A PROCEDURE FOR THE IMPROVED CONTINUOUS STRESS-FIELD OF COMPOSITE MEDIA

Interfacial tractions at the interface of two different materials and the initial displacement field over the entire domain are obtained by modifying the potential energy functional with a penalty function, whi ch enforces continuity of the stresses at the interface of two differe nt materials. Based on the initial displacement field and the interfac ial tractions, a method to build a continuous stress field over the en tire domain has been proposed by combining the modified projection met hod for the stress-smoothing and the Loubignac-Cantin iteration for th e restoration of momentum balance in the smoothed stress fields. Stres s analysis is carried out on two examples made of highly dissimilar ma terials. Results of the analysis show that the proposed method provide s an improved continuous stress field over the entire domain, and accu rately predicts the nodal stresses at the interface of two different m aterials. In contrast, the conventional displacement-based finite elem ent method produces significant stress discontinuities at the interfac e of two different materials. In addition, the total strain energy eva luated from the improved continuous stress field rapidly converges to the exact solution as the number of iterations increases.