plate. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be arbitrarily combined with each other.

[0027] Example 1: As Figures 1-4 As shown, according to a first aspect of the present invention, a multi-chamber pressure block force sensor is provided, including a multi-chamber pressure block 1 and a strain gauge sensor 2; the multi-chamber pressure block 1 includes an outer cylinder 6 and a nested plate 7, the outer cylinder 6 is a hollow cylinder, the nested plate 7 extends radially from one end of the hollow cylinder to the other end and is connected to the inner wall of the hollow cylinder to form a multi-chamber; a first detection mounting part is provided on the nested plate 7, a second detection mounting part is provided on the outer wall of the outer cylinder 6 along the length direction of the nested plate 7, and a third detection mounting part is provided on the inner and outer walls of the outer cylinder 6 along the direction of a preset rotation angle of the nested plate 7, and strain gauge sensors 2 are arranged in the first detection mounting part, the second detection mounting part, and the third detection mounting part.

[0028] For example, such as Figure 4As shown, the multi-chamber pressure block force sensor is used in a multi-chamber pressure isolation bearing, the multi-chamber pressure isolation bearing comprising a horizontal reset body and a vertical pressure bearing body, the vertical pressure bearing body comprising a polytetrafluoroethylene pad 8, a cover plate 9, a multi-chamber pressure block force sensor, the horizontal reset body comprising a sliding friction surface 10, an upper connecting plate 11, a lower connecting plate 12, a rubber connecting plate 13, rubber 14, a middle connecting plate 15; wherein the sliding friction surface 10 of the horizontal reset body is symmetrically welded and fixed to the inner side of the upper connecting plate 11 and the lower connecting plate 12 to form double-sided friction, the rubber 14 vulcanized on the rubber connecting plate 13 is connected through the rubber connecting plate 13 to the four corners of the parallelly arranged upper connecting plate 11 and middle connecting plate 15 and the parallelly arranged middle connecting plate 15 and lower connecting plate 12 by high-strength bolts; the middle connecting plate 15 is centrally perforated so that the multi-chamber pressure block force sensor passes through; the cover plate 9 with a clamping groove is buckled on the upper and lower multi-chamber pressure block force sensors, and each of the two cover plates 9 away from the multi-chamber pressure block force sensor is provided with a groove, the polytetrafluoroethylene pad 8 is embedded in the groove, and the polytetrafluoroethylene pad 8 is in sliding cooperation with the sliding friction surface 10. The vertical pressure bearing body and the horizontal reset body are bidirectionally decoupled, the vertical pressure bearing body provides support force for the upper structure, and the horizontal reset body only provides reset force.

[0029] Reference Figure 1 The height of the outer cylinder body 6 is the same as the height of the nesting plate 7, and the height direction is the axial direction of the hollow cylinder body; and the length direction of the nesting plate 7 is the radial direction of the hollow cylinder body.

[0030] Further, the first detection mounting part, the second detection mounting part and the third detection mounting part are located at 1 / 2 height of the multi-chamber pressure block 1.

[0031] As Figures 1-3 shown, the nesting plate 7 adopts a cross-shaped nesting plate, one first detection mounting part is distributed at the center of one side surface of each of the four branch plates of the cross-shaped nesting plate, and the side on which the first detection mounting part is arranged for any two adjacent branch plates is the side away from each other of the two adjacent branch plates. Figure 3 There are four first detection mounting parts in total, one strain sensor is fixed in each first detection mounting part along the longitudinal direction, and the four strain sensors are strain gauges 1-4, for example, the strain gauges 2 and 3 are installed on one side of the two adjacent branch plates, and the side of the branch plate on which the strain gauge 2 is installed and the side of the branch plate on which the strain gauge 3 is installed are the sides away from each other.

