Abstract

The ultimate limit state criteria (yielding surfaces) applied to structural designs are easier in stress resultants. There are many difficulties to generating interaction surfaces with six sectional efforts obtained through to numerical or experimental models of a space-frame analysis. The approach, in the literature, to nonlinear analysis of structures with 3D beams is use of interaction surfaces with only three combined efforts in the cross-section. Therefore, a better understanding of load types, of interactions between the six efforts and of local and global stability of structure are necessary. The interaction surfaces with three efforts are presented in planes, quadrics, more complex, or a mixture of them shapes, so that techniques which use analytical formulations with combined efforts and several section shapes are more or less complex. Multiple linear regression allows to treat the resultant efforts of several analyses for obtaining a yielding surface with the combined efforts. In this paper, the formulation to obtaining of the surfaces and their applications in the analysis of elasto-plastic frame structures are presented.

Abstract

The interaction surfaces in stress resultants can be of great use in the structural analysis processes, but their obtaining for plane or space frames, generally, is in combined efforts of bending moments and normal. The literature presents the surfaces in plane, quadric, complex or mixed forms for nonlinear analysis of structures that have the problems of local and global instability in the executing. The multiple linear regression model is a method that permit obtain interaction surfaces in the stress resultants from 3D solid element analysis. The plane and space frames elastoplastic analysis using these surfaces facilitate the structural analysis processes for the execution of projects with better structural safety. In this work, the approach will be for metallic structures with stress resultants surfaces obtained by Timoshenko 3D beams damage model non-linear analysis.