Extending robotic NDT to aerospace

摘要

Nondestructive testing (NDT) has been used in the manufacture and evaluation of advanced composite structures for decades. In that time, NDT has evolved significantly. Early ultrasound testing (UT), for example, used a single piezoelectric element, and the NDT process was excruciatingly slow. Today, phased-array UT systems electronically combine and simultaneously digitally process information from hundreds of these elements, enabling the user to more productively sweep large surfaces and scan more complex geometries. Improvements in digital signal processing and the incorporation of industrial robots have enabled greater flexibility and automated the testing process. Most recently, the use of laser UT - or laser ultrasonics (LUS) - has freed the process from coupling agents (water or gels), and from the need for precise probe alignment - the energy beam no longer has to be perpendicular to the inspected surface (see "Learn More," p. 33). Despite this push toward industrial-scale, inline inspection of production parts, little has been done, until now, to apply automated NDT to the thousands of structural tests required for composite aerostruc-tures certification.