Issue 39

S. Seitl et alii, Frattura ed Integrità Strutturale, 39 (2017) 118-128; DOI: 10.3221/IGF-ESIS.39.13

The B 1 curves are practically the same values for all five various materials. It only changes for values of relative crack length longer than α =0.5 (see Fig. 4). The functions of calibration curves for selected Young’s modulus of concrete E = 5, 20 and 100 GPa can be introduced as follows: B 1 ( E =5)= 5.5881 - 34.181α + 239.39α 2 - 594.79α 3 + 688.58α 4 - 251.61α 5 (6) B 1 ( E =20)= -2.3617 + 117.22α - 736.11α 2 + 2191.5α 3 - 2926.8α 4 + 1503.9α 5 (7) B 1 ( E =100)= -16.91 + 389.22α - 2465.6α 2 + 7030.8α 3 - 9049.3α 4 + 4371.4α 5 (8)

120

E=5 GPa

100

E=20 GPa

80

E=60 GPa

60

E=100 GPa

B 1 [‐]

40

20

0

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1

a/W [‐]

Figure 4 : Values of dimensionless B 1

factor (stress intensity factor) versus a/W , the effect of elasticity modulus ratio (steel E =210 GPa).

0,0 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8

E=5 GPa

E=20 GPa

E=60 GPa

E=100 GPa

B 2  [‐]

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1

‐0,4 ‐0,2

a/W [‐]

Figure 5 : Values of dimensionless B 2

factor ( T -stress) versus a/W , the effect of elasticity modulus ratio (steel E =210 GPa).

Fig. 5 shows that the B 2

parameter changes practically negligibly, only for very low values of Young’s modulus E =5 GPa,

there is relatively small deviation from another curves.

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