[0032] As Figure 1 , Figure 3As shown, the outer wall of the outer cylinder 6 is distributed with four second detection mounting parts along the length direction of the nesting plate 7, and one strain sensor is fixed in the longitudinal direction of each second detection mounting part, and the four strain sensors are strain gauges 5, 7, 9 and 11 respectively; wherein the strain gauges 5 and 9 are located along the first length direction of the nesting plate 7, and the strain gauges 7 and 11 are located along the second length direction of the nesting plate 7; the inner and outer walls of the outer cylinder 6 are distributed with four pairs of third detection mounting parts (i.e. eight) along the rotation direction of the nesting plate 7 by a preset angle, and the four pairs of third detection mounting parts are arranged at equal intervals, and one strain sensor is fixed in the longitudinal direction of each third detection mounting part, that is, including the first pair of strain gauges (strain gauges 8 and 14), the second pair of strain gauges (strain gauges 6 and 13), the third pair of strain gauges (strain gauges 12 and 16) and the fourth pair of strain gauges (strain gauges 10 and 15) located on the inner and outer walls of the outer cylinder 6; wherein the first pair of strain gauges and the third pair of strain gauges are located along the first length rotation direction of the nesting plate 7 by a preset angle, and the second pair of strain gauges and the fourth pair of strain gauges are located along the second length rotation direction of the nesting plate 7 by a preset angle. Exemplarily, the preset angle is 45 degrees.

[0033] According to the second aspect of the embodiment of the utility model, a multi-chamber pressure block force sensor testing device is provided, which comprises a multi-chamber pressure block force sensor and a data processing module 5; the information collected by the strain sensor 2 in the multi-chamber pressure block force sensor is transmitted to the data processing module 5 through the acquisition module 3 / transmission module 4 for obtaining pressure and horizontal shear force according to the multi-chamber pressure block force sensor testing method.

[0034] Specifically, the data processing module 5 is an upper computer. If the acquisition module 3 is used, wired communication with the upper computer is used; if the transmission module 4 is used, the information is transmitted to the upper computer by wireless communication. Exemplarily, the acquisition module 3 is a strain tester; the transmission module 4 is a wifi module / Bluetooth module, etc., and the wifi module is used for illustration, which is placed in the cavity, and the lead port is connected with each strain sensor, and at the same time, the lead port of the outer cylinder 6 is used for accessing the battery, so as to replace the battery from the outside of the cavity.

[0035] As Figures 1-12 shown, according to the third aspect of the embodiment of the utility model, a testing method of a multi-chamber pressure block force sensor is provided, which comprises the following steps:

[0036] S1, a vertical pressure-bearing body finite element analysis model is established, and the strain response of the vertical pressure-bearing body under the design load is simulated; wherein the vertical pressure-bearing body comprises a polytetrafluoroethylene pad 8, a cover plate 9, and a multi-chamber pressure-bearing block force sensor, the multi-chamber pressure-bearing block force sensor is buckled with a cover plate 9 with a clamping groove on the upper and lower sides, both cover plates 9 are provided with a groove away from the multi-chamber pressure-bearing block force sensor, and the polytetrafluoroethylene pad 8 is embedded in the groove; it should be noted that when the finite element analysis model is established, the influence of the polytetrafluoroethylene pad 8 and the cover plate 9 on the mutual action of the multi-chamber pressure-bearing block force sensor is considered, so that the finite element analysis model of the vertical pressure-bearing body is more in line with the actual stress state than the direct establishment of the finite element analysis model of the multi-chamber pressure-bearing block force sensor;

[0037] S2, based on the simulation results, the vertical strain value of each detection installation part on the multi-chamber pressure-bearing block 1 is extracted, and the plane section assumption is verified;

[0038] S3, on the basis of the verification of the plane section assumption, the multi-chamber pressure-bearing block 1 is selected as the design area, and the design target is defined, the design target is set as: measuring the pressure and horizontal shear force of the multi-chamber pressure-bearing block 1 during the earthquake action;

[0039] S4, according to the design target, a Wheatstone bridge is designed to solve the pressure value of the outer cylinder 6 and the nested plate 7 through the strain value; and then the pressure of the nested plate 7, the pressure of the outer cylinder 6 are obtained to obtain the pressure of the multi-chamber pressure-bearing block 1.

[0040] Further, it also includes:

[0041] S5, according to the pressure of the multi-chamber pressure-bearing block 1, the horizontal shear force of the multi-chamber pressure-bearing isolation bearing is obtained.

