Click here to view fulltext PDF

Permanent link:
https://www.ias.ac.in/article/fulltext/boms/019/05/0759-0765

Indentation; fatigue; elastic stress; yield stress; critical stress; residual stress; cracks; median; lateral; radial

Fracture mechanics studies on glass by indentation has become predominant in recent times. Interest in it has become more prominent due to a large application of such materials in areas of engineering applications encountering fluctuating stresses induced thermally, mechanically or physically. However, glass subjected to repeated indentation at a point prior to crack initiation with subcritical loads phenomenological to metal fatigue has not been systematically investigated. Repeated indentation at a single point with different subcritical loads (0·1N, 0·15N, 0·25N, 0·50N, 1·0N) was performed till radial cracks occurred. The length of the diagonal was measured after each indentation, which was found to increase with indentation cycle eventually leading to crack initiation. This observation was analysed considering the elastic plastic component and the residual stress developed during each cycle. A mathematical model has been postulated to correlate the contribution of cumulative residual stress for crack initiation.

Rajat Banerjee¹ B K Sarkar^{1 2}

1. Central Glass and Ceramic Research Institute, Jadavpur, Calcutta - 700 032, India
2. Indian Association for the Cultivation of Science, Jadavpur, Calcutta - 700 032, India

Published

October 1996