Background: Breakup is an important reaction channel in the scattering of loosely bound nuclei especially at sub-barrier energies. Experimental efforts have been put to study the influence of breakup on sub-barrier fusion. Purpose: In order to explore the breakup effects of weakly bound nuclei on different target nuclei

we systematically analyzed the angular distribution of their elastic scatterings. Methods: The barrier parameters of reaction systems were obtained by the S?o Paulo potential

and the total cross sections were obtained from the experimental angular distribution of elastic scattering. Results: The F(x)s were obtained for weakly and tightly bound projectiles on light

medium-mass and heavy target nuclei

and compared with the universal function F0(x) which has no coupling channels. Conclusion: From the comparison we can conclude that the breakup effect is not important for weakly bound projectiles on the light target nuclei

while it is suppressed on medium-mass and heavy target nuclei above the Coulomb barrier and is enhanced for some weakly bound projectiles at sub-barrier energies. More experiments need to be developed on medium-mass and heavy target nuclei. Abstract