A model for the axisymmetric growth and coalescence of small internal voids in elastoplastic solids is proposed and assessed using void cell computations. Two contributions existing in the literature have been integrated into the enhanced model. The first is the model of Gologanu-Leblond-Devaux, extending the Gurson model to void shape effects. The second is the approach of Thomason for the onset of void coalescence. Each of these has been extended heuristically to account for strain hardening. In addition, a micromechanically-based simple constitutive model for the void coalescence stage is proposed to supplement the criterion for the onset of coalescence. The fully enhanced Gurson model depends on the flow properties of the material and the dimensional ratios of the void-cell representative volume element. Phenomenological parameters such as critical porosities are not employed in the enhanced model. It incorporates the effect of void shape, relative void spacing, strain hardening, and porosity. The effect of the relative void spacing on void coalescence, which has not yet been carefully addressed in the literature. has received special attention. Using cell model computations, accurate predictions through final fracture have been obtained for a wide range of porosity, void spacing, initial void shape, strain hardening, and stress triaxiality. These predictions have been used to assess the enhanced model. (C) 2000 Elsevier Science Ltd. All rights reserved.

An extended model for void growth and coalescence - application to anisotropic ductile fracture

Free vibration analysis of functionally graded conical, cylindrical shell and annular plate structures with a four-parameter power-law distribution

Recent developments in finite element analysis for laminated composite plates

A review of theories for the modeling and analysis of functionally graded plates and shells

A review of meshless methods for laminated and functionally graded plates and shells

Large deformation analysis of functionally graded shells

Tensor-based finite element formulation for geometrically nonlinear analysis of shell structures

In this paper, a review of the shear deformation plate and shell theories is presented and a consistent third-order theory for composite shells is proposed. The discussion of plate and shell theories from Stavsky to the present is largely a review of various theories for modeling laminated shells, including shear effects and some analytical studies. Following this discussion, a finite element formulation of the proposed theory is developed. The formulation has seven displacement functions satisfying the tangential traction-free conditions on the inner and outer surfaces of the shell. Exact computations of stress resultants are carried out through numerical integration of material stiffness coefficients of the laminate. Numerical examples are presented for typical benchmark problems involving isotropic and composite plates, and cylindrical and spherical shells.

Shear Deformation Plate and Shell Theories: From Stavsky to Present

Hermite–Lagrangian finite element formulation to study functionally graded sandwich beams

A consistent third-order shell theory with applications to composite circular cylinders is presented and its finite element formulation is developed. The formulation has seven displacement functions and requires C 0 continuity in the displacement field. The exact computation of stress resultants is carried out through numerical integration of material stiffness coefficients of the laminate. A displacement finite element model is developed using Lagrange elements with higher-order interpolation polynomials. These elements preclude any effect of shear and membranes locking. Comparisons of the present results with those found in the literature for typical benchmark problems involving isotropic and composite cylindrical shells are found to be excellent and show the validity of the developed shell theory and its implementation into a finite element code.

R.A. Arciniega

Papers

Large deformation analysis of functionally graded shells

Tensor-based finite element formulation for geometrically nonlinear analysis of shell structures

Shear Deformation Plate and Shell Theories: From Stavsky to Present

Hermite–Lagrangian finite element formulation to study functionally graded sandwich beams

Consistent Third-Order Shell Theory with Application to Composite Cylindrical Cylinders