Abstract: The mechanical performances of joint interfaces which with different surface roughness are studied through cyclic compression experiments.And the distributions of the maximum indentation depths and plastic works along the layer depths are tested based on the Instrumented Indentation Test(IIT).In addition,the stress strain relationship and the contact mechanism of joint interfaces under cyclic compression loading is explored.Compared with the continuum model,the joint interface makes the stress-strain relationship nonlinear.The plastic deformation and plastic accumulation are detected occur below the interface based on IIT,and the plastic zone and uneven stress zone formed.Under cycling loads,both the plastic deformation and the uneven stress zone increase.It also demonstrate that the compressive stress increments and the plastic deformation increments increase with the increasing of surface roughness.Reveals the nonlinear characteristics and the plastic deformation mechanism of the mechanical joint interface,which lays experimental basis for the joint interface stiffness theory.

Key words: joint interface, surface roughness, instrument indentertion test, indentation depth, plastic work