Innovations in Structures and Materials

Kurzfassung

Structural and material research in aeronautics strives to broaden and deepen the knowledge base for improvements of the design and manufacturing process, of structural safety and reliability, of the certification procedure, of cost effectiveness, passenger comfort and of the environmental impact. In the sense of a pre-competitive research GARTEUR SM action groups (AGs) are or recently have been active in a number of different topics. Main objective of AG17 was to identify alternatives to cadmium plating and to establish their technical, environmental and economical aspects. In AG19 the phase resonance method has been found to remain necessary for identifying closely coupled modes whereas phase separation methods may be used to measure more isolated or linear modes. New fractographic features of unidirectional CFRP under fatigue load has been identified by AG20. This finding may contribute to a better understanding of composite failure. In AG27 this work will be extended to multi-layer composites. As a first step towards a comprehensive multi disciplinary aircraft optimisation the AG21 included aero-elastic constraints into the primary optimisation cycle. AG22 addresses more efficient design methods for damage tolerant composite stiffened wing panels in order to reduce development cost of such panels, improve their reliability and shorten the time for verification and certification. AG23 analyses the scope of active vibration suppression with piezo-electric actuators by means of tests and numerical computations. Activities of AG24 are focussed on an improved acceptability of numerical impact simulation. Based on three well documented panel tests, AG25 intends to build up confidence in computational results of geometric and material nonlinear problems. AG26 is gathering experience in the application of the Equivalent Initial Flaw Size concept and its implementation in design in order to avoid unduly conservative requirements in case of changes to the airworthiness regulations. All these topic are tackled by multi-national groups with contributions from universities, research establishments and the industry. Though the work is performed with rather limited resources the joint effort often leads to highly recognised results.