基于柔度法与截面轴力弯矩屈服面本构的梁柱单元

基于截面层次的梁柱单元能兼顾计算精度与效率,但现有截面上的本构模型不能准确反映轴力存在与变化对弯矩的影响,且柔度法在构建梁柱单元中未发挥优势,为此提出了基于截面轴力与弯矩屈服面本构和柔度法的梁柱单元模型。首先,根据截面组合思想构建截面上轴力与弯矩的屈服面;然后,依托柔度法和塑性理论进行单元状态和截面状态确定;最后,利用提出的单元进行平面钢框架的动力弹塑性分析。结果表明,所选用的基于截面轴力弯矩屈服面的本构能很好考虑轴力存在及变化对弯矩的影响;相对于刚度法,使用一个由柔度法构建的单元就足够描述一个梁-柱构件,其计算精度接近基于柔度法的纤维单元模型。

Beam-column element based on flexibility method and constitutive law of yield surface of section axial force and bending moment

Beam-column element based on section level can consider the calculation accuracy and efficiency at the same time.However,the existing section constitutive model didn't accurately reflect axial-flexure interaction (AFI),and the flexibility method was not made full use of in the Beam-column element.Herein,a beam-column element based on flexibility method and constitutive model derived from yield surface(YS) of section axial force and bending moment (AFBM) was proposed.Firstly,the YS of section AFBM is formed by section assemblage concept.Then,element and section state were determinated based on flexibility method and plastic theory respectively.Finally,dynamic elastoplastic analysis was implemented for a planar steel frame.The results show that the constitutive model derived from YS of section AFBM can account for AFI accurately,and that the element formulated by flexibility method can well represent a member with only one element.