CN113009325B - Embedded high-temperature displacement testing method based on elastic element strain - Google Patents
Embedded high-temperature displacement testing method based on elastic element strain Download PDFInfo
- Publication number
- CN113009325B CN113009325B CN202011585344.5A CN202011585344A CN113009325B CN 113009325 B CN113009325 B CN 113009325B CN 202011585344 A CN202011585344 A CN 202011585344A CN 113009325 B CN113009325 B CN 113009325B
- Authority
- CN
- China
- Prior art keywords
- strain
- displacement
- elastic element
- test
- temperature
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/28—Testing of electronic circuits, e.g. by signal tracer
- G01R31/317—Testing of digital circuits
- G01R31/3181—Functional testing
- G01R31/3187—Built-in tests
Abstract
The invention belongs to the technical field of displacement testing, and particularly relates to an embedded high-temperature displacement testing method based on elastic element strain. The invention adopts a high-temperature strain test mode to realize deformation test, further converts the deformation into a displacement test result, and realizes the purpose of embedded displacement test with high reliability, high temperature resistance and no additional influence on a pressurizing device on a compact type brake pressurizing actuating device. On the premise of meeting the original compact space arrangement requirement of the existing elastic element of the brake, the displacement test of the pressurized actuating element of the high-temperature brake at the temperature of more than 300 ℃ is realized by adopting the embedded patch of the high-temperature-resistant micro strain gauge, so that not only can the static displacement test be realized, but also the dynamic displacement test at the temperature of not less than 20Hz can be realized. The method and the sensor have no additional influence on the measured object, and are particularly suitable for the state detection, fault diagnosis and the like of the product loading test with high temperature, large vibration impact, tense layout space and the like.
Description
Technical Field
The invention belongs to the technical field of displacement testing, and particularly relates to an embedded high-temperature displacement testing method based on elastic element strain.
Background
The existing brake adopts a method of additionally installing a compact displacement sensor with small volume and high temperature resistance to realize the test of the pressurizing actuating position of the brake, has the problems of additional sensor weight increase, complex arrangement, low reliability of the displacement sensor in high-temperature and impact use environments and the like, and has the influence of additional force on a pressurizing device due to the additional sensor, thereby reducing the working efficiency of a tested object.
Therefore, a testing method which is suitable for the working conditions of loading application such as high temperature, large impact, compact arrangement space and the like of the brake and does not have additional influence on the working of the brake pressurizing device is needed to be formed, so that the inherent parts of the brake pressurizing device are analyzed, the working parts and the characteristics thereof related to the pressurizing action position are found, and the embedded testing method which is suitable for the working conditions of the brake is adopted to meet the testing requirement.
At present, in a displacement testing technology, an elastic element is mainly used for realizing the action of a return force required by a displacement test, and no report of realizing the displacement test by using an embedded strain test of a braking spiral elastic element is available.
Disclosure of Invention
Technical problem to be solved
The technical problem to be solved by the invention is as follows: how to provide an embedded high-temperature displacement test method based on elastic element strain.
(II) technical scheme
In order to solve the technical problems, the invention provides an embedded high-temperature displacement testing method based on elastic element strain, which is based on the discovery that the strain rule of an elastic element for returning a brake and the displacement of a brake pressurizing actuating device have a determined corresponding relation, and comprises the following steps:
step 1: calculating a patch of strain displacement and a frequency domain test range;
calculating the relation between the strain and the displacement of the elastic element by adopting a finite element or an analytical algorithm, and determining the position suitable for the patch according to the three principles of obvious stress strain, small stress gradient and easiness in leading; and avoid the resonance dynamic load of the elastic element from generating larger interference influence on the displacement test through modal calculation; the elastic element with displacement/strain testability formed in the process is the basis of the next calibration;
step 2: calibrating;
based on a conventional strain test method, calibrating the deformation/displacement and strain of the elastic element, and determining a calibration table or curve required by the displacement test; during calibration, hot air is adopted to realize high-temperature environment simulation, and the high-temperature characteristic of the test is determined;
and step 3: the lead is led from the fixed end of the elastic element, and the reliability of the lead is ensured by small displacement of the fixed end; for the spiral elastic element, the fixing and leading-out of the lead with high reliability are realized through the connection structure of the hook and the fixed part.
