Advanced N.D. Techniques for Composite Primary Structures

Abstract : The applications of composite materials in primary aircraft structures need deep investigations on the materials themselves and reliable techniques of control of the products. The last topic rappresents one of the most weak points in the composites and adhesives technology because there is no one N.D. method useful and valid for all kinds of defects but a variety of N.D. methods in order to achieve good results in the inspectability of the configurations are necessary. This paper contains, in its first part, an overview of some most popular techniques for maximum sensitivity, determination on standard defects using a proof specimens, that is: X-ray radiography and in-line radioscopy electronically supported; X-ray xeroradiography; Neutron radiography; U.S. investigation; The second part presents some examples of application of the above mentioned techniques on significant aircraft components i.e.: main rotor spar and blade main rotor blade grip and the results are discussed.