臺灣博碩士論文加值系統

本文應用動態分析方法輔以等高線技巧，來探討含非延伸性張開型
裂縫之$Bernoulli-Euler$ $column$，在材料遵循虎克定律下，承受到
部份跟隨力作用時，切向係數、裂縫深度、裂縫位置、邊界條件及彈性
束制等參數，對其臨界不穩定機構和臨界挫曲負荷的影響。從各種參數變化狀況下，我們觀察到在非保守系統時，隨著切向係數的增加，使得臨界不穩定機構由發散型轉變到顫振型，同理可說，增加切向係數一般能夠增加臨界挫曲負荷值；倘若切向係數繼續增加，則臨界不穩定機構又由顫振型到發散型，其臨界挫曲負荷值將跟隨切向係數增加而減小；在保守系統時，切向係數則不影響臨界挫曲負荷值。對於裂縫深度的影響，除了一些比較深的裂縫會因為材料強度之改變，非線性因素的存在，造成臨界挫曲負荷值增加之外，其餘皆會隨裂縫深度的增加而遞減。而對於保守系統下，裂縫的位置愈靠近束制性支承或自由端時，其臨界挫曲負荷值的強度愈大，反之則愈小，並且關於束制性較強的邊界支承，其不同裂縫深度造成臨界挫曲負荷值之減少量，有比較小的下降趨勢。

This essay, based on the dynamic or kinetic approach and contour method, is dedicated to the study of the influence of the tangency coefficient, the depth of the crack, the location of the crack, the boundary conditions and the elastic restraints on the critical instability mechanism and critical buckling load of the Bernoulli-Euler column of the nonpropagating open cracks, whose material is subject to Hooke's law, which undertake the partially follower force. Firstly, by means of characteristic curves diagrams with changes in parameters, we notice that as the tangential coefficient increases, the nonconservative system makes the critical instability mechanism transform form divergence to flutter; also, the increase in tangential coefficient results in the increase of the value of the critical buckling load. If tangential coefficient keeps increasing and critical instability mechanism transforms from flutter to divergence, the value of the critical buckling load will decrease. However, the value of the critical buckling load won't be affected by the tangential coefficient when it is under conservative systems. Secondly, as for the effect of the depth of the crack, the value of the critical buckling load will increase when some deeper cracks are with the changes in the flutter instability. Otherwise, the value of the critical buckling load will decrease as the depth of crack increases. Thirdly, the closer the ( nonpropagating single sided and the pair of double sided open ) crack approaches the constrained support and/or free end, the greater the value of the critical buckling load. On the contrary, the value of the critical buckling load diminishes. Last but not least, as for the effect of the boundary conditions, the more strongly constrained support leads to less diminution of the value of the critical buckling load which results from different crack depth.

摘要 i
英文摘要 ii
目錄 iii
圖目錄 v
表目錄 x
符號說明 xi
第一章 緒論 1
1 - 1 前言 1
1 - 2 文獻回顧 4
第二章 理論分析 7
2 - 1 裂縫柱的柔度矩陣 7
2 - 2 裂縫柱的彈性行為 11
2 - 3 控制方程式與邊界條件 14
2 - 4 特徵方程式與探討的問題 16
第三章 結果分析與討論 23
3 - 1 驗證比較 23
3 - 2 結果與討論 23
第四章 結論 35
參考文獻 37
附表 40
附圖 42
附錄I：矩陣F的元素 112

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