Homogeneous Generalized Yield Function for Frame Members with Box Section

In order to overcome limitations of the traditional generalized yield function (GYF), a homogeneous generalized yield function (HGYF) is proposed for box sections, which is insensitive to sectional geometry of box sections and applicable for plane and spatial frame structures; and a linear-elastic iterative method with higher efficiency is presented for ultimate bearing capacity of framed structures. Firstly, different generalized yield functions (GYF) are investigated and the suitable one is selected as insensitive to the geometric parameters of box sections. Then a set of fitting points are determined according to the comprehensive test method, based on which an HGYF was developed by regression analysis with a wide range of application for box sections. Finally, a linear-elastic iterative method is presented with high efficiency for the ultimate bearing capacity of frames with box section on the basis of elastic modulus reduction method (EMRM). Numerical examples show that the proposed HGYF achieves satisfying stable results with a wide range of application for plane and spatial frames, overcoming not only the instability of the traditional GYF, but also the sensitivity of the existing HGYF to geometry of sections which is unsuitable for spatial frames. The relative error of the established method is less than 3% compared with the traditional elasto-plastic incremental analysis method, and the calculation time is less than 10% that of the traditional analysis method, which shows the accuracy and efficiency of this method.