This paper investigates shear horizontal （SH） waves propagating in a periodically layered structure that consists of piezoelectric （PE） layers perfectly bonded with piezomagnetic （PM） layers alternately. The exp...This paper investigates shear horizontal （SH） waves propagating in a periodically layered structure that consists of piezoelectric （PE） layers perfectly bonded with piezomagnetic （PM） layers alternately. The explicit dispersion relations are derived for the two cases when the propagation directions of SH waves are normal to the interface and parallel to the interface, respectively. The asymptotic expressions for dispersion relations are also given when the wave number is extremely small. Numerical results for stop band effect and phase velocity are presented for a periodic system of alternating BaTiO3 and Terfenol-D layers. The influence of volume fraction on stop band effect and dispersion behaviors is discussed and revealed.展开更多
The relative change of in-situ stress is an inevitable outcome of differential movement among the crust plates. Conversely, changes of in-situ stress can also lead to deformation and instability of crustal rock mass, ...The relative change of in-situ stress is an inevitable outcome of differential movement among the crust plates. Conversely, changes of in-situ stress can also lead to deformation and instability of crustal rock mass, trigger activity of faults, and induce earthquakes. Hence, monitoring real-time change of in-situ stress is of great significance. Piezomagnetic in-situ stress monitoring has good and longtime applications in large engineering constructions and geoscience study fields in China. In this paper, the new piezomagnetic in-situ stress monitoring system is introduced and it not only has overall improvements in measuring cell＇s structure and property, stressing and orienting way, but also enhances integration and intelligence of control and data transmission system, in general, which greatly promotes installing efficiency of measuring probe and quality of monitoring data. This paper also discusses the responses of new piezomagnetic system in large earthquake events of in-situ stress monitoring station at Qiaoqi of Baoxing and Wenxian of Gansu. The monitoring data reflect adjustments and changes of tectonic stress field at the southwestern segment of and the northern area near the Longmenshan fault zone, which shows that the new system has a good performance and application prospect in the geoscience field. Data of the Qiaoqi stress-monitoring station manifest that the Lushan Earthquake did not release stress of the southwestern segment of the Longmenshan fault zone adequately and there still probably exists seismic risk in this region in the future. Combined with absolute in-situ stress measurement, carrying out long-term in-situ stress monitoring in typical tectonic position of important regions is of great importance for researchers to assess and study regional crust stability.展开更多
Magnetoelastic couplings in giant magnetostrictive materials(GMMs)attract significant interests due to their extensive applications in the fields of spintronics and energy harvesting devices.Understanding the role of ...Magnetoelastic couplings in giant magnetostrictive materials(GMMs)attract significant interests due to their extensive applications in the fields of spintronics and energy harvesting devices.Understanding the role of the selection of materials and the response to external fields is essential for attaining desired functionality of a GMM.Herein,machine learning(ML)models are conducted to predict saturation magnetostrictions(λ_(s))in RFe_(2)-type(R=rare earth)GMMs with different compositions.According to ML-predicted composition–λsrelations,it is discovered that the values ofλshigher than1100×10^(-6)are almost situated in the composition space surrounded by 0.26≤x≤0.60 and 1.90≤y≤2.00 for the ternary compounds of Tb_(x)Dy_(1-x)Fe_(y).Assisted by ML predictions,the compositions are further narrowed down to the space surrounded by 0.26≤x≤0.32 and 1.92≤y≤1.97 for the excellent piezomagnetic(PM)performance in the Tb_(x)Dy_(1-x)Fe_(y)based PM device through our developed high-throughput(HTP)micromagnetic simulation(MMS)algorithm.Accordingly,high sensitivities up to10.22-13.61 m T·MPa^(-1)are observed in the optimized range within which the available experimental data fall well.This work not only provides valuable insights toward understanding the mechanism of magnetoelastic couplings,but also paves the way for designing and optimizing highperformance magnetostrictive materials and PM sensing devices.展开更多
The direction dependence of surface wave speed and the influence of electrically and magnetically short/open circuit are investigated in this paper. First, the elastic, piezoelectric and piezomagnetic coefficients in ...The direction dependence of surface wave speed and the influence of electrically and magnetically short/open circuit are investigated in this paper. First, the elastic, piezoelectric and piezomagnetic coefficients in the considered ordinate system are obtained by Bonde transformation from those in the crystal axis ordinate system. Then, the secular equation of surface wave is derived from the free traction condition on the surface of half space with consideration of short/open circuit case. Some numerical examples are given. The direction dependence of surface wave speed and the influences of short/open circuit are shown graphically and discussed based on the numerical results.展开更多
