Additional Information - Posters # 1995 Edinburgh
Previous research has concluded that rapid crack propagation (RCP) cannot be sustained in 100% water pressurised pipe. However, this paper shows that by reducing the decompression wave speed in water to below the crack speed, it is possible t o sustain fast cracks in thermoplastic pressure pipe. T h e prediction of R C P by finite element/volume analysis requires adequate material property data. The Irwin-Corten analysis has been used to calculate dynamic fracture resistance, Go,from the critical pressures of a wide range of water pressurised thermoplastic pipes. The data from a water-pressurised pipe test show good agreement with predictions from a recent analytical model of RCP, based on a melting mechanism local to the crack tip. Many conventional fracture tests require a correction factor to solve GD for specimens of finite size. In the water pipe test the specimen geometry is accounted for in the analysis, with no need for correction factors. The test provides data suitable for pipe numerical modelling by maintaining the original morphology and intemal stresses of the material.