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CN-121977463-A - Three-dimensional strain field calibration device and method

CN121977463ACN 121977463 ACN121977463 ACN 121977463ACN-121977463-A

Abstract

The invention provides a three-dimensional strain field calibration device and method, the device comprises a strain field loading module, a strain field measurement module and a strain field comparison module, after the three-dimensional strain field is generated on the surface of a standard sample plate of the strain field loading module during calibration, the strain field measurement module is used for measuring the displacement change value of the center position of the standard sample plate, and the strain field on the surface of the standard sample plate is calculated after substituting into a Von-K rm n model, so that the standard three-dimensional strain field distribution is obtained. The three-dimensional strain field generated by the device can be used for strain compensation and correction of an optical strain field measurement system, can realize loading and measurement of the three-dimensional strain field based on the Von-K-rmn large deflection theory, and has important application value in the field of strain field test of aeroengines, civil engineering, material mechanics and the like.

Inventors

  • CHENG SHUAI
  • Lin Bixue
  • DUAN XIAOYAN
  • ZHANG DAZHI

Assignees

  • 中国航空工业集团公司北京长城计量测试技术研究所

Dates

Publication Date
20260505
Application Date
20251230

Claims (10)

  1. 1. The three-dimensional strain field calibration device is used for constructing and calibrating a three-dimensional strain field and is characterized by comprising a strain field loading module, a strain field measuring module and a strain field comparison module; The strain field loading module comprises a standard template (104), wherein the strain field loading module deforms the standard template (104) through gas pressure and generates a standard three-dimensional strain field on the upper surface ; The strain field measurement module comprises a two-dimensional guide rail (105) and a laser range finder (106), and is used for accurately positioning the center point position of the standard template (104) and measuring the deflection change value of the center position of the standard template (104) before and after loading ; The strain field comparison module comprises strain field comparison software (107), wherein the strain field comparison software (107) is used for comparing a central deflection change value Substituting the strain field into a mechanical model to calculate a standard three-dimensional strain field And measuring strain field with three-dimensional strain field measuring system And (3) comparing to realize the calibration of the three-dimensional strain field measurement system.
  2. 2. The three-dimensional strain field calibration device according to claim 1, wherein the strain field loading module is used for realizing uniform loading and parameter controllable combination, and specifically comprises a high-pressure air source (101), a pressure container (102) and a pressure controller (103), wherein the strain field loading module charges air into the pressure container (102) through the high-pressure air source (101), the pressure container (102) clamps the edge of a standard template (104) in a flange mode to ensure uniform loading of a specific loading area, and the pressure controller (103) is provided with a digital barometer and adopts a double-valve automatic control mechanism to ensure air pressure stability, so that stable loading and adjustment of the three-dimensional strain field are realized.
  3. 3. The three-dimensional strain field calibration device of claim 2, wherein the material of the standard template (104) comprises poisson's ratio Is that To ensure that a three-dimensional strain field of high strain is stably generated under the action of gas pressure and can be restored after unloading.
  4. 4. The three-dimensional strain field calibration device according to claim 1, wherein in the strain field measurement module, a two-dimensional guide rail (105) is used for precisely positioning the center point position of the standard template (104) The laser distance measuring instrument (106) measures the absolute distance between the central positions before and after loading And Calculating the central deflection change value The measuring process combines a high-precision laser ranging technology and a two-dimensional guide rail system with closed-loop control, and ensures the accuracy and reliability of input data.
  5. 5. A three-dimensional strain field calibration device according to claim 3, wherein the laser rangefinder (106) obtains the central deflection change value by non-contact measurement To avoid interference with the deformation of the surface of the standard template (104) and to adapt the non-contact operating characteristics of the optical strain field measurement system.
  6. 6. The three-dimensional strain field calibration device of claim 1, wherein the strain field comparison software (107) calculates a standard three-dimensional strain field The algorithm of the method adopts a Von-K-rmn theoretical model algorithm, which is to solve an axisymmetric bending strain model with uniformly distributed load by edge clamping under a cylindrical coordinate system.
  7. 7. The three-dimensional strain field calibration device of claim 6, wherein the Von-K-rmn theory model algorithm further comprises introducing boundary conditions, establishing a balance relationship using in-plane and out-of-plane balance equations, combining geometric equations and physical equations, describing the relationship between strain and displacement, and deriving a solution The required coordination equation.
  8. 8. The three-dimensional strain field calibration device of claim 7, wherein the algorithm uses the coordination equation to determine the radius of the standard template (104) And poisson's ratio On the premise of measuring the central deflection Conversion to radial strain And hoop strain Component description standard strain field 。
  9. 9. The three-dimensional strain field calibration device according to claim 8, wherein the strain field comparison module further comprises a dynamic error correction mechanism, namely, a two-dimensional guide rail (105) is used for carrying a laser range finder (106) to perform systematic scanning on a three-dimensional displacement field generated on the surface of a standard template (104), and calculation errors of a Von-krm n theoretical model are corrected by using full-field displacement data obtained by scanning, so that a final calibration model is optimized.
  10. 10. A three-dimensional strain field calibration method for constructing and calibrating a three-dimensional strain field, comprising the steps of: The loading step is to precisely control the air pressure through a high-pressure air source (101) and a pressure controller (103) Applying uniform load to a standard template (104) clamped by a flange, deforming the standard template (104), and generating a standard three-dimensional strain field on the upper surface of the standard template ; A measuring step of carrying a laser range finder (106) by using a two-dimensional guide rail (105), precisely positioning the center point position of the standard template (106), and measuring the deflection change value of the center position of the standard template (105) before and after loading ; A comparison and calibration step, namely, the central deflection change value is compared by strain field comparison software (107) Substituting the standard three-dimensional strain field into a mechanical model to calculate the standard three-dimensional strain field And measuring strain field with three-dimensional strain field measuring system And performing comparison so as to realize the calibration of the measurement system.

