PSI - Issue 25

Author name / Structural Integrity Procedia 00 (2019) 000 – 000

10

Victor Rizov / Procedia Structural Integrity 25 (2020) 88–100

97

/ p E E 3

0.5 1

1 3 / p p   ratio (curve 1 – at

 p

Fig. 10. The strain energy release rate in non-dimensional form plotted against

, curve 2 –

/ p E E 3

/ p E E 3

1.0 1

2.0 1

 p

 p

at

and curve 3 – at

).

The influence of the coefficient of viscosity on the delamination fracture behaviour is illustrated in Fig. 6 where the strain energy release rate in non-dimensional form is plotted against 2 1 /   ratio at three 3 1 /   ratios. The three-layered beam configuration with a delamination crack located between layers 2 and 3 is considered (Fig. 4a). The analysis is carried-out by applying the rheological model shown in Fig. 1a. It can be observed in Fig. 6 that the strain energy release rate decreases with increasing of 2 1 /   and 3 1 /   ratios. The delamination fracture behaviour is studied also by using the rheological model consisting of a linear spring that is mounted parallel to a linear dashpot (Fig. 1b). The strain energy release rate is presented in non-dimensional form by using the formula   G G E b p N 1 /  . The beam with a delamination crack located between layers 2 and 3 is investigated (Fig. 4a). The evolution of the delamination fracture behaviour of the beam with the time is examined in Fig. 7 where the strain energy release rate in non-dimensional form is plotted against the non-dimensional time at three 1 2 / p p   ratios. The time along the abscissa in Fig. 7 is expressed in non-dimensional form by the formula . It is evident form Fig. 7 that the strain energy release rate increases with the time. One can The influence of the moduli of elasticity on the delamination fracture is also studied. The three-layered cantilever beam configuration with a delaminaton crack located between layers 2 and 3 is analyzed. The rheological model shown in Fig. 1b is applied. The influence of the moduli of elasticity is illustrated in Fig. 8 where the strain energy release rate in non-dimensional form is plotted against the 1 2 / p p E E ratio at three 1 3 / p p E E ratios. The curves in Fig. 8 indicate that the strain energy release rate decreases with increasing of 1 2 / p p E E and 1 3 / p p E E ratios. The delamination fracture behaviour is analyzed also by applying the rheological model consisting of a linear spring that is connected consecutively to a parallel combination of a second linear spring and a linear dashpot (Fig. 1c). The three-layered beam with a delamination crack between layers 2 and 3 is under consideration (Fig. 4b). The effect of the time on the delamination fracture is evaluated. For this purpose, the strain energy release rate in non dimensional form is plotted against the non-dimensional time in Fig. 9 at three 2 1 / E E ratios. One can observe in Fig. 9 that the strain energy release rate increases with the time. 1 1 / p p  N t tE  observe also in Fig. 7 that the increase of 1 2 / p p   ratio leads to decrease of the strain energy release rate.