| Abstract: | Investigation of the Fracture Behaviour of Three-Dimensionally Reinforced Composites by Electron Scan Micorscopy By the use of woven or braided textile performs it is possible to reduce manufacturing costs and to improve damage tolerance of composite materials due to a three-dimensional fibre reinforcement. An important requirement for the application of these new technology is a basic understanding of the fracture behaviour because the unique fibre architecture can cause totally different effect. In an experimental program composite specimen with 3D woven and braided fibre reinforcement have been tested in the special fixture of an electron microscope, allowing the detection and monitoring of smallest damages (fibre-fracture, matrix-fracture, interphase-fracture, delaminations notch-growth) and the investigation of damaging effects directly during static and dynamic tests. The loading condition of the notched and un-notched specimen was three-point bending. The Electron Scan Microscope in combination with the in-situ loading fixture has been prooven to be a very interesting tool to investigate micromechanical damaging effects. It shows that the 3D reinforcement, especially o the woven material, leads to a significant improvement o damage tolerance resulting for example in a drastical limitation of notch growth in static and dynamic tests. |
