Journal of Science and Technology of Composites

Journal of Science and Technology of Composites

Experimental and theoretical fracture analysis of quasi-brittle polymer components containing V-notches with end holes under combined tensile-shear loading

Document Type : Research Paper

Authors
Alireza Torabi
Shahab Amininejad
Department of New Science and Technologies, University of Tehran, Tehran, Iran
Abstract
In the present investigation, first, 48 fracture tests were conducted on the Brazilian disk specimens made of the quasi-brittle polymer Polymethyl-methacrylate and weakened by central V-notches with end holes (VO-notches) under combined tensile-shear loading with different mode mixity ratios. The fracture loads and the fracture initiation angles (FIAs) were experimentally measured. Then, two brittle fracture criteria were developed on the basis of the failure concepts of the maximum tangential stress (MTS) and the mean stress (MS) for predicting the experimental fracture loads and the FIAs, and the theoretical results were obtained in the form of the fracture curves and curves of  fracture initiation angle. A very good agreement was shown to exist between the theoretical and the experimental results. Moreover, it was found that both the criteria provide almost identical predictions to the experimental results.  
Keywords
V-notch with end hole
Fracture load
Fracture initiation angle
MTS criterion
MS criterion
[1] Ayatollahi, M. R. and Torabi, A. R., “Investigation of fracture in V-notched brittle polymers under pure shear loading”, Polym Sci Technol, Vol. 1, pp. 63-73, 2009.
[2] Zappalorto, M. and Lazzarin, P., “In-plane and out-of-plane stress field solutions for V-notches with end holes”, Int J Fract, Vol. 168, pp. 167-180, 2011.
[3] Lazzarin, P., Zappalorto, M. and Berto, F., “Generalised stress intensity factors for rounded notches in plates under in-plane shear loading”, Int J Fract, Vol. 170, pp. 123-144, 2011.
[4] Berto, F. and Zappalorto, M., “Fictitious notch rounding concept applied to V-notches with end holes under mode I loading”, Int J Fract, Vol. 171, pp. 91-98, 2011.
[5] Lazzarin, P. Berto, F. and Ayatollahi, M.R., “Brittle failure of inclined key-hole notches in isostatic graphite under in-plane mixed mode loading”, Fatigue Fract Eng Mater Struct, Vol. 36, pp. 1-14, 2013.
[6] Torabi, A. R., “Closed-form expressions of mode I apparent notch fracture toughness for key-hole notches”, J Strain Anal Eng Design, Vol. 49, No. 8, pp. 583-591, 2014.
[7] Torabi, A. R. and Pirhadi. E., “Stress-based criteria for brittle fracture in key-hole notches under mixed mode loading”, European J Mech A/ Solids, Vol. 49, pp. 1-12, 2015.
[8] Torabi, A. R. and Amininejad. SH., “Brittle fracture in V-notches with end holes”, Int. J. Damag Mech., Vol. 24, No. 4, pp. 529-545, 2015.
[9] Ayatollahi, M. R. and Torabi. A. R., “Investigation of mixed mode brittle fracture in rounded-tip V-notched components”, Eng Fract Mech, Vol. 77, pp. 3087-3104, 2010.