Effects of indenter geometry and material properties on the correction factor of Sneddon’s relationship for nanoindentation of elastic and elastic–plastic materials

2008 ◽  
Vol 56 (6) ◽  
pp. 1399-1405 ◽  
Author(s):  
Z XU
2011 ◽  
Vol 1 (3) ◽  
Author(s):  
Marcin Graba

AbstractIn this paper a short theoretical background about elastic-plastic fracture mechanics is presented and the O’Dowd-Shih theory is discussed. Using FEM, the values of the Q-stress determined for various elastic-plastic materials for two specimens in tension — SEN(T) specimen and CC(T) specimen are presented. The influence of geometry of the specimen, crack length and material properties (work-hardening exponent and yield stress) on the Q-parameter are tested. The numerical results were approximated by closed form formulas. The results are summarized in a catalogue of the Q-stress value, which may be used in engineering analysis for calculation of the real fracture toughness and the stress distribution near crack tip.


2013 ◽  
Vol 668 ◽  
pp. 616-620
Author(s):  
Shuai Huang ◽  
Huang Yuan

Computational simulations of indentations in elastic-plastic materials showed overestimate in determining elastic modulus using the Oliver & Pharr’s method. Deviations significantly increase with decreasing material hardening. Based on extensive finite element computations the correlation between elastic-plastic material property and indentation has been carried out. A modified method was introduced for estimating elastic modulus from dimensional analysis associated with indentation data. Experimental verifications confirm that the new method produces more accurate prediction of elastic modulus than the Oliver & Pharr’s method.


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