Polymer matrix composites are currently used in many structural applications that require a significant reduction in weight for energy and/or environmental reasons. A paradigmatic example is the new composites developed for aeronautical applications.
For example, as much as 25% of the weight of the new AIRBUS A380 aircraft is made up of composites (GLARE® and fibreglass and carbon fibre composites) in its wings, fuselage and tail sections and the new Boeing 787 Dreamliner boasts the first fuselage made entirely of composites. However, for these structural designs to be truly efficient, these new materials must be exploited to their maximum potential.
Unless our knowledge of the materials progresses, this potential will be restricted by the presence of internal defects (delaminations, voids, wrinkles, etc.), which arise either from the manufacturing process or during the assembly and maintenance of these structures.
But, how can these internal defects be found? And once they have been located, what makes the difference between a defect being harmless and it genuinely compromising the structural integrity of the material? Currently, the aeronautical industry is required to carry out vast batteries of mechanical tests on different scales (from the material itself, through sub-components, to the entire structure), which can take as long as seven years, to validate and certify new materials for use. Wouldn't it be better to have the necessary understanding to be able to predict the mechanical behaviour of a new composite and, more importantly, the effect of any defects that could occur? Following several recent advances, this understanding is now within the reach of Materials Science and Engineering.On the one hand, non-destructive analysis techniques have been developed, such as X-ray computed tomography. This technique is based on computer-assisted reconstruction of the three-dimensional microstructure of the material based on X-ray radiographies taken from various viewing angles. The development of new X-ray generation and detection techniques means it is now possible to achieve sub-micrometer resolutions, making this technique a valuable tool for internal characterisation of defects and the study of propagation of damage in composites with great reliability, as can be seen in the following images.
On the other, new simulation strategies and the increase in computational power over recent years have made it possible to develop powerful micro- and meso-mechanical models. These explicitly take into account the configuration of fibres (and the typology of the defects), making it possible to predict both the mechanical behaviour and the mechanisms responsible for failure, as well as how they interact with pre-existing defects in the material.
In order to go into greater depth on these aspects and to develop tools that will enable composite manufacturers to distinguish between the various types of defects, IMDEA-Materiales is leading the DEFCOM project, with funding from the regional government of Madrid through the ERA-net MATERA network. The consortium, made up of Austrian universities and companies from aeronautical industry (SECAR) and the wind power sector, will spend three years working in this subject. For this, IMDEA-Materiales has a state-of-the-art X-ray nanotomography device, Phoenix Nanotom, with a nominal resolution of 0.3?m, and is using the most advanced multi-scale simulation techniques applied to composites.
IMDEA | alfa
Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously
17.01.2017 | Sonderforschungsbereich 668
Manchester scientists tie the tightest knot ever achieved
13.01.2017 | University of Manchester
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
17.01.2017 | Earth Sciences
17.01.2017 | Materials Sciences
17.01.2017 | Architecture and Construction