The focus of the current contribution is on the development of the unified geometrical formulation of contact algorithms in a covariant form for various geometrical situations of contacting bodies leading to contact p...The focus of the current contribution is on the development of the unified geometrical formulation of contact algorithms in a covariant form for various geometrical situations of contacting bodies leading to contact pairs: surface-to-surface, line-to-surface, point-to-surface, line-to-line, point-to-line, point-to-point. The construction of the corresponding computational contact algorithms are considered in accordance with the geometry of contact bodies in a covariant form. These forms can be easily discredited within finite element methods independently of order of approximation and, therefore, the result is straightforwardly applied within iso-geometric finite element methods. This approach is recently became known as geometrically exact theory of contact interaction [10]. Application for contact between bodies with iso- and anisotropic surface, for contact between cables and curvilinear beams as well as recent development for contact between cables and bodies is straightforward. Recent developments include the improvement of the curve-to-surface (deformable) contact algorithm.展开更多
A surface with gradient surface energy was fabricated on a silicon wafer by using the chemical vapor deposition (CVD) technology with the dodecyltrichlorosilane (C12H25Cl3Si) vapor which was adsorbed chemically on the...A surface with gradient surface energy was fabricated on a silicon wafer by using the chemical vapor deposition (CVD) technology with the dodecyltrichlorosilane (C12H25Cl3Si) vapor which was adsorbed chemically on the surface of the silicon wafer to form a self-assemble monolayer (ASM); thus a gradient profile of wettability. The microscopic contours of the gradient surface were measured with Seiko SPA400 atom force microscope (AFM). And the surface wettability profile was characterized by the sessile drop method, measuring the contact angle of fine water droplets that lay on the gradient surface, to represent the distribution of the surface energy on the surface. Using a high-speed video imaging system, the motion of water droplet on the horizontal gradient surface was visualized; the transient velocity was measured under ambient condition. The experimental results show that the liquid droplets can be driven to move from hydrophobic side to hydrophilic side on the horizontal gradient surface; the velocity of droplet can reach up to 40 mm/s. In addition, the motion of the water droplet can be generally divided into two stages: an acceleration stage; a deceleration stage. The droplet presents a squirming movement on the surface with a lower peak velocity; a larger extent of deceleration motion. And the static advancing contact angle of the droplet is obviously larger than the dynamic advancing contact angle on the gradient energy surface.展开更多
文摘The focus of the current contribution is on the development of the unified geometrical formulation of contact algorithms in a covariant form for various geometrical situations of contacting bodies leading to contact pairs: surface-to-surface, line-to-surface, point-to-surface, line-to-line, point-to-line, point-to-point. The construction of the corresponding computational contact algorithms are considered in accordance with the geometry of contact bodies in a covariant form. These forms can be easily discredited within finite element methods independently of order of approximation and, therefore, the result is straightforwardly applied within iso-geometric finite element methods. This approach is recently became known as geometrically exact theory of contact interaction [10]. Application for contact between bodies with iso- and anisotropic surface, for contact between cables and curvilinear beams as well as recent development for contact between cables and bodies is straightforward. Recent developments include the improvement of the curve-to-surface (deformable) contact algorithm.
基金supported by the National Natural Science Foundation of China(Grant No.50276072).
文摘A surface with gradient surface energy was fabricated on a silicon wafer by using the chemical vapor deposition (CVD) technology with the dodecyltrichlorosilane (C12H25Cl3Si) vapor which was adsorbed chemically on the surface of the silicon wafer to form a self-assemble monolayer (ASM); thus a gradient profile of wettability. The microscopic contours of the gradient surface were measured with Seiko SPA400 atom force microscope (AFM). And the surface wettability profile was characterized by the sessile drop method, measuring the contact angle of fine water droplets that lay on the gradient surface, to represent the distribution of the surface energy on the surface. Using a high-speed video imaging system, the motion of water droplet on the horizontal gradient surface was visualized; the transient velocity was measured under ambient condition. The experimental results show that the liquid droplets can be driven to move from hydrophobic side to hydrophilic side on the horizontal gradient surface; the velocity of droplet can reach up to 40 mm/s. In addition, the motion of the water droplet can be generally divided into two stages: an acceleration stage; a deceleration stage. The droplet presents a squirming movement on the surface with a lower peak velocity; a larger extent of deceleration motion. And the static advancing contact angle of the droplet is obviously larger than the dynamic advancing contact angle on the gradient energy surface.
