An improved dc potential drop system for crack length measurement
Journal
Journal of the Chinese Institute of Engineers, Transactions of the Chinese Institute of Engineers,Series A/Chung-kuo Kung Ch'eng Hsuch K'an
Journal Volume
16
Journal Issue
1
Pages
29-40
Date Issued
1993
Author(s)
Abstract
DC potential drop has long been used for automatic crack length monitoring, yet details about its set-up, causes of errors, precautions to achieve optimum performance and actual long term stability and accuracy under practical conditions have seldom been documented in detail. A DCPD system was established and details about its long term performance under varying loading and temperature parameters were evaluated. Necessary precautions to reduce error and improve accuracy are discussed. The system resolution is 0.003mm when applied to a compact tension specimen. The long term system accuracy achieved was ± 0.012mm. Two approaches for improvement were also attempted. It was found that the switch-off approach at least doubled the accuracy and the reversing polarity approach raised the accuracy by nearly ten times. The improved system has been applied to a large pipe fracture specimen. The resulting empirical calibration data agrees closely with independently obtained finite element results. © 1993 Taylor & Francis Group, LLC.
SDGs
Type
journal article