Papers by Keyword: Soft Material

Abstract: This paper presents the effect of surface roughness in line contact under isothermal soft mixed lubrication with non-Newtonian based on Power law viscosity model. The time independent modified Reynolds equation, elasticity equation and the load capacity of asperities equation were numerically solved using finite different method, Newton-Raphson method and multigrid multilevel methods to obtain the film pressure profiles, film thickness profiles and contact pressure in the contact regions. The simulation results showed that the the amplitude of surface roughness has a significant effects on the film pressure, film thickness and surface contact pressure in the contact region. The minimum gap between surface, friction coefficient and asperity load increase when the amplitude of surface roughness increases. For increasing surface velocity, the minimum gap between surface increases but asperity load decreases.

Abstract: In this work, the influence of a rigid cylindrical inclusion on the elastic field in a transparent soft material is studied by an embedded-grating technique. The same experimental procedure was implemented on two specimens, a homogeneous bulk soft material and the same material containing a rigid cylindrical inhomogeneity. Under the indentation of a rigid wedge, two kinds of deformation sectors underneath the contacting boundary are observed from experimental results. Furthermore, the shape of the deformation sectors is horizontally expanded due to the inclusion. A local fluctuation of contact stresses between the soft matrix and rigid inclusion are discussed.

Abstract: This paper investigates the reversible retraction of a spherical perforated shell that is made from nonlinear soft material. The buckling and post-buckling simulation in Abaqus shows the skeleton ligaments of such a buckliball rotate in the beginning and buckle thereafter, resulting in the shrinkage and encapsulation of the whole structure in the final stage. We used dynamic-explicit method in the simulation and its superiority over others is verified by obtaining correct buckling patterns efficiently and stably.

Abstract: This paper presents the effects of rough surface air-soft elastohydrodynamic lubrication (EHL) of rollers for soft material under the effect of air molecular slip. The time independent modified Reynolds equation and elasticity equation were solved numerically using finite different method, Newton-Raphson method and multigrid multilevel methods were used to obtain the film pressure profiles and film thickness in the contact region. The effects of amplitude of surface roughness, modulus of elasticity and air inlet temperature are examined. The simulation results showed surface roughness has effect on film thickness but it little effect to air film pressure. When the amplitude of surface roughness and modulus of elasticity increased, the air film thickness decreased but air film pressure increased. However, the air inlet temperature increased when the air film thickness increased.

Abstract: This paper presents the effects of transient rough surface air-soft elastohydrodynamic lubrication (EHL) of rollers for soft material. The time independent modified Reynolds equation, and elasticity equation were solved numerically using finite different method, Newton-Raphson method and multigrid multilevel method to obtain the film pressure profiles and film thickness in the contact region. The effects of overload, surface roughness and time period are examined. The simulation results show surface roughness has effect on film thickness. The impact of sudden load condition is that the air film pressure increases but film thickness decreases. The minimum film thickness decreases when the amplitude of surface roughness increases. Increasing of impact from sudden loads resulted in minimal film thickness decrease.

Abstract: This paper presents the effects of transient rough surface thermo-elastohydrodynamic lubrication (TEHL) of rollers for soft material with non-Newtonian fluid base on power law model. The time independent modified Reynolds equation, energy equation and elasticity equation were solved numerically using finite different method, Newton-Raphson method and multigrid multilevel method to obtain the film pressure profiles, film thickness profiles and friction coefficient in the contact region. The simulation results show surface roughness has effect on film thickness but its effect on film temperature is insignificant. The minimum film thickness decreases while the coefficient increases when the amplitude of surface roughness increases. Meanwhile, increasing applied loads causes the friction coefficient to decrease.

Abstract: Cartilage and bone are specialized connective tissues composed of roughly the same material: cell embedded in an extracellular matrix, permeated by the network of fibers. Then the properties of cartilage are anisotropic and inhomogeneous structure. At the same time, the structure of cartilage is rather porous allowing fluid to move in and out of the tissue. Thus the properties of cartilage were changed with the fluid content. The objective of this study is to demonstrate that the biomechanical properties of the pericellular matrix vary with depth from the coated cartilage surface, and observed regions of cartilage failure. This objective is achieved by solving problems with the finite element method. The conceptual model was subjected to the boundary conditions of confined compression on porous of cartilage anisotropy. The experimental results were demonstrated that neither the Young’s modulus nor the Poisson’s ratios exhibit the same values when measured along the loading directions. The results were supported an essential functional property of the tissue which the glenoid surface may be susceptible to cartilage degeneration.