Long-term performance of thermoplastic composites
Start / End:
April 2016 to April 2010
University of Twente
Faculty of Engineering Technology
Chair of Production Technology
P.O. Box 217
7500 AE Enschede
Room N202, “Horst” building
Phone : +31-53-489 2726
This project is funded by DSM.
Smart, lightweight, reinforced polymer systems are used in a multitude of load bearing applications where structural integrity and long-term reliability are of utmost relevance. Examples run from energy saving constructions in mobility, like lightweight airplanes, cars, trucks and trains, to replacements of expensive and rare metals in pumps, pipes and components in (hot) water management and gas transport and distribution. In all these areas, high performance thermoplastic engineering polymers are used as matrix materials and combined with different volume fractions of either short or long reinforcing fibres. Failure under static or dynamic loading conditions is a major concern in these products; it is not the question whether failure will occur, but rather on what time scale.At present, two important factors still limit the widespread application of these materials. The first is that, due to the lack of predictive theories for long-term (fatigue) failure, the reliability of these materials can only be warranted after full-scale testing of actual products. This procedure is costly and time-consuming, hampering optimization and a flexible response to market demands. Additionally, the long-term performance can usually only be checked over a limited loading time which is usually orders in magnitude smaller than the desired lifetime under service loads.
In this research project, we aim to clarify the role of different failure processes in time-dependent failure of continuous fibre-reinforced thermoplastic composites, and develop novel experimental and modelling methods that will provide a fundamental basis for fast and accurate lifetime estimation. Such tools will enable optimization in various stages of design, leading to lighter, more reliable products with short time-to-market and an enhanced service life.
First step is to investigate the long-term failure of continuous-fibre 90°C unidirectional coupons and identify the governing failure mechanisms, which are expected to be similar to those of pure polymers and short-fibre reinforced composites since for all cases matrix dominates the behaviour under the load. The starting material used for manufacturing laminates is iPP/fiberglass tape. Afterwards, laminates made of different material systems (fibre and matrix combinations) will be tested to see whether the observed failure mechanisms are generic or not. After gaining experience with 90°C coupons, the work will continue with off-the axis unidirectional coupons with different fibre orientations.