With the rapid development of mechanical equipment,mechanical health monitoring field has entered the era of big data.Deep learning has made a great achievement in the processing of large data of image and speech due ...With the rapid development of mechanical equipment,mechanical health monitoring field has entered the era of big data.Deep learning has made a great achievement in the processing of large data of image and speech due to the powerful modeling capabilities,this also brings influence to the mechanical fault diagnosis field.Therefore,according to the characteristics of motor vibration signals(nonstationary and difficult to deal with)and mechanical‘big data’,combined with deep learning,a motor fault diagnosis method based on stacked de-noising auto-encoder is proposed.The frequency domain signals obtained by the Fourier transform are used as input to the network.This method can extract features adaptively and unsupervised,and get rid of the dependence of traditional machine learning methods on human extraction features.A supervised fine tuning of the model is then carried out by backpropagation.The Asynchronous motor in Drivetrain Dynamics Simulator system was taken as the research object,the effectiveness of the proposed method was verified by a large number of data,and research on visualization of network output,the results shown that the SDAE method is more efficient and more intelligent.展开更多
The Mg-8Gd-3Er-0.5Ag-0.5Zr(wt.%)alloy fabricated by hot-extrusion+stamping exhibits an exceptional aging hardening response,with the yield strength being improved by>200 MPa.Traditional extrusion microstructure was...The Mg-8Gd-3Er-0.5Ag-0.5Zr(wt.%)alloy fabricated by hot-extrusion+stamping exhibits an exceptional aging hardening response,with the yield strength being improved by>200 MPa.Traditional extrusion microstructure was observed in the as-extruded sample,with the elongated non-recrystallized grains showing typical(10.10)fiber texture.After stamping,almost all non-recrystallized grains were twinned mainly following the(10.12)twin orientation.This significantly changed precipitate morphologies formed during the following aging,from the well-known granularβ'precipitate into net-workβ'+β'H structure,with the granularβ'precipitates being connected by chain-likeβ'H precipitates.Additionally,a novel fault was found in theβ'precipitates,whose formation is highly related to the metastable I2-type stacking fault.This new precipitation structure means the effective interparticle spacing being approximately zero,and the faults in theβ'precipitates can not only enhance strength of precipitates but also could efficiently impede dislocation motion,thus resulted in positive contribution on alloy’s yield strength.This work provides new insights in developing high-strength Mg alloys by modifying precipitation structure along with the inner faults in precipitation.展开更多
A bimodal structure in the WE43 alloy was constructed through traditional extrusion.The results suggest that the dominant dynamic recrystallization(DRX)mechanism in the alloy extruded at 300℃(E300)is twin-induced DRX...A bimodal structure in the WE43 alloy was constructed through traditional extrusion.The results suggest that the dominant dynamic recrystallization(DRX)mechanism in the alloy extruded at 300℃(E300)is twin-induced DRX(TDRX),while the discontinuous DRX(DDRX)prevails when extruded at 330℃(E330)and 370℃(E370).For all three kinds of alloys,a decrease in extrusion temperature results in enhanced strength without a significant loss of ductility.Notably,the E300 alloy demonstrates outstanding comprehensive mechanical properties,with a yield strength of 325 MPa,an ultimate tensile strength of 365 MPa,and an elongation of 10.2%.Numerous blocky Mg14Nd2Y with size of~100 nm is formed within elongated grains,which contributes to the increased strength of E300 alloy.Additionally,the high-density of I1 stacking faults and fine blocky precipitates within elongated grains enhance ductility.展开更多
The high operating temperatures and sluggish kinetics of Mg-based hydrogen storage materials(HSMs)are urgently being addressed.In this work,a novel Mg-Ni-Ga HSM with dual-phase synergistic catalysis is developed,inclu...The high operating temperatures and sluggish kinetics of Mg-based hydrogen storage materials(HSMs)are urgently being addressed.In this work,a novel Mg-Ni-Ga HSM with dual-phase synergistic catalysis is developed,including the fishbone-like Mg3Ni2Ga1 catalytic phase and the Mg2Ni phase with stacking faults(SFs).The spheroidization of Mg grains is inhibited by the pinning effect of the Mg3Ni2Ga1 phase,and the high-energy Mg grain boundaries are obtained.High-density SFs are induced in the Mg2Ni phase via Ga dissolution.It is worth noting that Mg94.5Ni5Ga0.5 alloy absorbs 0.37 wt%H2 merely at 25℃,and absorbs 2.71 wt%H2 at 150℃ under even 0.1 MPa.The dehydrogenation activation energy is significantly decreased from 81.86 kJ mol-1 in Mg95Ni5 alloy to 67.68 kJ mol-1.The room temperature and low-pressure hydrogenation performance are achieved through these multiphase synergistic catalysis:H2 molecule dissociation facilitated by the Mg3Ni2Ga1 phase,hydride nucleation promoted by high-energy Mg grain boundaries,additional rapid diffusion channels for H atoms,and the enhanced"hydrogen pump"effect provided by the Mg2Ni phase with SFs structure.展开更多
