A study of the fast crack propagation in DCB specimens under impulsive loading by the eddy-current sensing method
✍ Scribed by Chao-Tsien Tang; Ya-Peng Shen
- Publisher
- Elsevier Science
- Year
- 1982
- Tongue
- English
- Weight
- 107 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0013-7944
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✦ Synopsis
This paper describes the experimental investigation of the fast (unstable) propagation of a crack in DCB specimens under impulsive loading and the loading time is in the order of IO-' set (mechanical shock, 10-2-10~4sec). A new eddy-current method is developed. In contrast to several other methods commonly used and also to that using an eddy-current probe-serve system for "locking on" the crack tip, this method does not have disadvantages that other methods have and has recorded the whole extension-time history of the fast propagation, especially the initial portion just after the onset of extension of which little is known today. From the oscillograph, the acceleration and the displacement responses, the onset of extension as well as the small displacements of the loading points on the specimen can be accurately determined. From this the Kiy is easily calculated. From experimental results, it can be concluded that, for materials which have the K\y values increasing with the increase in loading speed, the extension or propagation of sharp crack under impulsive load is fully equivalent to a blunt crack under static load with the grip fixed, i.e. calculations can be made by using the concept of equivalent Ko values.