It is well-known that the cell morphology plays an important role on the mechanical properties of the closed-cell aluminum foam.In this present work,a three-dimensional(3D)realistic structure was obtained by using the sync hrotron x-ray micro-tomography technique and then translated into a numerical model for the further finite element simulation.The numerical results quantitatively show that the strain concentration is initiated in some large ellipsoidal cells when their longest semiaxes are nearly perpendicular to the loading direction.Subsequently,the strain concentration propagates from the tips of the ellipsoidal cells.Once the strain concentration forms one band which crosses through the Al foam,a decrease in elastic resistance of the specimen to the compressive loading appears.It is also found that the collapsed band situates at the firstly formed concentration band.Furthermore,our observation is in agreement with the previous report that the foam cell shape is more important than size in in determining the yielding susceptibility of the cells.