High-temperature strain gauge characteristic parameter calibration device and characteristic parameter calibration method

Abstract

The invention provides a high-temperature strain gauge characteristic parameter calibration device and a characteristic parameter calibration method, and relates to the technical field of high-temperature strain testing, the high-temperature strain gauge characteristic parameter calibration device comprises a temperature control system, a support system, a displacement measurement system, a loading system and a data acquisition system; the temperature control system comprises a heating furnace and a control box body, the heating furnace is arranged at the top of the control box body, and a control device for adjusting the temperature of the heating furnace is arranged in the control box body; the supporting system comprises a furnace body base and a support structure, and the control box body and the support structure are arranged on the furnace body base; the displacement measurement system comprises a micrometer assembly and a calibration assembly. The loading system comprises a door-shaped pull rod and a weight assembly, and the weight assembly is connected with the support structure; the data acquisition system is connected with the calibration assembly through a cable. According to the invention, the accuracy of calibration data is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of high temperature strain testing, and in particular to a high temperature strain gauge characteristic parameter calibration device and a characteristic parameter calibration method. Background Art

[0002] Strain gauges are contact strain measurement sensors that are widely used due to their high precision, high sensitivity and high reliability. However, when measuring high-temperature strain, the strain gauges’ sensitivity coefficient changes at high temperatures, the heat output is huge, and the strain gauges’ thermal hysteresis, creep, mechanical hysteresis and other characteristics cannot be effectively compensated, resulting in a large deviation between the actual strain measurement results and the true strain.

[0003] At present, the characteristic parameters of high-temperature strain gauges are mainly calibrated under specific temperature conditions to ensure that the strain gauges can provide accurate and reliable measurement results. However, the existing high-temperature strain gauge characteristic parameter calibration device uses the method of supporting and loading the calibration beam in a high-temperature furnace to test the performance of the strain gauge. In a high-temperature environment, the calibration beam support structure undergoes thermal deformation, resulting in changes in the constraint position and loading position of the calibration beam, affecting the accuracy of the calibration data. In addition, the temperature control inside the heating furnace is not precise enough, and there may be an error between the actual temperature of the calibration beam and the set temperature due to design reasons, resulting in inaccurate calibration data. Summary of the invention

[0004] The present invention aims to solve at least one of the above problems.

[0005] In order to solve the above problems, the present invention provides a high temperature strain gauge characteristic parameter calibration device and a characteristic parameter calibration method.

[0006] In the first aspect, the present invention provides a high-temperature strain gauge characteristic parameter calibration device, including a temperature control system, a support system, a displacement measurement system, a loading system and a data acquisition system; the temperature control system includes a heating furnace and a control box, the heating furnace is arranged on the top of the control box, and a control device for adjusting the temperature of the heating furnace is provided in the control box; the support system includes a furnace base and a support structure, and the control box and the support structure are arranged on the furnace base; the displacement measurement system includes a micrometer assembly and a calibration assembly, one end of the micrometer assembly is placed outside the furnace, and the other end passes through the upper cover plate of the heating furnace and is connected to the calibration assembly, and the calibration assembly is placed in the heating furnace, and the calibration assembly includes a high-temperature strain gauge; the loading system includes a gate-type pull rod and a weight assembly, the weight assembly is connected to the support structure, one end of the gate-type pull rod is connected to the weight assembly, and the other end passes through the upper cover plate of the heating furnace and is connected to the calibration assembly; the data acquisition system is connected to the calibration assembly through a cable.

[0007] Optionally, the support structure includes a gate-type support and a T-shaped support, the gate-type support includes two side beams and a middle cross beam, the two ends of the middle cross beam are respectively connected to the two side beams, the middle cross beam is connected to the upper cover plate of the heating furnace, the side beam is connected to the furnace base, and the T-shaped support includes an upper vertical beam and an upper cross beam connected to each other, and the upper vertical beam is arranged on the side beam on one side.

[0008] Optionally, the support structure also includes a connecting piece, which includes two calibration beam positioning blocks and at least two square steel pipes, the two calibration beam positioning blocks are respectively overlapped with the two ends of the calibration component in the length direction, one end of the square steel pipe is connected to the middle cross beam, and the other end passes through the upper cover plate of the heating furnace and is connected to the calibration beam positioning block.

[0009] Optionally, the connecting member also includes four connecting rods and a micrometer fixing seat, one end of the four connecting rods is respectively fixed to the four corners of the micrometer fixing seat, and the other end passes through the upper cover plate of the heating furnace and is vertically fixed to the calibration beam positioning block, and the micrometer fixing seat is placed above the middle cross beam.

