Abstract:

The method of controlling the presence of microcracks in metal pipeline materials for aircraft systems in a commercial medium (on the stage of quality selection of the systems for the specific aircraft model) is proposed. The structure of the echosignal from the cylindrical pipeline in water is investigated in comparison with the pipeline standard section without microcracks. In the presence of microcracks in shell material, changes in the effective Young's modulus and Poisson's ratio due to echosignal structure and the meaning of statistical longitudinal and shear material modules are defined. That effective modulus contains information about microcracks in the pipeline material measuring 1x3 mm (the cylindrical crack). Approximately 50 cm of the length of the main part is allowed to register changes in material. In particular, it is noticed in the frequency range f(3--10) MHz, where the resonance microcrack's peculiarities become apparent. The analytical formulas of effective elasticity modules that contain information about the presence of the many microcracks (including the sole) are obtained. The proposed method can be applied in the case of aircraft pipeline quality control.