For the epoxy resin RTM6 only brittle fracture is observed, starting directly at the notch tip. As for PTFE, the crack stops after a certain crack length L\(_1\) (see Fig. 13). The length L\(_1\) of this first fracture event is almost the full available specimen length. This first fracture emits a pair of well measurable AE and EME signals. Subsequently one or more additional macroscopic fracture events occur with much smaller crack lengths. The EME signals emitted by these events are very weak but still measurable with our set-up. The EME signals of RTM6 are the weakest of all tested polymers. The polarisation of the first rise in EME voltage signal seems to be completely random.
Postmortem: One Must Die (Extended Cut) Full Crack [Xforce]l
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