Showing papers on "Tangent stiffness matrix published in 1977"
TL;DR: In this article, a finite element model is presented which enables the analyst to trace the history of strains, stresses, and crack propagation in reinforced concrete beams subject to a plane state of stress, for a monotonic increase of external load.
Abstract: A finite element model is presented which enables the analyst to trace the history of strains, stresses, and crack propagation in reinforced concrete beams subject to a plane state of stress, for a monotonic increase of external load. Concrete nonlinear behavior is assigned analytically, as resulting from biaxial tests. Steel-concrete interaction is described through experimental nonlinear bond-slip curves. Concrete cracking is taken into account by considering the element unable to sustain stresses in a direction normal to the crack, but capable of transmitting friction forces parallel to the crack itself, through a value of the shear stiffness fixed on the basis of experimental information on aggregate interlock. An iterative solution procedure is used. The effects of updating the tangent stiffness matrix at each iteration are considered, and provisions are included to prevent the occurrence of numerical ill conditioning. The validity of the method is demonstrated against a well-controlled set of experiments on reinforced concrete beams.
92 citations
TL;DR: In this article, the spatial elasto-plastic behavior of steel arches is investigated in the case where they collapse due to inelastic lateral instability producing flexural-torsional deformations towards out-of-plane of the arch.
Abstract: The spatial elasto-plastic behavior of steel arches is investigated in the case where they collapse due to inelastic lateral instability producing flexural-torsional deformations towards out-of-plane of the arch. A tangent stiffness matrix for large deflections of the spatial members in an elasto-plastic state is newly derived and used in the numerical calculations. Attention is paid mainly to the following parameters, i.e., slenderness ratios, residual stresses, initial lateral deflections, loading directions, and properties of the materials. Their effects on the ultimate load carrying capacity of two-hinged parabolic arches are examined and illustrated in several figures. In addition to the parametric study, a typical numerical example of the ultimate strength analysis of a central-arch-girder bridge is presented as one of applications to the actual bridge.
45 citations
TL;DR: The structural characteristics of the human knee have been determined using the stiffness influence coefficient method, where the nonlinear load-displacement data is approximated by a least squares polynomial and differentiated to determine the stiffness coefficient as a function of displacement.
43 citations
TL;DR: In this article, the authors describe the derivation of the element stiffness factor for some familiar elements as needed in conjunction with the recently developed factor formulation of the stiffness for the matrix displacement method.
2 citations