Investigation of Fibre Movement in Molten Polymer during Shaping Processes of Thermoplastic Composites

• Published in: Key engineering materials 2014-05, Vol.611-612, p.375-381
• Main Authors: Engel, Bernd, Aldudak, Fettah, Foysi, Holger, Soemer, Evelyne
• Format: Article
• Language: English
• Subjects: Computational fluid dynamics; Fibre; Forming; Mathematical analysis; Mathematical models; Matrix materials; Polymer matrix composites; Thermoplastic resins
• ISSN: 1013-9826; 1662-9795; 1662-9795
• DOI: 10.4028/www.scientific.net/KEM.611-612.375

In forming processes of thermoplastic composites, the combined forming behaviour of matrix material and fibre reinforcement determines the resulting geometry and structure. These specific characteristics of the components and their interaction vary during the processing steps, especially for the matrix material with change in temperature. During the forming step, the molten thermoplastic polymer exhibits viscoelastic behaviour. Therefore, the fibres encounter resistance if a forming load is applied. The resulting fibre alignment is dependent on the forming temperature, the forming speed, and the time between the release of load and cooling. An investigation into the specific matrix characteristics during the forming step is presented. In the experiments a representing fibre is drawn through a molten polymer specimen under variation of speed and temperature and the resistance force is measured. The experimental findings are compared to numerical results obtained with a computational fluid dynamics (CFD) package using a finite volume approach and its ability for the prediction of fibre movement in molten matrix during forming processes is evaluated. In addition, a better understanding of the impact of forming speed and temperature during forming processes due to the characteristics of the molten matrix is obtained.