High speed study of composite failure

Louise Smyth

Specialised Imaging reports on how the Institute for Carbon Composites, Technical University of Munich, Germany, is using a Kirana Ultra High-Speed camera to record high resolution images of a unidirectional Carbon-Epoxy composite material undergoing a dynamic tension test on a split-Hopkinson Tension Bar.

The experimental setup was to determine the mechanical properties of Carbon Epoxy composites under high strain rates (100 – 1000 1/s). The deformation and the failure patterns of these composite materials, was observed and recorded in tests that lasted less than 200 micro seconds.

Using the Kirana camera has provided the LCC with the ability to capture high-resolution images of the ultra high-speed events that often occur when undertaking dynamic tension tests. Taking up to 5,000,000 frames per second, and shuttering every 100 nanoseconds, there is no compromise in capturing high quality data. The data is exported in 180 frames so each test can be easily saved and viewed.

Using the images captured by the Kirana ultra high-speed camera, the LCC researchers imported them into state-of-the-art Digital-Image-Correlation (DIC) software** enabling the calculation of the in-plane strain-field. In addition, the images revealed useful information regarding the deformation and failure mechanisms of the specimens.

The Institute for Carbon Composites (LCC) undertakes fundamental research and application-oriented industry cooperation in the field of fibre-reinforced composites. Experimental methods are of great importance for the investigation of material behaviour and the further development of fibre-reinforced polymer matrix composites At the LCC a broad spectrum of state-of-the-art test methods and equipment is available for the determination of the physical and mechanical properties of matrix systems and laminates. In addition to the application of various standards, the LCC also investigates and develops new and innovative testing techniques.

** DIC software used – GOM Aramis

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