Issue 42

J. Klon et alii, Frattura ed Integrità Strutturale, 42 (2017) 161-169; DOI: 10.3221/IGF-ESIS.42.17 164 Calibration curves for MCT For a standard CT specimen it is defined as the polynomial function, see [11, 13], based on the following formula:   I / P K F a W B W   (2) where K I is the stress intensity factor for mode I, P is force, B is the thickness of the specimen, W is the width of the specimen and a is crack length. The calibration curves for the MCT specimen were published in [12] and their polynomial functions for the range 0.3  a/W  0.7 are as follows:   2 3 4 MCT A 47.288 412.63 1403.5 2039.7 1127.4 a a a a F W W W W                              (3)   2 3 4 MCT B 37.434 329.09 1119.2 1626.5 898.75 a a a a F W W W W                              (4)   2 3 4 MCT C 27.729 246.48 837.45 1216.7 671.67 a a a a F W W W W                              (5) Initial estimation of the size of the fracture zone from a purely elastic solution (linear elastic fracture mechanics) under the condition of plane stress is as follows, see [13]: 2 I y 0 1 2 K r          (6) where  0 is the material characteristic in tension. Figure 3 : Scheme of test configurations of the MCT tests for specimens of size XL.