英文篇名
Use of Electro-Optical Technique in Analyzing the Failure Mechanism of Solid Materials
作者
陳立憲、李昶佑、胡光宇、陳堯中、劉信良
關鍵字
電子斑紋干涉術(ESPI)、貫切試驗、三點彎矩試驗、巴西試驗
摘要
以往土木固態材料之力學特徵量測多為巨觀行為之觀察(毫米尺度),而對微觀特徵之研究則較寡;且研究多以受力後之峰前行為(如強度及勁度之探討)居多,對於材料真正峰後行為如失穩型(snap-back)之破壞韌度等,則較少進行研析。故為求全方位研究固態材料之延、脆性之破壞演化,並求得材料之完整加載歷程曲線,本文介紹較新穎之光電非破壞檢測技術-電子斑紋干涉術(Electronic Speckle Pattern Interferometry, ESPI),利用其高精度、全域性、即時性與非接觸之優點,可供求算延性之變形連續階段與脆性之變形不連續之力學行為特徵。
電子斑紋干涉術於光電、機械工程之應用較早,而稍後於土木工程中,亦有國外學者先後使用此技術應用於實驗室尺度之不同試驗如貫切(貫入)試驗(Indentation fracture test)、三點彎矩試驗(three-point bending test)及巴西試驗(Brazilian test)等。採用此一技術可探討材料彈-塑性變形與脆性破壞之初裂與裂衍(crack initiation and propagation)之行為,故使用此技術可由試體表面求得材料微觀破壞之演化,進而真正了解材料巨觀破壞之漸變過程,對未來其工程實務上之新材料、新工法及新技術之研發,亦應有所裨益。
英文摘要
In the past, measurements on the mechanical characteristics of solid materials were carried out mostly in macroscopic scale (i.e., in millimeters), and microscopic scale studies were rare. In addition, most of the researches focused on the pre-failure behavior of materials, such as strength and stiffness before failure. Post-failure behavior, such as snap-back failure strength, was rarely addressed. In order to cover a full spectrum on the development of ductile to brittle failure of solid materials, and to achieve a complete load-displacement curve, a non-destructive electro-optical technique so-called ESPI (Electronic Speckle Pattern Interferometry) was developed. ESPI is a high resolution, full spectrum, real-time, and non-contact tool which is capable of delineating both the continuous ductile and non-continuous brittle deformation of solid materials.
ESPI was first use in the fields of electro-optical and mechanical engineering. Civil engineering researchers latter adopted this technique in laboratory tests such as indentation fracture test, three-point bending test, and Brazilian test, etc. to study the elasto-plastic behavior, crack initiation and propagation of solid materials. Observing the microscopic change of displacement on the surface of stressed material can lead to a full understanding of the macroscopic behavior of engineering materials. It is believed that the ESPI technique could help in the development of new materials and new methods for practical application in the future.