Technique for Monitoring Environmentally Induced Changes in Polymeric Sealants
Donald L. Hunston, Kar T. Tan, Christopher C. White
A new procedure was developed to utilize stress relaxation tests to monitor damage induced in sealant materials exposed to environmental variables and changing strains. By combining tension and compression tests, it was possible to monitor both molecular level changes and macroscopic damage such as cracks and debonds. Calibration curves were developed using sealant speciments with known cracks and debonds. The procedure was then tested with sealant specimens exposed in a chamber designed to control exposure to environmental variables and strain. Stress relaxation test on these sapeciments following exposure gave results consistent with visual observations.