PSI - Issue 13

Saeed Mousa et al. / Procedia Structural Integrity 13 (2018) 686–693 Author name / Structural Integrity Procedia 00 (2018) 000 – 000

691

6

The effect of width of the contact area of Al-brass-Al sandwich composite on the peeling load is illustrated in Figure 67. Different widths of contact area of Al-brass-Al sandwich composite has been studied, namely W , 1.2  W , 1.4  W , 1.6  W , and 2  W (where W = 20 mm). It can be seen that, the peeling load increased with increasing the width of the contact area. A relation between the peeling strength, P Peel /W, and the width to length ratio of contact area, W/L for L = constant, is shown in Figure 6.b. It can be concluded that, P Peel /W is a good parameter to predict the peeling strength regarding the value of W/L. On the other hand, the value of U Z at which the peeling failure initiated is recorded in table 4. It is clear that, U Z increased by increasing the value of W.

100 120 140 160

4

(a) Effect of Width of the Contact area on P-  curve

(b) Effect of Width of Contact Area on Peel Strength

20 24 28 32 40 Width,mm

3.8

3.6

0 20 40 60 80

3.4

3.2

Mean = 3.64 N/mm S.D. = 0.018 N/mm CV = 0.49%

Peeling Load (N)

Peeling strength, P/W, N/mm

3

0.3

0.4

0.5

0.6

0.7

0

1

2

3

Width of contact area / Its Length, W / L, L = 60 mm

Displacement, (mm)

Figure 6: The effect of width of the contact area of Al-brass-Al sandwich composite on the peeling load: (a) P- δ curve (b) Relation between peeling strength and Width to Length ratio. Table 4 U Z at which the peeling failure initiated in Al-Brass-AL composite

Contact area

U Z (mm)

A

1.2 x W

1.4 x W

1.6 x W

1.8 x W

2 x W

0.6735 0.6747 0.6751 0.6759 0.6766 0.6777

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









5.2. Effect of imperfection hole on peeling load The main objective of the present work is study the effect of the presence of imperfection in the interface between Al and brass strips of Al-brass-Al sandwich composite on the peeling load. Figure 7 shows the effect of the presence of imperfection hole with different hole diameters, D , varied from 0 mm to 8 mm by step 1 mm on the peeling load. When the values of D less than or equal 4 mm ( D/W = 0.2), the maximum value of peeling load approximately the same, while beyond this value, the peeling load decreased with increasing the values of D , Figure 7.b. Based on the present analysis, it can be concluded that, the ratio of maximum size of undamaged defect ( d max ) to the interface width is equal to 20%. It is worth to note that, this value is valid for this shape of imperfection and the surface condition of the interface. Figure 8 shows the effect of imperfection hole on the distribution of von-Mises stresses in MPa formed during peeling process. Firstly at no imperfection hole ( D = 0) the maximum von-Mises values occurred along the width of strips by the same values approximately and this value decreases far away the peeling zone. Secondary when the value of imperfection hole diameter, D, > 0, the von-Mises stress concentrate around the imperfection hole so that, the maximum von-Mises value appeared around this hole. It can be concluded that, imperfection hole considered as source of stress concentration.