Issue34

Yu.G. Matvienko et alii, Frattura ed Integrità Strutturale, 34 (2015) 255-260; DOI: 10.3221/IGF-ESIS.34.27 259 Figure 3 : Crack propagation angle determined with the MATS criterion. Figure 4 : Crack propagation angle determined with MATS and MTS criteria (coefficient of friction 0.1   ). Further investigation should be connected with numerical and experimental research to validate the proposed MATS criterion for estimation of crack propagation angles under the rolling-sliding contact loading. C ONCLUSIONS he maximum average tangential stress (MATS) criterion, based on the concept of the average stress within the fracture process zone, has been proposed for predicting the direction of fracture angle. The effect of the constant term of the series of Williams has been expressed by the parameter T and it is incorporated into the MATS criterion. The predicted directions of fracture angle are good consistent with the experimental data for the mixed mode I/II crack growth behavior of Guiting limestone. The criterion of the maximum average tangential stress, taking into account the non-singular T-stress and the lubricant hydraulic pressure on crack surfaces, is also spread to estimate the surface crack path under the rolling-sliding contact loading. The effect of coefficient of friction and load position on the crack path has been analysed. It is shown that the influence of coefficient of friction on crack propagation angle is negligible. At the same time, there is significant effect of contact load position on the crack propagation angle. T