Bridge-indentation precracking of glass bars
- North Carolina State Univ., Raleigh, NC (United States)
Bridge indentation precracking was first reported by Sadahiro et al., and has been used by a number of subsequent investigators. The procedure involves placing a half-penny starter crack, formed by Vickers indentation, at the center of the bottom surface of a rectangular bar specimen. The bar is loaded between pusher and anvil platens. The bridge span S produces tensile bending stress on the bottom surface of the bar, which contains the starter crack. With increasing load, the crack grows stably outward and inward, and at a certain load the crack will propagate unstably (pop-in) to a straight, through-section crack of length c. The method is very convenient for producing sharp, through-section precracks in ceramic bars without the need for saw cutting or fatigue cycling. However, the effects of bridge geometry and friction on the precracking results will be presented here which point to an important influence of the friction between the specimen and anvil platens.
- OSTI ID:
- 6540504
- Journal Information:
- Scripta Metallurgica et Materialia; (United States), Vol. 29:1; ISSN 0956-716X
- Country of Publication:
- United States
- Language:
- English
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