Vol.11, No1, 2011, pp.15-19
UDC 539.42 : 519.6

Several mixed mode fracture mechanics experiments are realized by the author before the year 1984. Several types of specimens are used: Centered Cracked Tensile sheets (CCT), Compact Mixed Mode (CMM), Compact Shear Specimen (CSS), unsymmetrical loading Single Edge Notch Bending three-points (ULSENB-3), and four-points (ULSENB-4). Computations of mode I K_I and mode II K_II stress intensity factors are made using calibration functions found in the literature, if any.

Results are presented in terms of intrinsic curves K_II /K_Ic versus K_I /K_Ic. However, some uncertainties remain about these calculated values. As today we have available much more efficient computers and software, additional finite elements computing is done on two kinds of specimens (CCT and ULSENB-3) and exact representation of some intrinsic curves are drawn.

As an example, the Mandel's criterion is computed and intrinsic curves for it are drawn. It is shown that concordance between criterion and computing results depends on the kind of behaviour law included in the software.

Keywords: mixed modes fracture, finite elements, intrinsic curve