In the present paper, the multiple diffraction of plane harmonic compressional waves P-wave by two nanosized circular cylindrical holes embedded in an elastic solid is investigated. The surface elasticity theory is adopted to account for the effect of surface energy at nanoscales. It is found that when the radii of holes reduce to nanometers, surface energy significantly affects the diffraction of elastic waves. The dynamic stresses around the holes under incident waves of different frequencies are examined to display the influence of surface energy and the interaction between holes in the multiple scattering phenomena.

Based on the conventional Euler buckling model, uniaxial compression tests have been utilized recently to measure the mechanical properties of nanowires. However, owing to the increasing ratio of surface area to bulk at nanoscale, the influence of surface energy becomes prominent and should be taken into consideration. In this letter, an analytical relation is given for the critical force of axial buckling of a nanowire by accounting for both the effects of surface elasticity and residual surface tension. This study might be helpful to characterize the mechanical properties of nanowires or design nanobeam-based devices in a wide range of applications.

Based on the surface elasticity theory and using a local asymptotic approach, we analyzed the influences of surface energy on the stress distributions near a blunt crack tip. The dependence relationship of the crack-tip stresses on surface elastic parameters is obtained for both mode-I and mode-III cracks. It is found that when the curvature radius of a crack front decreases to nanometers, surface energy significantly affects the stress intensities near the crack tip. Using a kind of surface elements, we also performed finite element simulations to examine the surface effects on the near-tip stresses. The obtained analytical solution agrees well with the numerical results.

Surface effects often play a significant role in the physical properties of micro-and nanosized materials and structures. In this letter, the authors presented a theoretical model directed towards investigation of the effects of both surface elasticity and residual surface tension on the natural frequency of microbeams. A thin surface layer was introduced on the upper and lower surfaces to rationalize the near-surface material properties that are different from the bulk material. An explicit solution is derived for the natural frequency of microbeams with surface effects. This study might be helpful for the design of microbeam-based sensors and some related measurement techniques.

Based on the surface elasticity theory, we examined the effects of surface stresses on nanosized contact problems. The Fourier integral transform method is adopted to derive the general solution for the contact problem under pressure. As two examples, the deformations induced, respectively, by a uniform distributed pressure and a concentrated force are analyzed in detail. The results indicate some interesting characteristics in contact mechanics, which are distinctly different from those in classical elasticity theory. Both the contact normal stress and the deformation gradient on the deformed surface vary smoothly across the loading boundary as a result of surface stress. In addition, the indent depth and the maximum normal contact stress depend strongly on the surface stress for nanoindentation.