Numerical simulations of the normal impact of adhesive microparticles with a rigid substrate

The rebound behavior of elastic and elastoplastic microspheres impacting normally with a rigid wall is Studied using the finite element method. The interfacial adhesion forces are introduced by adding piecewise-linear spring elements with a particular constitutive relation characterizing the adhesion property. The effect of adhesion hysteresis is taken into account by assuming that the adhesion work during the incident stage is smaller than that during rebounding. The influences of the interfacial adhesion parameters, the constitutive relations, size, and incident velocity of the particle on the coefficient of restitution (COR) are all examined. We also analyze the changing tendency of the kinetic energy. elastic strain energy, adhesion work. and their interchange during impact. It is found that besides interfacial adhesion and plastic dissipation, the residual stress field caused by incompatible plastic deformation has a considerable influence on the impact behavior of the sphere as well. For smaller impact velocities, interfacial adhesion plays a dominant role in the impact process, while for higher incident velocities, the COR depends mainly on plastic deformation. In addition. the COR shows a distinct dependence oil the particle size. Finally, our numerical results are compared with the relevant experimental results. (C) 2008 Elsevier B.V. All rights reserved.