考虑旋转梯度效应的弹性薄膜黏附接触行为研究OA

To address the critical mechanical issue of coupled adhesion and size effects in micro-scale devices such as micro-electromechanical systems(MEMS),this study establishes a semi-analytical adhesive contact model between an elastic sphere and a thin film,incorporating size effects.The material size effect is characterized using couple stress theory,while the interfacial adhesive stress is described via the Maugis-Dugdale adhesive model.The pressure distribution and surface deformation are solved using the adhesive-driven conjugate gradient method combined with the discrete convolution-fast Fourier transform(DC-FFT)technique.The influences of film thickness,characteristic material length,shear modulus ratio,and adhesive parameters on the adhesive contact behavior of elatic thin films are systematically investigated.The results show that,under a fixed adhesive parameter,an increase in the characteristic material length or a decrease in either the film thickness or the shear modulus ratio leads to an increase in the peak contact pressure,a reduction in both compressive and tensile deformation—indicating enhanced contact stiffness—and a significant effect on the pull-off force.Specifically,when the dimensionless film thickness is 2,the pull-off force first decreases and then increases with increasing characteristic material length,stabilizing when the dimensionless characteristic length exceeds 3.Thinner films exhibit a larger pull-off force,and the influence range of the characteristic material length on the pull-off force narrows.For a dimensionless thickness less than 1,the pull-off force reaches a minimum at a characteristic material length around 0.25 and then remains stable.This study provides a theoretical foundation for the adhesive control and mechanical design of micro/nano-film structures.