Evaluation of Void Content in Epoxy-Glass Filament Wound Material by Microwave Tests

摘要

Several selected samples of epoxy-glass filament wound material were tested in free space by microwave measurement techniques. The purpose of these tests was to seek significant relationships between percentage of void content and dielectric properties for practical application in nondestructive test procedures. The test results revealed that substantial amounts of void content in the test samples caused very small changes in the measured value of dielectric constant. Furthermore, these changes could not be distinguished from the effects of various other factors related to the test. Therefore it was concluded that the free space measurement of dielectric constant was unsatisfactory as in indication of the distributed void content of the subject material. (Author)