Measurement of fatigue crack deformation on the macro- and micro-scale: Uniform and non-uniform loading. (August 2016)

• Record Type: Journal Article
• Authors: O'Connor, S.J.; Nowell, D.; Dragnevski, K.I.
• Is Part Of: International journal of fatigue. Volume 89(2016)
• Page Start: 66
• Page End: 76
• Publication Date: 2016-08
• Subjects: Crack tip displacements -- Digital image correlation -- Elastic–plastic fracture mechanics -- Overload; Materials -- Fatigue -- Periodicals; Materials -- Fatigue; Periodicals; 620.1122
• DOI: 10.1016/j.ijfatigue.2016.02.032
• Languages: English
• ISSNs: 0142-1123

Abstract

Abstract: This paper describes the experimental measurement of near-tip displacement fields for a fatigue crack growing in a small compact-tension specimen. The specimen is pre-cracked conventionally, but then loaded in-situ in a scanning electron microscope. Digital image correlation is applied to the images collected and is analysed using an elastic model to produce stress intensity factor histories. A simple elastic/plastic model due to Pommier and Hamam is also applied, and the resulting behaviour is discussed. A single overload is applied to the specimen, and the effect of this on the elastic and elastic–plastic results is examined. The results are also compared to earlier work of a similar nature using a long-distance microscope, which gives an understanding of crack behaviour at a macroscopic length scale.