New design paradigms and approaches for aircraft composite structures

Abstract

The use of composite materials in civil aviation is today certainly widespread, but sometimes this not implies that the final product is obtained exploiting the full potential of this kind of materials. The complexity of the composite material systems, the difficult repeatability of the products and their inspection, the high sensitivity to damages and defects, more severe certification constraints, often can discourage the use of these materials, especially for small aircrafts. New design approaches are necessary to overcome the current design methods applied by the aircraft manufactures, which often generate oversized and expensive structures respect to the expected ones. On the base of some results and experiences accrued, and in progress, in some projects coordinated by CIRA and funded by Italian Aerospace Research Programme, this work summarises advanced and new design approaches aimed at reducing the conservativisms of the current design. New protocols and paradigms are finalized to an improved and less time consuming building block approach, by means of the use of numerical procedures and more effective tests and tools for the material characterisation, also considering the use of structural health monitoring systems. Sensors/actuators, applied in the last decades for maintenance purpose, are now also under investigation to improve the design methods. In this framework, the use of general-purpose software, in-house developed codes and dedicated testing approaches, have become part of an improved new building block and structural sizing approach, for an efficient design of the next generation composite structures.