層板構件膠合品質的聲波超音波評估

Abstract

膠合接著已廣泛應用於工業產品，因此膠合構件的膠合品質評估為品質保證的一項重要工作。本研究以斜束入射的超音波及雷射超音波在金屬平板內部產行板波，板波在橡膠被覆界面膠合良好與不完全的區，域會有不同的傳遞波速，利用相位檢測原理計算通過不同膠合區域的板波訊號的相信與振幅，實驗分析結果顯示當橡膠膠合面積增時，板波訊號的相們延遲隨之增加，振幅則呈線性減少，若橡膠與鋼板脫膠但卻受正向壓力而壓合，則板波訊號之相位維持不變，振幅則隨著壓合面積增加呈線性減少。當作用於搭接試件之膠合界面的剪應力增加時，析波訊號的相位延遲會隨著膠合層破壞的發生而逐漸呈線性增加，膠合層的破壞是以音洩偵測技術同時進行監測。本研究利用析波訊號的相位延遲，提供了建立膠合元件品保標準的檢測技術。

Adhesively bonded joints are being used increasingly in industrial products. It has resulted in a critical need for quality assurance methods to determine the integrity and strength of adhesively bonded components. In general, the inspection regions are ofren difficult of direct access. In this study both obliquely incident Lamb waves and laser-induced ultrasonic techniques were applied to evaluate the bonding conditions at interfaces of layered components. Wavespeeds of the dispersive plate waves slightly change while wanes propagate from a plate to the region adhesively bonded with other materials (e.q., rubber in this study). Phase and amplitude of the plate waves is calculated numerically by quadrature amplitude modulation technique.The results showed that phase changes of the plate waves were only well correlated with the well-bonded area but were approximately constant for intimate contact disbond under compression. The attenuation increased linearly with the width of rubber overlaid area in both cases. The residual bonding strength in lap-joined plate specimens decreases as the external payload increases. Most fractures of the adhesives were found to appear in the edge region of the bonded area by acoustic emission monitoring. The increasing disbond area results in increasing phase delay of the edge reflected extensional plate waves. Phase delay of the plate waves could be used as a quantitative index to inspect for the bonding quality and residual strength of adhesively bonded components.