應用平坦度評估模式對衝擊平台半正弦波產生器之設計分析

本研究目的在於發展一套半正弦波產生器之幾何理論預測程式，並同時考慮平坦度與衝擊座數量之影響，以期得到最佳之預測結果。首先以單自由度系統模擬衝擊平台與膠塊，發展衝擊力與膠塊幾何形狀預測模式，並建立MATLAB軟體之半正弦波預測程式，設定規範所要求半正弦波之加速度峰值、時間間隔等參數與衝擊平台質量、測試高度等，以得到膠塊幾何大小。進一步可擴充設計膠塊的放置位置與膠塊數量，使其撞擊後在平台上所產生之瞬間衝擊應力能最均勻分布，且符合規範中半正弦波之標準響應區間外型。並導入電腦輔助工程分析(CAE)技術，模擬撞擊過程，也結合實驗模態分析(EMA)技術驗證模型等效性，以得知平台上所產生之波形變化，使能進一步了解其膠塊各項參數對衝擊時間與加速度之關係，並套入平坦度評估模式，利用分析所得之加速度結果對衝擊平台進行平坦度評估分析，用以選定各種尺寸、大小及位置之衝擊座，達到較佳之平坦度，以符合於各種試驗條件及規格之衝擊試驗規範。

關鍵字

衝擊試驗機；衝擊平台；衝擊試驗； LS-DYNA ；撓性平台理論；操作模態實驗；半正弦波產生器；半正弦波產生器

並列摘要

This work aims to develop the prediction method for the geometry design of half-sine programmer in considering the shock table flatness and numbers of programmers. First, the single degree-of-freedom (SDOF) model is adopted to develop the predictive model for the selection of programmer as well as the impact force. The MATLAB software is used to implement the code to obtain the geometry of the programmer and the shock table free-fall height by setting the system parameters, such as the acceleration peak value, impact time duration and shock table physical properties. The developed method can account for the number and location of the programmers such that the shock table can maintain better surface flatness during shock impact and in accordance with the specified shock waveform. The computer aided engineering (CAE) technique is also employed to simulate the impact process to predict the shock waveform after impact, while the experimental modal analysis (EMA) is used to validate the FE model. Various parameters are studied to correlate the programmer geometry design with the peak acceleration and impact time. The shock table flatness is also of interest and is shown to calibrate the effectiveness of the programmer design so as to fit the best conditions from different aspects of testing criteria.

並列關鍵字

shock testing equipment ； shock table ； shock testing ； LS-DYNA ； theory of flexible table ； operational modal analysis ； half-sine pulse programmer ； flatness evaluation

參考文獻

Low, K. H., Yang, A., Hoon, K. H., Zhang, X., Lim, J. K. T., and Lim, K. L., 2001, “Initial study on the Drop-Impact Behavior of Mini Hi-Fi Audio Products,” Advances in Engineering Software, Vol. 32, pp. 683-693.

王栢村，陳榮亮，2001，「頻譜分析儀之功能測試」，中華民國振動與噪音工程學會第九屆學術研討會論文集，新竹，第16~20頁。

Wang, Y. Y., Lu, C., Li, J., Tan, X. M., and Tse, Y. C., 2005, ”Simulation of Drop/Impact Reliability for Electronic Devices,” Finite Elements in Analysis and Design, Vol. 41, pp. 667-680.

Li, X. G., and Shemansky Jr., F. A., 2000, “Drop Test and Analysis on Micro-Machined Structure,” Sensors and Actuators, Vol. 85, pp.280-286.

Zeng, T., Fang, D. N., and Lu, T. J., 2005, “LS-DYNAmic Crashing and Impact Energy Absorption of 3D Braided Composite Tubes,” Materials Letters, Vol. 59, pp. 1491-1496.

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應用平坦度評估模式對衝擊平台半正弦波產生器之設計分析

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