Delamination behavior and energy release rate evaluation of CFRP/SPCC hybrid laminates under ENF test: Corrected with residual thermal stresses

Delamination behavior and energy release rate on mode II interlaminar fracture toughness are investigated experimentally and theoretically. The calculation method was included with residual thermal stresses and applied to hybrid laminates. Experimental results showed that G(IIC) value was affected by specimen position where CFRP on top has a higher value compared to SPCC on top. The difference of G(IIC) value was about 60% higher. On-line monitoring method was applied during the test by using an optical microscope at the outer surface of hybrid laminates while delamination behavior of laminates was observed. CFRP and SPCC inner surfaces were investigated by using a microscope and SEM-EDS analysis. ENF test results revealed that failure exhibits at CFRP-SPCC interface laminates during ENF test with different position (CFRP on top or SPCC on top) because of different delamination behavior. The calculation model conformed experimental results with a good agreement. Prediction of the effect of thermal difference on ENF test of hybrid laminates also presented.