Evaluation Method of the Bolt Conclusion Using the Scattering Parameter for Ultrasonic Waves

An evaluation method of the bolt conclusion using the reflection coefficient, S 11 , from the scattering parameter of ultrasonic waves was proposed. First, the optimal resonance frequency of the transducer was determined. As the result, the transducer of the 2 MHz resonance frequency would be used in the next experiment because the variation of the reflection coefficient was the greatest compared with transducers of other resonance frequencies. Second, the reflection coefficient, S 11 , of the axial force was measured. The reflection coefficient decreased as the axial force was increased. The reflection coefficient greatly decreased at the almost standard axial force of the bolt. The usefulness of this evaluation method of the bolt conclusion was demonstrated.