Geometrical optics applied to composites heating by laser beam

Abstract

Consulta en la Biblioteca ETSI Industriales (Riunet)

[EN] Recently a novel composites manufacturing process using thermoplastic materials, known as Laser Assisted Tape Placement (LATP) has awaken great interest due to its broad range of applications in the automotive, aeronautic and space industries. The rationale behind the substitution of thermoset by thermoplastics materials is avoiding the use of autoclaves, traditionally required when considering the use of thermosets, that implies costly resources, long processing times and high energy consumption. ATP technologies use a laser beam for melting the thermoplastic ensuring the tape consolidation. In order to simulate the heating process one must consider one of the available models related to geometrical optics. The most widely used are ray-tracing models that despite their conceptual simplicity require too much computation for tracking individual laser trajectories. The purpose of this work is developing an alternative methodology for simulating laser-composite interaction. In fact fibers surface acts as a mirror that absorb a part of the incoming flux contributing to its heating. Our approach, instead of simulating the path of any given beam, establishes the relations between the power reaching and leaving each portion of the fibers surface, the last described from a polygon whose faces act as mirrors, and the visibility between these different mirrors. A large matrix containing all this information is obtained and solved only once to obtain all the valuable information. The main disadvantage of this method is the size of the resulting matrix whose dimension scales with the number of mirrors considered in the discretization of the fibers surface. Noting that the number of mirrors could be of several millions, coarser descriptions and/or the use of GPU-based computation seem compulsory.