The contribution to residual stress by differential resin shrinkage

A new method is introduced to measure the dimensional changes of the polymeric resins while they go through the curing process. The dimensional change of the resin can be detected by implanting two markers into the resin and looking at the relative movement of them under an optical microscope. In the next part of this study, a partially-filled polymer specimen was made with continuous fibers. The measurement of the residual strain in the un-reinforced polymer phase of the specimen and comparison of it to the shrinkage value, indicated that only 3.3% of the resin shrinkage remained as residual strain in the polymer. Furthermore, the reheating of the bi-layer sample revealed that the stress free temperature is much lower than the curing temperature of the composite.