N2 and N3 are known as the transition points of the three principal stages of fatigue: initial accommodation, accretion of damage and terminal fatigue. Many experiments show that the ratios of N2/Nf and N3/Nf tend to ...N2 and N3 are known as the transition points of the three principal stages of fatigue: initial accommodation, accretion of damage and terminal fatigue. Many experiments show that the ratios of N2/Nf and N3/Nf tend to be stable even though the specific N2 and N3 values may fluctuate widely. The primary goal of this research is to study the piezomagnetic field surrounding AISI 1018 steel specimen under repeated loads and to find the ratio values of N2/Nf and N3/Nf by analyzing 11 sets of low-cycle fatigue data. An MTS-810 testing system with a peak capacity of 222 kN was used to obtain the data which consisted of stress, strain, and piezomagnetic field. A computer program was constructed to track the evolution of the piezomagnetic field and re- gression analysis was carried out to determine N2 and N3 values. It was observed that there exists a consistent relationship between N2 and Nf. The apparent invariance of the ratio N2/Nf implies that N2 may be identified as an index of performance in the early loading response of a specimen that forecasts its fatigue life, Nf. It has been demonstrated that measurements of the magnetic and mechanical hysteresis can yield significant insights into the various stages of the development of a fatigue critical microstructure which culminates in complete rupture of the material.展开更多
We study the bending of a magnetically saturated ferromagnetoelastic plate.The plate is rectangular and simply-supported along its edges.It is under a local distribution of normal mechanical load on its top surface,si...We study the bending of a magnetically saturated ferromagnetoelastic plate.The plate is rectangular and simply-supported along its edges.It is under a local distribution of normal mechanical load on its top surface,simulating a mechanical probe or manipulation of the magnetization field.The three-dimensional equations of saturated ferromagnetoelasticity for small fields superposed on finite biasing fields due to spontaneous magnetization are used.The plate is effectively piezomagnetic under the biasing fields.A trigonometric series solution is obtained.The perturbation of the magnetization field by the mechanical load is calculated and examined.It is found that the magnetization is sensitive to the mechanical load,particularly near the loading area.The perturbation of the magnetization is found to be associated with the transverse shear stresses in bending.展开更多
In this paper, a three-dimensional finite-element formulation for the multiferroic composite is developed and implemented into the commercial software ABAQUS for its transient analysis. First, a special three-dimensio...In this paper, a three-dimensional finite-element formulation for the multiferroic composite is developed and implemented into the commercial software ABAQUS for its transient analysis. First, a special three-dimensional eight-node solid element is designed to handle the multiferroic composite made of elastic, piezoelectric, and piezomagnetic materials. Second, a userdefined subroutine for this newly developed element is implemented into ABAQUS. Finally, the transient responses of a bi-layered multiferroic composite are calculated by using the direct time integration method. Two typical magnetic potential signals, Gauss and Ricker pulses, are applied to the composite with various time durations of excitation. The induced electric field shows that the transient response can be substantially influenced by the input signal, which could be tuned for the strongest electric output.展开更多
The piezomagnetic properties of rapidly quenched Fe73.5Cu1Nb3Si13.5B9 alloy strips were investigated in as-quenched state and after annealing for 2 h in vacuum in the temperature range of 100-300 ℃. The impedance of ...The piezomagnetic properties of rapidly quenched Fe73.5Cu1Nb3Si13.5B9 alloy strips were investigated in as-quenched state and after annealing for 2 h in vacuum in the temperature range of 100-300 ℃. The impedance of amorphous strips increases with frequency, and sensitively de-creases with stress increasing, especially in the frequency range of 10-100 MHz. The impedance in-creases approximately linearly with frequency below the critical frequency, but begins to decrease non-linearly with frequency above the critical frequency. The higher the point compressive stress is, the smaller the critical frequency will be. The stability of piezomagnetic properties is very excellent. The impedance of amorphous strips after annealing, especially at 300 ℃, decreases very strongly. The impedance and the absolute values of the sensitive degree of couple layers＇ amorphous strips are lower than those of single layer strips.展开更多
We study the electrical response of a multiferroic composite semiconductor fiber consisting of a piezoelectric semiconductor layer and two piezomagnetic layers under a transverse magnetic field applied locally to a fi...We study the electrical response of a multiferroic composite semiconductor fiber consisting of a piezoelectric semiconductor layer and two piezomagnetic layers under a transverse magnetic field applied locally to a finite part of the fiber.The phenomenological theory of piezomagnetic-piezoelectric semiconductors is employed.A one-dimensional model is derived for magnetically induced extension of the fiber.For open-circuit boundary conditions at the two ends of the fiber,an analytical solution is obtained from the model linearized for small carrier perturbations.The solution shows a local electric polarization and a pair of local electric potential barrier-well.When the two ends of the fiber are under a voltage,a nonlinear numerical solution shows that the potential barrier and well forbid the passage of currents when the voltage is low.The results have potential applications in piezotronic devices when magnetic fields are involved for manipulating the devices or sensing and transduction.展开更多