[0010] Optionally, the calibration component further includes a thermocouple and a calibration beam, the high temperature strain gauge and the thermocouple are welded to the calibration beam, and two ends of the calibration beam are respectively placed in the slots of two calibration beam positioning blocks.

[0011] Optionally, the door-type pull rod includes two pull rods and a pull rope connecting block, one end of the two pull rods is connected to the pull rope connecting block through a pin shaft, and the other end passes through the middle cross beam and the upper cover plate of the heating furnace in sequence and is connected to the calibration beam; the weight assembly includes a weight seat, two fixed pulleys and a pull rope, the two fixed pulleys are respectively fixedly connected to the two ends of the upper cross beam in the length direction, one end of the pull rope is connected to the pull rope connecting block, and the other end passes through the two fixed pulleys and is connected to the weight seat.

[0012] Optionally, the micrometer assembly includes a digital micrometer and a measuring rod, the housing of the digital micrometer is fixedly arranged at the middle position of the micrometer fixing seat, one end of the measuring rod abuts against the pointer of the digital micrometer, and the other end is provided with a clamp, which sequentially passes through the middle crossbeam and the upper cover plate of the heating furnace and is clamped on the calibration beam by the clamp.

[0013] Optionally, the data acquisition system includes a cable, a multi-point measurement data recorder, a resistance data acquisition instrument, a switch and a computer connected in sequence, one end of the cable is connected to the multi-point measurement data recorder, and the other end passes through an opening in the rear panel of the heating furnace to be connected to the high-temperature strain gauge and the thermocouple.

[0014] In a second aspect, the present invention provides a method for calibrating characteristic parameters of a high temperature strain gauge, comprising:

[0015] The heating furnace is arranged on the top of the control box, and the control box and the support structure are arranged on the furnace base;

[0016] One end of the micrometer assembly is placed outside the furnace, and the other end passes through the upper cover plate of the heating furnace and is connected to the calibration assembly, and the calibration assembly is placed in the heating furnace, and the calibration assembly includes a high-temperature strain gauge;

[0017] One end of the door-shaped pull rod is connected to the weight assembly, and the other end passes through the upper cover plate of the heating furnace and is connected to the calibration assembly;

[0018] Connecting the data acquisition system to the calibration component via a cable;

[0019] Regulating the temperature of the heating furnace through the control box;

[0020] The target high-temperature strain gauge characteristic parameters are obtained through the data acquisition system.

[0021] Optionally, obtaining the target high temperature strain gauge characteristic parameters through the data acquisition system includes:

[0022] Acquiring the measured deflection value of the calibration beam through the data acquisition system;

[0023] The measured deflection value of the calibration beam is corrected according to the preset error value to obtain the true deflection value of the calibration beam, wherein the true deflection value of the calibration beam is:

[0024] ωTt=ωTm-ωT0,

[0025] Wherein, ωTt is the true deflection value of the calibration beam, ωTm is the measured deflection value of the calibration beam, and ωT0 is the preset error value;

[0026] The high temperature strain gauge characteristic parameter is obtained according to the true deflection value of the calibration beam, wherein the high temperature strain gauge characteristic parameter includes the true strain value of the calibration beam, and the true strain value of the calibration beam is:

[0027] εTt=f(ωTm-f0(T)),

[0028] Wherein, εTt is the true strain value of the calibration beam, ωTm is the measured deflection value of the calibration beam, and ωT0=f0(T).

[0029] The high temperature strain gauge characteristic parameter calibration device and characteristic parameter calibration method of the present invention have the beneficial effects of: the heating furnace is set on the top of the control box through the temperature control system, and the temperature of the heating furnace is adjusted by the control device in the control box to achieve accurate control of the temperature inside the heating furnace. The control box and the support structure are set on the furnace base, and the support structure is connected to the heating furnace and arranged outside the heating furnace, which not only ensures the stability of the heating furnace and the test assembly therein during operation, but also avoids the structural deformation of the support system due to temperature. The calibration assembly is placed in the heating furnace, one end of the micrometer assembly is placed outside the furnace, and the other end passes through the upper cover plate of the heating furnace and is connected to the calibration assembly, thereby reducing the influence of the high temperature environment on the micrometer assembly. The weight assembly of the loading system is connected to the support structure, one end of the door-shaped pull rod is connected to the weight assembly, and the other end passes through the support structure and the heating furnace in turn and is connected to the calibration assembly, and an upward pulling force is applied to the calibration assembly through the weight assembly, thereby realizing the loading process. The data acquisition system is connected to the calibration assembly through a cable to quickly collect data and improve the accuracy of the calibration data. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of a high temperature strain gauge characteristic parameter calibration device in an embodiment of the present invention;

