Author(s): Mangualde, Pedro Miguel Ferreira de Sousa Pepe
Date: 2016
Persistent ID: http://hdl.handle.net/10362/21553
Origin: Repositório Institucional da UNL
Subject(s): Meso-mechanics; Interface elements; Failure criteria; Delamination; Damage propagation; Mesh generator; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia Mecânica
Composite materials, specifically Carbon Fiber Reinforced Polymers, have a complex mechanical behaviour, therefore it is extremely complicated to predict failure and damage. There has been an increasing use of composite materials for structural applications as an alternative to metal due its lightweight and strength properties. Consequently, it is important to consolidate the knowledge about its behaviour under different loads in order to apply them correctly in structural applications. The Carbon Fiber Reinforced Polymer studied in this dissertation is a spread tow carbon fabric with four different arrangements - 0°/-90°, 15°/-75°, 30°/-60° and 45°/-45° under tension loads. A computational tool was developed in order to predict failure and damage propagation in Carbon Fiber Reinforced Polymers specimens. It is an interface program between the software Matlab and ANSYS. A mesh generator algorithm was developed in Matlab in order to automatically model specimens with different arrangements. Afterwards, an incremental iterative analysis is performed using an optimized methodology developed in Crespo’s dissertation [3] which gradually increments the displacement applied to the specimen. This analysis uses ANSYS as a solver, using the finite element method, to calculate the specimen’s mechanical behaviour and stress. The results are exported to Matlab, which applies a proposed failure criterion to the specimen’s elements and initiates ANSYS “killing” the failed elements and applying a new displacement. The program executes several iterations until the specimen’s failure and, in the end, plots the force applied and displacement in the specimen’s end. The numerical models were validated with numerous analysis using experimental and numerical results from articles and dissertations from different authors in order to guarantee the precision of the results and simulations.