This theoretical work provides with results of characteristics calculation of the ultrasonic surface Zakharenko waves (USZWs) existing in piezomagnetic cubic monocrystals of class m3m that can be readily used for non-...This theoretical work provides with results of characteristics calculation of the ultrasonic surface Zakharenko waves (USZWs) existing in piezomagnetic cubic monocrystals of class m3m that can be readily used for non-destructive testing. The piezomagnetic waves propagate in direction [101] corresponding to relatively easy magnetization for the following piezomagnetics: Galfenol, Terfenol-D, and CoFe2O4 with cubic structures. The phase velocities of the USZW-waves and the coefficient of magnetomechanical coupling (CMMC) K2 were calculated for the crystals. It was found that the coefficient K2 for piezomagnetics with Km2 > 1/3 and Km2 >> 1/3 is about 8% to 9%, where K2 = 2 (VUSZW,o – VUSZW,c)/VUSZW,o and Km2 = h2/(Cμ). Knowledge of piezomagnetic properties of cubic crystals makes possible the use of them in new products utilizing the phenomenon called the magnetoelectric effect. Also, this study is useful for possible application of cubic piezomagnetics in composite structures consisting of piezoelectric and (or) piezomagnetic materials and in the microwave technology. This broadens choice of possible piezomagnetic materials for utilization in various technical devices.展开更多
When strain wave passes through rock, a changing magnetic field due to piezomagnetic effect will propagate at the velocity of sound. The changing magnetic field will stimulate electromagnetic ef fect in the surroundin...When strain wave passes through rock, a changing magnetic field due to piezomagnetic effect will propagate at the velocity of sound. The changing magnetic field will stimulate electromagnetic ef fect in the surrounding area. This paper reports the experimental results which proves the existence of such phenomena. And the synthetic piezomagnetic coefficients of rock are measured from experimental results. The piezomagnetic effect can be used to explain some electromagnetic phenomena produced in the process of earthquakes.展开更多
基金supported by the National Natural Science Foundation of China (Nos.10672108,10572069 and 10820101048)
文摘This paper investigates shear horizontal （SH） waves propagating in a periodically layered structure that consists of piezoelectric （PE） layers perfectly bonded with piezomagnetic （PM） layers alternately. The explicit dispersion relations are derived for the two cases when the propagation directions of SH waves are normal to the interface and parallel to the interface, respectively. The asymptotic expressions for dispersion relations are also given when the wave number is extremely small. Numerical results for stop band effect and phase velocity are presented for a periodic system of alternating BaTiO3 and Terfenol-D layers. The influence of volume fraction on stop band effect and dispersion behaviors is discussed and revealed.
基金finically supported by the Sino Probe-06-01,Special Fund Research in the Public Interest (Grant No. 201211076)National Key Basic Project (973) (Grant No. 2008CB425702)
文摘The relative change of in-situ stress is an inevitable outcome of differential movement among the crust plates. Conversely, changes of in-situ stress can also lead to deformation and instability of crustal rock mass, trigger activity of faults, and induce earthquakes. Hence, monitoring real-time change of in-situ stress is of great significance. Piezomagnetic in-situ stress monitoring has good and longtime applications in large engineering constructions and geoscience study fields in China. In this paper, the new piezomagnetic in-situ stress monitoring system is introduced and it not only has overall improvements in measuring cell＇s structure and property, stressing and orienting way, but also enhances integration and intelligence of control and data transmission system, in general, which greatly promotes installing efficiency of measuring probe and quality of monitoring data. This paper also discusses the responses of new piezomagnetic system in large earthquake events of in-situ stress monitoring station at Qiaoqi of Baoxing and Wenxian of Gansu. The monitoring data reflect adjustments and changes of tectonic stress field at the southwestern segment of and the northern area near the Longmenshan fault zone, which shows that the new system has a good performance and application prospect in the geoscience field. Data of the Qiaoqi stress-monitoring station manifest that the Lushan Earthquake did not release stress of the southwestern segment of the Longmenshan fault zone adequately and there still probably exists seismic risk in this region in the future. Combined with absolute in-situ stress measurement, carrying out long-term in-situ stress monitoring in typical tectonic position of important regions is of great importance for researchers to assess and study regional crust stability.
