抄録
This paper introduces a numerical method which is able to predict with good accuracy the elastic-plastic behavior of plane skeletal structures. This method, called FERT-P, is a combined and integrated version of the following two methods. One is the combined geometrically and materially nonlinear one-dimensional finite element method proposed by Nakamura, Ishida and further developed by the authors (Refs. 2-7), which has recently been called PERT (Finite Element method with Rigid-body-motion coordinates and Transfer matrix technique). The other is the incremental perturbation method developed by Nakamura, Uetani et al. (Refs. 8-11) to provide means of finding every point on an equilibrium path at which a new element will start yielding or unloading. The incremental perturbation method is able to determine automatically computational step lengths. Several benchmark tests have been carried out on the elastic-plastic buckling of steel structures. The following conclusions for the FERT-P have been derived: (1) By adopting the rigid-body-motion coordinates, the perturbation calculation in the FERT-P is concerned only in the transformation of global and local coordinates. The development of the FERT-P program is very easy. (2) The transfer matrix technique is effective for deriving the perturbation equations of members from those of elements. (3) The FERT-P is a very reliable numerical method to analyze elastic-plastic behaviors, including in particular the unstable behavior, of plane skeletal structures.