According to the embedded high-temperature displacement testing method, two types of 3 positions suitable for the patch are found, wherein the two types comprise a hook and a spiral ring, and the 3 types refer to the following steps: the hook comprises 2 types of hooks on two sides and the front part, the spiral ring is the first ring of 1 type, the embedded high-temperature displacement sensor is implemented on the spiral elastic element for returning the dry-plate brake, and the test verification is passed.
Wherein the step 1 comprises:
step 11: according to the relationship between the strain MPa and the displacement mm of the elastic element, outputting a calculation result with the dimension of MPa/mm as a strain gauge selection basis according to the maximum displacement of the elastic element, namely the measuring range of the test displacement and the maximum strain thereof;
step 12: evaluating the testable position of the elastic element according to the test precision requirement;
step 13: according to the size of a common elastic element, in order to meet the requirement of the test stability of the strain gauge, the gradient of the stress distribution of the testable position of the elastic element is evaluated, and the strain gradient or the maximum difference of the strain at the testable position is not more than 180 MPa/strain test area;
step 14: after the test position and the size of the strain gauge are determined, the lead position arranged by the strain gauge is designed near the fixed end of the elastic element, so that the influence of the displacement change of the elastic element on the reliable work of the lead is reduced;
step 15: and finally, completing modal calculation of the elastic element and determining the applicable working frequency domain of the elastic element displacement testing device.
In the step 12, when the displacement test precision is 0.1mm, the strain sensitivity of the testable position is required to be not less than 10MPa/mm.
In the step 13, the recommended value of the high-precision test strain gradient of the conventional small high-temperature strain gauge is 60MPa/mm, so that the maximum allowable size of the strain gauge meeting the test precision requirement is determined to be 3mm.
Wherein the step 2 comprises:
step 21: according to the requirement of the test range, the calibration of the full stroke/range of the elastic element is completed on a stroke calibration device which meets the test precision, and the number of the calibration points at equal intervals is not less than 5;
step 22: according to the service temperature, in the whole calibration process, hot air is adopted to simulate the highest service temperature for the strain test area, and the error caused by high temperature is determined to be smaller than an allowable value. The high-temperature strain displacement test error is less than 5% under the condition of 300 ℃ according to the method.
In step 21, if the working stroke of the elastic element is 10mm and the test precision is 0.1mm, the strain values are tested at 10 positions of 1, 2, 3, 8230, 9 and 10 in sequence at intervals of 1mm, and a calibration curve is drawn.
Wherein, in the step 21, the position recording precision is better than 0.01mm.
(III) advantageous effects
Compared with the prior art, the invention provides an embedded high-temperature displacement test method and an application device, and particularly relates to an embedded test method suitable for a pressurization actuating position of a pressurization actuating device of a high-energy capacity mechanical brake and a high-temperature strain displacement test sensor realized based on an existing elastic element of the brake.
The invention realizes the deformation test by finding and determining the corresponding relation between the deformation of the inherent elastic element of the brake pressurizing device and the position of the inherent elastic element, further converts the deformation into a displacement test result, and realizes the purpose of embedded displacement test with high reliability, high temperature resistance and no additional influence on the pressurizing device on the compact brake pressurizing actuating device.
By exploring the relationship between the strain of the elastic element for returning the brake and the displacement of the pressurizing actuating element, the displacement test of the pressurizing actuating element of the high-temperature brake at the temperature of more than 300 ℃ is realized by adopting the embedded patch of the high-temperature-resistant micro strain gauge on the premise that the existing elastic element of the brake meets the original compact space arrangement requirement, and not only can the static displacement test be realized, but also the dynamic displacement test at the temperature of not less than 20Hz can be realized. The method and the sensor have no additional influence on the tested object, and are particularly suitable for the state detection, fault diagnosis and the like of the test along with product loading, such as high temperature, large vibration impact, tense layout space and the like.
Drawings
Fig. 1 (a) -1 (d) are schematic diagrams of the elastic element patch for brake return of the invention.
FIG. 2 is a dynamic displacement test curve diagram of the tangential return elastic element of the brake.
