Showing papers by "Eduardo N. Dvorkin published in 2003"

Modeling of the Solidification Process in a Continuous Casting Installation for Steel Slabs

Abstract: The development of a computational simulation system for modeling the solidification process in a continuous casting facility for steel slabs is discussed. The system couples a module for solving the direct problem (the calculation of temperatures in the steel strand) with an inverse analysis module that was developed for evaluating the steel/mold heat fluxes from the information provided by thermocouples installed in the continuous casting mold copper plates. In order to cope with the non-uniqueness of the inverse analysis, a priori information on the solution, based on the consideration of the problem physics, is incorporated. The stability of the system predictions are analyzed and the influence of the first trial used to start the evaluation procedure is discussed. An industrial case is analyzed.

Determination of the collapse and propagation pressure of ultra-deepwater pipelines

Abstract: In the design of ultra-deepwater steel pipelines, it is important to be able to determine the pipe behaviour while subjected to external pressure and bending. In many cases, the ultra-deepwater lay process, where these high loads exist, governs the structural design of the pipeline. Much work has been performed in this area, and it is generally recognized that there is a lack of test data on full-scale samples of line pipe from which analyses can be accurately benchmarked. This paper presents the results of a nil-scale test program and finite element analyses performed on seamless steel line pipe samples intended for ultra-deepwater applications. The work involved obtaining full-scale test data and further enhancing existing finite element analysis models to accurately predict the collapse and post-collapse response of ultra-deepwater pipelines. The work and results represent a continuing effort aimed at understanding the behaviour of pipes subjected to external pressure and bending, accounting for the numerous variables influencing pipeline collapse, and predicting collapse and post-collapse behaviour with increasing confidence. The test program was performed at C-FER Technologies (C-FER), Canada, with the analyses undertaken by the Center for Industrial Research (CINI), Argentina. The results of this work have demonstrated very good agreement between the finite element predictions and the laboratory observations. This allows increased confidence in using the finite element models to predict collapse and post-collapse behaviour of pipelines subject to external pressure and bending.Copyright © 2003 by ASME

Experimental validation of a finite element model that simulates the collapse and post-collapse behavior of steel pipes

Abstract: In previous publications CINI presented finite element models that simulated the collapse and post-collapse behavior of steel pipes under external pressure and bending. Those finite element models were used to analyze the effect of different imperfections on the collapse pressure and collapse propagation pressure of the steel pipes. Laboratory tests were carried out at CFER (Edmonton, Canada) in order to obtain experimental results that could be used to validate the numerical models. In this paper we compare the numerical and experimental results for the case of external pressure without bending.

A new rigid‐viscoplastic model for simulating thermal strain effects in metal‐forming processes

Abstract: A new rigid-viscoplastic model that includes the effect of thermal strains when modelling steady-state metal-forming processes was developed. A symmetric approximation to the resulting non-symmetric stiffness matrix was derived. The thermo-mechanical flow formulation was implemented using the pseudo-concentrations technique. The new formulation was numerically tested showing that it provides reliable results. Copyright © 2003 John Wiley & Sons, Ltd.

Steel industry: Simulation of production processes and product performance evaluation using finite element models

Abstract: Publisher Summary Computational models are nowadays a powerful and reliable tool for simulating different thermo-mechanical metallurgical processes, hence, they are increasingly being used to investigate the technological windows of different processes in the steel industry—for example, continuous casting, hot and cold rolling, and heat treatments. In the steel industry the use of computational models is a powerful engineering tool for developing new production processes or optimizing existing ones and for developing new products or optimizing existing ones The first requirement for the development of a successful set-up for a production process is to have an in-depth knowledge of the process technological window, that is to say, of the locus in the space of the process control variables— where the products resulting from the analyzed process meet their specifications.