Abstract—Several methodologies have been proposed to model the effect of length scale parameters to improve constitutive equations for analyzing microstructures and nanostructure materials. Most of them are developed based on strain gradient theory. The main restriction is contributed to the large scale of imposed plastic deformation in comparison with implementation of length scale parameters. Also comparing to the scale of dislocation movement and hardening mechanisms, the plastic deformation in microstructures and nanostructure materials is sufficiently large that finite plasticity theory could be well justified. Therefore, the main intention of this paper is to develop strain gradient deformation with the corporation of finite plastic and dislocation theory as physically based attribution in constitutive equations. This procedure is accomplished with intrinsic length scale relation, which is dedicated to develop phenomenological of plasticity laws for microstructures in finite plasticity. Finally, the result of new theory gives for microstructures, and its predictable results are discussed for nanostructure materials.

Index Terms—Strain gradient plasticity; micromechanical modelling; dislocation theory; microstructures; nanostructure materials.

H. Farahmand is with Department of mechanical Engineering, Young researcher club, Kerman Branch, Islamic Azad University, Kerman, Iran(email: hamed_1256@yahoo.com; farahmand@iauk.ac.ir).



Cite: Hamed Farahmand, "A Novel Methodology in Modelling Dislocations for Analyzing Microstructures and Nanostructure Materials in Plastic Media ," International Journal of Applied Physics and Mathematics  vol. 1, no. 3, pp. 206-212, 2011.