臺灣博碩士論文加值系統

本論文主要目的為利用有限元素分析法，進行機槍塔結構之動態模擬分析，評估槍塔於機槍射擊之動態負載下之結構剛性與強度。首先採用分析軟體HyperWorks建構槍塔結構之有限元素分析模型。為提升模擬分析準確性，先透過拉伸試驗獲取結構材料機械性質，以及量測實際 結構之重量、重心位置，並以實驗模態分析(Experimental Modal Analysis, EMA)所獲得之模態參數與分析模型互相比對驗證，確認有限元素分析模型質量與剛性分佈情形，獲得足以代表實際槍塔結構之分析模型。然後使用分析軟體LS-DYNA模擬機槍射擊之動態負載傳遞至機槍塔結構之動態響應，並輸出分析結果之加速度響應。搭配實彈射擊測試，採用頻譜分析儀與加速規量取槍塔結構之加速度響應。兩者相互驗證比對，以提升分析可靠性。分析結果顯示，高應力值多集中於螺栓鎖固位置，但降伏比皆小於20 %，未產生塑性變形。除此之外，結構彈性變形皆小於0.3 mm，顯示槍塔結構設計具備足夠剛性與強度承受機槍射擊動態負載，不致於干擾射擊精確度。

The purpose of this research is to investigate the structure stiffness and strength of machine gun mount under dynamic load by using finite element method. The finite element model (FEM) is established by using commercial code HyperWorks. The material properties of machine gun mount are obtained from tensile test. The weight and center of gravity are measured by expirement to validate FEM. Experimental modal analysis (EMA) is conducted on the body structure to obtain the natural frequencies and mode shapes, which are used to validate the FEM. Good correlation between analysis and test ensures the FEM is equivalent to the actual structure of machine gun mount. Dynamic analysis is performed to simulation the structure dynamic response of machine gun mount under shooting by using commercial code LS-DYNA. Use SigLab and accelerameter to measure acceleration response of machine gun mount, which is obtained from experiment of machine gun shooting test. The correlation between experiment and simulation is relevant. The maximum von Mises stress is located on the position closed to bolt, but the yielding ratio is lower than 20 %. Furthermore, the structure deformations are lower than 0.3 mm. Therefore, we can conclude that the machine gun mount structure is well designed in stiffness and strength.

摘要 I
Abstract II
謝 誌 IV
目錄 V
表目錄 VIII
圖目錄 X
第1章 緒論 1
1.1研究動機與目的 1
1.2文獻回顧 5
1.3全文概述 12
第2章 機槍塔結構之有限元素分析模型 13
2.1 機槍塔系統介紹 13
2.2 機槍塔之電腦輔助設計(Computer Aided Design, CAD)模型 14
2.3 建立有限元素分析(Computer Aided Engineering, CAE)模型 15
2.4 材料機械性質測試 19
2.5分析模型連接定義與分析 25
第3章 機槍塔主結構物性量測與模型驗證 28
3.1機槍塔主結構物性量測 28
3.2實驗模態分析 31
3.2.1實驗儀器選用 32
3.2.2實驗量測點規劃 33
3.2.3實驗架設與方法 36
3.3機槍塔主結構有限元素模型驗證 38
3.3.1機槍塔結構物性比對 39
3.3.2機槍塔結構模型驗證 40
3.3.3整體機槍塔結構總成模態分析 47
第4章 機槍塔結構動態測試 52
4.1實驗測試規劃 52
4.2實驗儀器選用 53
4.3實驗架設與方法 54
4.4實驗量測結果 57
第5章 機槍塔結構之動態模擬分析 67
5.1結構材料彈塑性模型 67
5.2機槍塔總成重心量測 69
5.3機槍塔結構之動態模擬分析 71
5.3.1機槍擊發之負載與邊界條件 71
5.3.2緩衝彈簧剛性值設定 73
5.3.3槍塔結構之動態分析結果與討論 (水平擊發) 75
5.3.4槍塔結構之動態分析結果與討論 (最大仰角及俯角擊發) 95
第6章 結論與建議 106
6.1結論 106
6.2建議 108
參考文獻 109
作者簡介 111

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