A proposal for evaluation of running shear fracture propagation distance calculated by design factors in high-pressure gas pipeline

摘要

Many investigations have been conducted to evaluate a crack propagating distance of running shear fracture propagation in high- pressure gas pipeline. Four important equations, which they were gas decompression behavior, the crack velocity-pressure relation, the pressure at a crack arrest and change of crack velocity, were presented by their efforts from the results of many full- scale burst tests or application of the fundamental formulae.A combination of these equations made it possible to calculate a crack propagating distance of running shear fracture propagation in high-pressure gas pipeline. But, there are two remaining problems for the calculation used only design factors. One is the reconstruction of two constants in the velocity- pressure relation to evaluate the influence of pipe diameter, and the other is to give the initial distance and the initial time which could be calculated from design factors for the numerical calculationof a crack propagating distance.Recently, author proposed an estimable method for each problem, and these methods may be possible to be taken in above combination for the calculation of a crack propagating distance.In this paper, a calculation method was presented which used only a few of design factors such as a sort of gas, internal pressure, pipe geometry and the characteristics of the pipe material, and the calculated crack distances were compared with theresults of the full- scale burst tests, which include five kinds of pipe diameters, conducted by AISI.The results showed good coincidence, therefore, this calculation method by only a few of design factors would be successful for the evaluation of a crack propagating distance of running shear fracture propagation in high-pressure gas pipeline.