| Title |
Visualization of Crack Propagation and Bridging Stress using the Mechano-luminescence of SrAl2O4: Eu,Dy,Nd |
| Authors |
김지식(Ji Sik Kim); 권용남(Young Nam Kwon); 손기선(Kee Sun Sohn) |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
Mechano-luminescence (ML) material; Crack propagation; Bridging (shielding) stress |
| Abstract |
The goal of the present investigation was to visualize the propagating crack in a mechano-luminescence (ML) material to enable the measurement of instantaneous R-curves and directly observe the bridging (shielding) stress in a fast-propagating crack system. The well-known ML compound, SrAl₂O₄: Eu^(2+), was used as a model test material. Two additional trivalent rare earth elements, Dy and Nd, were introduced as co-dopants to improve the luminescent efficiency. The initiation and growth of a crack from the mechanically machined sharp notch tip in a disc shaped compact tension (CT) specimen at a relatively high loading rate were found to be associated with the extent of light emission around the crack. An in-situ measurement of crack length and applied load for 0.3 sec yielded an instantaneous R-curve at the conventional crack propagation speed. |