Response and cyclic strain accumulation of pressurized piping elbows under dynamic in-plane bending

Abstract

Eight pairs of carbon and stainless steel, long and short radius welding elbows were tested under conditions of steady internal pressure and in-plane, resonant dynamic moments that simulated seismic excitations. The elbows had an outside diameter of 60.3 mm and thicknesses of 3.91 and 5.54 mm. The material properties are reported, and the testing procedure and experimental programme fully described. The dynamic response of the comonents indicates that the stainless steel elbows behave differently from the carbon steel elbows. The cyclic strain accumulation for each component is assessed and ratios of applied to limit moments of the elbows at onset of ratcheting are given for each material. While the gross deformation range increased with level of input in testing, no permanent overall swelling or ovalization was recorded; this is contrasted with similar results reported in the general literature.