STUDY ON PLASTIC-ZONE MODELS FOR ADVANCED ANALYSIS OF STEEL FRAME

摘要

Plastic zone approaches of advanced analysis can accurately predict the limit strength and stability of space steel frames, and accurately simulate initial imperfections, residual stresses and the coupling effects between compression, bending and torsion forces, and eliminate the need for separate member capacity checks. The plastic-zone models based on the M-P-Φ relations of member section, shell elements and fiber elements of finite element methods are presented also with their application methods, advantages and disadvantages. On the bases of the research, mixed element technique based on the distributed plasticity models is introduced since a large part of the structures will remain elastic up to the system collapse load, which provides a foundation for the further research of the theory and its wide use, meanwhile, provides an alternative method for the accurate nonlinear analysis of steel frames.