Fig. 3 is a schematic diagram of stress field distribution of the tangential return elastic element of the brake.
Fig. 4 is a schematic diagram of modal analysis results of the tangential return elastic element of the brake.
FIG. 5 is a schematic diagram showing the calibration result of the tangential return elastic element of the brake.
FIG. 6 is a diagram illustrating the sensitivity coefficient change rate influencing characteristics of the high temperature strain gauge of the elastic element.
FIG. 7 is a schematic view of the brake after the tangential return elastic element solidifies the leads.
Detailed Description
In order to make the objects, contents, and advantages of the present invention more apparent, the following detailed description of the present invention will be made in conjunction with the accompanying drawings and examples.
In order to solve the technical problems, the invention provides an embedded high-temperature displacement testing method based on elastic element strain, which is based on the discovery that the strain rule of an elastic element for returning a brake and the displacement of a brake pressurizing actuating device have a determined corresponding relationship, and comprises the following steps:
step 1: calculating a patch of strain displacement and a frequency domain test range;
calculating the relation between the strain and the displacement of the elastic element by adopting a finite element or an analytical algorithm, and determining the position suitable for the patch according to the three principles of obvious stress strain, small stress gradient and easiness in leading; and avoid the resonance dynamic load of the elastic element from generating larger interference influence on the displacement test through modal calculation; the elastic element with displacement/strain testability formed in the process is the basis of next calibration;
step 2: calibrating;
based on a conventional strain test method, calibrating the deformation/displacement and strain of the elastic element, and determining a calibration table or curve required by the displacement test; in the calibration, hot air is adopted to realize high-temperature environment simulation, and the high-temperature characteristic of the test is determined;
and step 3: the lead is led from the fixed end of the elastic element, and the reliability of the lead is ensured by small displacement of the fixed end; for the spiral elastic element, the fixing and leading-out of the lead with high reliability are realized through the connection structure of the hook and the fixed part.
According to the embedded high-temperature displacement testing method, two types of 3 positions suitable for the patch are found, wherein the two types comprise a hook and a spiral ring, and the 3 types refer to the following steps: the hook comprises 2 types at two sides and the front part, the spiral ring is the first ring of 1 type, as shown in figure 1, an embedded high-temperature displacement sensor is implemented on a spiral elastic element for returning the dry plate type brake, and the test verification is passed.
Wherein the step 1 comprises:
step 11: according to the relationship between the strain MPa and the displacement mm of the elastic element, outputting a calculation result with the dimension of MPa/mm as a strain gauge selection basis according to the maximum displacement of the elastic element, namely the measuring range of the test displacement and the maximum strain thereof;
step 12: evaluating the testable position of the elastic element according to the test precision requirement;
step 13: according to the size of a common elastic element, in order to meet the requirement of the test stability of the strain gauge, the gradient of the stress distribution of the testable position of the elastic element is evaluated, and the strain gradient or the maximum difference of the strain at the testable position is not more than 180 MPa/strain test area;
step 14: after the test position and the size of the strain gauge are determined, the lead position arranged by the strain gauge is designed near the fixed end of the elastic element, so that the influence of the displacement change of the elastic element on the reliable work of the lead is reduced;
step 15: and finally, completing modal calculation of the elastic element and determining an applicable working frequency domain of the elastic element displacement testing device.
In the step 12, when the displacement test precision is 0.1mm, the strain sensitivity of the testable position is required to be not less than 10MPa/mm.
In the step 13, the recommended value of the high-precision test strain gradient of the conventional small high-temperature strain gauge is 60MPa/mm, so that the maximum allowable size of the strain gauge meeting the test precision requirement is determined to be 3mm.
Wherein the step 2 comprises:
step 21: according to the requirement of the test range, the calibration of the full stroke/range of the elastic element is completed on a stroke calibration device which meets the test precision, and the number of the calibration points at equal intervals is not less than 5;
step 22: according to the service temperature, in the whole calibration process, hot air is adopted to simulate the highest service temperature for the strain test area, and the error caused by high temperature is determined to be smaller than an allowable value. The high-temperature strain displacement test error is less than 5% under the condition of 300 ℃ according to the method.
