Abstract

La principal dificultad que se encuentra en el momento de diseñar estructuras
con materiales compuestos es la falta de modelos constitutivos que permitan si- mular su
comportamiento.  Las técnicas analíticas convencionales utilizadas para el estudio de materiales
simples isótropos no resultan adecuadas para el análisis de materiales compuestos. Tampoco ha
resultado satisfactoria la representación de un compuesto mediante un único material ortótropo con
propiedades del conjunto. Puede observarse en distintas referencias los intentos que ha habido para
modelar el comportamiento de materiales compuestos, utilizando la técnica de elementos fi- nitos
para el análisis y diseño de estructuras, donde la correlación entre los análisis y los resultados
experimentales no resulta satisfactoria (Ali, 1996) (Klintworth y Macmillian, 1992). El proceso de
diseño de componentes en materiales compuestos se ha basado, principalmente, en métodos empíricos,
observándose en la literatura la ausencia de análisis o simulaciones del comportamiento de
materiales compuestos sometidos a niveles de esfuerzos que sobrepasan el límite elástico.

Abstract

Materiales Compuestos is the journal edited by the Spanish Association of Composite Materials (AEMAC). Its first volume has been published in year 2017. The journal aims to be a gathering point for researchers, developers, technicians, engineers, scientists and, summarizing, all those professionals conducting their activity in the field of composite materials.

The main objective of the journal is to disseminate the scientific and technological developments made in the field of composite materials, which might be of interest to AEMAC and to all other professionals to whom this journal is addressed. Under this scenario, are of special interest for the journal all works developed in Spain, Portugal and Latin America, as well as works from any other origin that might be of interest to be shared in the journal’s forum.

Abstract

Compression After Impact (CAI) test is normally used for the assessment of damage tolerance of composite laminates. The applicable specification for the execution of these tests is AITM 1-0010. However, for thicknessess under 4mm were buckling occurs, the applicable specification is the AITM 1-0077, which introduces the use of anti-buckling tooling covering the entire surface of the specimens. The tooling, which is used in the aeronautical industry  for the testing of thin specimens presents two problems which are the difficulty of assembly and of obtaining realiable results, and the visibility of the specimen during the test.

This work comprises the design, manufacturing and validation of a novel anti-buckling device for compression after impact thin specimens. For that purpose, a study of the specification toolings along with a review of the already developed anti-buckling tooling literature has been carried. As part of the validation process three series of impacted specimens of 3mm thickness.

This activity is developed as part of the project CERES, which is framed under Clean Sky 2, and has the main objective of validating the manufactured anti-buckling tooling. This tooling has been developed as an innovative solution for its application in compression after impact thin specimens. 

Abstract

This paper presents the experimental validation of a thermal treatment technology to recover added-value substances from the plastic matrix of end-of-life wind turbine blades, when these are subjected to a pyrolysis process to recover the glass fibres. The experiments have been carried out in a laboratory installation consisting of two reactors in series, in which pyrolysis and thermal treatment of pyrolysis gases and vapours take place, respectively. The application of this treatment enables a 25 wt.% reduction in the production of pyrolysis liquids, increasing the production of gases in an equivalent way and without compromising the pyrolysis conditions to be used to recover the glass fibres. The two-phase liquids are converted into single-phase aqueous ones, while the hydrogen concentration in the gases increases from 4 % to almost 50 % in volume. This high concentration of hydrogen in the gases allows them to be used as a source of hydrogen for various applications. Consequently, the technology demonstrates that the plastic matrix of wind turbine blades can be valorised in a pyrolysis based recycling process.

Abstract

It is estimated that the aeronautic industry in the European Union produces annually around 10 tn of uncured prepreg scraps, generated mainly from manual and automated lamination processes of composites, and that the treatment cost for these residues is between 3 and 12 € per kilogram.

This work presents a technology for the reuse of the unidirectional prepreg scrap using a machine that allows the manufacturing companies, mainly form aeronautic sector, the reuse and valorisation of the leftovers of PREPREG in the workshop, involving a reduction in the economic and environmental impact.

The developed solution consists in a machine able to perform the needed processes to reuse the prepreg scrap leftovers in an automatic and efficient way, maintaining the quality and the material properties for the manufacturing of non-critical components. The equipment integrates different technologies that include computer vision to identify the shape of the leftovers and the fibre direction, cutting technology to generate regular rectangular chips aligned with the fibre direction, and a robotic system to pick and place the chips generating an ordered pattern.

The result of the process is a material sheet aiming to control the mechanical properties by using homogeneous chips with controlled fibre orientation following a predefined pattern.

Abstract