Fracture Toughness of Multi-layer Pipes

0308835 - ÚFM 2008 CZ eng A - Abstrakt
Nezbedová, E. - Fiedler, L. - Majer, Zdeněk - Vlach, B. - Knésl, Zdeněk
Fracture Toughness of Multi-layer Pipes.
5th International Conference on Materials Structure and Micromechanics of Fracture. Abstract booklet. Brno: VUTIUM, 2007 - (Šandera, P.). s. 126-126. ISBN 978-80-214-3434-9.
[MSMF /5./. 27.06.2007-29.06.2007, Brno]
Výzkumný záměr: CEZ:AV0Z20410507
Klíčová slova: polyethylene pipes * K - calibration * fracture toughness
Kód oboru RIV: JL - Únava materiálu a lomová mechanika

In the contribution life-time expectation of the three layer commercial plastic pipe with dimensional integrated protective surfaces was investigated. The fracture toughness is chosen as a relevant parameter for evaluation the resistance of the pipes material against slow crack growth. To evaluate fracture toughness values of the interlayer PE 100 pipe material the following steps have been done: The material parameters (tensile modulus E and yield stress sy) for both inner and outer layers of the three layers pipe were determined for temperatures 230C and –600C. A new non-homogeneous C-shaped fracture mechanics specimen machined directly from the pipe, see Fig. 1A, has been suggested. The corresponding values of the stress intensity factor KI, represented by the geometric factor f(a/W), have been calculated. The numerical analyses were carried out under plane strain conditions by using a finite element method. The values of dynamic fracture toughness KQd for two different specimen thicknesses and for temperatures 230C and –600C were determined on the two types of instrumented Charpy impact testers.
Trvalý link: http://hdl.handle.net/11104/0161182