A method for the calculation of inter-element stresses in 3D

In a previous paper, the authors have proposed a local post-processing method out of the standard results of 2D FE-displacement calculations, for the evaluation of the “inter-element” forces and stress tractions transmitted across mesh lines. The method is based on a double minimization of the differences between the inter-element tractions and the projections on the same lines of the (also initially unknown) nodal stress tensor. In the present paper, the method is extended to 3D. Inter-element lines become surfaces, and overall geometric and equilibrium conditions turn out significantly more complex. In spite of that, a formulation based on the same principles is developed and demonstrated with basic numerical applications. The method is always applicable for linear elements but it shows some peculiarities for the corner nodes of some quadratic elements.