In step 21, if the working stroke of the elastic element is 10mm and the test precision is 0.1mm, the strain values are tested at 10 positions of 1, 2, 3, 8230, 9 and 10 in sequence at intervals of 1mm, and a calibration curve is drawn.
Wherein, in the step 21, the position recording precision is better than 0.01mm.
Example 1
In order to solve the problems that the conventional displacement sensor is poor in reliability and changes the state of a test object under working environments such as loading impact, high temperature and the like, the strain characteristics of an elastic element of the test object along with displacement are researched through finite element simulation, the scheme that a high-temperature strain gauge is arranged at the connection position of the elastic element is determined, the relation curve of the displacement and the strain is further determined through calibration, the aim of obtaining displacement parameters through the strain test of the elastic element is achieved, and finally the new embedded displacement test technology is verified through a high-frequency dynamic test.
On the tangential return elastic element of a certain dry plate type brake, the displacement test and the dynamic displacement test verification are realized according to the three steps provided by the invention.
1) Calculating and designing:
the relation between the strain and the displacement of the elastic element is calculated by adopting a finite element, and meanwhile, according to the distribution condition of a stress field, as shown in figure 3, the hook position and the head loop position suitable for the patch are determined according to the principles of obvious stress strain, small stress gradient and easiness in leading, and are particularly shown in figure 1.
Then, the influence of the resonance and other dynamic loads of the elastic element on the displacement test is avoided through modal calculation, specifically, as shown in fig. 4, the lowest natural frequency of the elastic element is 148.16Hz through modal analysis, and is far greater than the working frequency of the brake actuation device, which is not greater than 20Hz, so that stable and reliable static and dynamic displacement test data can be provided for the brake actuation device.
2) Calibration:
based on a conventional strain testing method, the deformation/displacement and the strain of the elastic element are calibrated, a calibration table/curve required by the displacement test is determined, the calibration result is shown in figure 5, the simulation strain and the strain measured by the test are subjected to straight line fitting, the slope of the fitted straight line of the simulation strain-displacement is 121.6, the slope of the fitted straight line of the actual measurement strain-displacement is 114.82, and the difference between the slope of the actual measurement strain-displacement and the slope of the simulation is about 5.5%.
In the embodiment, a 300 ℃ high-temperature strain gauge is adopted, and through a high-temperature environment test, as shown in fig. 6, when the temperature is increased from 20 ℃ to 300 ℃, the sensitivity coefficient change rate of the strain gauge is changed from 0% to-3.9%, and the error caused by temperature change is less than 3.9%; the highest temperature-resistant index of the strain gauge reaches more than 500 ℃.
3) And (3) solidifying the lead and verifying dynamic tests:
the lead wire is fixed at the fixed end of the elastic element, and the reliability of the lead wire is ensured by small displacement of the fixed end. For the spiral elastic element, the fixing and leading-out of the high-reliability lead wire are realized mainly through a hook connecting structure with a fixed part: the lead wire is solidified by resin adhesive along the hook and finally led out from the tail end of the hook (no displacement during working). The curing structure is verified through a 20Hz dynamic displacement test (a test system comprises a tester, an embedded high-temperature displacement test sensor comprising a brake elastic element and a strain gauge, a DRA-30A strain gauge, a data acquisition computer and the like), the error is less than 0.11mm (as shown in figure 2), and the test use requirement of 0.2mm of the brake actuation displacement is met.
The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.
Claims (7)
1. An embedded high-temperature displacement testing method based on elastic element strain is characterized in that the method is based on the discovery that the strain rule of an elastic element for brake return and the displacement of a brake pressurization actuating device have a determined corresponding relationship, and the provided embedded high-temperature displacement testing method comprises the following steps:
step 1: calculating a patch of strain displacement and a frequency domain test range;
calculating the relation between the strain and the displacement of the elastic element by adopting a finite element or an analytical algorithm, and determining the position suitable for the patch according to the three principles of obvious stress strain, small stress gradient and easiness in leading; and avoid the resonance dynamic load of the elastic element from generating larger interference influence on the displacement test through modal calculation; the elastic element with displacement/strain testability formed in the process is the basis of next calibration;
and 2, step: calibrating;
based on a conventional strain test method, calibrating the deformation/displacement and strain of the elastic element, and determining a calibration table or curve required by the displacement test; in the calibration, hot air is adopted to realize high-temperature environment simulation, and the high-temperature characteristic of the test is determined;
and step 3: the lead is led from the fixed end of the elastic element, and the reliability of the lead is ensured by small displacement of the fixed end;
according to the embedded high-temperature displacement testing method, the embedded high-temperature displacement sensor is implemented on the spiral elastic element for returning the dry plate brake, and the test verification is passed.
