Buckling Assessment of Heat Exchanger Tubes Considering the Manufacturing Eccentricity: A Simplified Methodology Based on Experimental Insights

Abstract Slender tubes are prone to buckling failure under compressive loads, which remains a critical challenge in the design of thin tubes. The fabrication of slender tubes is susceptible to manufacturing eccentricity, which reduces the buckling strength. The geometric axes of a practical 3D heat exchanger tube may not align perfectly due to manufacturing eccentricities that span multiple planes. This study introduces a novel methodology that consolidates multidirectional eccentricities into a single representative parameter, thereby enabling the application of the simplified Euler's buckling equation for strength assessment. Based on detailed buckling experiments on slender heat exchanger tubes, the proposed bracket square sum and root (BSSR)-based combination method is shown to reliably predict axial compression behavior by accounting for multiplane eccentricities within a 1.0% variation. These findings provide a robust framework for integrating experimental insights with classical theory, offering improved reliability and efficiency in the structural evaluation of buckling strength in practical three-dimensional tubular structures under compressive loads.