The resulting equivalent stress (Huber-Mises-Hencky – HMH, von Mises) and plastic strain are calculated on plates. Elasto-plastic material model is used for steel plates. A check of an equivalent plastic strain is performed. The limiting value of 5 % is suggested in Eurocode (EN 1993-1-5, app. C, par. C8, note 1), this value can be modified by the user in Code setup.
Plate element is divided into 5 layers and elastic/plastic behavior is investigated in each layer separately. Output summary lists the most critical check from all 5 layers.
CBFEM method can provide stress rather higher than the yield strength. The reason is the slight inclination of the plastic branch of the stress-strain diagram which is used in the analysis to improve the stability of interaction calculation. This is not a problem for practical design. At higher loads, the equivalent plastic strain is rising and the joint fails while exceeding the plastic strain limit.