Spread Plasticity Model
Inelastic deformations vary along element’s length. Consequently an element will also exhibit different flexibility characteristics. In order to formulate the elastoplastic flexibility matrix of such an element a spread plasticity model is introduced. This model can formulate an element’s flexibility matrix by taking into account the current stiffness (i. e. flexural stiffness concerning beams and columns and also shear stiffness for walls) at each end section, a corresponding yield penetration length and/or the elastic core stiffness depending on the values of the yield penetration lengths.