Test device and test method for measuring residual stress of bent pipe

A technology of residual stress and experimental equipment, which is applied in the direction of measuring the change force of optical properties of materials when they are stressed, and can solve problems such as cumbersome procedures

Inactive Publication Date: 2011-05-11
TSINGHUA UNIV
View PDF4 Cites 20 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the measurement of residual stress mainly uses the electric measurement drilling method. A hole is drilled on the component to be measured, so that the residual stress of the component around the hole is

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Test device and test method for measuring residual stress of bent pipe
  • Test device and test method for measuring residual stress of bent pipe
  • Test device and test method for measuring residual stress of bent pipe

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0065] Consider a concrete situation: image 3 is the displacement field calculated by digital speckle correlation before and after drilling, where image 3 (a) is the displacement field in the X direction, image 3 (b) is the displacement field in the Y direction, and the distance from the center of the small hole is r=1.7mm. The opening displacement at both ends is 0.10 μm in the X direction and 1.39 μm in the Y direction. The drilling radius a is 0.85mm, the elbow radius R=12.5mm, the wall thickness h=5mm, the material elastic modulus E=210GPa, and the material Poisson’s ratio v=0.3 into the formula ⑥, the residual stress in the X direction is 101.0MPa , the residual stress in the Y direction is 187.9MPa. The residual stress of the same specimen measured by the traditional electric drilling method is 105.4MPa in the Y direction and 200.5MPa in the X direction, and the two results are in good agreement.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

Abstract

The invention relates to a test device and test method for measuring residual stress of a bent pipe and belongs to the technical field of experimental mechanics and residual stress measurement. In the method provided by the invention, the digital speckle correlation technique is combined with the drilling technique, and the method comprises the following steps: using a CCD (charge coupled device) camera to take photos of the bent pipe before and after the bent pipe is drilled; utilizing the digital speckle technique to measure the stretched displacement of two ends of the front and back drilled round holes; and measuring the residual stress of the bent test piece with a confirmed principal stress direction, so as to acquire the residual stress. The digital speckle correlation technique used in the method refers to non-contact measurement. Compared with the traditional electrical testing method, the method has the advantage that the complex process of sticking a foil gauge each time is omitted, thereby being more convenient and simpler. For the measurement of the residual stress of the bent pipe, a column correcting process is added in the method provided by the invention as compared with the traditional method, thus the acquired result is more accurate.

Description

technical field [0001] The invention relates to a device and method for measuring the residual stress of an elbow by combining digital speckle correlation and drilling technology, and belongs to the technical fields of experimental mechanics and residual stress detection. Background technique [0002] In the process of processing the bent pipe from the straight pipe, it will be subjected to various external forces and influences; when these external forces disappear, plastic deformation will occur in the component, and the influence of plastic deformation will prevent the external force from acting on the component. Completely disappear, there are still some effects and influences remaining in the component, so a large residual stress remains in the elbow. At present, the measurement of residual stress mainly uses the electric measurement drilling method. A hole is drilled on the component to be measured, so that the residual stress of the component around the hole is releas...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
IPC IPC(8): G01L1/24
Inventor 姚学锋马寅佶刘检华陈涛殷雅俊方岱宁
Owner TSINGHUA UNIV
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap