TL;DR: In this article, a finite element model is established to study the vibration characteristics of fan blades, and natural frequencies and vibration modes are calculated when the shroud is free and constrained respectively.
Abstract: For high bypass ratio fans,the aeroengine always failures to work because the shrouded blades constantly suffer great centrifugal and vibration loadsTo study the vibration characteristics of fan blades,the finite element model is established,and natural frequencies and vibration modes are calculated when the shroud is free and constrained respectivelyIt is found that the natural frequencies are effected by the engine speed and shroud stationThe conclusions are of significance for further study on vibration characteristics of high bypass ratio fan blade
TL;DR: In this paper, the influence of the Rib Number and the Rib Thickness to Wide-Chord Hollow Fan Blade Vibration Characteristics has been analyzed and the results show that the wide-chord Hollow fan blades greatly improved the first-order VIBration Frequency compared with the Solid Blades.
Abstract: Wide-Chord Hollow Fan Blade is One of the New Technologies Used in Aircraft Engines. in this Paper, the Modal Analysis Method is Used to Analyze the Influence of the Rib Number and the Rib Thickness to Wide-Chord Hollow Fan Blade Vibration Characteristics. the Result Shows that the Wide-Chord Hollow Fan Blades Greatly Improves the First-Order Vibration Frequency Compared with the Solid Blades, and the First-Order Vibration Frequency of the Wide-Chord Hollow Fan Blades is Reduced with the Increasing Rib Number which is Not Good for Vibration Elimination. the Wide-Chord Hollow Fan Blades’ Vibration Frequency Changes a Little when the Rib Number is Larger than Three. in Addition, the Rib Thickness has Smaller Effect on Wide-Chord Hollow Fan Blade.
••01 Aug 2017
TL;DR: In this article, the root cause analysis of an unexpected fracture occurred on the blades of a motor fan used in a natural gas reciprocating compressor unit was presented, and some recommendations were given to improve the reliability of the motor fan.
Abstract: This paper presents the root cause analysis of an unexpected fracture occurred on the blades of a motor fan used in a natural gas reciprocating compressor unit. A finite element model was established to investigate the natural frequencies and modal shapes of the fan, and a modal test was performed to verify the numerical results. It was indicated that the numerical results agreed well with experimental data. The third order natural frequency was close to the six times excitation frequency, and the corresponding modal shape was the combination of bending and torsional vibration, which consequently contributed to low-order resonance and fracture failure of the fan. The torsional moment obtained by a torsional vibration analysis of the compressor shaft system was exerted on the numerical model of the fan to evaluate the dynamic stress response of the fan. The results showed that the stress concentration regions on the numerical model were consistent with the location of fractures on the fan. Based on the numerical simulation and experimental validation, some recommendations were given to improve the reliability of the motor fan.