[0031] Figure 2 It is a structural schematic diagram of a displacement measurement system of a high temperature strain gauge characteristic parameter calibration device in an embodiment of the present invention;

[0032] Figure 3 It is a cross-sectional schematic diagram of a device for calibrating characteristic parameters of a high-temperature strain gauge in an embodiment of the present invention;

[0033] Figure 4 It is a transverse cross-sectional view of a displacement measurement system of a high temperature strain gauge characteristic parameter calibration device according to an embodiment of the present invention;

[0034] Figure 5 Schematic diagram of a method for calibrating characteristic parameters of a high temperature strain gauge in an embodiment of the present invention.

[0035] Description of reference numerals:

[0036] 1. Heating furnace; 2. Control box; 3. Furnace base; 4. Support structure; 41. Door-type support; 411. Side beam; 412. Middle cross beam; 42. T-shaped support; 421. Upper vertical beam; 422. Upper cross beam; 43. Connecting piece; 431. Calibration beam positioning block; 432. Square steel pipe; 433. Connecting rod; 434. Micrometer fixing seat; 5. Micrometer assembly; 51. Digital micrometer; 52. Measuring rod; 6. Calibration assembly; 61. High-temperature strain gauge; 62. Thermocouple; 63. Calibration beam; 7. Door-type pull rod; 71. Pull rod; 72. Pull rope connecting block; 8. Weight assembly; 81. Weight seat; 82. Fixed pulley; 83. Pull rope; 9. Multi-point measurement data recorder; 10. Resistance data acquisition instrument; 11. Switch; 12. Computer. DETAILED DESCRIPTION

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.

[0038] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to"; the term "based on" means "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc. mentioned in the present invention are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0039] It should be noted that the modifications of "one" and "plurality" mentioned in the present invention are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0040] Combination Figure 1 , Figure 2 As shown, a high-temperature strain gauge characteristic parameter calibration device provided by an embodiment of the present invention includes a temperature control system, a support system, a displacement measurement system, a loading system and a data acquisition system;

[0041] The temperature control system comprises a heating furnace 1 and a control box 2, wherein the heating furnace 1 is arranged on the top of the control box 2, and a control device for adjusting the temperature of the heating furnace 1 is arranged in the control box 2;

[0042] The support system includes a furnace base 3 and a support structure 4, and the control box 2 and the support structure 4 are arranged on the furnace base 3;

[0043] The displacement measurement system includes a micrometer component 5 and a calibration component 6, one end of the micrometer component 5 is placed outside the furnace, and the other end passes through the upper cover plate of the heating furnace 1 and is connected to the calibration component 6, and the calibration component 6 is placed in the heating furnace 1, and the calibration component 6 includes a high-temperature strain gauge 61;

[0044] The loading system includes a gate-shaped pull rod 7 and a weight assembly 8, wherein the weight assembly 8 is connected to the support structure 4, one end of the gate-shaped pull rod 7 is connected to the weight assembly 8, and the other end passes through the support structure 4 and the heating furnace 1 in sequence and is connected to the calibration assembly 6;

[0045] The data acquisition system is connected to the calibration component 6 via a cable.

[0046] Specifically, the temperature control system is heated by a heating furnace 1, and the heating furnace 1 has an insulation layer inside. The front panel of the furnace body has an observation hole, through which the stress and deformation of the calibration beam can be observed. The rear panel of the furnace body has a hole for cable outlet. The control panel 2 is used for temperature control operation, and is composed of a temperature control meter, a current and voltage monitoring window, and control buttons. The support system includes a furnace base 3 and a support structure 4. The control box 2 and the support structure 4 are arranged on the furnace base 3. The support structure 4 is arranged on both sides of the control box 2. The support structure 4 is connected to the heating furnace 1. The furnace base 3 is used to support and fix the furnace body, and the support structure 4 is used to fix the calibration beam positioning block 19. The end of the micrometer assembly 5 facing the furnace base 3 passes through the support structure 4 and the upper cover plate of the heating furnace 1 in sequence. The micrometer assembly 5 can be a quartz rod in the internal section of the heating furnace 1, and the micrometer assembly 5 can use a high-precision micrometer to ensure accurate measurement of small displacements. The data acquisition system is connected to the calibration component 6 via a cable, collects the output signal of the strain gauge in real time, and can automatically record and process the experimental data.

