Nonlinear Stress-Modulated Ultrasonic Method for Bond Strength Characterization

Award Information
Agency: National Aeronautics and Space Administration
Branch: N/A
Contract: N/A
Agency Tracking Number: 990057
Amount: $600,000.00
Phase: Phase II
Program: SBIR
Awards Year: 2001
Solicitation Year: N/A
Solicitation Topic Code: N/A
Solicitation Number: N/A
Small Business Information
1275 Kinnear Road, Columbus, Oh, 43212
HUBZone Owned: N
Woman Owned: N
Socially and Economically Disadvantaged: N
Principal Investigator
 Dr. Adler
 () -
Business Contact
 Dr. Adler
Title: President
Phone: (614) 487-3631
Research Institution
Environmental degradation of adhesive bonds of composite or metallic structures affects predominantly the adhesive/adherent interface by decreasing the number of molecular bonds between the adhesive and the substrate. The objective of the proposed Phase I work is to perform a feasibility study of a novel non-linear ultrasonic method for quantitative characterization of molecular bond density with the objective of determining the local bond strength.The innovation of the proposed method is to perform an ultrasonic characterization of the interface enhanced by parametric dynamic vibrations. The density of molecular bonds, described by an equivalent interfacial spring density, is quantitatively determined using dual beam ultrasonic spectroscopy at different points of the dynamic loading curve. The method permits separating the linear and non-linear behavior of the bulk adhesive and adhesive/substrate interface. Comparison between the measured spring density at tensile and compressive loads leads to a characterization of the local interfacial strength.Based on the accomplishments of Phase I, Phase II developments will be proposed including extended study of the method applicability for assessment of adhesively bonded structures and the delivery to NASA of the dedicated Angle Beam Ultrasonic Spectroscopy acquisition system for evaluation of Adhesive Joints under Parametric Excitation.

* Information listed above is at the time of submission. *

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