PSI - Issue 13

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

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0 10 20 30 40 50 60 70 80

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0 2 3 4 5 6 D (mm)

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Peeling Load (N)

Normalized Peeling Load

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Imperfection Diameter to Interface Width Ratio

Displacement, (mm)

Figure 7: The effect of the presence of imperfection hole in Al-brass interface of Al-brass-Al sandwich composites on the peeling load (a) Load Displacement curve (b) normalized peeling load versus imperfection size.

D = 0 mm

D = 2 mm

D = 3 mm D = 5 mm Figure 8: The effect of imperfection hole on the distribution of von-Mises stresses in MPa

Figure 9 shows the effect of surface roughness on the peeling load of Al-brass-Al sandwich composite. As mentioned before, the initial surface roughness of the as-received Al1100 sheet had R a =0.6 µm, while, after using sandpapers of grit 80 and 50, the surface roughness values changed to 3.75 µm, 5.63 µm, respectively. The peeling load increased with increasing the surface roughness as confirmed with the previous work (Mousa, 2015). This may be due to the increase of the area of the interface and the interlock and may be also due to work hardening of the sheets increased and caused a more brittle layer to form on the surface that could be broken more easily so that the virgin metal could be extruded more easily as well (Mousa, 2017).To generalized and/or confirm the validity of the d max concept for predicting the quality of interface, d max will be predicted for different thickness reductions, rolling speeds, and surface roughness in future.

Conclusions

The conclusions drawn from this study can be summarized as follows:  Experimental results showed that mechanical interlocking was the primary adhesion mechanism in WRB process.  Interface surfaces with higher roughness provided larger true surface area, and higher temperatures softened the metal and help to reduce the work needed for robust bonding.