基金financially supported by the National Key R&D Program of China(No.2021YFB3501401)the National Natural Science Foundation of China(Nos.52001103,U22A20117)Zhejiang Provincial Natural Science Foundation of China(No.LQ21E010001)。
文摘Magnetoelastic couplings in giant magnetostrictive materials(GMMs)attract significant interests due to their extensive applications in the fields of spintronics and energy harvesting devices.Understanding the role of the selection of materials and the response to external fields is essential for attaining desired functionality of a GMM.Herein,machine learning(ML)models are conducted to predict saturation magnetostrictions(λ_(s))in RFe_(2)-type(R=rare earth)GMMs with different compositions.According to ML-predicted composition–λsrelations,it is discovered that the values ofλshigher than1100×10^(-6)are almost situated in the composition space surrounded by 0.26≤x≤0.60 and 1.90≤y≤2.00 for the ternary compounds of Tb_(x)Dy_(1-x)Fe_(y).Assisted by ML predictions,the compositions are further narrowed down to the space surrounded by 0.26≤x≤0.32 and 1.92≤y≤1.97 for the excellent piezomagnetic(PM)performance in the Tb_(x)Dy_(1-x)Fe_(y)based PM device through our developed high-throughput(HTP)micromagnetic simulation(MMS)algorithm.Accordingly,high sensitivities up to10.22-13.61 m T·MPa^(-1)are observed in the optimized range within which the available experimental data fall well.This work not only provides valuable insights toward understanding the mechanism of magnetoelastic couplings,but also paves the way for designing and optimizing highperformance magnetostrictive materials and PM sensing devices.
基金Project supported by the National Natural Science Foundation of China(No.10972029)the Science and Technology Program of Educational Commission of Heilongjiang Province of China(No.12541869)the Program of Young Teachers Scientific Research in Qiqihar University(No.2014K-Z03)
文摘The direction dependence of surface wave speed and the influence of electrically and magnetically short/open circuit are investigated in this paper. First, the elastic, piezoelectric and piezomagnetic coefficients in the considered ordinate system are obtained by Bonde transformation from those in the crystal axis ordinate system. Then, the secular equation of surface wave is derived from the free traction condition on the surface of half space with consideration of short/open circuit case. Some numerical examples are given. The direction dependence of surface wave speed and the influences of short/open circuit are shown graphically and discussed based on the numerical results.
基金Project supported by the National Natural Science Foundation of China (No. 50901067)the Technological Research and Development Programs of the Ministry of Railways (No. 2010G007-E), China
文摘N2 and N3 are known as the transition points of the three principal stages of fatigue: initial accommodation, accretion of damage and terminal fatigue. Many experiments show that the ratios of N2/Nf and N3/Nf tend to be stable even though the specific N2 and N3 values may fluctuate widely. The primary goal of this research is to study the piezomagnetic field surrounding AISI 1018 steel specimen under repeated loads and to find the ratio values of N2/Nf and N3/Nf by analyzing 11 sets of low-cycle fatigue data. An MTS-810 testing system with a peak capacity of 222 kN was used to obtain the data which consisted of stress, strain, and piezomagnetic field. A computer program was constructed to track the evolution of the piezomagnetic field and re- gression analysis was carried out to determine N2 and N3 values. It was observed that there exists a consistent relationship between N2 and Nf. The apparent invariance of the ratio N2/Nf implies that N2 may be identified as an index of performance in the early loading response of a specimen that forecasts its fatigue life, Nf. It has been demonstrated that measurements of the magnetic and mechanical hysteresis can yield significant insights into the various stages of the development of a fatigue critical microstructure which culminates in complete rupture of the material.
基金funded by the National Natural Science Foundation of China[No.11572244,Xiaoshan Cao]supported by the Natural Science Foundation of Shaanxi Province,China[No.2021JZ-47,Xiaoshan Cao].
文摘We study the bending of a magnetically saturated ferromagnetoelastic plate.The plate is rectangular and simply-supported along its edges.It is under a local distribution of normal mechanical load on its top surface,simulating a mechanical probe or manipulation of the magnetization field.The three-dimensional equations of saturated ferromagnetoelasticity for small fields superposed on finite biasing fields due to spontaneous magnetization are used.The plate is effectively piezomagnetic under the biasing fields.A trigonometric series solution is obtained.The perturbation of the magnetization field by the mechanical load is calculated and examined.It is found that the magnetization is sensitive to the mechanical load,particularly near the loading area.The perturbation of the magnetization is found to be associated with the transverse shear stresses in bending.
