Design of Hybrid Dynamic Balancer and Vibration Absorber

[[abstract]]This study proposed a novel hybrid dynamic balancer and vibration absorber that is cheaper than active dampers and more effective than passive dampers. The proposed damping system does not need to be altered structurally to deal with different damping targets. Rather, the proposed vibration absorber is capable of self-adjustment to the optimal damping location in order to achieve balance and, thereby, optimize damping effects. The proposed device includes a groove under the damping target with inertial mass hung from a coil spring beneath. This allows the device to bounce vertically or rotate in order to reduce vibrations in the main body. The coil spring vibration absorber can also slide along the groove in order to adjust its location continuously until the vibrations in the system are minimized and the main body is balanced. Experiments verify the efficacy of the proposed device in improving damping performance beyond what has been achieved using conventional devices. We also provide an explanation of the theoretical underpinnings of the design as well as the implications of these findings with regard to future developments.[[notice]]補正完畢[[journaltype]]國外[[incitationindex]]SCI[[cooperationtype]]國外[[ispeerreviewed]]Y[[booktype]]電子版[[countrycodes]]NL

減振器位置對於雙層振動平板減振效能之研究

[[sponsorship]]中華民國航空太空學會; 交通大學機械工程系; 交通大學前瞻火箭研究中心; 國家科學委員會工程技術發展處工程科技推展中心[[conferencetype]]兩岸[[conferencedate]]20121215~20121215[[booktype]]電子版[[iscallforpapers]]Y[[conferencelocation]]新竹, 臺

非線性懸吊彈性樑及端點減振器之研究

[[abstract]]本研究考慮一Bernoulli-Euler Beam 之彈性樑以鋼纜懸掛，而鋼纜以非線性彈簧與線性阻尼組成，彈性樑的一端為鉸接邊界支撐，另一端則掛載時變之動態減振器 (DVA) 。本研究因具有時間變化之邊界條件，所以採用 Mindlin-Goodman 法分析此問題。此外本文使用多尺度法解析此非線性系統，發現系統中第一模態及第二模態存在一對三的內共振情形，並繪製系統於穩態固定點的情況下，各模態的頻率響應圖，以觀察其非線性內共振現象，且以數值模擬其時間域之振動情形，相互驗證之。另外本研究將分析DVA 的質量及彈簧係數對於整個系統之減振影響，並提出最佳的質量與彈簧係數組 合，可使系統達到最佳減振效果。最後，吾人以一簡單的空氣動力函數模擬氣流對於本彈性樑系統之阻尼的影響，利用Floquet Theory 搭配Floquet Multipliers (F.M.) 判定法則，繪製出Basin of Attraction圖形，觀察此系統之穩定性，以獲得最後結論。[[abstract]]This study investigated the performance of a mass-spring dynamic vibration absorber (DVA) at the free end of a hinged-free elastic beam under simple harmonic excitation. This beam system was suspended by suspension cables. These cables were simulated by cubic nonlinear springs to examine the nonlinear characteristics of this system. This time-dependent non-homogeneous boundary condition problem was solved by Mindlin-Goodman method. The method of multiple scales was performed to solve the nonlinear equations. The 1:3 internal resonance was found at the 1st and 2nd modes of this beam system. The fixed point plots were obtained and compared with the numerical results to verify the system internal resonance. The Poincaré Map was also utilized to identify the system instability frequency region of the jump phenomenon. The optimal DVA mass and the spring constant were provided for best beam vibration reduction. Finally, the wind speeds and aerodynamic loads were included to investigate the stability of this system. The system stability was analyzed by Floquet theory and Floquet multipliers. The basin of attraction charts were made to verify the effects of the combinations of DVA’s mass and the spring constant at diverge speed.[[sponsorship]]中華民國航太學會; 淡江大學機電工程學系; 淡江大學航空太空工程學系[[cooperationtype]]國內[[conferencetype]]國內[[conferencetkucampus]]淡水校園[[conferencedate]]20131130~20131130[[booktype]]電子版[[iscallforpapers]]Y[[conferencelocation]]新北市, 臺

可調式之多質點減振器對於振動機構減振效能之研究

[[sponsorship]]北京航空航天大學[[conferencetype]]兩岸[[conferencedate]]20120903~20120905[[booktype]]紙本[[iscallforpapers]]Y[[conferencelocation]]北京市, 中

