In comparison with the pseudo-static test results of buckling-restrained braces（BRBs）

finite element analysis with ABAQUS software was carried out.Metallic Combine constitutive model

which improves the traditional bilinear-constitutive model

was used to lead in attribute of the kernel steel panel material.Result shows a better simulation relative to the test data.On the other hand

the simulation results verify that BRBs have a good damping performance under axial loading.Even though axial displacement increases up to seven times of the yield displacement

BRBs can still keep a good hysteretic performance.Based on reasonable setting of unbonded-rubber layers

the deformation characteristics of frictionless sliding and energy slow-release transformation of the kernel steel panel in unsteady deformation were researched.Analysis indicates that

when peripheral constraints supply enough strength and stiffness

the deformation of kernel steel panel under axial loading can only expresses a small flexural buckle with multiple waves.Simulation process also confirms that as the effective clearance between the kernel steel and peripheral constraint increases

the deformation wave is getting larger

at the same time

supporting capacity and energy dissipation capacity are significantly reducing.