VARI成型纤维增强复合材料的孔隙率超声评价研究OA

With the development of Marine composite materials,its quality control is becoming more and more important.Aiming at the problem of pore defects in vacuum assisted molding of fiber reinforced composites,ultrasonic nondestructive testing(NDT)technology was used to evaluate and study the problem.Based on sound field simulation,this paper explores the influence of pore defects with different shapes,numbers and distribution ranges on ultrasonic wave propagation laws.Optical microscopy and micro-focus industrial CT were used to characterize the defect samples to explore the characteristics of pore defects under the vacuum-assisted forming process.Using porosity gradient specimens,combined with ultrasonic non-destructive testing technology,a relationship model between sound velocity and center frequency of ultrasonic echo signal and material porosity is established using sound velocity method and spectrum method.