- 作者: 李賢華
- 作者服務機構: 國立中山大學海洋環境系
- 中文摘要: 本研究主要在探討黏彈性阻尼解析模式的發展,及其應用於海洋結構時之減振效應。在結構上由風力及地震力所產生的劇烈振動,常導致結構的變形及破壞。為了改善這種情形,具有高度吸能能力的黏彈性阻尼,乃被應用於結構中,來加強結構體的動力性能。而海洋結構、除了風力之外、由波浪及流所產生的振動,更將加重結構的變形及破壞。因此,如果能將具有良好吸能能力的黏彈性阻尼應用於海洋結構中,對於結構的動力性能將有良好改善。 本文中分析一簡化的海洋結構系統,受到規則波或隨機波浪所產生外力,分別作用時的動力行為。其中,波力引用Morrison的方程式作用於細小物體,波浪則假設為微小振幅波。針對此非線性系統在時間域的反應分析,本文中導出了一包含了黏彈性阻尼解析模式的增量運動方程式。由分析的結果中發現,加了黏彈性阻尼後,海洋結構物受到動力作用時所產生的振動,有明顯的降低效果。
- 英文摘要: The research described in this paper involves the development of techniques for new damping devicesapplied to typical offshore structural systems, and a method for time domain analysis on offshore structuralsystems incorporating nonlinear viscoelastic material. Mitigation of vibration and enhancement of dynamicperformance for the offshore structural system were observed during the analysis. This investigation wasperformed for typical offshore structures subjected to wave forces induced by both harmonic and randomtype waves. The wave force was based on the Airy wave theory and Morison equation for a small body.Based on the Newmark method for nonlinear systems, a numerical method for analysis of offshore structuresincorporating a viscoelastic damper is developed. After carrying out computation in the time domain,results of the vibration responses for the system with added dampers are used to evaluate the effect ofthe vibration mitigation. In the cases analyzed, it is found that the amplitude of the vibration of the structurecan be reduced by up to one half compared to the original amplitude.
- 中文關鍵字: offshore structure; dynamic analysis; viscoelastic damper; vibration mitigation
- 英文關鍵字: --