SBIR-STTR Award

Adhesive joining of materials has found widespread use in industry because of the simplicity and versatility of the process. However, adhesive applications in critical structural joints are still limited by the absence of reliable, rapid industrial NDE methods. Significant progress has been achieved recently in several research laboratories in quantitative NDE of adhesive joint integrity of metals. The most advanced ultrasonic techniques of adhesive joints utilize spectral analysis at oblique incidence. We propose to demonstrate the possibility of oblique ultrasonic spectroscopy for adhesive bond integrity evaluation of composites. The major differences from the evaluation of the metal joints are the laminated structure of the composites and the anisotropy of the laminates. Theoretical modeling will be performed to optimize the measurement technique, followed by ultrasonic and mechanical tests. Thus the correlation between ultrasonic signature and joint strength will be established.

Keywords:
Adhesive Bond Adhesive Bond Composites Composites Ultrasonic Spectroscopy Ultrasonic Spectroscopy

In the phase I of this project, we have demonstrated the feasibility of Angle Beam Ultrasonic Spectroscopy for quantitative evaluation of adhesive bond integrity. The technique allows determination of interfacial (adhesion) characteristics of the bond line such as kissing bonds. The concept of an Angle Beam Ultrasonic Spectroscopy (ABUS) scanner has been developed and tested. This technique allows a mapping of the bond line quality. To optimize the inspection parameters, the composite anisotropy has been accounted for in the developed ABUS model. Validation results have showed a good correlation between the bond quality characterized with the ABUS method and the bond strength. The ABUS scanner is a promising new technique for rapid and reliable evaluation of adhesive bond integrity of composites. The object of the second phase is to implement ABUS concept and develop the ABUS scanning system prototype for reliable inspection of adhesive bond quality of composites. Software and hardware will be developed to insure system operation and data processing in real-time. The proposed activities include: 1) Development of the ABUS system prototype with an universal scanning head. 2) Development and integration of software and hardware controls with real-time data acquisition and processing. 3) Initiation of the follow on research and development, and marketing of the ABUS scanning system.

Keywords:
Adhesive Bond Composites Ultrasonic Spectroscopy Quantitative Nde