Description

Three-dimensional strain field calibration device and method Technical Field The invention belongs to the field of calibration, and relates to a three-dimensional strain field calibration device and method. Background Strain is a physical quantity describing shape change of an object after being stressed, and is a key parameter for evaluating mechanical properties, structural safety and reliability of materials. Strain measurement techniques are largely divided into contact and non-contact measurement methods. The non-contact measuring method mainly comprises a resistance strain gauge, a capacitance strain gauge, an optical Fiber Bragg Grating (FBG) sensor, a vibrating wire strain gauge and the like, and the non-contact measuring method mainly comprises a digital image correlation method (DIC), an electronic speckle interferometry (ESPI), a moire interferometry, a photoelastic method, a laser Doppler vibration meter and the like. At present, non-contact strain field measurement technology based on optical principle is probably less mature than resistance strain gauge in industry standardization and application popularity, but the advantages of full-field measurement, non-contact, high precision and the like are rapidly developed, and new algorithms and applications are continuously emerging. The optical strain field measurement system mainly based on the digital image correlation measurement method relies on a single camera at the beginning of birth, so that only an object with a flat surface can be measured in-plane strain, and the optical axis of the camera is required to be perpendicular to the surface of a test piece. This also results in the fact that the three-dimensional strain field measurement requirements cannot be met in practical applications. In order to solve the limitation, researchers combine a two-dimensional digital image correlation method with a stereoscopic vision principle, acquire images of the surfaces of the object before and after deformation from different visual angles by configuring two cameras, calculate three-dimensional space coordinates of a to-be-measured point by utilizing a matching algorithm and a camera calibration technology, thereby acquiring full-field strain information of the object and realizing accurate measurement of a three-dimensional strain field of the surface of the object. Aiming at the fact that a three-dimensional optical strain field measurement system taking a digital image correlation method as a measurement principle can introduce systematic calculation errors in practical application, janJecmen et al realize real-time full-field strain analysis of a high-speed deformation process through a GPU parallel algorithm based on OpenCL in 2017, the calculation efficiency of the digital image correlation principle is improved by 30 times compared with the traditional method, pan Bing proposes a Gaussian point-like DIC method, under-matching errors are fundamentally restrained through a reconstruction function mathematical framework, and in 2020, hu Xiaoliang researches the relation between a second-order shape function and distortion correction and correlation matching sequences, so that the interference of imaging distortion on correlation matching can be effectively reduced by using a special second-order shape function. These developments have increased the measurement level of optical strain field measurement systems and have provided increasingly powerful support for three-dimensional strain field measurements in complex environments. How to accurately describe the measurement level of an optical strain field measurement system, thereby achieving accurate measurement of a three-dimensional strain field, remains a key technical challenge and an important development direction in the future that is currently faced. In practical application, aiming at the problems that an optical strain field measurement system lacks a calibration device and the existing measurement system cannot calibrate and the like, in 2006, a set of optical strain field measurement system calibration device based on four-point bending beams is commonly designed by 11 groups of scientific research teams in 7 countries such as switzerland, france and the united kingdom of michigan state university, and results are published in 45, 5, 550 and 564 papers of OpticsandLasersinEngineering. Patterson et al fully evaluate and verify the applicability of complex strain measurement optical systems by developing standardized test materials. The developed calibration device for the optical strain field measurement system based on the four-point bending beam utilizes the force and bending moment applied to the material to enable the material to bend and deform, so that a traceable two-dimensional strain field is generated on the side surface of the material, and the measurement result of the measurement system is calibrated through the strain gauge. In 2018, in order to further research the calibra