Abstract
Carbon steel pipe specimens, which had been experimentally ruptured or deformed by hydrogen-oxygen detonation, were analysed by dynamic analysis using a finite element method (FEM). Pressure load histories induced by detonation were estimated by computational fluid dynamics (CFD). These pressures were applied to the inner surface of finite element models of pipe specimens. The relationship between stress and strain for piping material was obtained by performing a tensile test at a high strain rate of up to 5000 s-1. The thickness of the pipe specimens measured by an ultra sonic thickness meter was used for the FEM model geometry. In the case of the straight pipe specimens with a closed valve, FEM analyses estimated larger deformation caused by a detonation pressure than that of the test specimens. For the ruptured elbow specimen, the rate of increase in circumferential strain calculated by FEM was as high as or higher than that of the experiment. In the case of an elbow specimen deformed by detonation pressure, CFD predicted that the peak pressure at the extrados of the elbow was increased by reflection off the pipe wall. However, it did not deform the extrados of the elbow by a large amount in both the experiment and FEM analysis. In all cases, analyses of the strains caused by detonation pressure showed that they were as high as or higher than those of the measured results in the pipe specimens. Therefore, piping design using the proposed analysis method conservatively estimates the strength of piping against detonation pressure.
