X-ray computed tomography for non-destructive evaluation of steel wire ropes: Comparison of laboratory XCT configurations for image quality and damage visualization

Abstract

Steel wire ropes are critical structural components whose internal damage often cannot be reliably assessed using conventional non-destructive testing methods. This study evaluates the applicability of laboratory X-ray computed microtomography (XCT) for detailed inspection of steel wire ropes by comparing three complementary XCT configurations: one employing a liquid-metal anode microfocus source with a large-area flat-panel detector, a conventional sealed-type microfocus tube with CMOS detector, and a high-power X-ray source coupled with scintillating screen and a laboratory camera. Intact and damaged rope specimens together with an individual fractured steel wire were investigated under various acquisition conditions. Image quality was quantitatively assessed using the contrast-to-noise ratio (CNR) and the full width at half maximum (FWHM) of the line spread function, complemented by qualitative evaluation of reconstructed three-dimensional models. The results demonstrate the influence of X-ray source characteristics and the acquisition parameters on image quality and defect detectability. Although the high-power system provided superior penetration capability and the highest CNR, its large focal point substantially limited the achievable spatial resolution. In contrast, both microfocus configurations enabled reliable visualization of individual wires and internal damage features, with image quality strongly dependent on the number of acquired projections. The presented comparison provides practical guidance for selecting appropriate laboratory XCT configurations for non-destructive evaluation of steel wire ropes and similar highly attenuating engineering components.