Issue 46

S.M. Medjdoub et alii, Frattura ed Integrità Strutturale, 46 (2018) 102-112; DOI: 10.3221/IGF-ESIS.46.11 106 The mathematical model proposed by MODDE 5.0 is expressed as follows: 2 2 2 w w w 21 3496 4.71944 14.7872 7.66384 3.41241 1.43191 3.47017 3.794 3.06383t 6.11351A I w w w w w w w w w K . L t A L t L A t A L           (3) Exp. no Lw (mm) tw (mm) Aw (°) K I (MPa√m) 1 100 6 30 60.65 2 350 6 30 54.29 3 600 6 30 55.07 4 100 18 30 50.641 5 350 18 30 40.04 6 600 18 30 35.77 7 100 30 30 30.19 8 350 30 30 19.65 9 600 30 30 10.988 10 100 6 195 41.61 11 350 6 195 42.2 12 600 6 195 45.92 13 100 18 195 30 14 350 18 195 16.95 15 600 18 195 16.33 16 100 30 195 21.83 17 350 30 195 10.09 18 600 30 195 8.363 19 100 6 360 39.22 20 350 6 360 35.81 21 600 6 360 37.48 22 100 18 360 27.42 23 350 18 360 16.46 24 600 18 360 17.98 25 100 30 360 22.27 26 350 30 360 11.72 27 600 30 360 10.98 Table 3 : The conducted table experiments given by the experimental design. K I Coeff. SC Std. Err. P Conf. int(±) Constant 21.3496 1.77809 9.97244e-010 3.75146 Lw -4.71944 0.823094 2.43432e-005 1.73659 tw -14.7872 0.823094 1.71477e-012 1.73659 Aw -7.66384 0.823094 4.36222e-008 1.73659 Lw*Lw 3.794 1.42564 0.0164509 3.00786 tw*tw 3.06383 1.42564 0.0463223 3.00786 Aw*Aw 6.11351 1.42564 0.000497399 3.00786 Lw*tw -3.41241 1.00808 0.00351972 2.12688 Lw*Aw 1.43191 1.00808 0.173562 2.12688 tw*Aw 3.47017 1.00808 0.00310919 2.12688 N = 27 Q2 =0.919 Cond. no. =5.2299 DF = 17 R2 =0.967 Y-miss =0 Table 4 : SIF K I coefficients list.