2. The method for embedded high temperature displacement testing based on elastic element strain according to claim 1, wherein the step 1 comprises:
step 11: according to the relationship between the strain MPa and the displacement mm of the elastic element, outputting a calculation result with the dimension of MPa/mm as a strain gauge selection basis according to the maximum displacement of the elastic element, namely the measuring range of the test displacement and the maximum strain thereof;
step 12: evaluating the testable position of the elastic element according to the test precision requirement;
step 13: according to the size of a common elastic element, in order to meet the requirement of the test stability of the strain gauge, the gradient of the stress distribution of the testable position of the elastic element is evaluated, and the strain gradient or the maximum difference of the strain at the testable position is not more than 180 MPa/strain test area;
step 14: after the test position and the size of the strain gauge are determined, the lead position arranged by the strain gauge is designed near the fixed end of the elastic element, so that the influence of the displacement change of the elastic element on the reliable work of the lead is reduced;
step 15: and finally, completing modal calculation of the elastic element and determining an applicable working frequency domain of the elastic element displacement testing device.
3. The method according to claim 2, wherein in the step 12, the strain sensitivity of the testable position is not less than 10MPa/mm when the displacement test precision is 0.1 mm.
4. The method according to claim 2, wherein in the step 13, the recommended value of the strain gradient for the high-precision test of the conventional small high-temperature strain gauge is 60MPa/mm, so as to determine that the maximum allowable dimension of the strain gauge meeting the test precision requirement is 3mm.
5. The embedded high temperature displacement test method based on elastic element strain of claim 1, wherein the step 2 comprises:
step 21: according to the requirement of the test range, completing the calibration of the full stroke/range of the elastic element on a stroke calibration device meeting the test precision, wherein the number of equally spaced calibration points is not less than 5;
step 22: according to the service temperature, in the whole calibration process, hot air is adopted to simulate the highest service temperature for the strain test area, and the error caused by high temperature is determined to be smaller than an allowable value; the high-temperature strain displacement test error is less than 5% under the condition of 300 ℃ according to the method.
6. The method for embedded high-temperature displacement testing based on the elastic element strain as claimed in claim 5, wherein in the step 21, if the working stroke of the elastic element is 10mm and the testing precision is 0.1mm, the strain value is tested at 10 positions of 1, 2, 3 \8230, 9, 10 sequentially at intervals of 1mm, and a calibration curve is drawn.
