In order to study the contact stiffness of the bonding surface in more detail from the perspective of fractal theory

on the basis of the M-B fractal model and the Hertz theory

a domain expansion factor is introduced to represent the fractal dimension to establish the normal and tangential contact stiffness fractal models of the bonding surface

respectively. The model comprehensively considers the effects of load

fractal dimension and material parameters on the contact stiffness. At the same time

the change trend of the contact stiffness of the joint surface and each parameter is obtained through numerical simulation.The change trend of normal contact stiffness and normal load is the same

which is opposite to the fractal characteristics and length scale coefficient

but the change trend of the fractal dimension is more complicated

no longer monotonic. The changetrend caused by tangential contact stiffness and the above parameters is similar to that caused by normal contact stiffness.