Modeling and evaluation of curing pressure-defects-mechanical properties of carbon fiber reinforced resin composites based on image processing

The carbon fiber composite laminates were manufactured in different curing pressures by autoclave process. The relationship between the ultrasonic phased array C scanning image and the defects of microstructure was analyzed, and the correlations among curing pressure, voids and mechanical properties were studied. The results indicate that ultrasonic C scanning image can be used to characterize the content of voids. In this experiment condition, the curing pressure increases from 0 MPa to 0.6 MPa, the porosity decreases by 96.7%, and the tensile strength(TS) and interlaminar shear strength(ILSS) increase by 56.1% and 68.8%, respectively. On this basis, the C scanning images of composite laminate in different curing pressures were processed, and the forming quality index was defined. Thus, the quantitative characterization of voids based on C scanning images was realized. Finally, through mathematical fitting of the results of voids detection, mechanical properties test and image quantitative evaluation, a mathematical model(CPDMP model) among curing pressure-defects-mechanical properties based on image processing was established. In addition, the forming quality index threshold of 81%, the acceptable porosity of more than 1.1% and the corresponding curing pressure of more than 0.35 MPa were presented.