波紋管(Bellow Tube)為一特別之受力結構體，在使用時一方面要求它需具有高承載力，另一方面又要求它具有良好的柔性，在此狀況下，它的設計、製造、分析都不同於一般之管狀結構體，因此必須直接對波紋管進行測試，藉以作為波紋管產品在設計及實際量產製造時的參考依據。
　　本研究運用數位影像相關法（Digital-Image-Correlation method）所建立的一套分析軟體，配合CCD照相機對波紋管在承受實際工作外力前後進行取像，藉分析變形前和變形後之數位影像，即可求得波紋管之水平和垂直變形量，搭配力量感測器的使用，便可求得波紋管之剛性。
　　文中並探討波紋管在承受內壓後對剛性之影響，從實驗結果中發現，波紋管在充入內壓後，由於內壓力及軸向力的對抗，因此剛性會急遽上升，隨著內壓的增大，波紋管剛性最後會趨近一穩定值。實驗中並使用應變規來量測波紋管之軸向及環向應變，壓縮實驗量測結果顯示，在波高、波距及口徑等設計參數相同時，波紋管之子午向應變值與管壁厚度有直接之關係，當管壁較厚時，於波紋管波峰處呈現拉伸之狀態，而當管壁較薄時，波紋管波峰處則呈現壓縮之狀態。
　　經由本次實驗的實際測試，驗證了本系統的可行性，誤差分析結果顯示，只要斑點及硬體設備架設完善時，利用影像關係法來進行位移量測可得到十分精確之結果。

　　The bellow tube is a special structure. On one hand, it requires high strength. On the other hand it requires good flexibility. Under these conditions, its design, manufacture, and analysis are all different from the other general tube structures. Therefore, it is necessary to test the bellow tube directly.
　　This research used the Digital-Image-Correlation method to measure the vertical and horizontal deformations of the bellow tubes. With using the load cell, the stiffness of the bellow tubes can be obtained.
　　In this paper we also discussed about the influence of the stiffness after the bellow tubes bearing the internal pressure. Because of the internal pressure against with the axial force, the stiffness of the bellow tubes rise rapidly. And the stiffness will converge on a stable value with the internal pressure increase. We also used the strain gages to measure the meridional and hoop strains. The results show that the meridional strains have the direct correlation with the thickness of the bellow tube.
　　Via the experiment, the feasibility of this system is verified. Using the digital-image-correlation method to measure the displacement will get excellent results as long as the pattern of image and installation of the hardware is suitable.

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