Análisis de tensión y deformación de un material con el método de Correlación digital de imágenes (DIC)

Abstract

[ES] Para medir la tensión durante el ensayo de tracción de las muestras a veces se requieren imágenes que deben ser relacionadas con los datos de la máquina de tracción. Esto podría hacerse pulverizando un polvo punteado sobre la superficie de la muestra, para crear un patrón. A continuación, se toman fotografías para medir el movimiento de los puntos de la superficie en función de la tensión aplicada en el ensayo. Por lo tanto, la tarea será desarrollar un método para realizar estas imágenes cada 0.5 segundos y sincronizar los datos con un software de análisis de correlación digital de imágenes. Se puede comparar los datos obtenidos con el método de correlación digital de imágenes con los datos de un extensómetro.

[EN] This document offers an overview of the potentialities and limitations of digital image correlation (DIC) as a technique for measuring displacements and strain in biomechanical applications. As DIC involves a high degree of computation, and of operator-dependent decisions, reliability of displacement and strain measurements by means of DIC cannot be taken for granted. This review includes many tests as well as the study of many different factors and variables that can affect the reliability of the results obtained through the testing. Problems involving methods used are addressed as well as possible or existing solutions, as well as variations of the method tha can lead to better results in terms of optimization or cheapening. Topics addressed include: speckle pattern and its acquisition, analysis of relative error and a theoretical approach not only to the software but to the classic strain test. The obtained results are compared to measuremnets obtained through different methods. Limitations of the method are discussed as well as repeatability and the possibility of new sources of error when taking our method to an industrial approach. In order to provide an overview accessible to many scientists not necessarily mathematical based, this document intentionally does not include details of the complicated mathematical methods used by the software the thesis is based on.