[0042] Further, the S4 is specifically:

[0043] According to the principle of Wheatstone bridge, the strain gauges 1-4 are connected in series and connected to the first branch (such as AB branch) of the Wheatstone bridge, the four temperature compensation gauges are connected in series and connected to the second branch (such as BC branch) adjacent to the first branch, and the other two branches are connected to a fixed resistor R, so as to obtain the first strain value based on the Wheatstone bridge; the first normal stress value is obtained according to the first strain value; the first normal stress value is multiplied by the first cross-sectional area to obtain the pressure on the nested plate 7; wherein the first cross-sectional area is the cross-sectional area of the nested plate 7 (i.e. the length*thickness of the nested plate 7, the length is the length in the first length direction / the length in the second length direction, and the length in the first length direction is equal to the length in the second length direction);

[0044] The strain gauge 5 and the strain gauge 9 are connected in series and then connected to the first branch (such as the AB branch) of the Wheatstone bridge, two temperature compensation gauges are connected in series and then connected to the second branch (such as the BC branch) adjacent to the first branch, and the other two branches are connected to a fixed resistor R, so as to obtain a second strain value based on the Wheatstone bridge; a second normal stress value is obtained according to the second strain value;

[0045] The strain gauge 7 and the strain gauge 11 are connected in series and then connected to the first branch (such as the AB branch) of the Wheatstone bridge, two temperature compensation gauges are connected in series and then connected to the second branch (such as the BC branch) adjacent to the first branch, and the other two branches are connected to a fixed resistor R, so as to obtain a third strain value based on the Wheatstone bridge; a third normal stress value is obtained according to the third strain value;

[0046] The strain gauge 8, the strain gauge 14, the strain gauge 12 and the strain gauge 16 are connected in series and then connected to the first branch (such as the AB branch) of the Wheatstone bridge, four temperature compensation gauges are connected in series and then connected to the second branch (such as the BC branch) adjacent to the first branch, and the other two branches are connected to a fixed resistor R, so as to obtain a fourth strain value based on the Wheatstone bridge; a fourth normal stress value is obtained according to the fourth strain value;

[0047] The strain gauge 6, the strain gauge 13, the strain gauge 10 and the strain gauge 15 are connected in series and then connected to the first branch (such as the AB branch) of the Wheatstone bridge, four temperature compensation gauges are connected in series and then connected to the second branch (such as the BC branch) adjacent to the first branch, and the other two branches are connected to a fixed resistor R, so as to obtain a fifth strain value based on the Wheatstone bridge; a fifth normal stress value is obtained according to the fifth strain value;

[0048] An interpolation curve fitting is performed according to the second normal stress value, the third normal stress value, the fourth normal stress value and the fifth normal stress value to obtain a normal stress curve function; the length of the flattened cylinder at the middle thickness of the outer cylinder 6 is calculated (the length is the circumference of the cylinder at the middle thickness), the second cross-sectional area is obtained by multiplying the flattened length by the thickness of the outer cylinder 6; the normal stress curve function and the second cross-sectional area are multiplied and solved by a numerical integration method to obtain the pressure of the outer cylinder 6; in the above, the interpolation curve fitting specifically adopts cubic spline interpolation; the numerical integration method specifically adopts Gauss integration.

[0049] The pressure of the nested plate 7 and the pressure of the outer cylinder 6 are added to obtain the pressure of the multi-chamber pressure-bearing block 1.

[0050] In the above, the general expression for solving the normal stress value from the strain value is: σ = Eε; wherein σ is the normal stress on the cross section, E is the elastic modulus, and ε is the strain value.

[0051] Further, the S5 specifically includes:

[0052] The horizontal shear force of the isolation bearing is the sum of the yield force and the friction force. Therefore, the horizontal shear force of the multi-chamber pressure bearing isolation bearing is obtained according to the pressure of the multi-chamber pressure bearing 1, and specifically:

[0053] The friction force of the multi-chamber pressure bearing isolation bearing is obtained according to the pressure of the multi-chamber pressure bearing 1;

[0054] The yield force of the multi-chamber pressure bearing isolation bearing is obtained according to the horizontal displacement of the multi-chamber pressure bearing isolation bearing and the parameters of the rubber 14;

[0055] The sum of the friction force of the multi-chamber pressure bearing isolation bearing and the yield force of the multi-chamber pressure bearing isolation bearing is taken as the horizontal shear force of the multi-chamber pressure bearing isolation bearing.

