The magnetostriction and acoustics properties of Tb1-x xDyx (Fe1-yMny) 1.95 alloys and their application to sonar transducers were studied. The following results were obtained from experiments. When the applied magn...The magnetostriction and acoustics properties of Tb1-x xDyx (Fe1-yMny) 1.95 alloys and their application to sonar transducers were studied. The following results were obtained from experiments. When the applied magnetic field intensity is ≥ 800 kA·m-1, the magnetostrictive coefficients are (1300- 1800)× 10-6. The electromechanical coupling factors are 0.84-0.93, the sound velocities 2168-2856 m·s-1 and the Young's modulus (5.06- 7.26) ×10 N·m-2. A sonar transducer made of the alloy rod, which has a total length of 300 mm and a total weight of 2 kg, is characterized by 2.4 kHz specified resonant frequency, 1 kHz frequency band, 173 kB current response and 45% electroacoustic efficiency.展开更多
In this research, using the energy approach, a generalized dynamic model is derived for Galfenol (Iron-Gallium Alloy) based on the mechanical strain theory and the Jiles-Atherton model. Experiments have been conducted...In this research, using the energy approach, a generalized dynamic model is derived for Galfenol (Iron-Gallium Alloy) based on the mechanical strain theory and the Jiles-Atherton model. Experiments have been conducted to measure the relationship between the strain and the magnetic field. Using experimental data, unknown parameters in the model have been identified by a developed optimization algorithm. Results show that the novel dynamic model with identified parameters is capable of describing the performance of the Galfenol rod. Simulation and experiment dynamic responses of Galfenol rods are derived. The simulation and the experiment both agree that the magnitude of the strain output decreases with the increase of the excitation frequency.展开更多
A new ultrasonic transducer with multi-belts coil for generating and receiving longitudinal guided wave in ferromagnetic material pipes is proposed.The theory backgrounds and transduction principle of the proposed tra...A new ultrasonic transducer with multi-belts coil for generating and receiving longitudinal guided wave in ferromagnetic material pipes is proposed.The theory backgrounds and transduction principle of the proposed transducer are presented and ana- lyzed.To verify the performance of the transducer,several experiments are performed.The performance of inspecting crack, frequency-tuned characteristic,effect of bias static magnetic field and dynamic magnetic field,lift-off effect and effect of the period number of the exciting current are investigated.The results show that the proposed coils not only could tune the center frequency but also could improve the amplitude and signal-to-noise(SNR)of the detected signals.Bias static magnetic field and dynamic magnetic field are two important factors influencing the amplitude of the longitudinal guided wave.The amplitude of the longitudinal guided wave is exponentially decreased versus the lift-off distance of the transmitter and receiver.Period number of excitation signal could influence the amplitude and wave width of the ultrasonic wave.The proposed transducer could easily control the wave modes and would be a better choice for pipes’monitoring and inspection compared to traditional single-belt coil transducer.展开更多
The giant magnetostrictive rotary ultrasonic processing system(GMUPS)with a loosely-coupled contactless power transfer(LCCPT)has emerged as a high-performance technique for the processing of hard and brittle materials...The giant magnetostrictive rotary ultrasonic processing system(GMUPS)with a loosely-coupled contactless power transfer(LCCPT)has emerged as a high-performance technique for the processing of hard and brittle materials,owing to its high power density.A capacitive compensation is required to achieve the highest energy efficiency of GMUPS to provide sufficient vibration amplitude when it works in the resonance state.In this study,an accurate model of the optimal compensation capacitance is derived from a new electromechanical equivalent circuit model of the GMUPS with LCCPT,which consists of an equivalent mechanical circuit and an electrical circuit.The phase lag angle between the mechanical and electrical circuits is established,taking into account the non-negligible loss in energy conversion of giant magnetostrictive material at ultrasonic frequency.The change of system impedance characteristics and the effectiveness of the system compensation method under load are analyzed.Both idle vibration experiments and machining tests are conducted to verify the developed model.The results show that the GMUPS with optimal compensation capacitance can achieve the maximum idle vibration amplitude and smallest cutting force.In addition,the effects of magnetic conductive material and driving voltages on the phase lag angle are also evaluated.展开更多
基金the Rare Earth Office of MMI and the National Natural Science Foundation of China!59501008
文摘The magnetostriction and acoustics properties of Tb1-x xDyx (Fe1-yMny) 1.95 alloys and their application to sonar transducers were studied. The following results were obtained from experiments. When the applied magnetic field intensity is ≥ 800 kA·m-1, the magnetostrictive coefficients are (1300- 1800)× 10-6. The electromechanical coupling factors are 0.84-0.93, the sound velocities 2168-2856 m·s-1 and the Young's modulus (5.06- 7.26) ×10 N·m-2. A sonar transducer made of the alloy rod, which has a total length of 300 mm and a total weight of 2 kg, is characterized by 2.4 kHz specified resonant frequency, 1 kHz frequency band, 173 kB current response and 45% electroacoustic efficiency.
