Prof. Anoush Poursartip
,
The University of British Columbia, Vancouver, BC, Canada
Mr. Daniel Fricke
,
German Aerospace Center (DLR e.V.), Stuttgart, Baden-Württemberg, Germany
Ms. Ines Mössinger
,
German Aerospace Center (DLR e.V.), Stuttgart, Baden-Württemberg, Germany
Dr. Ashley Chadwick
,
German Aerospace Center (DLR e.V.), Stuttgart, Baden-Württemberg, Germany
Mr. Tristan Wiedmann
,
German Aerospace Center (DLR e.V.), Stuttgart, Baden-Württemberg, Germany, The University of British Columbia, Vancouver, BC, Canada
Dr. Kamyar Gordnian
,
Convergent Manufacturing Technologies Inc., Vancouver, BC, Canada
Dr. Alireza Forghani
,
Convergent Manufacturing Technologies Inc., Vancouver, BC, Canada
Mr. Sebastian Nowotny
,
German Aerospace Center (DLR e.V.), Stuttgart, Baden-Württemberg, Germany
Semi-crystalline thermoplastics as a matrix material of fibre reinforced composites have become increasingly common in the aerospace industry. The crystallisation of the polymer matrix heavily influences part quality and performance and is also a common source of internal stress and warping when not accurately predicted. A detailed material model coupled with robust process simulations can help to alleviate uncertainties and produce high quality parts. In order to understand the crystallisation mechanics of the composite material, experimental techniques such as differential scanning calorimetry are used to develop digital material models and determine the influence of thermal gradients and different material parameters on the final degree of crystallisation.
In a first study at the DLR a simple method for adapting existing material models developed by the UBC and Convergent Inc. to a new material has been developed. Recent works at the DLR, UBC and Convergent showed that the crystallisation process is influenced both by the matrix material itself and by the fibres. The fibre volume content and fibre diameter, among other material properties, change the crystallisation process and must be considered when creating material models. These influences on the crystallisation temperature and rate increase with higher rates of cooling.
Future works will focus on understanding the influences on crystallisation and in turn the influence of crystallinity on material parameters even further. Process simulations rely on detailed material models, and understanding all influencing parameters is crucial in predicting material behaviour during processing and more firmly establish processes like Automated Fibre Placement.
