內含圓洞與裂縫之超音波檢測與辨識

The Measurement and Distinction of Voids and Cracks by Ultrasonic Technique

張明致(Ming-Chih Chang)

指導教授 ： 何旭川

元智大學/工程學院/機械工程學系/碩士(2000年)

摘要

超音波非破壞性檢測可偵測結構體內部與表面缺陷如空孔、裂縫等，是應用最廣的非破壞性檢測方法。本文首先以鑽床加工方法製作之圓洞取代真實空孔，探討不同方法之圓洞孔徑量測。實驗方法為將此試塊，以不同探頭頻率與入射角量測圓洞孔徑，比較這些參數對量測圓洞孔徑的影響及準確度。其次探討試塊內含圓孔與裂縫缺陷形狀之辨識。辨識方法為分別將波入射於內含圓洞與人工溝槽之試塊，觀察不同角度所接收之圓洞表面散射振幅強度與溝槽尖端繞射振幅強度，藉由兩振幅強度於相同接收角之差距作為缺陷形式辨識之依據。實驗結果可以做為有效量測結構物內含圓孔與裂縫缺陷形狀辨別的參考。

關鍵字

超音波 ； 裂縫 ； 圓洞 ； 振幅 ； 缺陷辨識

並列摘要

Ultrasonic is the most common use of nondestructive examination technique. It could detect defects inside the structures and on the surface such as voids and cracks. In this investigation, a cylindrical hole manufactured by a drilling machine is used to simulate the void. Three different methods are presented to measure the diameter of the hole. The effects of frequency and incident angle on the measurement accuracy are evaluated. The distinction between voids and cracks by ultrasonic technique is investigated. The amplitude ratio of scattering on a hole and the amplitude ratio on a crack are defined separately. The defects of void and crack are distinguished by comparing the amplitude ratio. The experiment result and the theoretical calculation of the amplitude ratio are presented. The best way to distinguished voids and cracks are proposed, based on the amplitude ratio.

並列關鍵字

ultrasonic technique ； crack ； void ； amplitude ratio ； defect distinction

參考文獻

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