[0047] The high temperature strain gauge characteristic parameter calibration device in this embodiment sets the heating furnace on the top of the control box through the temperature control system, and uses the control device in the control box to adjust the temperature of the heating furnace to achieve precise control of the temperature inside the heating furnace. The control box and the bracket structure are set on the furnace base, and the bracket structure is connected to the heating furnace and set outside the heating furnace, which not only ensures the stability of the heating furnace and the test components therein during operation, but also avoids the structural deformation of the support system due to temperature. The calibration component is placed in the heating furnace, one end of the micrometer component is placed outside the furnace, and the other end passes through the upper cover plate of the heating furnace and is connected to the calibration component, reducing the impact of the high temperature environment on the micrometer component. The weight component of the loading system is connected to the bracket structure, one end of the door-shaped pull rod is connected to the weight component, and the other end passes through the bracket structure and the heating furnace and is connected to the calibration component in turn, and an upward pulling force is applied to the calibration component through the weight component, thereby realizing the loading process. And the data acquisition system is connected to the calibration component through a cable to quickly collect data and improve the accuracy of the calibration data.

[0048] Optionally, the support structure 4 includes a gate-type support 41 and a T-shaped support 42, the gate-type support includes two side beams 411 and a middle cross beam 412, the two ends of the middle cross beam 412 are respectively connected to the two side beams 411, the side beams 411 are connected to the furnace base 3, and the T-shaped support 42 includes an upper vertical beam 421 and an upper cross beam 422 connected to each other, and the upper vertical beam 421 is arranged on one side of the side beam 411.

[0049] Specifically, combined Figure 1 As shown, the side beam 411 includes two vertical beams, and the middle cross beam 412 of the portal bracket 41 is fixed to the furnace base 3 through the left and right vertical beams. The portal bracket 41 includes two side beams 411 and a middle cross beam 412. The function of the side beam 411 is to provide a stable basic support for the entire device, and to ensure the stability of the overall structure by connecting with the furnace base 3, and to provide structural support for the calibration component 6 connected to the micrometer component 5. The T-shaped bracket 42 is composed of an upper vertical beam 421 and an upper cross beam 422. The upper vertical beam 421 is installed on a side beam 411 of the portal bracket, and the upper cross beam 422 is mainly used to carry the loading system, and is connected to the calibration component 6 through its part that passes through the heating furnace. The end of the micrometer component 5 facing the base passes through the middle cross beam 412 and the upper cover plate of the heating furnace 1 in turn, and is connected to the calibration component 6.

[0050] In this optional embodiment, the calibration component 6 is fixed outside the heating furnace 1 by the door-shaped bracket 41 and the T-shaped bracket 42, which combines the advantages of both, ensures good support in the horizontal and vertical directions, and greatly improves the stability of the entire system. It can ensure the stability of the overall structure, and will not introduce calculation errors due to changes in the support structure and loading position along the length direction of the calibration beam caused by temperature changes.

[0051] Optionally, the support structure 4 also includes a connecting member 43, which includes two calibration beam positioning blocks 431 and at least two square steel tubes 432. The two calibration beam positioning blocks 431 are respectively overlapped with the two ends of the calibration component 6 in the length direction, one end of the square steel tube 432 is connected to the middle cross beam 412, and the other end passes through the upper cover plate of the heating furnace 1 and is connected to the calibration beam positioning block 431.

[0052] Specifically, combined Figure 2 , Figure 4 As shown, the middle cross beam 412 passes through the furnace insulation layer through eight square steel pipes 432 to fix two calibration beam positioning blocks 431 , and the calibration beam positioning blocks 431 provide simple support constraints for the calibration beam 63 .

[0053] Optionally, the connecting member also includes four connecting rods 433 and a micrometer fixing seat 434, one end of the four connecting rods 433 is respectively fixed to the four corners of the micrometer fixing seat 434, and the other end passes through the upper cover plate of the heating furnace 1 and is vertically fixed on the calibration beam positioning block 431, and the micrometer fixing seat 434 is placed above the middle cross beam.

[0054] Specifically, combined Figure 1 , Figure 2 As shown, the calibration beam positioning block 431 provides a fixing point for the dial gauge fixing seat 434, and the dial gauge fixing seat 434 is fixed by four connecting rods 433, and the connecting rods 433 are divided into quartz rods inside the furnace. The connecting rods 433 reduce the thermal expansion at high temperature in the furnace, and the thermal expansion is consistent, ensuring the measurement accuracy.

