A model technique for bending strength of tubular joints

Abstract

One shape of ‘Y—T’ joint has been die-cast in a tin-lead alloy. Twenty-one models have been tested in in-plane or out-of-plane bending, loading one or both braces. The results are presented non-dimensionally as Ultimate Strength Reduction Ratios (USRR) i.e., as fractions of (simply calculated) bending moments which would have ensured failure of the brace remote from the joint. The results from the tin-lead models agreed with relevant results from steel models. Parametric equations derived mainly from ‘T’ joint data predict the failure of 90 degree braces well, but underestimate the strength of 45 degree braces in in-plane and out-of-plane bending. Plastic collapse occurs on the compressed side of the braces before tearing on the tension side.