  Evolution of quadrupole deformations in $sd$ and $pf$ shell nuclei with mass
A= 18$\sim$56 is studied by using deformed Skyrme Hartree-Fock (HF) model with
pairing correlations. We point out that the quadrupole deformations of the
nuclei with the isospin T=0 and T=1 show strong mass number dependence as a
clear manifestation of dynamical evolution of deformation in nuclear many-body
systems. The competition between the deformation driving particle-vibration
coupling and the closed shell structure is shown in a systematic study of the
ratios between the proton and neutron deformations in nuclei with
T=$|$T$_z|$=1. Calculated quadrupole and hexadecapole deformations are compared
with shell model results and available experimental data. A relation between
the skin thickness and the intrinsic Q$_2$ moments is also discussed.
