Please login first
Analysis of preload effect in the axisymmetric damped steel wire using ultrasonic guided wave monitoring
1  Indian Institute of Technology (IIT) Bhubaneswar, India


In this research paper, the guided ultrasonic wave propagation characteristics in the axisymmetric prestressed viscoelastic waveguide for acoustic emission (AE) monitoring using the semi-analytical finite element (SAFE) method is studied broadly. The formulation demonstrated in this work uses a cylindrical coordinate system to reduce the finite element discretization to one-dimensional mesh over the cross-section of the axisymmetric waveguide. For the numerical investigation, a single high strength steel wire is considered. Based on the axisymmetric SAFE method, a comprehensive and in-depth study on the propagation characteristics of the AE signal in a single wire is carried out. Both undamped and damped waveguides are considered for attaining SAFE solutions and presented in a detailed manner. The SAFE method for an axisymmetric cross-section in cylindrical coordinates is utilized to analyze the two main influencing factors of steel wire in a practical scenario, namely, material damping and initial tension. For steel wire of viscoelastic material, energy velocity and attenuation factor are indicators that are more suitable for describing their fluctuation characteristics. For the effect of initial stress, the calculation shows that the initial tensile stress can increase and decrease the energy velocity and attenuation factor of most modal waves above the cut-off frequency, and the effect is linear. Finally, a mode suitable for cable AE monitoring is carefully chosen. Some longitudinal wave modes in the high-frequency region show their potential for AE monitoring as these modes have a low attenuation factor and small external surface vibration. By considering various states of initial stress in a cylindrical damped waveguide, the effect of prestress on the dispersion characteristics is understood in a better manner. It showed potential for non-destructive evaluation and health monitoring application of overhead transmission line conductors.

Keywords: guided wave propagation; damped waveguide; semi-analytical finite element method; acoustic emission; steel wire; prestress load; structural health monitoring