Steel plate cold commercial - carbon fiber reinforced plastics hybrid laminates for automotive applications: curing perspective with thermal residual effect

The curing effect on hybrid materials consisting of steel plate cold commercial - carbon fiber reinforced plastics (SPCC-CFRP) hybrid laminates that have potential applications in automobile structures were evaluated in the present study. Specimens with stacking sequences consists of one SPCC plate and six layers of CFRP ([SPCC/[0]6]) under a double cantilever beam (DCB) test were investigated experimentally and analytically. The characterization was performed using a differential scanning calorimetry (DSC) and fourier transform infrared (FTIR) analysis. The specimens were exposed to two different curing times to observe the different strain energy release rates. The results show specimens with a curing time of three hours have stability in strain energy release rate value compared to one-hour curing time. However, in the early stage of fracture, the fracture toughness of 1-hour has a higher value than 3-hour. The critical crack length in this study occurred between 40 and 70 mm. Furthermore, the average strain energy release rate value of GI in 1-hour and 3-hour curing time from the crack length between 98 and 104 mm was 116.6687 J/m2 based on compliance calibration (CC) method, 113.3966 J/m2 based on correction factor, and 116.3831 J/m2 from considering temperature effect theory compared to 1-hour curing time with 81.3232; 79.1026; and 81.0376 J/m2, respectively. Based on this study, the fracture toughness and energy release rate of hybrid laminate significantly affected by the curing conditions during the manufacturing process.