Estimation of ultimate tensile strength of tubular materials using Ring Hoop Tension Test with cylindrical pins

Abstract

Mechanical characterization of metallic pipes is essential for assessing their structural integrity in industrial applications. The Ring Hoop Tension Test (RHTT) offers a simpler alternative to traditional methods for determining hoop strength, with two primary variants: the D-shaped pin configuration, which requires custom tooling for each pipe geometry, and the cylindrical pin system, which simplifies testing but introduces bending stresses. While the cylindrical pin method reduces friction-related uncertainties, its applicability for estimating ultimate tensile strength (UTS) had not been explored. This study develops a correlation between the minimum slope of the RHTT load–displacement curve and UTS in the hoop direction, specifically for cylindrical pins. A dual approach combining finite element analysis (FEA) and experimental validation was employed. Numerical simulations examined the influence of pipe slenderness, pin diameter, and strain-hardening behavior, leading to an empirical model. Experimental tests on aluminum 6061-T6 pipes confirmed the method’s accuracy, with deviations below 3 % compared to standard tensile tests. The results highlight the impact of geometric factors, particularly the diameter-to-thickness ratio, and introduce a pin-size correction factor to refine the methodology. This work demonstrates that RHTT with cylindrical pins can effectively estimate UTS, offering a practical and reliable alternative to conventional methods.