Incorporation of Elastic Local Buckling in a Plain Channel Section Beam Subjected to Double-curvature Bending: An Effective-width Approach

摘要

When electrical cabinets are subjected to lateral loads, such as earthquakes, the beams of the cabinet frame typically experience double-curvature bending deformation. These beams are usually constructed from cold-formed plain channel sections so they are vulnerable to elastic local buckling near their ends, where high stresses from applied loads are more likely to develop. To capture local buckling behavior, structural engineers typically use high-fidelity finite element models, but this approach can be complex and computationally expensive. A Timoshenko beam element model is simpler and less computationally cosdy but it is not capable of capturing local buckling behavior. In this paper, a hybrid Timoshenko beam element model augmented with nonlinear nodal springs is proposed to capture elastic local buckling. Local buckling behavior is computed using cross sectional moment-curvature data generated by an effective-width equation, and the results of computations are validated using a high fidelity finite element model (referred to as the benchmark model) of the beam. The resulting reduced rotational stiffness is incorporated in nonlinear elastic rotational nodal springs introduced at the beam ends. A comparison of the hybrid and benchmark model results is presented to confirm the accuracy of the hybrid model.