With the progresses of material sciences and technologies, carbon fiber composite shell-plate structures have been widely used in aerospace industry. Suffering from the drastic change of penetration thickness during the 360°scanning, conventional computed tomography (CT) is difficult to be applied to this kind of structures with a big length-width-thickness ratio, and not easy to implement the defect detection and the performance analysis. Based on the existing diffraction enhanced imaging (DEI) device at Beijing Synchrotron Radiation Facility beam-line 4W1A, a new computed laminography (CL) scanning system was designed and developed. It was integrated with the DEI device to form a synchrotron radiation DEI-CL system for plate-shell structures. Within this system, the components such as light source, detector and turntable and the working principle were discussed in detail. The experiment results of a decimeter-scale carbon fiber composite laminate sample validate the developed scanning system.
Carbon fiber composites have been wildly used in aerospace industry due to the excellent performance. However, the research on defect evolution law and the performance analysis have been limited by the lack of effective tools. Two kinds of computed tomography (CT) slice images of carbon fiber composites, x-ray attenuation contrast and phase contrast, were obtained with the diffraction enhancement imaging (DEI) device at Beijing Synchrotron Radiation Facility (BSRF). The structure details and the defects in the sample could be clearly distinguished from the image. Moreover, phase contrast CT provides higher contrast and can identify the defects difficult to be recognized in attenuation contrast CT. DEI provides a method for in-situ observation of the carbon fiber composites and would be a valuable tool for the development of carbon fiber composite material.