[0055] Optionally, combined Figure 2 As shown, the calibration component 6 also includes a thermocouple 62 and a calibration beam 63. The high temperature strain gauge 61 and the thermocouple 62 are welded to the calibration beam 63. The two ends of the calibration beam 63 are respectively placed in the slots of the two calibration beam positioning blocks 431.

[0056] Specifically, the slots of the calibration beam positioning block 431 include a first slot and a second slot, wherein the first slot is used to constrain the displacement of the calibration beam 63 in the vertical direction, and the second slot is used to constrain the displacement of the calibration beam 63 in the width direction. The two ends of the calibration beam 63 are placed on the calibration beam positioning block 431, and the calibration beam positioning block 431 constrains the vertical displacement of the beam, and the beam end can rotate freely. The two ends of the calibration beam 63 are respectively placed in the slots of the calibration beam positioning blocks 431 on both sides, and the calibration beam positioning blocks 431 only constrain the displacement of the calibration beam 63 along the vertical direction of the calibration beam, forming a simply supported beam structure.

[0057] Optionally, the door-type pull rod 7 includes two pull rods 71 ​​and a pull rope connecting block 72, one end of the two pull rods 71 ​​is connected to the pull rope connecting block 72 through a pin shaft, and the other end passes through the middle cross beam 412 and the upper cover plate of the heating furnace 1 in sequence and is connected to the calibration beam 63; the weight assembly 8 includes a weight seat 81, two fixed pulleys 82 and a pull rope 83, the two fixed pulleys 82 are fixedly connected to the two ends of the upper cross beam 422 in the length direction, one end of the pull rope 83 is connected to the pull rope connecting block 72, and the other end passes through the two fixed pulleys 82 and is connected to the weight seat 81.

[0058] Specifically, combined Figures 1 to 3 As shown, a fixed pulley 82 is located directly above the micrometer assembly 5, and is used as the first fixed pulley. Another fixed pulley 82 is located on the end of the upper beam 422 away from the heating furnace 1, and is used as the second fixed pulley. One end of the pull rope 83 is connected to the pull rope connecting block 72, and the other end is connected to the weight seat 81 after passing through the first fixed pulley and the second fixed pulley in sequence. The pull rope 83 between the first fixed pulley and the pull rope connecting block 72 is perpendicular to the horizontal plane. The weight seat 81 converts the downward gravity of the weight into an upward pulling force on the calibration beam 63 through the pull rope 83 and the fixed pulley 82, completing the loading process. A clamp is provided at one end of the pull rod 71, which passes through the middle beam 412 and the upper cover plate of the heating furnace 1 in sequence and is clamped on the calibration beam 63 by the clamp.

[0059] In this optional embodiment, two relatively independent calibration beam positioning blocks 431 provide constraints for the calibration beam 63, two pull rods 71 ​​provide load for the beam, and the calibration beam positioning blocks 431 and the pull rods 71 ​​are both constrained on the upper cross beam 422 outside the furnace, thereby ensuring the stability of the constraint position and the loading position. The calibration device will not introduce calculation errors due to changes in the supporting structure and the loading position along the length direction of the calibration beam due to temperature changes.

[0060] Optionally, the micrometer assembly includes a digital micrometer 51 and a measuring rod 52, the shell of the digital micrometer 51 is fixedly arranged at the middle position of the micrometer fixing seat 434, one end of the measuring rod 52 abuts against the pointer of the digital micrometer 51, and the other end is provided with a clamp, and passes through the middle cross beam 412 and the upper cover plate of the heating furnace 1 in sequence and is clamped on the calibration beam 63 by the clamp.

[0061] Specifically, combined Figure 2 , Figure 3 As shown, the measuring rod 52 is clamped in the middle position of the calibration beam 63 by a clamp, and can move up and down in the linear bearing as the calibration beam 63 deforms, and finally transmits the displacement value to the digital micrometer 51. One end of the two pull rods 531 is clamped on the calibration beam 63 by a clamp, and the other end is connected to the pull rope connecting block 72 through a pin shaft, so that the pulling force is evenly distributed to the two pull rods 531, and finally acts on the calibration beam 63. The two pull rods 531 pass through the two linear bearings on the middle cross beam 412 respectively, so that the load can be accurately applied to the loading point of the calibration beam 63.