基金supported by the National Natural Science Foundation of China (No.50775028)
文摘In this paper, a three-dimensional finite-element formulation for the multiferroic composite is developed and implemented into the commercial software ABAQUS for its transient analysis. First, a special three-dimensional eight-node solid element is designed to handle the multiferroic composite made of elastic, piezoelectric, and piezomagnetic materials. Second, a userdefined subroutine for this newly developed element is implemented into ABAQUS. Finally, the transient responses of a bi-layered multiferroic composite are calculated by using the direct time integration method. Two typical magnetic potential signals, Gauss and Ricker pulses, are applied to the composite with various time durations of excitation. The induced electric field shows that the transient response can be substantially influenced by the input signal, which could be tuned for the strongest electric output.
基金Funded by the National Natural Science Foundation of China (No.0576014)
文摘The piezomagnetic properties of rapidly quenched Fe73.5Cu1Nb3Si13.5B9 alloy strips were investigated in as-quenched state and after annealing for 2 h in vacuum in the temperature range of 100-300 ℃. The impedance of amorphous strips increases with frequency, and sensitively de-creases with stress increasing, especially in the frequency range of 10-100 MHz. The impedance in-creases approximately linearly with frequency below the critical frequency, but begins to decrease non-linearly with frequency above the critical frequency. The higher the point compressive stress is, the smaller the critical frequency will be. The stability of piezomagnetic properties is very excellent. The impedance of amorphous strips after annealing, especially at 300 ℃, decreases very strongly. The impedance and the absolute values of the sensitive degree of couple layers＇ amorphous strips are lower than those of single layer strips.
基金This work was supported by the National Natural Science Foundation of China(Nos.11672265,11972139,and 11621062)the Science and Technology Innovation Committee of Shenzhen(No.JCYJ20180227175523802)+1 种基金the State Key Laboratory of Mechanics and Control of Mechanical Structures(Nanjing University of Aeronautics and astronautics,No.MCMS-E-0220K01)Department of Water Resources of Zhejiang Province(No.RC1719).
文摘We study the electrical response of a multiferroic composite semiconductor fiber consisting of a piezoelectric semiconductor layer and two piezomagnetic layers under a transverse magnetic field applied locally to a finite part of the fiber.The phenomenological theory of piezomagnetic-piezoelectric semiconductors is employed.A one-dimensional model is derived for magnetically induced extension of the fiber.For open-circuit boundary conditions at the two ends of the fiber,an analytical solution is obtained from the model linearized for small carrier perturbations.The solution shows a local electric polarization and a pair of local electric potential barrier-well.When the two ends of the fiber are under a voltage,a nonlinear numerical solution shows that the potential barrier and well forbid the passage of currents when the voltage is low.The results have potential applications in piezotronic devices when magnetic fields are involved for manipulating the devices or sensing and transduction.
文摘This theoretical work provides with results of characteristics calculation of the ultrasonic surface Zakharenko waves (USZWs) existing in piezomagnetic cubic monocrystals of class m3m that can be readily used for non-destructive testing. The piezomagnetic waves propagate in direction [101] corresponding to relatively easy magnetization for the following piezomagnetics: Galfenol, Terfenol-D, and CoFe2O4 with cubic structures. The phase velocities of the USZW-waves and the coefficient of magnetomechanical coupling (CMMC) K2 were calculated for the crystals. It was found that the coefficient K2 for piezomagnetics with Km2 > 1/3 and Km2 >> 1/3 is about 8% to 9%, where K2 = 2 (VUSZW,o – VUSZW,c)/VUSZW,o and Km2 = h2/(Cμ). Knowledge of piezomagnetic properties of cubic crystals makes possible the use of them in new products utilizing the phenomenon called the magnetoelectric effect. Also, this study is useful for possible application of cubic piezomagnetics in composite structures consisting of piezoelectric and (or) piezomagnetic materials and in the microwave technology. This broadens choice of possible piezomagnetic materials for utilization in various technical devices.
文摘When strain wave passes through rock, a changing magnetic field due to piezomagnetic effect will propagate at the velocity of sound. The changing magnetic field will stimulate electromagnetic ef fect in the surrounding area. This paper reports the experimental results which proves the existence of such phenomena. And the synthetic piezomagnetic coefficients of rock are measured from experimental results. The piezomagnetic effect can be used to explain some electromagnetic phenomena produced in the process of earthquakes.
