Fracture mechanics of polymers. Critical evaluation for linear elastic behaviour at high speed testing

摘要: Over the last few years considerable effort has been made to obtain reliable stress intensity factor and strain energy release rate (K IC andG IC) data on polymeric materials. Experience shown that a valuable method minimize viscoelastic losses plastic deformation is work at high speed. However, some problems remain, for this kind of experimental method, which have be solved before standard methods can defined. On basis measurements done with 3-point bending geometry poly(vinylchloride) (PVC) poly(propylene) (PP) room temperature over large range notch depths, present demonstrates linearity both in load (F) (U) against (2BW 2/3LY√a) (BWφ) plot not critical test linear elastic behaviour, so values affected by errors. Only knowledge curves, obtained means instrumented pendula optimized conditions, allows applied based comparison between predicted load, displacement energy. These tests show fracture mechanics, LEFM, criterion satisfied PVC, but PP. This conclusion further supported morphologies surfaces.