臺灣博碩士論文加值系統

本研究將針對鋁合金蜂巢夾層板在常溫環境下進行四點彎矩之基本及兩階段累積疲勞試驗，以期能對鋁合金蜂巢夾層板的累積疲勞性質能有更完整的了解。
本研究首先針對鋁合金蜂巢夾層板在常溫下進行四點彎矩靜態基本疲勞試驗，利用其靜態極限強度之75%、70%、65%、60%、55%及50%作為基本疲勞實驗之最大負荷，透過疲勞實驗可得到室溫下之負荷-壽命曲線並觀察其破壞模式。基本疲勞實驗結果顯示：在常溫環境下鋁合金蜂巢夾層板四點彎矩疲勞實驗破壞主因是面板壓痕(indentation)破壞。本研究中的兩階段累積疲勞實驗選擇基本疲勞壽命曲線中，對應疲勞壽命為10萬週次及50萬週次的負荷階分別作為兩階段累積疲勞實驗之負荷階。實驗內容的研究變數包括兩階段負荷階之高低變化與第一階段疲勞實驗之週次比。本研究對於第一階段週次比對累積疲勞行為之影響，以Miner’s rule的理論公式來預測第二階段殘餘壽命。研究結果顯示，兩階段累積疲勞中負荷階由高做到低時，其兩階段週次比和有小於1之趨勢，反之則大於1。這顯示了當試片先受到較低負荷階之疲勞負荷對其疲勞壽命較有助益，反之可能降低此試片之疲勞壽命。由此結果可說明鋁合金蜂巢夾層板在承受兩階段疲勞負荷時存在者與金屬材料相同的負荷順序效應。

Two-stage cumulative bending fatigue behavior of the adhesively joint aluminum honeycomb sandwich panels has been experimentally investigated in this study.The loading levels for the two-stage cumulative fatigue experiments were selected from the fatigue baseline of the same kind of honeycomb sandwich panels. The high and low loading levels of the two stage represent the applied loads corresponding to the fatigue lives of 100,000 and 500,000 cycles, respectively. The loading sequence effect and the cycle ratio of the first level were the variables considered in the experimental program. The experimental results show that the sum of the cycle ratios of the two stage is larger than unity when the loading sequence of the two stage is from low to high, while the sum of the cycle ratios of the two stage is less than unity when the loading sequence of the two stage is high-to-low. The results imply that the loading sequence effect exists in the two stage cumulative fatigue tests for the studied sandwich panels and the Miner’s rule fails to predict the remaining cycle ratio of the second level. The indentation of face sheet is the mail failure mode observed in the cumulative fatigue tests, which is the same as that obtained in the constant-amplitude fatigue tests.

中文摘要...........................................i
英文摘要..........................................ii
誌 謝...........................................iii
目 錄............................................iv
表目錄............................................vi
圖目錄...........................................vii
符號說明..........................................ix
第一章 序論........................................1
1-1 引言........................................1
1-2 研究內容.....................................1
1-3 章節概要.....................................2
第二章 文獻回顧.....................................3
第三章 實驗內容與程序................................6
3-1 研究對象.....................................6
3-2 儀器介紹.....................................7
3-3 實驗步驟與內容................................7
3-3-2 鋁合金蜂巢夾層板基本疲勞實驗..................8
3-3-3 鋁合金蜂巢夾層板兩階段累積疲勞實驗.............8
第四章 結果與討論...................................15
4-1 鋁合金蜂巢夾層板承受四點彎矩靜態實驗結果.........15
4-2 鋁合金蜂巢夾層板承受四點彎矩疲勞實驗結果.........15
4-3 勁度變化量之觀察結果..........................16
4-4 鋁合金蜂巢夾層板兩階段累積疲勞實驗結果...........16
4-5 利用線性疲勞損傷理論Miner’s Rule預測之結果.....17
第五章 結論………………………………………………………………………............55
參考文獻…………………………………………………………………………………..56

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