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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/80599


    Title: 數位影像相關法應用於雷射積層製造工件應變分佈量測;Digital Image Correlation Method for Strain Distribution of Workpiece by Laser Additive Manufacturing
    Authors: 蘇芷甯;Su, Zhi-Ning
    Contributors: 光機電工程研究所
    Keywords: 數位影像相關法;雷射積層製造;應變;digital image correlation;Ncorr;additive manufacturing
    Date: 2019-08-14
    Issue Date: 2019-09-03 14:47:11 (UTC+8)
    Publisher: 國立中央大學
    Abstract: 本論文目的為量測不同條件所製造之雷射積層工件應變分佈變化,並可根據本實驗,得知雷射積層參數對應變分佈造成之差異。變異的參數包括雷射積層掃描以及生長方向、熱處理與否。應變分佈量測所使用之方法為數位影像相關法,其軟體為Ncorr;將工件進行拉伸試驗,並透過攝影機拍攝工件拉伸過程,再將其進行應變分析。而在進行雷射積層製造工件應變分佈量測實驗前,我們需要確認數位影像相關法之精度以及效能,先以位移平台搭配雷射位移計進行種子點個數、子集大小的參數研究。在種子點個數2或4時,使用子集大小60 pixel進行分析,結果與雷射位移計其平均差量相差僅有0.1 μm;接著我們使用此參數量測傳統製造之鋁合金,並與雷射積層工件比較之。
    量測以AISI420粉末積層製造的工件,並觀察其應變分佈,記錄於第四章。從本實驗得知,雷射積層工件應變分佈變化呈週期性,故可說明雷射積層此種製造方式,材料黏結處會因燒融,造成與過去鋁合金的應變分佈結果不同。
    本論文也針對量測的誤差進行討論,分別為環境所造成的隨機誤差以及系統誤差;在相機架設方面,相機和試片的垂直、水平軸是否吻合也會因此帶來誤差,而斑點大小和校正也會帶來微小的誤差。本系統的實驗架構相較於其他的應變量測方式,既有不接觸到工件的優點;其還能對於大面積的全域變化進行探討,且能降低成本,在量測機械參數上為一套具有潛力的技術。;The purpose of this paper is to measure the strain distribution of workpieces fabricated by laser additive manufacturing. According to the experiment, the influence of the laser additive manufacturing parameter on the variable distribution is known, such as different growth directions and heat treatment. The method used for strain distribution measurement is the digital image correlation method, and the software is Ncorr.
    We perform the tensile test on the workpiece and record it with the camera. The image is Gaussian filtered for strain analysis. Before performing the strain distribution measurement experiment, we need to confirm the accuracy and efficiency of the digital image correlation method. Experiments on the effects of different parameters on digital image correlation methods, use a laser displacement meter with a displacement platform. When the number of seed points is 2 or 4, the analysis is performed using the subset size of 60 pixels. The result is only 0.1 μm from the average difference of the laser displacement meter.
    This paper also discusses the error of measurement, which is the random error and system error caused by the environment. In terms of camera erection, the vertical and horizontal axes of the camera and the test piece will also cause errors, and the spot size and correction will also bring a slight error. Compared with other strain measurement methods, the experimental structure of the system not only has the advantage of not touching the workpiece, but also can discuss the large-area changes and reduce the cost. Therefore, the digital image correlation method is a set of potential technologies for measuring mechanical parameters.
    Appears in Collections:[光機電工程研究所 ] 博碩士論文

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