[0062] In this optional embodiment, two relatively independent calibration beam positioning blocks 431 provide constraints for the calibration beam 63, two pull rods 531 provide load for the beam, and the calibration beam positioning blocks 431 and the pull rods 531 are both constrained on the upper cross beam 422 outside the furnace, thereby ensuring the stability of the constraint position and the loading position. The calibration device will not introduce calculation errors due to changes in the supporting structure and the loading position along the length of the calibration beam due to temperature changes.

[0063] Optionally, the data acquisition system includes a cable, a multi-point measurement data recorder 9, a resistance data acquisition instrument 10, a switch 11 and a computer 12 connected in sequence, one end of the cable is connected to the multi-point measurement data recorder 9, and the other end passes through an opening in the rear panel of the heating furnace 1 and is connected to the high-temperature strain gauge 61 and the thermocouple 62.

[0064] Specifically, combined Figure 1 As shown, the cable is led out through the opening of the rear panel of the heating furnace 1 and connected to the multi-point measurement data recorder 9 and the resistance data acquisition instrument 10, and the resistance value of the high-temperature strain gauge 61, the temperature value and the strain value of the calibration beam 63 are transmitted to the data processing program of the computer 12 through the switch 11. At the same time, the measurement data of the digital micrometer 51 can transmit the maximum deflection value of the calibration beam 63 to the computer 12 via Bluetooth, completing the data acquisition process.

[0065] A method for calibrating characteristic parameters of a high temperature strain gauge provided by an embodiment of the present invention is combined with Figure 5 As shown, including:

[0066] The heating furnace 1 is arranged on the top of the control box 2, and the control box 2 and the support structure 4 are arranged on the furnace base 3;

[0067] One end of the micrometer assembly 5 is placed outside the furnace, and the other end passes through the upper cover plate of the heating furnace and is connected to the calibration assembly 6, and the calibration assembly 6 is placed in the heating furnace 1, and the calibration assembly 6 includes a high-temperature strain gauge 61;

[0068] One end of the door-shaped pull rod 7 is connected to the weight assembly 8, and the other end passes through the upper cover plate of the heating furnace 1 and is connected to the calibration assembly 6;

[0069] Connecting the data acquisition system to the calibration component 6 via a cable;

[0070] The temperature of the heating furnace 1 is adjusted by the control box 2;

[0071] The target high-temperature strain gauge characteristic parameters are obtained through the data acquisition system.

[0072] The beneficial effects of the high temperature strain gauge characteristic parameter calibration method of this embodiment relative to the prior art are the same as those of the above-mentioned high temperature strain gauge characteristic parameter calibration device, which will not be described in detail here.

[0073] Optionally, obtaining the target high temperature strain gauge characteristic parameters through the data acquisition system includes:

[0074] Acquiring the measured deflection value of the calibration beam through the data acquisition system;

[0075] The measured deflection value of the calibration beam is corrected according to the preset error value to obtain the true deflection value of the calibration beam, wherein the true deflection value of the calibration beam is:

[0076] ωTt=ωTm-ωT0,

[0077] Wherein, ωTt is the true deflection value of the calibration beam, ωTm is the measured deflection value of the calibration beam, and ωT0 is the preset error value;

[0078] The high temperature strain gauge characteristic parameter is obtained according to the true deflection value of the calibration beam, wherein the high temperature strain gauge characteristic parameter includes the true strain value of the calibration beam, and the true strain value of the calibration beam is:

[0079] εTt=f(ωTm-f0(T)),

[0080] Wherein, εTt is the true strain value of the calibration beam, ωTm is the measured deflection value of the calibration beam, and ωT0=f0(T).

[0081] Specifically, the fulcrum is used to indicate the position of the slotted edge support on the calibration beam positioning block 431; the loading point is used to indicate the position where the two tie rods 71 ​​are clamped on the calibration beam 63; and the midpoint of the calibration beam is used to indicate the position where the measuring rod 52 is clamped on the calibration beam 63. The fulcrum of the calibration beam positioning block constrains the displacement of both ends of the calibration beam along the normal direction of the calibration beam surface, and l is defined as the distance between the two fulcrums. The same load is applied to the two tie rods 531 at a distance a from the fulcrum. According to the material mechanics theory, the relationship between the strain value ε between the two loading points of the calibration beam and the maximum deflection ω of the calibration beam is obtained, that is, the preset strain value function is:

[0082]

[0083] Among them, ε is the strain value, h is the thickness of the calibration beam, l is the distance between the two supports, a is the distance between the loading point and the support, and ω is the maximum deflection of the calibration beam.

