Use of an In-Situ Electrochemical Sensor for Predictive Assessment of Bonded Repair

Abstract

A series of B/epoxy-A1 double lap shear specimens were prepared and exposed to high humidity and temperature. Half of these were prepared using the commercial DynCorp process used for bonded repair of aircraft. The other half was prepared using a modified process to reduce durability. Electrochemical impedance spectroscopy (EIS) measurements were taken on these specimens using a patented DACCO SCI sensor. A set of these specimens was mechanically tested each month to determine pull strength. The EIS impedance spectra were analyzed using equivalent circuit analysis. Several circuit parameters upon exposure to moisture. Changes in the capacitance allowed moisture uptake to be calculated. By placing the sensor electrodes in different locations, variations in moisture concentration in the bonded system can be determined. This approach provides advance warning before any significant reduction of bond strength. Thus, it has the potential to monitor adhesively bonded repair patches and allow preventative maintenance prior to any degradation of bond performance.

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Document Details

Document Type
Technical Report
Publication Date
Sep 20, 2001
Accession Number
ADA394570

Entities

People

  • Brian J. Harkless
  • Guy D. Davis

Tags

Communities of Interest

  • Advanced Electronics
  • Air Platforms
  • Biomedical
  • Sensors

DTIC Thesaurus Topics

  • Air Force Research Laboratories
  • Aircrafts
  • Capacitance
  • Circuit Analysis
  • Circuits
  • Composite Materials
  • Degradation
  • Dielectric Permittivity
  • Electrodes
  • Engineering
  • Equivalent Circuits
  • Impedance
  • Maintenance
  • Materials
  • Measurement
  • Moisture
  • Spectra

Readers

  • Electronics Engineering
  • Materials Science and Engineering.
  • Surface Coatings Technology.