Sharif Digital Repository

Rings are widely used in mechanical equipment, and their fitness may undergo some damage under severe vibration. In these structures, functionally graded rings can be used to optimize the resistance, energy consumption, and fitness. Due to their complexity, the finite-element analysis may be implemented using special elements. Enhancement of accuracy and minimization of time consumption play an important role in the analysis of these rings. In this study, a new cylindrical superelement for the FGM rings is designed and implemented to facilitate the vibration analysis of the rings. The power-law distribution is used for the modeling of the FGM rings in the thickness direction. Natural... 

In the special zones of frame elements, which are used for seismic energy dissipation, inelastic interaction among the internal forces needs to be considered more precisely. This paper describes a special element called a VM link element for modeling the shear-flexural interaction in the inelastic zones of beam elements. The element may be used in the any inelastic location of frames subjected to the monotonic or cyclic loadings. The inelastic shear and flexural deformations are considered by using the multi-surfaces plasticity concept with dissimilar yield surfaces. A new kinematic hardening and new non-associated flow rules are introduced for definition of the plastic deformations and... 

Reduced web section beams in shear-yielding moment-resistant steel frames are used for energy dissipating of earthquakes. The finite element analysis indicates that failure mode of these beams are governed by the combination of shear force and flexural moment. Therefore the analysis of frames with reduced web section beams needs consideration of shear-flexural interaction in those sections. In the present paper, modeling and analysis of reduced web section beams are investigated by using a special element which is called VM link element. The elastic and inelastic shear and flexural deformations and tangential stiffnesses in this link element are considered by using the multi- surfaces...