| 摘要 |
PROBLEM TO BE SOLVED: To provide a vibration fatigue control method for a material allowing determination of whether a vibration fatigue in the material is in a progressing state or not by a simple method. SOLUTION: While a normal forced vibration applied to a socket welded part 40 is stopped, an elastic wave is applied by hitting a part of the socket welded part 40 with a hammer to damp the forced vibration, a relative displacement between first and second measuring parts T1, T2 is measured by accelerometers 31, 32. An intensity of an n-th harmonic wave in respect to a base vibration wave at the socket welded part 40 is obtained by analyzing the damping vibration in terms of time-frequency. A displacement width in a transition area where the n-th harmonic wave increases/decreases is obtained as a lower fatigue limit amplitude. Then, while the normal forced vibration is recovered, a management on whether a vibration fatigue is progressing or not is conducted based on whether a relative displacement between the first and the second measuring parts T1, T2 exceeds the lower fatigue limit amplitude. |
