Mechanical Failure Processes in Nanomaterials

Abstract

The definition of the failure of a material is of course determined by the intended application. For example, in the majority of traditional mechanical design problems, the material is intended to operate in the elastic range. Therefore, in that application, the material may be said to fail when it begins to deform plastically (that is, when the yield strength is reached).We have discussed the onset of plasticity (yield, or the elastic limit) in the previous chapter. Beyond yield, the material continues to carry load in a nonlinear manner, corresponding to the plastic deformation; the nonlinear response is something that designers often avoid because of the complexity associated with the constitutive behavior in that domain. In this chapter, our interest is primarily in the applications of nanomaterials beyond the elastic limit, assuming a modicum of plastic deformations. Situations where there is no nonlinear deformation after the elastic limit is reached, as in ceramics, will be discussed as well.

Stone cracks from a hard enough blow. Steel shatters. The oak fights the wind and breaks. The willow bends where it must and survives.

Robert Jordan, The Wheel of Time