PSI - Issue 26

Victor Rizov et al. / Procedia Structural Integrity 26 (2020) 86–96 Rizov / Structural Integrity Procedia 00 (2019) 000 – 000

93

8

3. Numerical results

Investigations of the influence of the material inhomogeneity and aging on the lengthwise fracture are carried-out. For this purpose, calculations of the strain energy release rate are performed by applying formula (34). It is assumed that b =0.020 m, h =0.003 m, l =0.080 m, a =0.050 m, 25 1 = M Nm and 20 2 = M Nm.

d K K

Fig. 3. The strain energy release rate in non-dimensional form plotted against non-dimensional time (curve 1 – at /

0.5 = g

, curve 2 –

/ d K K

/ d K K

1.0 = g

2.0 = g

and curve 3 – at

at

).

First, the aging induced variation of the strain energy release rate with the time is investigated. For this purpose, the strain energy release rate is calculated at various values of the time. The strain energy release rate is presented in non-dimensional form by using the formula ( ) G G K b gF N / = . The effect of aging on the lengthwise fracture behaviour is illustrated in Fig. 3 where the strain energy release rate in non-dimensional form is plotted against the non-dimensional time at three g d K K / ratios. It should be noted that g d K K / ratio characterizes the continuous variation of K along the width of the beam. It is evident from Fig. 3 that the strain energy release rate increases with the time. This finding is attributed to the aging of the material. One can observe in Fig. 3 that the strain energy release rate decreases with increasing of g d K K / ratio.

g l K K / ratio (curve 1 - at

/ d m m

0.5 = g

, curve 2 – at

Fig.4. The strain energy release rate in non-dimensional form plotted against

/ d m m

/ d m m

1.0 = g

2.0 = g

and curve 3 – at

).