[0084] From the preset strain value function, it can be seen that the strain value of the calibration beam between the two loading points is the same, the calibration beam strain is linearly related to the maximum deflection, and has nothing to do with the elastic modulus of the beam. For convenience, it is expressed in function form here:

[0085] ε=f(ω).

[0086] When calibrating the strain gauge's sensitivity coefficient and thermal output and other characteristic parameters, the actual deflection value ω of the calibration beam at different temperatures T is used. Tt and the true strain value ε of the calibration beam Tt However, through the calibration device, we can only directly obtain the measured deflection value ω of the calibration beam at temperature T. Tm and the measured strain value ε of the calibration beam Tm , in this case the measured deflection value ω Tm There is a mechanical error introduced by the calibration device, and the measured strain value ε Tm This includes errors such as the thermal output of the strain gauge.

[0087] Due to the difference in thermal expansion between the measuring rod and the connecting rod in the heating furnace, the value measured by the dial gauge is not the actual deflection value of the calibrated beam. Here, the measured values ​​of the dial gauge at different temperatures under 0 load are used to correct the error caused by the difference in thermal expansion between the measuring rod and the connecting rod in the heating furnace. The functional relationship between the measured value of the dial gauge under 0 load and the temperature T is obtained:

[0088] ωT0=f0(T).

[0089] The actual deflection value of the calibrated beam is:

[0090] ωTt=ωTm-ωT0,

[0091] Among them, ωTt is the true deflection value of the calibration beam, ωTm is the measured deflection value of the calibration beam, and ωT0 is the preset error value.

[0092] Substitute the true deflection value ωTt of the calibration beam into the preset strain value function to obtain the true strain value εTt of the calibration beam:

[0093] εTt=f(ωTm-f0(T)).

[0094] In this optional embodiment, the above two-step data correction method can eliminate the measurement error introduced by the calibration device, and obtain the true deflection value and the true strain value of the calibration beam at different temperatures. Subsequently, the sensitivity coefficient, thermal output, thermal hysteresis, creep, mechanical hysteresis and other characteristics of the high-temperature strain gauge can be calculated and calibrated through the calibration device and existing mature calculation formulas.

[0095] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A high temperature strain gauge characteristic parameter calibration device, characterized in that: Including temperature control system, support system, displacement measurement system, loading system and data acquisition system; The temperature control system comprises a heating furnace (1) and a control box (2), wherein the heating furnace (1) is arranged on the top of the control box (2), and a control device for adjusting the temperature of the heating furnace (1) is arranged inside the control box (2); The support system comprises a furnace base (3) and a support structure (4), and the control box (2) and the support structure (4) are arranged on the furnace base (3); The displacement measurement system comprises a micrometer component (5) and a calibration component (6), one end of the micrometer component (5) is placed outside the furnace, and the other end passes through the upper cover plate of the heating furnace (1) and is connected to the calibration component (6), and the calibration component (6) is placed in the heating furnace (1), and the calibration component (6) comprises a high-temperature strain gauge (61); The loading system comprises a gate-shaped pull rod (7) and a weight assembly (8), wherein the weight assembly (8) is connected to the support structure (4), one end of the gate-shaped pull rod (7) is connected to the weight assembly (8), and the other end passes through the support structure (4) and the heating furnace (1) in sequence and is connected to the calibration assembly (6); The data acquisition system is connected to the calibration component (6) via a cable.

2. The high temperature strain gauge characteristic parameter calibration device according to claim 1, characterized in that: The support structure (4) comprises a gate-shaped support (41) and a T-shaped support (42); the gate-shaped support comprises two side beams (411) and a middle cross beam (412); two ends of the middle cross beam (412) are respectively connected to the two side beams (411); the side beams (411) are connected to the furnace base (3); the T-shaped support (42) comprises an upper vertical beam (421) and an upper cross beam (422) connected to each other; the upper vertical beam (421) is arranged on one side of the side beam (411).

3. The high temperature strain gauge characteristic parameter calibration device according to claim 2, characterized in that: The support structure (4) also includes a connecting member (43), and the connecting member (43) includes two calibration beam positioning blocks (431) and at least two square steel pipes (432). The two calibration beam positioning blocks (431) are respectively overlapped with the two ends of the calibration component (6) in the length direction, and one end of the square steel pipe (432) is connected to the middle cross beam (412), and the other end passes through the upper cover plate of the heating furnace (1) and is connected to the calibration beam positioning block (431).

