Elastic Stresses in Single Mitred Bends

Abstract

Experimental results are presented for the stresses caused by internal pressure in thin pipes which are mitred and welded together to form a single mitred bend without any type of elliptical insert at the intersection. The frozen-stress photoelastic technique is used, the models being carefully machined and cemented to form a joint free from welding imperfections. The results are compared with the theoretical analysis for small-angle mitred bends, of Green and Emmerson (I)†. An alternative derivation of this theory is given in Appendix I. Good agreement with the theory is shown for small-angle bends for each of the two thicknesses of pipe used. For larger angles of bend, the agreement is less good. The results of a test carried out on a mitred joint subjected to an in-plane bending moment, are included.