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Abstract: The present paper analytically investigates the adhesive behavior of power-law graded elastic solids under a combined action of external normal loading and a substrate stretch-induced mismatch strain with the effect of mode-mixity taken into account. A plane strain non-slipping model, a plane strain non-coupling model and an axisymmetric non-coupling model have been analyzed, respectively. Our results show that under a finite normal force, the equilibrium of the adhesive system may lost its stability at a critical value of mismatch strain, which significantly depends on both the graded material constants and the degree of mode-mixity. This indicates that the strongest or weakest adhesion strength under substrate stretching can be achieved by designing the physical constants of the adhesive system appropriately. These results provide a theoretical foundation for novel applications of functional graded materials in adhesion systems. [Copyright &y& Elsevier]

Abstract: In this paper, adhesive contact of a rigid cylinder on an elastic power-law graded half-space is studied analytically with the theory of weakly singular integral equation and orthogonal polynomial method. Emphasis is placed on the coupling effect between tangential and normal directions which was often neglected in previous works. Our analysis shows that the coupling effect tends to reduce the contact area in the compressive regime. The effect of bending moment on the adhesion behavior is also examined. Like a pull-off force, there also exists a critical bending moment at which the cylinder can be bended apart from the substrate. However, unlike pull-off force, the critical bending moment is insensitive to the gradient exponent of the graded material. [Copyright &y& Elsevier]

Abstract: The aim of the present paper is to investigate the adhesive behavior between a transversely isotropic piezoelectric half-space and a cylinder punch subjected to combined mechanical and electric loads under plane-strain condition. The effect of adhesion is described by using a generalized JKR-model which can account for the non-slip condition in the contact regions. Analytical function theory is employed to find the solution of the resulting singular integral equations. Our analysis shows that the adhesive contact behavior for different types of piezoelectric materials may be quite different. The results obtained in this paper may be helpful to understand the contact mechanics of piezoelectric materials at micro-scale. [Copyright &y& Elsevier]

This paper extends the double-Hertz model of Greenwood and Johnson (1998) to the plane strain problem of adhesive contact between a wavy surface and a flat surface, named as the double-Westergaard model. The adhesive force within the cohesive zone near contact edge is described by the difference between two Westergaard pressure distribution functions with different contact widths. Closed-form analytical solutions are obtained for different equilibrium states during loading and unloading stages. The proposed model captures a transition between Westergaard and JKR contact models through a dimensionless transition parameter. Depending on two dimensionless parameters, transitions between partial and full contact during loading/unloading are characterized by one or more jump instabilities. Decreasing waviness size by decreasing both the amplitude and period with a fixed curvature is found to enhance adhesion both by increasing the magnitude of the pull-off force and by inducing more energy loss through adhesion hysteresis. [ABSTRACT FROM AUTHOR]

A theoretical model of a power-law graded elastic half-space in contact with a randomly rough rigid surface is established by combining the Greenwood–Williamson rough contact model and the JKR type adhesion model for power-law graded materials. The rough surface is modeled as an ensemble of non-interacting asperities with identical radius of curvature and Gaussian distributed heights. By applying the JKR type theory for power-law graded solids to each individual asperity of the rough surface, the total normal forces for the rough surface are derived for loading and unloading stages, respectively, and a prominent adhesion hysteresis associated with dissipation energy is revealed. Our results include the solutions for homogeneous materials and Gibson solids as special cases and describe the complete transition between these two limiting situations. A dimensionless adhesion parameter, which influences both the total pull-off force and the energy dissipation due to adhesive hysteresis, is also identified. It is found that a small adhesion parameter results in higher energy dissipation and pull-off force, while a large adhesion parameter leads to lower energy dissipation and pull-off force. [ABSTRACT FROM AUTHOR]

Abstract: A cohesive zone model for two-dimensional adhesive contact between elastic cylinders is developed by extending the double-Hertz model of Greenwood and Johnson (1998). In this model, the adhesive force within the cohesive zone is described by the difference between two Hertzian pressure distributions of different contact widths. Closed-form analytical solutions are obtained for the interfacial traction, deformation field and the equilibrium relation among applied load, contact half-width and the size of cohesive zone. Based on these results, a complete transition between the JKR and the Hertz type contact models is captured by defining a dimensionless transition parameter μ, which governs the range of applicability of different models. The proposed model and the corresponding analytical results can serve as an alternative cohesive zone solution to the two-dimensional adhesive cylindrical contact. [Copyright &y& Elsevier]