An evaluation method for estimating the damping of loosely supported single U-bend tube used in a steam generator colliding with a support plate is proposed. First, we performed experimental modal analysis and obtained natural frequencies, modes and damping without collision by Impulse Modal Test and then analysed natural frequencies, modes and damping with collision employing FEM analysis taking account of the collision force. In modelling the characteristics of the collision force, we applied Bijlaard's model for the spring constant and assumed hysteresis. After that, we performed experiments for measuring the damping ratio by changing the gap size and the support plate position. Comparison between calculated and experimental results is made which shows good agreement. Experimentally observed fact showing damping coefficient increases with the initial amplitude is well explained by theoretical model.
|ジャーナル||Journal of Physics: Conference Series|
|出版ステータス||Published - 2012|
|イベント||Modern Practice in Stress and Vibration Analysis 2012, MPSVA 2012 - Glasgow, United Kingdom|
継続期間: 2012 8月 28 → 2012 8月 31
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