抄録
The present study is concerned with the development of a finite element program for collapse analysis of three-dimensional framed structures under static loading, which has the following features :
(1) A linear Timoshenko beam-column element is employed with a variable location of an integration point, which is equivalent to the beam bending element including the effect of shear deformation in the RBSM (Rigid Bodies-Spring Models) family, and can be considered to be suitable to the analysis of highly nonlinear problems including crush analysis.
(2) The program is equipped with the updated Lagrangian formulation as well as the total Lagrangian formulation, the former of which is used in the crush analysis accompanied by extremely large rotations and strains, and the latter is used in the ultimate strength analysis with moderately large deformations.
(3) A formulation using generalized stresses is adopted for the derivation of incremental stiffness equations, and the yield functions expressed in terms of resultant forces are assumed in the elastoplastic analysis, from a point of view of the generalization of the method of limit analysis.
Numerical studies for crush as well as elastica and inelastic stability problems are conducted to show the validity of the developed code. The treatment of strain-hardening and the experimental verifications for the crush analysis will be contained in a further report.
