In this paper we discuss the effect of neglecting relative tangential surface displacements in forming the boundary conditions of elastic contact problems between dissimilar materials. This is one of the known approximations made by Hertz in his original theory. Attempts have been made only recently to build up procedures to take this ‘convective’ effect into account, for simple plane problems ...

A study has been made of Hertzian contact damage in compressive shear stress field beneath the contact area. The observed microcrack density increases with grain size, porous and dense liquid-phase-sintered aluminas. Indentation stress–strain curves show increasing nonlinearity as the implying a threshold microstructural scale for crack initiation. In contrast, the micromechanisms controlling f...

With mechanical metamaterials that display force-torque coupling receiving recent attention, we tested the effect of twist on indentation resistance. We hypothesised force required to indent a twisting lattice set depth would increase with amount transverse deformation caused by twist. Based previous work, various chiral lattices were designed up 1.3° per 1 % compression. These designs 3D-print...

Atomic force microscopes (AFM) and nanoindenters have been used for decades to evaluate mechanical properties of thin films at the nanoscale. It is argued that elastic solutions indentation problem, which are most often associated with names Galin or Sneddon, may be extracting contact modulus bulk samples continual films, while their application between an AFM probe a polymer brush priori quest...

A simple analytical model is built up to account for the interface deformation effect in a spherical atomic force microscopy (AFM)-based quasi-static indentation of living cell covered with pericellular brush. The compression behaviour coat described using Alexander–de Gennes that allows nonlinear deformation. An approximate second-order relation between contact and indenter displacement obtain...

Indentation testing of a brittle material using a notionally `sharp' indenter may reveal several important physical properties, including fracture toughness, surface ®nish information and the residual stress state. In the case of shallow cone indenters, the contact and fracture mechanics is well de®ned and closed-form solutions exist in elasticity theory. However, no real indenter is atomically...

An earlier finite element modeling analysis of inner cone cracks in monolithic brittle solids subject to cyclic indentation in liquids is extended to include the case of a brittle layer bonded to a compliant substrate, using a model glass/polycarbonate bilayer system as an illustrative case study. Provision is made for incorporation of plate flexure stresses, along with hydraulic pumping stress...

The influence of in-plane residual stress on Hertzian nanoindentation for single-crystal copper thin film is investigated using molecular dynamics simulations (MD). It is found that: (i) the yield strength of incipient plasticity increases with compressive residual stress, but decreases with tensile residual stress; (ii) the hardness decreases with tensile residual stress, and increases with co...

Stiffness relations for voltage-dependent contact mechanics of piezoelectric material are derived for an indenter of arbitrary planform under normal force, centrally or noncentrally applied, and electric charge distribution at the base. Relations between indentation depth, indentation force, electric potential and electric charge are explicitly given in terms of indenter’s geometry and piezoele...