Influence of surface effects on the bending and buckling of nanowires

The static bending and longitudinal stability of nanowires under liquid or gas pressure are considered. Two surface effects are taken into account. The first is due to the difference in elastic properties in the thin surface layer and in the bulk of the material. Effective tensile and flexural stiffness can be more or less than conventional stiffness, depending on the material. The second effect is due to the interaction of excess pressure on the circular side surface of the wire and the difference of the areas of the convex and concave sides of the surface that appears during bending. This effect is manifested the stronger, the greater the ratio of pressure to the modulus of elasticity of the material and the length of the wire to its diameter. These effects are determined by dimensionless parameters. It has been established that a loss of wire stability may occur under the influence of the second effect. A possible method for determining the dimensionless parameter, which determines the differences of elastic properties in a thin layer near the surface and the base material, is proposed.