運用數位影像相關係數法於構架結構物幾何非線性行為實驗之探討

Investigation on Applying Digital Image Correlation Method for Experiment of Geometrically Nonlinear Behavior of Framed Structures

高洪斌(Hong-Bin Gao)

指導教授 ： 施明祥

國立暨南國際大學/科技學院/土木工程學系/碩士(2013年)

https://doi.org/10.6837/NCNU.2013.00102

摘要

細長桿件的挫曲行為是桿件受到極大的軸向力時，從軸向變形脫序產生側向變形，導致二次力矩分配，載重位置隨之移動的現象。此種非線性行為同時有可能發生在挫曲前與挫曲後。關於幾何非線性的研究，不論是挫曲前與挫曲後，理論上有非常完整的發展。但是在實驗方面，僅能針對臨界載重作實驗，而挫曲後大變位的非線性實驗，卻受限於試體過於敏感且彈性狀態難以維持等因素，而罕見於文獻與報告中。
幾何非線性實驗困難有二：(1)大變位的試體難以維持彈性狀態，因此試體通常都設計的極為細長而敏感。在此條件之下，使用傳統實驗之應變與位移測量計無法辦到，必須使用非接觸的實驗方式；(2)在此試體條件下，載重位置會不斷移動，而載重方向卻不能改變，故施加載重也是此類實驗的主要困難點之一。
本研究採用數位影像相關係數法(DIC)進行試體變形的量測，以克服上述第一個問題。數位影像相關係數法是一種非接觸式量測方法，可以對實驗物體作全域的位移量測，因此物體作極大的變位也可以應用，本實驗採用位移控制法做力量施載。本文使用數位影像相關係數法來施作幾何非線性實驗後，證實了數位影像相關係數法的確可以適合於幾何非線性實驗。本文介紹的實驗流程，可以供相關研究者證明理論與後人施做幾何非線性實驗之參考。

關鍵字

幾何非線性 ； 數位影像測量 ； 結構實驗

並列摘要

The research is mainly about Geometrically Nonlinear Behavior of Framed Structures, that is the slender bar since axial deformational stituation transform to lateral deformation by the great axial force, simultaneous occurrence of secondary moment distribution and Change the load direction. Such nonlinear behavior is at the same time may occur in buckling and post-buckling. Whether the reserch for buckling and post-buckling both be able to analysis accurate on the geometric nonlinearity theory. but have not enough sophisticated experiments in the literature.
This experiment is difficult by: (1) The specimen is so slender that difficult for measured. (2) Load of the position will continue to change in the experimental process, it’s hard to select load way.
In this research, Use DIC (digital image correlation) method for this problem, It is noncontact measurement method, Can be used for full-shift measurements on the specimen when the specimen have a great bit of change. The objectives of this paper is prove the DIC can be applied to the geometrically nonlinear large deformation experiments, and the experimental process design, For researchers to prove the theory and geometric nonlinear experimental reference.

並列關鍵字

Digital Image Correlation ； DIC ； Geometrically Nonlinear ； Buckling

參考文獻

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