Journal of Marine Science and Technology

, Volume 10, Issue 4, pp 203–210 | Cite as

Depth estimation of surface cracks based on the measurement of crack opening deformation and numerical–experimental iteration



We propose a new method to estimate the depth of a surface crack based on the measurement of crack opening deformation (COD) by using strain gauges. Through finite-element (FE) analysis of several surface cracks with different crack depth, it was found that the distribution of crack depth along the crack line can be approximated by multiplying a certain proportional α to the distribution of COD per unit nominal strain (normalized COD). The strain gauges are cemented just on the crack line and at a reference position, and the normalized CODs are measured under the impact load excited by hammer punching. The surface crack depth is estimated from the normalized COD measurements by a numerical–experimental iteration method based on FE analysis. The estimated distribution of the surface crack depth along the crack line shows good agreement with the shape of a real crack depth.

Key words

Crack opening deformation measurement Crack depth estimation Finite-element analysis Strain gauge Surface crack 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Weidner, A, Tirschler, W, Blochwitz, C 2005Overstraining effects on the crack-opening displacement of micro-structurally short cracksMater Sci Eng390414422Google Scholar
  2. 2.
    Toda, H, Sinclair, I, Buffière, J-Y,  et al. 2004A 3D measurement procedure for internal local crack driving forces via synchrotron X-ray microtomographyActa Mater5213051317CrossRefGoogle Scholar
  3. 3.
    Chen, W, Chen, J, Fang, H 2002A theoretical procedure for detection of simulated cracks in a pipe by the direct current–potential drop techniqueNucl Eng Design216203211CrossRefGoogle Scholar
  4. 4.
    Vanlanduit, S, Guillaume, P, Linden, GVD 2003On-line monitoring of fatigue cracks using ultrasonic surface wavesNDT E Int36601607Google Scholar
  5. 5.
    Sadler, DJ, Ahn, CH 2001On-chip eddy current sensor for proximity sensing and crack detectionSensors Actuators A: Phys91340345Google Scholar
  6. 6.
    Okamura, H 1976A guide to alignment destructive power studyBaifukanTokyo(in Japanese)Google Scholar

Copyright information

© JASNAOE 2005

Authors and Affiliations

  1. 1.Department of Social and Environmental Engineering, Graduate School of EngineeringHiroshima UniversityHigashi-hiroshimaJapan

Personalised recommendations