Development and characterization of composites consisting of woven fabrics with integrated prismatic shaped cavities

Composites are extensively used in automotive, construction, airplanes, wind turbines etc. because of their good mechanical properties such as high specific stiffness, high specific strength and resistance against fatigue. The main issues with composites are delamination and the manual labour in the production process. If hollow structures like stiffeners need to be manufactured, these problems become even more apparent. As a result, there is a lot of interest in woven fabrics with integrated prismatic shaped cavities for composites as they reduce the manual labour, have a higher resistance against delamination and can lead to special properties and applications. In this work several of these woven fabrics with integrated prismatic shaped cavities are designed and produced in high-tenacity polyester yarns. Then, the possibility to use these fabrics in composites is explored: reproducibility of the production process is assessed and static testing is performed. A reproducible production process is developed and static testing shows promising results

Postural adjustments in catching: on the interplay between segment stabilization and equilibrium control

The purpose of this study was to investigate postural adjustments in one-handed ball catching. Specifically, the functional role of anticipatory postural adjustments (APA) during the initial arm raising and subsequent postural adjustments (SPA) for equilibrium control and ball-hand impact were scrutinized. Full-body kinematics and kinetics allowed an analysis of the mechanical consequences of raising up the arm and preparing for ball-hand impact. APA for catching were suggested to be for segment stabilization. SPA had a functional role for equilibrium control by an inverted pendulum mechanism but were also involved in preparing for the impact of the ball on the hand, which was illustrated by an increased postural response at the end of the movement. These results were compared with raising up the arm in a well-studied reaction-time task, for which an additional counter rotation equilibrium mechanism was observed. Together, our findings demonstrate that postural adjustments should be investigated in relation to their specific functional task constraints, rather than generalizing the functional role of these postural adjustments over different tasks

Lenoweven: opportuniteiten en beperkingen van de naaldlenotechnologie

In het vorig nummer van Unitex werd de technologie van het lenoweven en meer in detail de naaldlenotechnologie uitvoerig beschreven. Daarin werden reeds kort de opportuniteiten en beperkingen van naaldeleno aangehaald. Door de verhoogde weefsnelheid worden meer toepassingsmogelijkheden voor lenoweefsels economisch haalbaar. Weefsels met hogere dichtheden, vooral dan hogere inslagdichtheden worden haalbaar evenals vervangingsweefsels voor open kettingbreisels. Voorbeelden van ontwikkelingen zijn: - weefsels met “engineered” rek-trekdiagram - weefsels met verhoogde dimensionale stabiliteit bij uitrekking - gaasweefsels voor speciale einddoelen - gordijnen en meubelstoffen - vloerbedekking Er blijven desalniettemin nog een aantal beperkingen die de ophang van deze technologie nog afremmen: (a) technologische kinderziekten, (b) beperkte dessineermogelijkheden, (c) een tekort aan wetenschappelijke kennis en praktijkervaring en (d) de nood aan een betrouwbare meetmethode voor de schuifweerstand. De Vakgroep Textiel van de Hogeschool Gent is, in nauwe samenwerking met de collega’s van de Universiteit Gent, jaren terug gestart met het verkennen en onderzoeken van de (naald)lenotechnologie, waarbij nauw werd samengewerkt met lokale wevers en Picanol. In de afgelopen jaren was dit onderzoek zeer intens in het kader van enerzijds een IWTTetraproject met als doel de mogelijkheden van de naaldlenotechnologie dieper te verkennen en anderzijds een HoGent OF-project om na te gaan in hoeverre met deze technologie ook textielvloerbekleding (“Lenotapijt”) kan geproduceerd worden. In dit artikel wordt ingegaan op een aantal resultaten van dit onderzoek

GRASS : flame retardant artificial turf : safe and sustainable

Artificial grass is mainly composed of organic polymers with a consequent potential fire hazard. However, the behaviour of artificial grass in case of fire has been poorly studied and is thus misunderstood. The GRASS project has two objectives: informing the public that natural turf has a different fire behaviour than artificial turf and improving fire behaviour of artificial turf by developing innovative, eco-friendly and industrially applicable processes. In the project, constant consultations take place with a resonance group of stake holders represented by producers, installers, sports organisations, governments and end users. The involvement of the resonance group is sufficient guarantee that the new processes emanating from this project will be acceptable for all actors involved in the artificial turf sector (from production and end usage to recycling) and that they will be put into practice