Design check of plates according to Hong Kong Standard

Plates in CBFEM are modeled by shell finite elements. The plastic strain must not exceed the limit.
$$The resulting equivalent stress (HMH, von Mises) and plastic strain are calculated on plates. When the design yield strength, $$p_y$$ (Cl. 3.1.2), on the bilinear material diagram is reached, the check of the equivalent plastic strain is performed. The limit value of 5 % is suggested in Eurocode (EN 1993-1-5 App. C, Par. C8, Note 1). This value can be modified in Code setup but verification studies were made for this recommended value. Plate element is divided into 5 layers and elastic/plastic behavior is investigated in each of them. The program shows the worst result of all of them.Stress may be a little bit higher than design yield strength. The reason is the slight inclination of the plastic branch of the stress-strain diagram, which is used in the analysis to improve the stability of the calculation.$p_y = \min \left \{ \frac{Y_s}{\gamma_{m1}}, \frac{U_s}{\gamma_{m2}} \right \}$where: $$p_y$$ – design yield strength $$Y_s$$ – characteristic yield strength $$U_s$$ – minimum tensile strength $$\gamma_{m1}$$ – material factor (Table 4.1); default value $$\gamma_{m1} = 1$$ editable in Code setup $$\gamma_{m2}$$ – material factor (Table 4.1); default value $$\gamma_{m2} = 1.2$$ editable in Code setup$$