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Nonlinear repulsive force between two solids with axial symmetry
D. Sun, C. Daraio,
Published in
2011
Volume: 83
   
Issue: 6
Abstract
We modify the formulation of Hertz contact theory between two elastic half-solids with axial symmetry and show that these modifications to Hertz's original framework allow the development of force laws of the form Fzn, 1<n<∞, where F is the force and z is the distance between the centers of the two solids. The study suggests that it may be possible to design physical systems that can realize such force laws. We let the half-solids be characterized by radii of curvatures R1 and R2 and invoke a factor m0 to describe any aspect ratio in the two bodies, all being valid near the contact surface. We let the x-y plane be the contact surface with an averaged pressure across the same as opposed to a pressure profile that depends on the contact area of a nonconformal contact as originally used by Hertz. We let the z axis connect the centers of the masses and define z 1,2=xα/R1,2α-1+yα/(mR1,2)α -1, where z1,2≥0 refers to the compression of bodies 1, 2, α1, m0, x,y≥0. The full cross section can be generated by appropriate reflections using the first quadrant part of the area. We show that the nonlinear repulsive force is F=azn, where n=1+1/α, and z=z 1+z2 is the overlap and we present an expression for a=f(E,σ,m,α,R1,R2) with E and σ as Young's modulus and the Poisson ratio, respectively. For α=2,∞, to similar geometry-dependent constants, we recover Hertz's law and the linear law, describing the repulsion between compressed spheres and disks, respectively. The work provides a connection between the contact geometry and the nonlinear repulsive law via α and m. © 2011 American Physical Society.
About the journal
JournalPhysical Review E - Statistical, Nonlinear, and Soft Matter Physics
ISSN15393755