Improving computational efficiency in LCM by using computational geometry and model reduction techniques Elias Cueto 1,a , Chady Ghnatios 2,b , Francisco Chinesta 2,c , Nicolas Montes 3,d , Fernando Sanchez 3,e , Antonio Falco 3,f 1 Aragon Institute of Engineering Research, Universidad de Zaragoza, Spain 2 Ecole Centrale de Nantes, France 3 Universidad Cardenal Herrera-CEU, Valencia, Spain a ecueto@unizar.es, b Chady.Ghnatios@ec-nantes.fr, c Francisco.Chinesta@ec-nantes.fr, d nicolas.montes@uch.ceu.es, e fernando.sanchez@uch.ceu.es, f afalco@uch.ceu.es Keywords: Liquid Composite Molding, Resin Transfer Molding, model order reduction, computational geometry. Abstract. LCM simulation is computationally expensive because it needs an accurate solution of flow equations during the mold filling process. When simulating large computing times are not compati- ble with standard optimization techniques (for example for locating optimally the injection nozzles) or with process control that in general requires fast decision-makings. In this work, inspired by the concept of medial axis, we propose a numerical technique that computes numerically approximate distance fields by invoking computational geometry concepts that can be used for the optimal location of injection nozzles in infusion processes. On the other hand we also analyze the possibilities that model order reduction offers to fast and accurate solutions of flow models in mold filling processes. Introduction In this work we pursue a fast and efficient method to locate an (approximate) optimal location for injection nozzles and vents in LCM processes. To this end, we consider the following main assump- tions: • We try to avoid to simulate processes based on Darcy's law (just to try to be as efficient as possible) • As a first approach, we consider homogeneous reinforcement with therefore homogeneous (and isotropic) permeability tensor. This will be later refined. • As a first approach, we consider the process linear and reversible. This means than an hypothet- ical process in which injection is made from the vents would locate the position of the nozzles. Under these hypothesis, it seems reasonable to assume that the medial axis of the geometry of the piece is a good indicator 4 of the position of injection nozzles. The medial axis [1] of an object is the set of all points having more than one closest point on the object's boundary. Since non-isotropic reinforcements would alter the velocity field during the process, and it is not clear how this would affect the position of the medial axis, we propose here an alternate algorithm to compute the medial axis that is amenable to changes in the case of non-isotropic reinforcements. This algorithm is based upon the use of level sets. 4 Still with some limitations. For instance, the medial axis of an object with sharp corners touches its boundary, thus provoking nozzles and vents to coincide at particular locations. Key Engineering Materials Vols. 611-612 (2014) pp 339-343 © (2014) Trans Tech Publications, Switzerland doi:10.4028/www.scientific.net/KEM.611-612.339 All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP, www.ttp.net. (ID: 79.108.132.85-08/05/14,09:56:51)