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A concrete material model is presented. The model is based on non‐associated plasticity for the pre‐failure and ductile post‐failure regimes and fracture (smeared crack approach) for the brittle post‐failure regime. The implementation of the constitutive model in the 2‐D elements of a general purpose non‐linear incremental finite element code is discussed. Some important numerical features of the implementation are the implicit integration of the stress/strain relation and the use of an efficient symmetric stiffness formulation for the equilibrium iterations.

This paper aims to develop a simple and efficient shell element for large strains hyper‐elastic analyses.

Based on the classical MITC4 shell element formulation a 3D shell element with finite strain kinematics is developed. The new quadrilateral shell element has five dof per node and two global dof to model the thickness stretching. The shell element is implemented for hyperelastic material models and the application of different hyperelastic constitutive relations is discussed.

The results obtained considering three of the hyperelastic material models available in the literature are quite different when the developed strains are relatively high; this indicates that, for analyzing actual engineering examples, experimental data should be used to decide on the most suitable constitutive relation.

The 3D version of the MITC4 element was developed.

A new four‐node (non‐flat) general quadrilateral shell element for geometric and material non‐linear analysis is presented. The element is formulated using three‐dimensional continuum mechanics theory and it is applicable to the analysis of thin and thick shells. The formulation of the element and the solutions to various test and demonstrative example problems are presented and discussed.

The production of steel pipes with guaranteed external collapse pressure (e.g. high collapse casings for oil wells) requires the implementation of an accurate process control. To develop that process control it is necessary to investigate how different parameters affect the external collapse pressure of the pipes. Experimental/numerical techniques implemented to investigate the collapse behavior of steel pipes are presented. The discussion of the experimental techniques includes the description of the facilities for performing external pressure collapse tests and the description of an imperfections measuring system. The numerical techniques include 2D and 3D finite element models. The effects on the value of the pipes’ external collapse pressure of their shape, residual stresses and material properties are discussed.

In order to develop an engineering tool for modelling 2D metal forming processes we implemented in the flow formulation the pseudo‐concentrations technique and a quadrilateral element based on mixed interpolation of tensorial components (QMITC). By doing this we obtained a reliable and efficient Eulerian formulation for modelling steady and transient metal forming problems. Some cases were analysed in order to test the performance of the formulation.

A quadrilateral 2‐D finite element for linear and non‐linear analysis of solids is presented. The element is based on the technique of mixed interpolation of tensorial components. It is shown that the new element is reliable and efficient, being apt, therefore, to be used in routine engineering applications.

The purpose of this paper is to model the strain localization in J₂ materials with damage evolution using embedded strong discontinuity modes.

In this procedure, an heuristic bandwidth scale is adopted to model the damage evolution in the shear bands. The bifurcation triggering conditions and band growth directions are studied for these materials.

The resulting formulation does not require a specific mesh refinement to model a localization, provides mesh independent results also insensitive to element distortions and allows calibration of the model response using experimental data. The formulation capability is shown embedding the strong discontinuity modes into quadrilateral and higher order elements.

The work described in this paper extends the use of strong discontinuity modes to materials with damage evolution.

A generalized Galerkin technique originally developed by Donea, Belytschko and Smolinski for solving the steady convection—diffusion equation using elements with quadratic interpolation has been modified to extend its application to the case of geometrically distorted 1D and 2D elements. The numerical results indicate that the modified scheme gives accurate results and presents a rather small sensitivity to element distortions.

Engineers have developed robust and efficient incompressible finite element formulations using tools such as the Patch Test and the counting of constraints/variables, the first one aimed at the development of consistent elements and the second one aimed at the development of non‐locking and stable elements. The mentioned tools are rooted in the physics of the continuum mechanics problem. Mathematicians, on the other side, developed complex and powerful tools to examine the convergence of finite element formulations, such as the inf‐sup condition, these methods are based on the properties of the elliptical PDEs that constitute the mathematical model of the continuum mechanics problem. In this paper we intend to understand the inf‐sup condition from an engineering perspective, so as to be able to incorporate it into the package of tools used in the development of finite element formulations.

The purpose of this paper is to describe the development of an embedded crack finite element (FE) model for reinforced concrete (RC) structures, including a bond‐slip methodology to take into consideration the steel contribution in the rupture process, capable of capturing the global behavior of the structure as well as details of cracking phenomenon.

The reinforcement contribution is added in the equilibrium at element level in an embedded crack FE model, based on displacement localization lines inside the elements.

The model is able to determine the steel stress in the crack besides the volumetric average steel stress. It is shown that the steel stress in the crack can be considerable greater than the average value. Other important aspect detected is the contribution of the concrete softening in the steel stress in the crack and in the overall behavior. The number, the distribution and the opening of cracks can be estimated too.

The yield of the steel in the cracking process can be detected more precisely by this methodology, allowing a better design and understanding of RC structures. In addition, the knowledge of crack openings is an important information to predict corrosion and other degradation phenomena of the reinforcement bars.

The bond‐slip procedure is linked with the embedded crack model in an original way: sliding gives the crack width. Moreover, the inclusion of steel forces in the crack equilibrium balance was not a usual procedure and permits an understanding of reinforcement effect in both levels (macro and micro) studied in this work.