文摘In this research, using the energy approach, a generalized dynamic model is derived for Galfenol (Iron-Gallium Alloy) based on the mechanical strain theory and the Jiles-Atherton model. Experiments have been conducted to measure the relationship between the strain and the magnetic field. Using experimental data, unknown parameters in the model have been identified by a developed optimization algorithm. Results show that the novel dynamic model with identified parameters is capable of describing the performance of the Galfenol rod. Simulation and experiment dynamic responses of Galfenol rods are derived. The simulation and the experiment both agree that the magnitude of the strain output decreases with the increase of the excitation frequency.
基金supported by the National Natural Science Foundation of China(Grant No.10974115)
文摘A new ultrasonic transducer with multi-belts coil for generating and receiving longitudinal guided wave in ferromagnetic material pipes is proposed.The theory backgrounds and transduction principle of the proposed transducer are presented and ana- lyzed.To verify the performance of the transducer,several experiments are performed.The performance of inspecting crack, frequency-tuned characteristic,effect of bias static magnetic field and dynamic magnetic field,lift-off effect and effect of the period number of the exciting current are investigated.The results show that the proposed coils not only could tune the center frequency but also could improve the amplitude and signal-to-noise(SNR)of the detected signals.Bias static magnetic field and dynamic magnetic field are two important factors influencing the amplitude of the longitudinal guided wave.The amplitude of the longitudinal guided wave is exponentially decreased versus the lift-off distance of the transmitter and receiver.Period number of excitation signal could influence the amplitude and wave width of the ultrasonic wave.The proposed transducer could easily control the wave modes and would be a better choice for pipes’monitoring and inspection compared to traditional single-belt coil transducer.
基金supported by the National Natural Science Foundation of China(Nos.51875311 and 52105458)the Tsinghua-Foshan Innovation Special Fund(No.2021THFS0204)the Huaneng Group Science and Technology Research Project(No.HNKJ22-U22YYJC08),China。
文摘The giant magnetostrictive rotary ultrasonic processing system(GMUPS)with a loosely-coupled contactless power transfer(LCCPT)has emerged as a high-performance technique for the processing of hard and brittle materials,owing to its high power density.A capacitive compensation is required to achieve the highest energy efficiency of GMUPS to provide sufficient vibration amplitude when it works in the resonance state.In this study,an accurate model of the optimal compensation capacitance is derived from a new electromechanical equivalent circuit model of the GMUPS with LCCPT,which consists of an equivalent mechanical circuit and an electrical circuit.The phase lag angle between the mechanical and electrical circuits is established,taking into account the non-negligible loss in energy conversion of giant magnetostrictive material at ultrasonic frequency.The change of system impedance characteristics and the effectiveness of the system compensation method under load are analyzed.Both idle vibration experiments and machining tests are conducted to verify the developed model.The results show that the GMUPS with optimal compensation capacitance can achieve the maximum idle vibration amplitude and smallest cutting force.In addition,the effects of magnetic conductive material and driving voltages on the phase lag angle are also evaluated.