4. The high temperature strain gauge characteristic parameter calibration device according to claim 3, characterized in that: The connecting member also includes four connecting rods (433) and a dial gauge fixing seat (434), one end of the four connecting rods (433) is respectively fixed to the four corners of the dial gauge fixing seat (434), and the other end passes through the upper cover plate of the heating furnace (1) and is vertically fixed to the calibration beam positioning block (431), and the dial gauge fixing seat (434) is placed above the middle cross beam (412).

5. The high temperature strain gauge characteristic parameter calibration device according to claim 4, characterized in that: The calibration component (6) further comprises a thermocouple (62) and a calibration beam (63), the high temperature strain gauge (61) and the thermocouple (62) being welded to the calibration beam (63), and the two ends of the calibration beam (63) being respectively placed in the slots of the two calibration beam positioning blocks (431).

6. The high temperature strain gauge characteristic parameter calibration device according to claim 5, characterized in that: The door-type pull rod (7) comprises two pull rods (71) and a pull rope connection block (72), one end of the two pull rods (71) is connected to the pull rope connection block (72) through a pin shaft, and the other end passes through the middle cross beam (412) and the upper cover plate of the heating furnace (1) in sequence to be connected to the calibration beam (63); the weight assembly (8) comprises a weight seat (81), two fixed pulleys (82) and a pull rope (83), the two fixed pulleys (82) are respectively fixedly connected to the two ends of the upper cross beam (422) in the length direction, one end of the pull rope (83) is connected to the pull rope connection block (72), and the other end passes through the two fixed pulleys (82) to be connected to the weight seat (81).

7. The high temperature strain gauge characteristic parameter calibration device according to claim 6, characterized in that: The micrometer assembly (5) comprises a digital micrometer (51) and a measuring rod (52); the housing of the digital micrometer (51) is fixedly arranged at the middle position of the micrometer fixing seat (434); one end of the measuring rod (52) abuts against the pointer of the digital micrometer (51); the other end is provided with a clamp, which passes through the middle cross beam (412) and the upper cover plate of the heating furnace (1) in sequence and is clamped on the calibration beam (63) through the clamp.

8. The high temperature strain gauge characteristic parameter calibration device according to claim 5, characterized in that: The data acquisition system comprises a cable, a multi-point measurement data recorder (9), a resistance data acquisition instrument (10), a switch (11) and a computer (12) which are connected in sequence, one end of the cable is connected to the multi-point measurement data recorder (9), and the other end passes through an opening of a rear panel of the heating furnace (1) and is connected to the high-temperature strain gauge (61) and the thermocouple (62).

9. A method for calibrating characteristic parameters of a high temperature strain gauge, characterized in that: The high temperature strain gauge characteristic parameter calibration device according to any one of claims 1 to 8 comprises: The heating furnace (1) is arranged on the top of the control box (2), and the control box (2) and the support structure (4) are arranged on the furnace base (3); One end of the micrometer assembly (5) is placed outside the furnace, and the other end passes through the upper cover plate of the heating furnace (1) and is connected to the calibration assembly (6), and the calibration assembly (6) is placed in the heating furnace (1), and the calibration assembly (6) includes a high-temperature strain gauge (61); One end of the door-shaped pull rod (7) is connected to the weight assembly (8), and the other end passes through the upper cover plate of the heating furnace (1) and is connected to the calibration assembly (6); Connecting the data acquisition system to the calibration component (6) via a cable; The temperature of the heating furnace (1) is adjusted by the control box (2); The target high-temperature strain gauge characteristic parameters are obtained through the data acquisition system.

10. The method for calibrating characteristic parameters of a high temperature strain gauge according to claim 9, characterized in that: The target high temperature strain gauge characteristic parameters are obtained through the data acquisition system, including: Acquiring the measured deflection value of the calibration beam through the data acquisition system; The measured deflection value of the calibration beam is corrected according to the preset error value to obtain the true deflection value of the calibration beam, wherein the true deflection value of the calibration beam is: oh Tt =ω Tm -oh T0 , Among them, ω Tt is the true deflection value of the calibration beam, ω Tm is the measured deflection value of the calibration beam, ω T0 is the preset error value; The high temperature strain gauge characteristic parameter is obtained according to the true deflection value of the calibration beam, wherein the high temperature strain gauge characteristic parameter includes the true strain value of the calibration beam, and the true strain value of the calibration beam is: ε Tt =f(ω Tm -f0(T)), Among them, ε Tt is the true strain value of the calibration beam, ω Tm is the measured deflection value of the calibration beam, ω T0 =f0(T).

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