The Effects of Wake Dynamics and Trailing Edge Flap on Wind Turbine Blade

[[abstract]]In the present study, we considered the bladewake interaction (BWI) and the TEF span length, index angle on a turbine blade. The aerodynamic loads and the stresses on the blade were studied. The wake dynamic theory, BEM, and the ANSYS-FORTRAN APDL method were employed. Results were correlation with a small turbine for blade stress distribution. The blade lift distribution was also compared with numerical results from [6]. Finally, the wake and the TEF configuration effects on a 5MW turbine blade in the lift distribution and stresses were presented in this work.[[cooperationtype]]國內[[conferencetype]]國際[[conferencetkucampus]]淡水校園[[conferencedate]]20140623~20140628[[booktype]]電子版[[iscallforpapers]]Y[[conferencelocation]]New Taipei City, Taiwa

[[alternative]]Study of Parameter Excitation of Dynamic Vibration absorbs

[[abstract]]本研究目的是研究一考慮參數激擾共振影響的動態減振器，在主體兩自由度的振動影響下穩定情形。此動態減振器由一非線性彈簧及質量塊組成，主體可視為精密加工或是傳統產業的機械製造工具機的基座。利用牛頓力學法、Lagrange法和時間多尺度法分析及推導此減振器的運動方程式，求出振 動頻率與振幅相對曲線，找出不穩定區域並求得能有最佳減震效果的耦合彈性係數及彈簧下質量塊的質量（轉動慣量）。[[sponsorship]]中華民國航太學會[[sponsorship]]成功大學航空太空工程學系[[cooperationtype]]國內[[conferencetype]]國內[[conferencedate]]20141115~20141115[[booktype]]電子版[[iscallforpapers]]Y[[conferencelocation]]台南市, 台

[[alternative]]Stochastic frontoer models with errors in variables: A GMM approach

[[abstract]]當隨機邊界模型逐漸被應用到不同的研究領域時，如何處理變數衡量誤差的問題，成爲亟待解決的課題。本文針對具有變數衡量誤差問題的隨機邊界模型，提出一組GMM估計式，以求得模型參數的不偏估計值。此GMM估計式是以模型的高階動差爲建構基礎，且是特別針對具有截斷式常態分配的隨機邊界模型所設計，而此類模型正是目前實證應用最廣的模型。蒙地卡羅的模擬結果顯示，該估計式在觀察數爲500的樣本中，即有良好的表現。[[abstract]]As the use of stochastic frontier (SF) models increases in the various fields of economics and finance, the need to address the problem of measurement errors in variables becomes urgent. In this paper, we propose a generalized method of moment (GMM) estimator for a stochastic frontier model to correct the measurement error problem. The estimator differs from the method of moment (MoM) estimator of Chen and Wang (2004) in two important ways: (1) The GMM estimator is proposed for a SF model with a truncated-normal random variable, which is a more flexible and empirically-popular model than the half-normal SF model targeted by the MoM estimator. (2) The GMM estimator uses more moment conditions and is more efficient. Simulation results show that the GMM estimator performs quite well for data with a reasonable sample size.[[journaltype]]國內[[incitationindex]]TSSCI[[ispeerreviewed]]Y[[booktype]]紙本[[booktype]]電子版[[countrycodes]]TW

具動態失速效應之非線性無鉸接葉片動態分析

[[conferencetype]]國內[[conferencedate]]20031219~20031219[[iscallforpapers]]Y[[conferencelocation]]臺南, 臺

旋翼葉片氣彈分析

[[abstract]]本文整合直昇機旋翼葉片之非線性複材葉片結構動力模式、動態失速模式，以及 三維動力尾流模式，將其組合成為一氣彈耦合模式，並建立一套多變數非線性方 程式的求解程序，藉以探討動態失速及尾流效應對複材主旋翼葉片形變與穩定性 之影響。本研究並以中科院研發之EAGLE600直昇機為範例進行一系列的氣彈分析 ，以期能兼顧理論與實用的價值，及充分掌握分析數據與設計參數之關聯性，並 對國內 旋翼葉片氣彈分析 技術之成長有所助益。[[conferencetype]]國內[[conferencedate]]20031219~20031219[[iscallforpapers]]Y[[conferencelocation]]臺南, 臺

[[alternative]]An optimum design for helicopter rotor blade shape and performance study in forward flight

[[conferencetype]]國內[[conferencedate]]19951208~19951209[[iscallforpapers]]Y[[conferencelocation]]桃園縣, 臺