PSI - Issue 26

Victor Rizov et al. / Procedia Structural Integrity 26 (2020) 97–105 Rizov / Structural Integrity Procedia 00 (2019) 000 – 000

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The effect of the damage zone depth on the lengthwise fracture is analyzed too. The damage zone depth is characterized by 0 2 / h  ratio. Calculations of the strain energy release rate are performed at various 0 2 / h  ratios.

100 = F N, curve 2 – at

150 = F N

Fig. 4. The strain energy release rate in non-dimensional form plotted against 0 2 / h  ratio (curve 1 – at

and curve 3 – at 200 = F N). The results of these calculations are illustrated in Fig. 4 where the strain energy release rate in non-dimensional form is plotted against 0 2 / h  ratio at three values of the external force, F . It is evident from Fig. 4 that the strain energy release rate increases with increasing of 0 2 / h  ratio. This behaviour is due to the reduction of the beam stiffness with increasing of the damage zone depth. The increase of the force, F , leads also to increase of the strain energy release rate (Fig. 4).

Fig. 5. The strain energy release rate in non-dimensional form plotted against f (curve 1 – at g=0.4, curve 2 – at g=0/6 and curve 3 – at g=0.8).

The influence of the continuous material inhomogeneity along the height and length of the beam on lengthwise fracture is studied. For this purpose, calculations of the strain energy release rate are carried-out at various values of f and g . The strain energy release rate calculated is plotted in non-dimensional form against f in Fig. 5 at three values of g . The curves in Fig. 5 show that the strain energy release rate decreases with increasing of f and g . This finding is attributed to the increase of the beam stiffness. Calculations of the strain energy release rate are carried-out also at various α / l 1 ratios in order to investigate the influence of the crack length on lengthwise fracture behaviour of the beam. The results obtained are shown in Fig. 6 where the strain energy release rate in non-dimensional form is plotted against α / l 1 ratio at three l / l 1 ratios. It can be