Cel
The major goal of this study is to improve the safety and the fatigue life of aircraft structures which are subjected to sonic excitation. The study is focused on 3 specific objectives:
Elaboration of acoustic fatigue strength data for advanced materials.
Development of semi-empirical models of acoustic loads and correlation between flight conditions and acoustic tests (testing strategy).
Computational calculation of the dynamic response and application of models of fracture mechanics to predict the life duration.
It has been found that the use of a frequency degradation criterion, usually applied to classical metallic materials and early carbon fibre reinforced plastic (CFRP) materials, is not suitable as the only parameter, for determination of CFRP specimen failure in acoustic fatigue. A suitable criterion should be based upon the degradation of the mechanical properties of the specimens.
It has been shown that the excitation of structures by aero-acoustic loads may not be simulated fully in progressive wave tube (PWT) by simply modifying and correctly shaping the spectral content. The effect of the spatial distribution of the loading was clearly different in both cases and the tested specimen endurance might be significantly different. A theoretical approach based on correctly predicting responses to both types of environment is required.
The work comprises:
Preparatory investigation for the acoustic fatigue tests: definition of the test specimens and test conditions.
Dynamic tests by shaker excitation in order to determine random vibration strength data for advanced metallic and composite materials:
S-N curves (stress endurance data);
dA/dN curves (damage growth rate data).
Acoustic tests in a wind tunnel and progressive Wave Tubes:
to validate aero-acoustic loads in a wind tunnel;
to calibrate tests in Progressive Wave Tube (PWT) by comparison of the structural response between wind tunnel tests and PWT tests.
to get response parameters for comparison with predictions;
to get acoustic fatigue strength data.
Theoretical analysis of acoustic fatigue and damage tolerance based on a validation of available loads, for application of available models and computational methods. Comparisons with test data should provide adjustments.
Dziedzina nauki
Temat(-y)
Data not availableZaproszenie do składania wniosków
Data not availableSystem finansowania
CSC - Cost-sharing contractsKoordynator
PARIS
Francja