Finite-Element Analysis of Polyhedra under Point and Line Forces in Second-Strain Gradient Elasticity

In this paper, a finite-element implementation of linear second-strain gradient elasticity is introduced based on a Hellinger-Reissner variational principle in order to use standard finite-element methods. Displacement boundary conditions are applied to one or more vertices of different polyhedrons. As a result, a smooth deformation around deformed vertices of the polyhedrons can be observed, in contrast to the appearance of singularities in the first-order theory, i.e., a Cauchy continuum, where strain singularities appear in such cases.