During the processing of long fiber-reinforced thermoplastics (LFT), various long fiber specific effects occur, which can have significant influence on the component properties. A major effect that results when processing LFT is Fiber Matrix Separation (FMS), which leads to a non-uniform fiber density distribution throughout the part. The development and impact of this effect is not thoroughly examined to date. Experimental investigations in compression molding with long fiber reinforced thermoplastics have shown an unequal distribution of fiber content with increasing fiber length. With effects already visible in flat plates, FMS especially leads to significant changes in fiber content in complex geometries. Particularly in specific rib sections, fiber content decreases greatly, leading to a significant change in component behavior. Furthermore, extensive fiber bundling and clogging is observed at the rib entrance. The appearance of these effects and the governing mechanisms of FMS are analyzed in a set of compression molding experiments with long fiber reinforced materials. It is observed that the interaction of fibers in narrow cross sections leads to excessive fiber bridging, interlocking and local accumulation. This leads to the creation of a fiber dam inside the base of the rib, hindering other reinforcement fibers from entering the middle and upper rib regions. The most significant influencing parameters on the appearance of FMS during compression molding are the fiber length and the rib geometry. In addition, the initial charge position and therefore the initial fiber position before rib entering have an increasing effect on FMS. Conclusively, design guidelines for the application of long fiber reinforced materials are introduced. With the results of the experiments as the governing mechanisms of FMS, a new approach for the simulative prediction of FMS is pursued. Due to the shortcomings of conventional process simulation software, a new simulative approach, the Direct Fiber Simulation (DFS) is applied. ...
Analysis and Prediction of Fiber Matrix Separation during Compression Molding of Fiber Reinforced Plastics ; Analyse und Vorhersage von Faser Matrix Trennung während des Fließpressens von faserverstärkten Kunststoffen
2018-01-01
Hochschulschrift
Elektronische Ressource
Englisch
DDC: | 629 |
Recycling von faserverstärkten Kunststoffen
IuD Bahn | 1997
|Fügen von faserverstärkten Kunststoffen im strukturellen Leichtbau
Tema Archiv | 2004
|