Methodology for in situ stress intensity factor determination on cracked structures by digital image correlation

Abstract

Purpose

The purpose of this paper is to develop a methodology for in situ stress intensity factor (SIF) determination that can be used for the analysis of cracked structures. The technique is based on digital image correlation (DIC) combined with an overdetermined algorithm.

Design/methodology/approach

The linear overdeterministic algorithm for calculating the SIF based on stress values around the crack tip is applied to a strain field obtained by DIC.

Findings

As long as the image quality is sufficiently high, a good accuracy can be obtained for the measured SIF. The crack tip can be automatically detected based on the same strain field. The use of the strain field instead of the displacement field, eliminates problems related to the rigid body motion of the analysed structure.

Practical implications

In future works, based on the applied techniques, the SIF of complex cracked plane stress structures can be accurately determined in real engineering applications.

Originality/value

The paper demonstrates application of known techniques, refined for other applications, also the use of stress field for SIF overdeterministic calculations.

Citation

Richter‐Trummer, V., Moreira, P.M.G.P., Pastrama, S.D., Vaz, M.A.P. and de Castro, P.M.S.T. (2010), "Methodology for in situ stress intensity factor determination on cracked structures by digital image correlation", International Journal of Structural Integrity, Vol. 1 No. 4, pp. 344-357. https://doi.org/10.1108/17579861011099178