Stress Analysis of Flanged Pipe Joints by the ‘Frozen Stress’ Photoelastic Method

In the paper is described an investigation carried out to determine the elastic distribution of stress in rings and flanges using the frozen stress photoelastic method. Preliminary tests on rings and flanges showed linear load-residual deflection relationships over the main test ranges. A series of tests was performed on plain rings of different thicknesses loaded uniformly round the inner edge and round a diameter corresponding to the pitch circle. Three series of tests, namely to investigate the influence of flange thickness, number of bolt holes and length of hub, were performed on model flanges subjected to simulated bolt loading. A further series of tests was performed on flanges integral with a short length of pipe and subjected to internal pressure. The complete distributions of tangential and radial contour stresses were obtained over the whole free surface of the rings and over the free surface at both types of radial section of symmetry in the flanges. The axial deflections were also measured. The test results are compared with those computed from the various theoretical solutions.