The model of normal contact stiffness of joint interfaces incorporating elastoplastic deformation mechanism

Based on the contact fractal theory and MB model,considering the elastic contact deformation,the plastic contact deformation and two different regimes of elastoplastic contact deformation,a fractal model of normal contact stiffness of joint interfaces was proposed.Numerical simulation results of this model show that the elastoplastic contact deformation mechanism has an obvious effect on the normal contact stiffness,and the dimensionless normal contact stiffness of this model is much more than that considering only elastic and plastic regime,respectively.It also shows that the dimensionless normal contact stiffness increases with the increase of the dimensionless normal load but the varying tendency is strongly nonlinear(when fractal dimension D=1.1~1.4)or near linear(when fractal dimension D=1.4~1.9),and it increases(when fractal dimension D=1.1~1.6)with the increase of the fractal dimension or decreases(when fractal dimension D=1.6~1.9)with the increase of the fractal dimension.It decreases with the increase of normal fractal roughness,and increases with the increase of plastic index.The validity of the model was verified with an experimental example.