[0056] Specifically:

[0057] In the above, only the correlation of compressive stress is considered, and the dynamic friction coefficient μ is only related to the pressure N. The expression of the friction force F is: F = μ(N) · N; wherein N is the pressure of the multi-chamber pressure bearing 1, μ is the dynamic friction coefficient, and the correlation curve of the dynamic friction coefficient μ and the pressure N can be obtained according to the compression-shear test.

[0058] The expression for solving the yield force f of the multi-chamber pressure bearing isolation bearing is: Wherein G is the shear modulus of the rubber in the multi-chamber pressure bearing isolation bearing, A is the cross-sectional area of the rubber 14 in the multi-chamber pressure bearing, T r is the total height of the two layers of rubber arranged in the multi-chamber pressure bearing isolation bearing (i.e. the height of the two rubbers 14), and x is the horizontal displacement of the multi-chamber pressure bearing isolation bearing. According to the actual design requirements, the volume of the rubber is determined, and thus the yield force of the multi-chamber pressure bearing isolation bearing is determined.

[0059] The test method is further described as follows in combination with the test and finite element simulation:

[0060] I. Verification of plane section assumption

[0061] To better illustrate the performance of the utility model, the vertical pressure bearing body for the multi-chamber pressure bearing isolation support is simulated by using ABAQUS software. The model parameters are as follows: the outer diameter of the multi-chamber pressure bearing block 1 is 230 mm; the thicknesses of the outer cylinder body 6 and the nested plate 7 are both 25 mm; the pressure bearing block is 62 mm high; the diameter of the cover plate 9 is 240 mm, and the thickness is 25 mm; the groove depth of the cover plate is 7 mm at the top and 5 mm at the bottom; the steel elastic modulus is defined as 210000 MPa, the Poisson's ratio is 0.3, the yield strength is 235 MPa, and the plastic strain is 0; the polytetrafluoroethylene pad 8 is 210 mm in diameter and 7 mm in thickness, and is defined as an elastic material with an elastic modulus of 280 MPa and a Poisson's ratio of 0.42; and the C3D8R unit is used for simulation; the normal stress applied to the vertical pressure bearing body is 25, 30 and 50 MPa respectively, and the bottom of the vertical pressure bearing body is completely fixed.

[0062] By establishing a finite element analysis model as shown in Figure 5 , the vertical strain values at the positions of the detection installation parts on the multi-chamber pressure bearing block 1 as shown in Figure 6 are extracted as shown in Figure 7 ; according to the finite element simulation results, when the compressive stress is the same, the displacement values at the positions of the first detection installation part on the nested plate 7 are basically the same, the displacement values at the positions of the second detection installation part on the outer wall of the outer cylinder body 6 and the third detection installation part on the inner and outer walls of the outer cylinder body 6 are basically the same, but the displacement values of the nested plate 7 and the outer cylinder body 6 are different, and it is considered that the nested plate 7 and the outer cylinder body 6 respectively approximately satisfy the plane cross-section assumption.

[0063] II. Acquisition of pressure value

[0064] As shown in Figure 8 , the strain gauges 1-4 are connected in series and connected to the AB branch of the Wheatstone bridge, four temperature compensation gauges are connected in series and connected to the adjacent BC branch, and the other two branches are connected to a fixed resistor R, so as to obtain a first strain value based on the Wheatstone bridge; a first normal stress value is obtained according to the first strain value; the first normal stress value is multiplied by a first cross-sectional area to obtain the pressure on the nested plate 7; wherein the first cross-sectional area is the cross-sectional area of the nested plate 7.

[0065] As shown in Figure 9 , the strain gauges 5 and 9 are connected in series and connected to the AB branch of the Wheatstone bridge, two temperature compensation gauges are connected in series and connected to the adjacent BC branch, and the other two branches are connected to a fixed resistor R, so as to obtain a second strain value based on the Wheatstone bridge; a second normal stress value is obtained according to the second strain value; the connection mode of the strain gauges 7 and 11 is the same as that of the strain gauges 5 and 9, and finally a third normal stress value is obtained;

[0066] As shown in Figure 8As shown, the strain gauges 8, 14, 12, 16 are connected in series and connected to the AB branch of the Wheatstone bridge, four temperature compensation gauges are connected in series and connected to the BC branch, and a fixed resistor R is connected to the other two branches for obtaining a fourth strain value based on the Wheatstone bridge; a fourth normal stress value is obtained according to the fourth strain value; the strain gauges 6, 13, 10, 15 are connected in the same way as the strain gauges 8, 14, 12, 16, and a fifth normal stress value is finally obtained.

