Microforming Technology

Chapter 4

Strain Gradient Plasticity Theory

Abstract

Conventional plasticity theories which possess no internal length scale are not suitable for the prediction of size dependence of material behavior in microscale. Strain gradient should be considered if the length scale associated with the deformation field is small. The smaller the length scale, the important the strain gradient will become for the plastic deformation, and in this case it becomes necessary to include the strain gradient term in the theoretical description of plasticity deformation at small length scales. In this chapter, higher-order strain gradient plasticity theories, including couple stress theory, phenomenological strain gradient plasticity theory, and mechanism-based strain ...