Interaction and deformation of viscoelastic particles: Nonadhesive particles - art. no. 061604

A viscoelastic theory is formulated for the deformation of particles that i nteract with finite-ranged surface forces. The theory generalizes the stati c approach based upon classic continuum elasticity theory to account for ti me-dependent effects, and goes beyond contact theories such as Hertz and th at given by Johnson, Kendall, and Roberts by including realistic surface in teractions. Common devices used to measure load and deformation are modeled and the theory takes into account the driving velocity of the apparatus an d the relaxation time of the material. Nonadhesive particles are modeled by an electric double layer repulsion. Triangular, step, and sinusoidal traje ctories are analyzed in a unified treatment of loading and unloading. The l oad-deformation and the load-contact area curves are shown to be velocity d ependent and hysteretic.