A Pressure-Moment Capacity Curve for 16-inch Induction Bends

摘要

Pipe bend pressure-moment capacity curves have been derived basedrnon full scale pipe bend tests and numerical simulations. The presentrncapacity curves show that pipe bends on Ormen Lange spoolpieces are,rnaccording to three different criteria, well within capacity limits, whilerndesign codes indicated that utilization of the bends was exceeded. FErnmodels have been performed in “LS-DYNA implicit” and calibratedrnagainst full scale tests with good match. Numerical analyses werernconducted to perform test runs with external and internal overpressurernin opening and closing bending mode. Moment capacities of bendsrnwere then evaluated using the three criteria: (1) twice elastic slopern(TES), (2) 3 % ovality and (3) 0.2% equivalent strain. Momentrncapacities were then calculated as a function of differential pressure.rnActual bending moments in Ormen Lange spoolpieces calculated byrnsimple beam models was then compared to the capacity curves for loadrnsteps; pressure test (190 bar), operation (169 bar) and depressurizationrn(-85 bar). Significant residual capacities in OLSFD spoolpieces are thenrndocumented. Even though the present study is project specific, arnpossible approach is presented to document capacity of pipe bendsrnunder large external and internal pressure in combination with bendingrnmoments.