APPROACH TO AN ESTIMATION DEFORMABILITY OF BENDING CONCRETE ELEMENTS BASED ON ITERATIVE CALCULATION METHOD

The article deals with existing methods for evaluating the load bearing capacity and deformability of bent reinforced-concrete elements, including the composite section. The analysis of idealized nonlinear dependencies and compressed concrete deformation diagrams. Iterative methods for structural analysis: the method of successive refinement of stiffness, the method of successive loadings, initial stress method. Results of their algorithms and shows the advantage of using the method of the dual stiffness are considered.

Elasto-Plastic Analysis of 3-D Inner Cracks Using the Finite Element Alternating Method

The finite element alternating method (FEAM) was extended to obtain fracture mechanics parameters and elasto-plastic stress fields for 3-D inner cracks. For solving a problem of a 3-D finite body with cracks, the FEAM alternates independently the finite element method (FEM) solution for the uncracked body and the solution for the crack in an infinite body. As the required solution for a crack in an infinite body, the symmetric Galerkin boundary element method formulated by Li and Mear was used. For elasto-plastic numerical analysis, the initial stress method proposed by Zienkiewicz and co-workers and the iteration procedure proposed by Nikishkov and Atluri were used after modification. The extended FEAM was examined through comparing with the results of commercial FEM program for several example 3-D crack problems.

Study of Elastic–Plastic Fracture Problem Using Finite Element Technique

Numerical methods for the analysis of the elastic-plastic fracture problem using a special finite element technique are presented. A brief description of some concepts in elastic-plastic fracture mechanics and of the finite element method is followed by the formulation procedure of the stiffness matrix using eight-noded quadrilateral isoparametric elements. After a terse discussion of the initial stress method, the procedure of computation is extended in the analysis by using an incremental load process. The size and the shape of the plastic zone of a center crack specimen is investigated. Results are presented in graphical form.