3D Simulation of defect accumulation in orientation-dependent fiber-reinforced polymers through computed tomography
3D-SFC: March 2012 – February 2014
The major goal of this project is to realise reliable strength and lifetime predictions for real fibre reinforced thermoplastic polymers that consider the effect of changes in microstructure at fatigue testing on the mechanical stability of the final product. Especially for highly loaded components from automotive industry, fatigue tests are performed in order to determine damage by use of three-dimensional computed tomography. Using this information, theoretical models will be established that consider the mechanisms of damage and local fibre orientation, which are able to predict the remaining lifetime of a product. Product design can be performed considerably more time- and material- efficient by use of the developed models. The results of this project are especially important for automotive industry, light weight applications as well as leisure-, electrical- and consumer goods industry.
Promoting Agency: FFG
For lightweight construction in automotive industry and other industry branches more and more highly loaded structural components are made from fibre reinforced polymers by injection moulding. The reason is the high design flexibility, the fast, economic and automated manufacturing and the improved mechanical properties along with low weight components.
For component designing simulation tools are used that provide information about strength at static and dynamic loading. However fibre reinforced material are prone to big variation in simulation and reality that are difficult to measure and to model. The variations are mainly caused by variations of morphological values like fibre orientation or fibre length distribution. Data of fatigue strength and engineering strength have to be determined by tedious and sophisticated mechanical long time fatigue tests at the components.
Methode / Goals
The project 3D-SFC deals with the development of theoretical models for simulation of strength that include mechanisms that lead to fatigue fracture at cyclic loading. To increase the accuracy of the simulation results, values for fibre orientation and length will be determined for real components. These values will be included into the model. The reason for failure is the development of damage within the matrix fibre composite. Defects like pores, cracks, fibre breakage or loss of fibre-matrix bonding will occur at cyclic loading. Damage of this kind will be detected and quantified by computed tomography three dimensionally.
Results / Findings
to be translated soon - Die Ergebnisse tragen dazu bei, den Materialeinsatz bei der Bauteilauslegung durch Überdimensionierungen und unnötig hohe Sicherheitsfaktoren zu reduzieren. Eine Reduktion von Entwicklungszyklen wird durch die Kenntnis der Beziehung - Schädigung zu Lebensdauer - und der Möglichkeit der Lebensdauerbestimmung durch Simulation in einem frühen Stadium der Bauteilentwicklung erzielt. Die angewendete Methodik stellt insofern eine grundlegende Neuerung dar, weil eine morphologische Beschreibung der Schädigung durch 3-dimensionale Computertomographiemessungen an realen Bauteilen als Basis für Festigkeitssimulationen verwendet wird und damit Lebensdauervorhersagen möglich werden. Aufwändige Langzeitbelastungstests an produzierten Realbauteilen werden dadurch eingespart.