Control of the stress-strain state of steel structures using the magnetoelastic method

The accuracy of mechanical stress monitoring in steel structures using magnetic methods is affected by the spread of the magnetoelastic properties of the material, which is related to its chemical composition, manufacturing technology, and heat treatment regime. The objective of this study was to monitor axial tensile stresses in steel using magnetoelastic demagnetization. Tests were conducted taking into account the magnetoelastic sensitivity of the material, which was determined under additional transverse compression. The working axial tensile stresses of the bottom flanges of I-beams made of 15KhSND steel were evaluated. The magnetoelastic memory of the flanges and plate steel specimens under axial tension and local transverse compression was analyzed. It was found that the relative change in the stray magnetic field strength of the local residual magnetization of the studied beams and specimens is directly proportional to tensile and transverse compressive stresses. It was shown that the magnetoelastic sensitivity of the analyzed steel grades to tensile and compressive stresses, determined by the slope of the identified dependencies, differs by 10 – 20%. The obtained results can be used to improve the methodology for monitoring the technical condition of operated steel structures.