Please use this identifier to cite or link to this item:
標題: 數位影像相關方法在地震防災及結構監測之應用研究-子計畫:混凝土構造物之數位影像檢測技術與破裂評估(II)
Cleavage Evaluation for the Concrete Structure Using Digital Image Correlation(II)
作者: 郭其珍
關鍵字: 土木水利工程類;應用研究
混凝土構造物之設計常以非張力設計(no-tension design)來考量。資料顯示,由於混凝土構造物之施工瑕疵,溫度收縮龜裂或其他非預期外力的引入,非張力設計,並不能完全避開張應力的發生,以確保混凝土構造物之安全。為防止混凝土構造物的崩潰,混凝土必須要有足夠的韌性強度(toughness)以阻止裂紋的擴張。而裂紋擴張的影響因子有二,材料強度與應力分佈的變化率(stress rate),而應力變化率理論上可以以奇異階數(singular order)來表示。於異質性材料(heterogeneous material),如混凝土之類,其奇異性階數與裂紋尖端材料異質性之相對變化程度相關,因此為確保混凝土構造物的安全,了解混凝土構造物異質程度成為破裂評估的必要條件。也因此,發展方便且有效之混凝土構造物異質程度的計測技術,以進行破裂評估,成為本計劃之主要目的。新發展的數位影像量測位移場的技術,以其方便與簡易, 應能提供混凝土構造物應力變化檢測的新方式,於混凝土構造物的異質程度的計測與安全評估,深具意義。由於數位影像技術量測資料的採用,必須控制在可信的範圍,因此品質指標與容忍度的設定,以及計量模式必須建立。針對此,研究計劃分二個面向,數位影像於混凝土開裂預測之應用技術以及數位影像技術與品質指標及容忍度的設定。

Concrete is a compound of aggregate in cement matrix. The fracture process ofconcrete takes place in two stages; an initial flow is present or a micro cracks initiated;second, the stable growth of the micro-cracking zone reaches a critical size and triggers anunstable running crack. To the concrete material, stress intensity due to tension is the majorfactor for the cleavage. Thus the no-tension design is the most considered in theconstruction of concrete structure. Nevertheless, the development of cracks during formingprocess is inevitable. Therefore, the induction of tension force into the concrete structure isexpected. To prevent the collapse of a concrete structure, the concrete with a sufficienttoughness to resist the extension of cracks is necessary. The fracture is influenced by twofactors, the strength of material and the stress rate induced by loading. The stress rate maybe presented using singular order. For a heterogeneous material such as concrete, itssingular order is dependent on the degree of heterogeneous variation at crack tip. Therefore,to ensure the integrity of concrete structure, checking the heterogeneous distribution of it inadvance is necessary for failure analysis. On this purpose, the development of a techniquefor detecting the heterogeneous variation in concrete for the evaluation of concretecleavage in handy way is proposed. This research proposal is emphasized on the linkage ofdigital-image-correlation (DIC) technique and the crack detection in concrete. The processcapability at the use of digital-image-correlation technique is also to be included to make aconclusion for practical use.PDF
其他識別: NSC97-2625-M005-003
Appears in Collections:土木工程學系所

Show full item record

Google ScholarTM


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.