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Keywords: digital image correlation, hole drilling method, residual stress.

Summary

As a result of hot forging during production processes or cyclic deformation, residual stress might be induced in structural or mechanical components. Residual stresses will reduce the strength or service life of the component. Therefore, the measurement of residual stress is very important to ensure the safety of structures or machinery in use.

The hole drilling method described in ASTM-E837-01 is a semi-destructive measurement method. Strain gauges are attached around the hole to measure the surface strain at various drilling depths. As the hole diameter decreases, the degree of damage of the specimen will also be reduced and this makes this method more and more close to non-destructive testing. However, if the hole is so small that the strain gauge cannot be attached around the hole, it can not meet the requirement of the ASTM standard. Digital image correlation (DIC) is a non-contact and multi-scale measurement technology. It can determine the displacement and strain field by comparing the grayscale of images before and after deformation.

The feasibility of using DIC to measure the strain in the hole drilling method is studied in this research. The images of the specimen at different drilling depths are taken, and these images are compared with the image before drilling with the aid of DIC.

The results show that the trend and values of the measured strain are consistent with the theoretical values of the ASTM standard and that the determined residual stresses and directions are close to the theoretical values. It shows that the DIC method can be applied in the micro-scale hole drilling method to determine the residual stresses of a specimen.

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Front Page Browse CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Proceedings ISSN 1759-3433 CCP: 96 PROCEEDINGS OF THE THIRTEENTH INTERNATIONAL CONFERENCE ON CIVIL, STRUCTURAL AND ENVIRONMENTAL ENGINEERING COMPUTING Edited by: B.H.V. Topping and Y. Tsompanakis Paper 113 Application of the Digital Image Correlation Method to Micro Hole Drilling S.H. Tung¹, M.H. Shih² and J.C. Kuo³ ¹Department of Civil and Environmental Engineering, National University of Kaohsiung, Taiwan ²Department of Civil Engineering, National Chi Nan University, Nantou, Taiwan ³Department of Materials Science and Engineering, National Cheng-Kung University, Tainan, Taiwan doi:10.4203/ccp.96.113 purchase the full-text of this paper Full Bibliographic Reference for this paper S.H. Tung, M.H. Shih, J.C. Kuo, "Application of the Digital Image Correlation Method to Micro Hole Drilling", in B.H.V. Topping, Y. Tsompanakis, (Editors), "Proceedings of the Thirteenth International Conference on Civil, Structural and Environmental Engineering Computing", Civil-Comp Press, Stirlingshire, UK, Paper 113, 2011. doi:10.4203/ccp.96.113 Keywords: digital image correlation, hole drilling method, residual stress. Summary As a result of hot forging during production processes or cyclic deformation, residual stress might be induced in structural or mechanical components. Residual stresses will reduce the strength or service life of the component. Therefore, the measurement of residual stress is very important to ensure the safety of structures or machinery in use. The hole drilling method described in ASTM-E837-01 is a semi-destructive measurement method. Strain gauges are attached around the hole to measure the surface strain at various drilling depths. As the hole diameter decreases, the degree of damage of the specimen will also be reduced and this makes this method more and more close to non-destructive testing. However, if the hole is so small that the strain gauge cannot be attached around the hole, it can not meet the requirement of the ASTM standard. Digital image correlation (DIC) is a non-contact and multi-scale measurement technology. It can determine the displacement and strain field by comparing the grayscale of images before and after deformation. The feasibility of using DIC to measure the strain in the hole drilling method is studied in this research. The images of the specimen at different drilling depths are taken, and these images are compared with the image before drilling with the aid of DIC. The results show that the trend and values of the measured strain are consistent with the theoretical values of the ASTM standard and that the determined residual stresses and directions are close to the theoretical values. It shows that the DIC method can be applied in the micro-scale hole drilling method to determine the residual stresses of a specimen. purchase the full-text of this paper (price £20) go to the previous paper go to the next paper return to the table of contents return to the book description purchase this book (price £130 +P&P)
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