7. The embedded high temperature displacement test method based on elastic element strain claimed in claim 6, characterized in that in step 21, the position recording precision is better than 0.01mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011585344.5A CN113009325B (en) | 2020-12-28 | 2020-12-28 | Embedded high-temperature displacement testing method based on elastic element strain |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011585344.5A CN113009325B (en) | 2020-12-28 | 2020-12-28 | Embedded high-temperature displacement testing method based on elastic element strain |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113009325A CN113009325A (en) | 2021-06-22 |
| CN113009325B true CN113009325B (en) | 2023-01-13 |
Family
ID=76383733
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011585344.5A Active CN113009325B (en) | 2020-12-28 | 2020-12-28 | Embedded high-temperature displacement testing method based on elastic element strain |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113009325B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5964327A (en) * | 1996-10-14 | 1999-10-12 | Hawse Company Limited | Active control apparatus and method for vibration reduction |
| CN102128584A (en) * | 2010-12-26 | 2011-07-20 | 中国第一汽车集团公司 | Method for testing work displacement of helical spring of automobile suspension |
| CN105157551A (en) * | 2015-05-22 | 2015-12-16 | 太原理工大学 | Triangle displacement sensor |
| CN105241590A (en) * | 2015-10-19 | 2016-01-13 | 西安航空动力股份有限公司 | Method for testing dynamic stress of rocker arm of air bleeding band under running state, and strain gauge fixing device |
| CN206378279U (en) * | 2016-12-30 | 2017-08-04 | 长城汽车股份有限公司 | Helical spring load test device and system |
-
2020
- 2020-12-28 CN CN202011585344.5A patent/CN113009325B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5964327A (en) * | 1996-10-14 | 1999-10-12 | Hawse Company Limited | Active control apparatus and method for vibration reduction |
| CN102128584A (en) * | 2010-12-26 | 2011-07-20 | 中国第一汽车集团公司 | Method for testing work displacement of helical spring of automobile suspension |
| CN105157551A (en) * | 2015-05-22 | 2015-12-16 | 太原理工大学 | Triangle displacement sensor |
| CN105241590A (en) * | 2015-10-19 | 2016-01-13 | 西安航空动力股份有限公司 | Method for testing dynamic stress of rocker arm of air bleeding band under running state, and strain gauge fixing device |
| CN206378279U (en) * | 2016-12-30 | 2017-08-04 | 长城汽车股份有限公司 | Helical spring load test device and system |
Non-Patent Citations (4)
| Title |
|---|
| 基于支座应变与光纤光栅的制动器力矩测量方法;李曼 等;《煤炭技术》;20180831;第37卷(第08期);第205-207页 * |
| 大型旋转机组轴向力在线监控测力弹性元件的结构方案设计;高红俐 等;《浙江工业大学学报》;20010331;第29卷(第01期);第34-39页 * |
| 弹子加压装置接触状态有限元分析;陈文滨 等;《车辆与动力技术》;20140131(第1期);第30-33页 * |
| 拉伸螺旋弹簧的可靠性研究;李忆莲 等;《理化检验.物理分册》;20041130;第40卷(第11期);第547-549、572页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113009325A (en) | 2021-06-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111829620B (en) | Weighing sensor, weighing network and monitoring method | |
| Lord et al. | Elastic modulus measurement—obtaining reliable data from the tensile test | |
| CN110073190B (en) | Device and method for monitoring oil pressure in oil cylinder of diaphragm compressor | |
| CN106768617B (en) | Separately excited type vibration cylinder pressure transducer performance test methods | |
| CN205940845U (en) | A dynamometer for measuring gas turbine high pressure rotor axial force | |
| CN105675329B (en) | A kind of static rigidity of lathe measuring device | |
| CN110657930B (en) | Method and system for measuring vibration stress of part | |
| CN108082534B (en) | Optical fiber arrangement and bridging method for helicopter rotor wing composite load test | |
| CN113009325B (en) | Embedded high-temperature displacement testing method based on elastic element strain | |
| CN205879107U (en) | Resistance strain sensor | |
| CN104964877A (en) | Rigidity testing device and system | |
| CN210426421U (en) | System for testing sensitivity coefficient of strain gauge with any resistance value | |
| Park et al. | Stress evolution in an encapsulated MEMS package due to viscoelasticity of packaging materials | |
| CN112781812A (en) | Fatigue testing method for metal diaphragm of diaphragm compressor | |
| CN113804119B (en) | High-temperature-resistant high-pressure optical fiber strain sensor | |
| CN207991561U (en) | A kind of device adjusted for resistance strain gage output | |
| CN110375905A (en) | A kind of engine valve spring force measuring device, method and device | |
| CN113820214A (en) | Method and system for measuring Poisson's ratio of solid propellant | |
| Kumar et al. | Design studies and optimization of position of strain gauge | |
| CN111623909A (en) | Stress test method for double-fork-arm two-force rod | |
| CN116222652B (en) | Nanometer film core and composite sensor | |
| CN117685898B (en) | Data processing method and device for in-situ detection of curing and forming of composite material | |
| CN214373034U (en) | Torque sensor for detecting force frequency characteristic of piezoelectric material | |
| CN110873643B (en) | Accelerated storage life test system for planar spiral spring | |
| CN115560888A (en) | Axial force measuring method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |