Adaptation of a library, to be released as free software, for the improvement of the finite element solution using the MLS-C recovery technique

[EN] The main objective of this master thesis is to adapt a library developed in Matlab [4] which implements the MLS-C technique to make it freely available for other researchers as a tool to evaluate recovered stress fields from the results obtained with different numerical analysis techniques like the FEM or the meshless methods. To illustrate the use of this MLS-C library, an interface with the commercial code Ansys [5] will also be created so that the library can be directly invoked from Ansys to postprocess the discontinuous 2D stress fields provided by this code. This would then represent a high quality alternative technique to the nodal averaging technique used by Ansys to obtain continuous stress fields. We have choosen to publish the MLS-C library under the GNU General Public License [6]introduced by Richard Stallman which aims to give computer users the freedom to modify, share, and even distribute it again. In this thesis Section 2 will describe the GNU License, Section 3 will present a resume of the Moving Least Squares Recovery Technique with constraints (MLS-C)[3]. Section 4 will describe the main Subroutines used for the Matlab implementation of the MLS-C technique and the Subroutines created using the Ansys macros language to invoke the MLS-C Subroutine. Section 5 will present illustrative numerical examples. Most of the material presented in this thesis in Sections 2 to 5 will be published together with the software under the GNU license. Finally Section 6 will present the conclusions of this work with an anex with all Matlab code in the Section 8.[ES] El objetivo principal de la tesis es adaptar una librería desarrollada en Matlab que implementa la tecnica de reconstrucción de tensiones MLS-C para que en el futuro pueda ser, bajo licencia GNU LGPL, de libre disposición para usuarios. La librería es una herramienta para evaluar los campos de tensiones recuperadas apartir de los resultados obtenidos por diferentes analisis numericos como el MEF o metodos sin malla. Para ilustrar el uso de la libreria MLS-C, se crearà una interface con el codigo comercial Ansys para que la libreria se llame directamente desde Ansys para postprocesar el campo discontinuo de tensiones en 2D proporcionado por este codigo. La librería presenta una alternativa de alta calidad al promediado nodal usado por Ansys para obtener campos continuos de tensiones. Para publicar la libreria MLS-C, hemos elegido la licencia GNU GPL introducida por Richard Stallman que a por objetivo dar a los usuarios la libertad de modificar, compartir, distribuir y redistribuir. En es tesis, la seccion 2 va a describir la licencia GNU, la seccion 3 va a presentar un resumen de la tecnica MLS-C. La seccion 4 describirà las subrutinas principales usada para la implementacion de la tecnica MLS-C en Matlab, y subrutinas creadas usando fichero macro de Ansys para llamar a la subrutina MLS. Seccion 5 presentarà ejemplos numericos ilustrativos. El material presente en esa tesis, de la seccion 2 a la seccion 5 se va a publicar bajo la licencia GNU. Finalemente, la seccion 6 presentarà la conclusion de este trabajo con un anexo con toda la subrutina implementada en Matlab en la seccion 8Ouallal, M. (2014). Adaptation of a library, to be released as free software, for the improvement of the finite element solution using the MLS-C recovery technique. http://hdl.handle.net/10251/47510Archivo delegad