[0067] An interpolation curve fitting is performed according to the second normal stress value, the third normal stress value, the fourth normal stress value, and the fifth normal stress value to obtain a normal stress curve function; the length of the flattened cylinder at the middle thickness of the outer cylinder 6 is calculated (the length is the circumference of the cylinder at the middle thickness), and the second cross-sectional area is obtained by multiplying the flattened length by the thickness of the outer cylinder 6; the pressure of the outer cylinder 6 is obtained by multiplying the normal stress curve function and the second cross-sectional area and solving by numerical integration; and the pressure of the nested plate 7 and the pressure of the outer cylinder 6 are added together to obtain the pressure of the multi-chamber pressure-bearing block 1.

[0068] In the above, the calculation process of each group of bridge modes is as follows (assuming that the directions of the strain gauges 5 and 9 are the x direction, the directions of the strain gauges 7 and 11 are the y direction, the strain in the compression area is positive, the strain in the tension area is negative, and the bending moments Mx and My are in the counterclockwise direction):

[0069] For Figure 8 As shown, the four strain gauges are connected in series in one bridge arm, and the measured strain of each strain gauge is (taking strain gauges 1-4 as an example, and the others are the same):

[0070] ε1=ε P -ε Mx -ε My +ε t

[0071] ε2=ε P +ε Mx -ε My +ε t

[0072] ε3=ε P +ε Mx +ε My +ε t

[0073] ε4=ε P -ε Mx +ε My +ε t

[0074] Then the strain value of the four strain gauges connected in series in one bridge arm is:

[0075] ε = ε AB - ε BC + ε CD - ε AD = (ε1+ ε2+ ε3+ ε4)-4× ε t = 4× ε P

[0076] For two strain gauges in series in a bridge arm as shown in Figure 9 , the strain measured by each strain gauge is (take strain gauges 5 and 9 measuring X direction as an example, the same for Y direction) :

[0077] ε5= ε P - ε Mx + ε t

[0078] ε9= ε P + ε Mx + ε t

[0079] The strain value of two strain gauges in series in a bridge arm is:

[0080] ε = ε AB - ε BC + ε CD - ε AD = (ε5+ ε9)-2× ε t = 2× ε P

[0081] To study the sensing stability of the multi-chamber pressure block force sensor, vertical pressure body specimens were prepared and a pad was placed on them to carry out pure compression and eccentric compression tests. The outer diameter of the multi-chamber pressure block 1 is 230 mm; the outer cylinder 6 and the nested plate 7 are both 25 mm thick; the pressure block is 62 mm high; the diameter of the cover plate 9 is 240 mm, and the thickness is 25 mm; the groove depth of the cover plate is 7 mm at the top and 5 mm at the bottom; the polytetrafluoroethylene pad 8 is 210 mm in diameter and 7 mm in thickness. A 10000kN microcomputer-controlled electro-hydraulic servo pressure testing machine was used to test the vertical pressure body, and the loading device is shown in Figure 10 . This test uses continuous loading method, and the loading speed is 1kN / s. Through the pressure control system matched with the microcomputer-controlled electro-hydraulic servo pressure testing machine, the load time history data is recorded; the strain data is recorded by the strain tester. The test conditions are shown in Table 1 (CY represents pure compression test, 1 / 4D-0°, 1 / 3D-0°, 1 / 3D-0°, 1 / 3D-45° represent eccentric compression test; PTFE pad refers to polytetrafluoroethylene pad). The instruments and equipment used in the test are shown in Table 2.

[0082] Table 1

[0083]

[0084] Table 2

[0085]

[0086] Steel elastic modulus E = 210 GPa, by the test method of the multi-chamber pressure block force sensor of the utility model, total pressure N on the cross section of the multi-chamber pressure block 1 under each working condition is calculated, and the relative error of the total pressure N and the actual load ((calculated total pressure N-actual load) / actual load) is calculated, and the results are shown in Table 3. Comparing pure pressure and eccentric pressure, different eccentric distances with the same deflection angle (working condition 1 / 4D-0° and 1 / 3D-0°) and different deflection angles with the same eccentric distance (working condition 1 / 3D-0° and 1 / 3D-45°), the relative error of the calculated total pressure N and the actual load is 2.26%, which shows that the multi-chamber pressure block force sensor can measure the total pressure without being affected by the force acting position, and can accurately measure the pressure received by the seismic isolation bearing, and has good sensing stability.

