全域式光學非破壞檢測技術應用於應力及缺陷檢測

Abstract

本論文之研究內容主要聚焦於全域光學非破壞檢測在應力與缺陷量測上的應用。第一部分探討光學干涉技術於結構振動特性量測之方法與創新，採用剪切干涉術以全域虛像疊合的方式，結合均時法與影像相減法，量測結構面外振動之平面微分剪切分量，並與電子斑點干涉術進行比較。研究結果顯示，兩者皆可進行全場量測，而全域式剪切干涉術具備可調式高靈敏度與高解析度之優勢，得以深入分析薄板與厚板結構之三維板殼振動分量，並評估其於裂紋缺陷檢測上的應用成效。第二部分則利用光彈應力量測技術，針對圓盤與圓環結構於三點徑向施力於多角度的負載下，探討應力分布特性並比較理論解析與有限元素數值計算的結果。 本研究基於薄板理論平面應力位移解析的假設，比較高階中厚板面內位移高階項，透過兩種全像干涉實驗量測欲驗證理論解析的振動位移特性，同時採用有限元素法進行數值計算，經由理論解析、數值模擬與實驗量測於三維振動的振形分布結果，驗證不同板殼振動的位移特性。為了釐清剪切干涉量測技術在位移定量過程中的精確度與可靠性，提出量測精度的定義方法並建立獲取解析度的流程，研究中利用雷射都卜勒振動儀擷取試片表面逐點之面外振動位移，計算面外振動於空間分布下於面內剪切方向的分量，並計算分析精度與探討量測誤差。本研究整體在全域式的剪接干涉量測技術利用振動特性進行量測，具備高解析與高準確度特性之外，在裂紋與缺陷的檢測上，也因裂紋斷差易使面外位移在試片平面空間分布之剪切位移不連續性容易顯現，故也可應用於非破壞檢測中，本研究驗證其缺陷檢測特性，選用壓電材料與鋁板並於表面加工不同的缺陷與裂紋，透過本技術以振動模態進行量測藉以進行缺陷裂紋檢測的可行性。 第二部分利用光彈應力研究量測圓盤與圓環結構於徑向載荷作用下之應力分布，除一般進行雙點對稱載荷探討之外，本研究也針對非對稱的三點施力進行不同載荷角度的研究，透過圓偏振光系統所獲得之等差干涉圖樣，可定性與定量分析內部應力場，實驗結果與理論解析及有限元素法所得到的結果進行比較與驗證。實驗結果顯示載荷處的剪切應力的控制效果，方能與理論解析與有限元素分析於正向力的加載具有良好的對應結果。 隨著科技快速發展，人工智慧已成為多數產業的核心趨勢，並推動半導體與精密製造技術朝向高密度與微小化發展。製程尺度的微縮使微缺陷、結構振動與應力集中等問題日益顯著，對元件可靠度與製程良率造成關鍵影響。因此，具備高靈敏度與高解析度之全場非破壞檢測技術已成為先進製造中不可或缺的關鍵工具。本論文所提出之全域光學干涉與光彈性量測方法，可有效量測結構振動、應力分布與缺陷特徵，展現其於高階製程監控與微尺度缺陷檢測上的應用潛力。

This dissertation primarily focuses on the application of full-field optical nondestructive testing techniques for stress and defect measurements. The first part investigates the methodologies and innovations of optical interferometric techniques for structural vibration characterization. A shearography approach with full-field virtual image superposition is employed, in conjunction with the time-averaging method and image subtraction technique, to measure the planar differential shear components of out-of-plane structural vibrations. The proposed method is compared with electronic speckle pattern interferometry (ESPI), which is commonly used for three-dimensional vibration measurements. While both techniques enable full-field measurements, full-field shearography offers adjustable high sensitivity and high spatial resolution, allowing for detailed analysis of three-dimensional plate and shell vibration components in both thin and thick structures. Furthermore, its effectiveness in crack defect detection is evaluated in this study. This research is based on the assumptions of plane stress and displacement analysis derived from thin plate theory, while higher-order in-plane displacement terms for moderately thick plates are also considered for comparison. Two holographic interferometric experimental configurations are employed to validate the theoretically derived vibration displacement characteristics, and finite element analysis is simultaneously conducted for numerical simulation. By correlating theoretical predictions, numerical simulations, and experimental measurements of three-dimensional vibration mode shapes, the displacement characteristics of various plate and shell vibration behaviors are verified. To clarify the accuracy and reliability of shearography-based displacement quantification, a definition of measurement accuracy and a procedure for determining spatial resolution are proposed. A laser Doppler vibrometer is utilized to acquire pointwise out-of-plane vibration displacement on the specimen surface, from which the in-plane shear components under spatially distributed out-of-plane vibrations are calculated, enabling quantitative accuracy evaluation and error analysis. Overall, the proposed full-field shearography-based vibration measurement technique demonstrates high spatial resolution and high accuracy. In addition, due to the discontinuity in shear displacement induced by cracks, which is readily manifested in the spatial distribution of out-of-plane vibration displacement, the method is well suited for nondestructive crack and defect detection. The feasibility of this approach is experimentally verified using piezoelectric materials and aluminum plates with artificially introduced defects and cracks, where vibration mode measurements are employed to detect and characterize structural damage. The second part of this dissertation applies photoelastic stress analysis to investigate the stress distribution in circular disk and ring structures subjected to radial loading. In addition to conventional symmetric two-point loading conditions, this study also examines asymmetric three-point loading configurations with varying load angles. Isochromatic fringe patterns obtained using a circularly polarized light system enable both qualitative and quantitative analyses of internal stress fields. The experimental results are compared and validated against theoretical solutions and finite element analyses. The results demonstrate that effective control of shear stress at the loading locations is essential to achieve good agreement between experimental observations, theoretical predictions, and finite element results under normal force loading conditions. With the rapid advancement of technology, artificial intelligence has become a core trend across many industries, driving semiconductor and precision manufacturing toward higher density and miniaturization. As fabrication scales shrink, micro-defects, structural vibrations, and stress concentrations increasingly affect device reliability and manufacturing yield. Therefore, high-sensitivity, high-resolution full-field nondestructive testing techniques have become essential in advanced manufacturing. The global optical interferometry and photoelastic methods proposed in this study enable effective measurement of structural vibrations, stress distributions, and defects, demonstrating strong potential for advanced process monitoring and microscale defect detection.