An iterative nonlocal residual constitutive model for nonlocal elasticity

TL;DR

This paper introduces iterative nonlocal residual constitutive models that address the ill-posedness of traditional nonlocal elasticity models, ensuring solvable boundary value problems and consistent solutions for various boundary conditions.

Contribution

It proposes novel integral and differential iterative nonlocal residual models that guarantee solutions and overcome limitations of Eringen's nonlocal constitutive models.

Findings

Proposed models produce identical, feasible results.

Traditional models lead to ill-posed boundary value problems.

Solutions are guaranteed for various boundary conditions.

Abstract

Recently, it was claimed that the two-phase local/nonlocal constitutive models give well-posed nonlocal field problems and eliminates the ill-posedness of the fully nonlocal constitutive models. In this study, it is demonstrated that, both, the fully nonlocal and the two-phase local/nonlocal constitutive models secrete ill-posed nonlocal boundary value problems. Moreover, it is revealed that all Eringen integral and differential nonlocal constitutive models secrete unsolvable nonlocal boundary value problems. In this study, it is demonstrated that solutions of nonlocal elasticity problems are exist, and Eringen constitutive model cannot determine these solutions. To overcome the limitations of Eringen constitutive models, novel integral and differential iterative nonlocal residual constitutive models are proposed. Using these two constitutive models, the sum of the nonlocal residual field at a point is iteratively formed. Then, this nonlocal residual is imposed to the local boundary value problem. Thus, the nonlocal elasticity is obtained in the form of a local boundary value problem with an imposed nonlocal residual field. Using any of these constitutive models, a solution is guaranteed for a nonlocal field problem. To show the effectiveness of the proposed constitutive models, the nonlocal field problems of beams with different natural boundary conditions are considered. The results of the proposed integral and differential constitutive models are identical and feasible.