Purpose
The purpose of this study is to propose a fractal model of thermal contact conductance (TCC) of two spherical joint surfaces, considering friction coefficient based on the three-dimensional fractal theory.
Design/methodology/approach
The effects of friction coefficient, fractal parameters, radius of curvature and contact type on TCC were analyzed using numerical simulation.
Findings
The results indicate that the TCC decreases with the increase of friction coefficient and fractal roughness and increases with the increase of fractal dimension and radius of curvature; the contact type of two spherical joint surfaces has an important influence on the TCC, and the TCC of external contact is smaller than that of internal contact under the same contact load.
Originality/value
A fractal model of TCC of two spherical joint surfaces considering friction coefficient is proposed in this paper. Achievements of this work provide some theoretical basis for the research of TCC of bearings and other curved surfaces.
Purpose
The purpose of this paper is to propose a fractal model of thermal contact conductance (TCC) of rough surfaces based on cone asperity.
Design/methodology/approach
A detailed numerical study is conducted to examine the effects of contact load, fractal dimensional, fractal roughness and material properties on the TCC of rough surfaces.
Findings
The results indicate that when the fractal dimension D is less than 2.5, the TCC of rough surfaces increases nonlinearly with the increase of the contact load. However, when the fractal dimension D is greater than or equal to 2.5, the TCC of rough surfaces increases linearly with the increase of the contact load; the TCC of the rough surfaces increases with the increase of the fractal dimension D and the decrease of the fractal roughness G; the material parameters also have an influence on the TCC of the rough surfaces, and the extent of the effect on the TCC is related to the fractal dimension D.
Originality/value
A fractal model of TCC of rough surfaces based on cone asperity is established in this paper. Some new results and conclusions are obtained from this work, which provides important theoretical guidance for further study of TCC of rough surfaces.
In this study, a novel, dynamic model of a graphene-platelet-reinforced, porous (GPLRP) double-cylindrical-panel system is proposed. The material properties of a graphene-platelet-reinforced, porous, double-cylindrical-panel system were determined by the Halpin–Tsai micromechanics model and the typical mechanical properties of open-cell metal foams. Different types of porosity distribution and graphene platelet (GPL) distribution patterns were considered. Love’s shell theory was utilized to derive the theoretical formulation, and the Rayleigh–Ritz method was used to calculate the natural frequencies of the system. The proposed model was validated by several comparison studies with the natural frequencies in the existing literature. Finally, the effects of stiffness of Winkler springs, boundary condition, porosity coefficient, porosity distribution, GPL distribution pattern, and GPL weight fraction on the free vibration characteristics of the system were evaluated.
Purpose
The purpose of this study is to establish a fractal model of thermal contact conductance (TCC) of micro-segment gear considering friction coefficient.
Design/methodology/approach
The influences of friction coefficient, fractal dimension, fractal roughness and contact type on the TCC of the rough surface were studied by using numerical simulation.
Findings
The results show that with the increase of the friction coefficient, the TCC of the rough surface will decrease. As the fractal dimension increases or the fractal roughness decreases, the rough surface becomes smoother and the TCC becomes larger. Under the same load conditions, the TCC of the internal contact type is greater than that of the external contact type. In engineering practice, the desired TCC can be achieved by changing the contact type.
Originality/value
A fractal model of TCC of micro-segment gear considering friction coefficient was established in this study. The achievements of this study provide some theoretical basis for the investigation of the TCC of the gear.
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