Tangent stiffness matrix for geometrically nonlinear analysis of space frames

Jianxin Gu, Siu Lai Chan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

2 Citations (Scopus)


A three-dimensional beam element is derived based on the principle of stationary total potential energy for geometrically nonlinear analysis of space frames. A new tangent stiffness matrix, which allows for high order effects of element deformations, replaces the conventional incremental secant stiffness matrix. Two deformation stiffness matrices due to the variation of axial force and bending moments are included in the tangent stiffness. They are functions of element deformations and incorporate the coupling among axial, lateral and torsional deformations. A correction matrix is added to the tangent stiffness matrix to make displacement derivatives equivalent to the commutative rotational degrees of freedom. Numerical examples show that the proposed element is accurate and efficient in predicting the nonlinear behavior, such as axial-torsional and flexural-torsional buckling, of space frames even when fewer elements are used to model a member.
Original languageEnglish
Pages (from-to)480-485
Number of pages6
JournalJournal of Southeast University (English Edition)
Issue number4
Publication statusPublished - 1 Dec 2005


  • Beam elements
  • Flexural-torsional buckling
  • Geometric nonlinearity
  • Second-order effects
  • Space frames
  • Tangent stiffness matrix

ASJC Scopus subject areas

  • General

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