The low Young's modulus of biological particles results in their large deformation against the AFM probe forces; therefore, it is necessary to study the contact mechanics of bioparticles in order to predict their mechanical behaviors. This paper specifically deals with the contact mechanics of DNA nanoparticles with spherical and cylindrical shapes during manipulation. In previous studies, ...

We present a force-displacement contact model for the compressive loading of elastoplastic spheres. This model builds from the well known Hertz contact law for elastic, quasistatic compression to incorporate a material's strain-rate-dependent plasticity in order to describe collisions between particles. In the quasistatic regime, finite-element analysis is used to derive an empirical function o...

In this article, the optimal control of static elasto-plastic contact problems are discussed. We present regularization approaches for the nondifferentiabilities arising from contact as well as from elastoplasticity in order to apply fast Newton-type solution algorithms. To achieve an efficient algorithm, we adaptively balance the both regularization, the discretization, and the numerical error...

I have developed a theory of contact mechanics between randomly rough surfaces. The solids are assumed to deform elastically when the stress sigma is below the yield stress sigma(Y), and plastically when sigma reaches sigma(Y). I study the dependence of the (apparent) area of contact on the magnification. I show that in most cases the area of real contact A is proportional to the load. If the r...

Researchers have developedmanymodels to simulate the elasto-plastic contact of spheres. However, there does not appear to exist a closed-form analytical model for elasto-plastic three-dimensional sinusoidal contact. This work uses a finite element model (FEM) to characterize elasto-plastic sinusoidal contact. Although at initial contact the sphere and sinusoidal case are very similar and can bo...

For short duration impulse loadings, elastic granular chains are known to support solitary waves, while elastoplastic chains have recently been shown to exhibit two force decay regimes [ Pal, Awasthi and Geubelle Granular Matter 15 747 (2013)]. In this work, the dynamics of monodisperse elastic and elastoplastic granular chains under a wide range of loading conditions is studied, and two distin...

We study the effect of the anisotropy induced by loading on the elastoplastic response of a two dimensional discrete element model granular material. The anisotropy of the contact network leads to a breakdown of the linear isotropic elasticity. We report on a linear dependence of the Young moduli and Poisson ratios on the fabric coefficients, measuring the anisotropy of the contact network. The...