Ein elasto-plastisches Materialmodell zur realistischen Berechnung der Verformungen mechanisch überhöhter Stahl- und Verbundträger

An elasto-plastic material model for realistic calculation of the deformations of mechanical cambered steel- and composite girders.

Steel and composite girders are often cambered before they are embedded into structures to compensate deflections. In case of a mechanical pre-deformation via a hydraulic press the steel girder contains plastic strains before assembly. As shown by Grages [3] this leads to a reduction of stiffness and strength during reverse loading. This phenomenon is also known as the Bauschinger-Effect [2] and may lead to an underestimation of the real deformation during a structural analysis. In this paper a rate-independent elastoplastic material model with linear and nonlinear isotropic as well as nonlinear kinematic hardening is introduced which allows a realistic estimation of deformations. The material model presented can be easily applied due to its low number of parameters. A straightforward algorithm to adjust the single parameters is described. The quality of the model is verified by a recalculation of experimental data from [3].