[0087] Table 3

[0088] Operating condition name Actual load / kN Calculated total pressure N / kN Relative error CY 1815 1781.46 1.85％ 1 / 4D-0° 930 909.02 2.26％ 1 / 3D-0° 930 910.60 2.09％ 1 / 3D-45° 930 917.15 1.38％

[0089] III. Obtaining of horizontal shear force

[0090] The fitting curve of dynamic friction coefficient under different pressures is shown in Figure 11 (load frequency 0.01 Hz), Figure 12 (load frequency 0.05 Hz). It can be seen that the dynamic friction coefficient μ and the pressure are basically in linear relationship at the same loading frequency. According to the μ-N fitting curve, the corresponding dynamic friction coefficient μ under different pressures can be obtained, and the friction force can be calculated according to F=μ(N)·N; then the rubber parameters are determined according to the actual design requirements, so as to determine the yield force, and then the horizontal shear force is calculated.

[0091] The specific embodiments of the utility model are described in detail above in combination with the drawings, but the utility model is not limited to the above-mentioned embodiments, and various changes can be made within the knowledge range of ordinary skilled persons in the art without departing from the purpose of the utility model.

Claims

1. A multi-chamber pressure cell force sensor, characterized by, The multi-chamber pressure block (1) includes an outer cylinder (6) and a nested plate (7), the outer cylinder (6) is a hollow cylinder, the nested plate (7) extends from one end to the other end of the hollow cylinder cavity in the radial direction and is connected with the inner wall of the hollow cylinder to form a multi-cavity; the first detection mounting part is arranged on the nested plate (7), the second detection mounting part is arranged on the outer wall of the outer cylinder (6) along the length direction of the nested plate (7), and the third detection mounting part is arranged on the inner and outer walls of the outer cylinder (6) along the rotation direction of the nested plate (7) by a preset angle, and the first detection mounting part, the second detection mounting part and the third detection mounting part are arranged with strain sensors (2).

2. The multi-chamber pressure cell force sensor of claim 1, wherein, The first detection mounting part, the second detection mounting part and the third detection mounting part are located at 1 / 2 height of the multi-chamber pressure block (1).

3. The multi-chamber pressure cell force sensor of claim 1, wherein, The nested plate (7) is a cross-shaped nested plate, and one first detection mounting part is distributed at the center of one side surface of each branch plate of the cross-shaped nested plate, and the side of each branch plate provided with the first detection mounting part is the side away from the adjacent branch plate; one strain sensor is fixed in the longitudinal direction of each first detection mounting part, and the four strain sensors are strain gauges I-IV.

4. The multi-chamber pressure cell force sensor of claim 3, wherein, The outer wall of the outer cylinder (6) is distributed with four second detection mounting parts along the length direction of the nested plate (7), one strain sensor is fixed in the longitudinal direction of each second detection mounting part, and the four strain sensors are strain gauges V, VII, IX and XI; wherein, the strain gauges V and IX are located on the outer wall of the outer cylinder (6) along the first length direction of the nested plate (7), and the strain gauges VII and XI are located on the outer wall of the outer cylinder (6) along the second length direction of the nested plate (7); the inner and outer walls of the outer cylinder (6) are distributed with four pairs of third detection mounting parts along the rotation direction of the nested plate (7) by a preset angle, the four pairs of third detection mounting parts are arranged at equal intervals, and one strain sensor is fixed in the longitudinal direction of each third detection mounting part, that is, the first pair of strain gauges, the second pair of strain gauges, the third pair of strain gauges and the fourth pair of strain gauges are arranged on the inner and outer walls of the outer cylinder (6).

5. A multi-chamber pressure cell force sensor testing apparatus, characterized by, The multi-chamber pressure block force sensor testing device includes the multi-chamber pressure block force sensor of any one of claims 1-4 and a data processing module (5); the information collected by the strain sensor (2) in the multi-chamber pressure block force sensor is transmitted to the data processing module (5).

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