Abstract:NiCrAlY coating was prepared on a stainless steel substrate by an arc ion plating machine and the annealing experiments were carried out at different temperatures using a tube furnace. The effects of annealing temperatures on the morphology, structure, chemical composition and phase structure of the coating were characterized by SEM, EDS and XRD, respectively. The change of microstructure is discussed. Dynamic mechanical analyzer results determined the suitable annealing temperature for the best damping perfor… Show more
“…Molten particles and semi-molten particles were impinged on the surface of substrates by high-speed flame flow. After continuous stacking and diffusion, island-structures are formed on the surface of the substrates, while non-stacked areas form pores [16-18]. Figure 2 Surface of CM4 coatings: (a)low magnification SEM, (b) high magnification SEM.…”
Mo-based coatings were prepared on stainless steel substrates by supersonic arc spraying. To investigate the phases, X-ray diffraction technique was utilised. Scanning electron microscopy technique was used to study the microstructure. The damping behaviours were studied by Dynamic Mechanical Analyser (DMA). It was observed that the coatings have better damping performance than substrates (without coating) in different conditions, and the loss factor of CM4 coatings reaches a maximum value of 0.06 at 300°C and 150 Hz. In addition, vibration modal analysis and harmonic response analysis were carried out by ABAQUS finite element analysis software. The amplitude-frequency curve was obtained through harmonic response analysis, and the relation between damping ratio and coating density was obtained by combining half power bandwidth method. For the analysis of damping mechanism of coatings, damping sources were not unique. With the change of temperature or frequency, various damping sources would be displayed successively or simultaneously.
“…Molten particles and semi-molten particles were impinged on the surface of substrates by high-speed flame flow. After continuous stacking and diffusion, island-structures are formed on the surface of the substrates, while non-stacked areas form pores [16-18]. Figure 2 Surface of CM4 coatings: (a)low magnification SEM, (b) high magnification SEM.…”
Mo-based coatings were prepared on stainless steel substrates by supersonic arc spraying. To investigate the phases, X-ray diffraction technique was utilised. Scanning electron microscopy technique was used to study the microstructure. The damping behaviours were studied by Dynamic Mechanical Analyser (DMA). It was observed that the coatings have better damping performance than substrates (without coating) in different conditions, and the loss factor of CM4 coatings reaches a maximum value of 0.06 at 300°C and 150 Hz. In addition, vibration modal analysis and harmonic response analysis were carried out by ABAQUS finite element analysis software. The amplitude-frequency curve was obtained through harmonic response analysis, and the relation between damping ratio and coating density was obtained by combining half power bandwidth method. For the analysis of damping mechanism of coatings, damping sources were not unique. With the change of temperature or frequency, various damping sources would be displayed successively or simultaneously.
“…The friction of particles inside a coating can effectively dissipate external energy [16], thereby reducing structural vibrations after coating and inhibiting fatigue caused by vibrations [17]. The use of hard coatings for vibration reduction has become a new research direction [18,19], and studies have been conducted on the vibration reduction of aeroengine hydraulic pipelines based on hard coatings.…”
Aviation hydraulic pipelines are an important channel for power transmission in aviation hydraulic systems. Due to long-term exposure to complex vibration environments, hydraulic pipeline systems are susceptible to accumulated fatigue damage failure, which poses a great threat to aircraft safety and reliability. At present, there are only passive ways to reduce hydraulic pipeline vibration, such as adding vibration isolators and damping bearings. These methods have a poor vibration damping effect and are not safe. In this study, a hard coating was used as a new vibration reduction method for aviation hydraulic pipelines to reduce the damage caused by vibrations. For this purpose, three different hard-coating materials were optimally selected, and model creation, finite element analysis, and experimental research were carried out to study the vibration responses of hard-coated aviation hydraulic pipelines under the actual working conditions of an aircraft. The optimal solution was obtained through orthogonal experiments. The vibration reduction rate of the aviation hydraulic pipelines could reach 20.33% under the constant-frequency excitation of the low-pressure rotor of the engine, and the vibration reduction rate under the constant-frequency excitation of the high-pressure rotor could reach 26.60%. The rationality of the model was verified, and it was proven that the hard coating could meet the demands of vibration control in practical engineering and provide a reference for the vibration analysis and vibration control design of aviation hydraulic piping systems.
“…The hard coating was found to effectively consume external energy due to the friction effect of the particles inside the coating, reducing the structural vibration after coating and offering a good suppression effect for the fatigue caused by vibration [16][17][18]. The use of hard coatings for vibration damping has become a new research direction [19][20][21][22][23][24], and therefore research has been conducted on the damping of aero-engine hydraulic clamppiping systems based on hard coatings.…”
Aviation hydraulic clamp-piping systems often experience damage due to vibration, which poses a great threat to the reliability and safety of the aircraft. In this paper, a hard coating is used as a new damping method to study the vibration characteristics of aviation hydraulic clamp-piping systems. Three kinds of coated clamp entities are obtained by optimization and preparation, and the combination of finite element simulation and experiment is used to analyze the vibration response of the high- and low-pressure rotor under fixed-frequency simple harmonic excitation, and the resonance response under sweep-frequency excitation of the aviation hydraulic clamp-piping system. Through orthogonal experiments, it is clear that 304 stainless steel clamps coated with 200-μm-thick YSZ-PTFE coating have the best vibration damping effect on the clamp-piping system; that is, the damping rate can reach 24.67% under fixed-frequency excitation, and swept frequency damping can reach 19.93%. The maximum error between the simulation and the experimental vibration response amplitude is 7.9%, which proves the correctness of the model and verifies that the YSZ-PTFE hard coating can significantly improve the vibration damping effect with very good application prospects.
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