Abstract
Radiation effects on mechanical properties of the glass fiber-reinforced bisphenol-A type epoxy resin were studied. The threshold dose, where 3-point bending strength started to change, was 30 MGy. Radiation-induced latent degradation within the threshold dose was observed by the analysis of differential modulus from the curve of load against displacement. The differential modulus curves could be divided into two displacement regions. It was concluded through the data of water absorption and observations with scanning acoustic microscopes, that the two regions were due to the debonding of matrix-fiber interface and the micro-cracking in the matrix resin, respectively.
