減震平台之樑柱結構分析

由於台灣位處環太平洋地震帶上，介於菲律賓海洋板塊與歐亞大陸板塊衝撞的交界帶上，使得台灣的地震活動非常頻繁。然而地震的發生，到目前的科技還是無法準確的預測到地震何時會發生，因此在設計結構時，結構的抗震能力是很重要的。隨著科技的進步，各種機械和電子元件的製造均朝向精密化，使越來越多微小精密的元件被製造，然而元件在製造時外在產生的震動或者是機台本身產生的震動，這些都會影響加工的品質，降低生產的效率，及製造成本的增加等。因此不管是提高機台本身的抗震能力，或者有效的抑制外來的震源，一直以來都是被重視的課題，也被廣為研究。本文使用ANSYS Workbench 12軟體來分析其震動平台的柱子，探討地震作用下對平台防震效果的影響，提供一個防震平台的參考依據。本文模擬是以一個強迫振動給予柱子結構，並藉由增加阻尼和修改結構設計以達到減震、防震的效果且對於抑制外來的震源也是有相當大的幫助。經由模態分析得到柱子本身的自然頻率以及模態振型，再由簡諧響應分析得到當柱子受到一個激振作用時所產生的頻率、位移及加速度曲線。由模擬後所得數據修改柱子的長度尺寸，最後再將整個防震平台做模態分析取得整體的模態振型。結果顯示柱子的剛性是會影響整個平台的抗震效果，所以在做結構設計時進行數值模擬分析對於結構的設計有一定的參考價值。關鍵詞：模態分析、自然頻率、簡諧響應分析、結構設計

關鍵字

模態分析；自然頻率；簡諧響應分析；結構設計

並列摘要

As Taiwan is located in Circum-Pacific Seismic Zone, between the Philippine Sea plate and the Eurasian continental plate collision at the junction belt, Taiwan's earthquake activity is frequent. However, the occurrence of the earthquake, the current technology still can not accurately predict when earthquakes will occur, so in the designing structure, the structure of the seismic capacity is very important. With technological advances, machinery and electronics manufacturing are towards precision, increasingly small precision components to be manufactured. However, when the components manufacture the external vibration or the vibration by the machine itself, which will affect the processing quality, reduce production efficiency and manufacturing cost increase etc. Therefore, improving the seismic capacity of the machine itself, or effectively inhibit external vibration, which has always been an important issue, also been widely studied. In this study, using ANSYS Workbench 12 software to analyze the vibration platform pillars, exploring the effect of platform seismic capacity under the earthquake, and providing a reference based on the Vibration-Proof Platform. The simulation was based on given the pillars structure a forced vibration, and achieved the effect of shockproof by increase the damping and changed structural design, and it was also helpful to restrain external vibration. After the modal analysis, obtained the natural frequency and mode shapes from pillar itself, and obtained the frequency, displacement and acceleration curves from harmonic analysis when the pillar was in the excitation frequency. The data obtained by simulation and then modified the length size of the pillars, and simulated the Vibration-Proof Platform by modal analysis to obtain the overall mode shape. The results showed that the rigidity of the pillars will affect the effect of the seismic capacity. So it has the reference value when doing the structural design by numerical simulation for the structural design. Keywords：modal analysis, natural frequency, harmonic analysis, structural design