Project 2.1

ZPT+HP P2.1 Bild B150px

3D microstructure, defect and damage investigations on polymeric systems

High resolution non- destructive testing methods will be developed for the characterization of the microstructure, defects and damage mechanisms of heterophasic polymeric materials.
Fibre and particle-reinforced composite materials (with e. g. glass-GFRP, carbon-CFRP, cellulose fibres etc.) offer excellent performance in terms of ease of fabrication, excellent mechanical properties, reduction in weight and low process costs and are therefore widely employed, especially in the automotive and aeronautical industries. The increasing use of reinforced polymers for safety-critical products requires strict quality control, thus promoting the development of novel non-destructive testing and evaluation techniques. Therefore, it is in the common interest of the company partners within this project to develop and apply enhanced NDT methods for quantitative characterization and quality control of these material systems. In particular, the detection and evaluation of properties such as fibre orientation and length distribution (FOD, FLD), orientation of phases, etc. as well as defects (e.g. pores, inclusions, cracks, delaminations, etc.) are the focus of interest.
Another aspect is fatigue damage accumulation and the failure processes, which appear to be particularly multi-faceted in these materials. These materials are characterized by a complex microstructure, in which multi-scale mechanisms occur. These interactions still need to be fully understood. The development of increasingly accurate predictive models is therefore closely related to the attainment of a qualitative and quantitative knowledge of the processes that govern the onset and development of damage. In order to reach this goal in-situ methods and the combination of material simulation with quantitative 3D-extraction from XCT-measurements play an important role. In addition to imaging the material properties by XCT before or after an experimental test (ex-situ), especially the knowledge of evolution over time is of particular interest (in-situ) e.g. defects or damage mechanism during tensile testing. The combination of tensile testing with XCT provides a powerful way of extracting quantitative material data for describing how specific material properties change under varying loading conditions.
Particularly for the design and production of light-weight components, hybrid metal/plastic components offer more advantages than purely metal parts because plastic can be more easily shaped to the desired form and weight is reduced. Because of the artefacts occurring at the polymer/metal interface it is currently very difficult to detect cracks and delaminations in hybrid components with XCT. Therefore, methods to reduce these artefacts need to be developed and applied.