Rolling bearings are important central components in rotating machines, whose fault diagnosis is crucial in condition-based maintenance to reduce the complexity of different kinds of faults. To classify various rollin...Rolling bearings are important central components in rotating machines, whose fault diagnosis is crucial in condition-based maintenance to reduce the complexity of different kinds of faults. To classify various rolling bearing faults, a prognostic algorithm consisting of four phases was proposed. Since stacked denoising auto-encoder can be filtered, noise of large numbers of mechanical vibration signals was used for deep learning structure to extract the characteristics of the noise. Unsupervised pre-training method, which can greatly simplify the traditional manual extraction approach, was utilized to process the depth of the data automatically. Furthermore, the aggregation layer of stacked denoising auto-encoder(SDA) was proposed to get rid of gradient disappearance in deeper layers of network, mix superficial nodes’ expression with deeper layers, and avoid the insufficient express ability in deeper layers. Principal component analysis(PCA) was adopted to extract different features for classification. According to the experimental data of this method and from the comparison results, the proposed method of rolling bearing fault classification reached 97.02% of correct rate, suggesting a better performance than other algorithms.展开更多
基金This research is supported financially by Natural Science Foundation of China(Grant No.51505234,51405241,51575283).
摘要With the rapid development of mechanical equipment,mechanical health monitoring field has entered the era of big data.Deep learning has made a great achievement in the processing of large data of image and speech due to the powerful modeling capabilities,this also brings influence to the mechanical fault diagnosis field.Therefore,according to the characteristics of motor vibration signals(nonstationary and difficult to deal with)and mechanical‘big data’,combined with deep learning,a motor fault diagnosis method based on stacked de-noising auto-encoder is proposed.The frequency domain signals obtained by the Fourier transform are used as input to the network.This method can extract features adaptively and unsupervised,and get rid of the dependence of traditional machine learning methods on human extraction features.A supervised fine tuning of the model is then carried out by backpropagation.The Asynchronous motor in Drivetrain Dynamics Simulator system was taken as the research object,the effectiveness of the proposed method was verified by a large number of data,and research on visualization of network output,the results shown that the SDAE method is more efficient and more intelligent.
基金supported by the Scientific and Technological Developing Scheme of Jilin Province under grants No.YDZJ202301ZYTS538the National Natural Science Foundation of China under grants No.U23A20128+3 种基金the Natural Science Foundation of Jilin Province under grants No.SKL202302038the Chinese Academy of Sciences Youth Innovation Promotion Association under grants No.2023234the CITIC Dicastal Technical Cooperation Project under grants No.DK-YJY-20240003the Innovation Capability Enhancement Project of Baoding City under grants No.2494G034.
摘要The Mg-8Gd-3Er-0.5Ag-0.5Zr(wt.%)alloy fabricated by hot-extrusion+stamping exhibits an exceptional aging hardening response,with the yield strength being improved by>200 MPa.Traditional extrusion microstructure was observed in the as-extruded sample,with the elongated non-recrystallized grains showing typical(10.10)fiber texture.After stamping,almost all non-recrystallized grains were twinned mainly following the(10.12)twin orientation.This significantly changed precipitate morphologies formed during the following aging,from the well-known granularβ'precipitate into net-workβ'+β'H structure,with the granularβ'precipitates being connected by chain-likeβ'H precipitates.Additionally,a novel fault was found in theβ'precipitates,whose formation is highly related to the metastable I2-type stacking fault.This new precipitation structure means the effective interparticle spacing being approximately zero,and the faults in theβ'precipitates can not only enhance strength of precipitates but also could efficiently impede dislocation motion,thus resulted in positive contribution on alloy’s yield strength.This work provides new insights in developing high-strength Mg alloys by modifying precipitation structure along with the inner faults in precipitation.
基金supported by the National Natural Science Foundation of China(Nos.52171121,52201132,52201131,52371037)the Natural Science Foundation of Liaoning Province,China(No.2022-NLTS-18-01).
摘要A bimodal structure in the WE43 alloy was constructed through traditional extrusion.The results suggest that the dominant dynamic recrystallization(DRX)mechanism in the alloy extruded at 300℃(E300)is twin-induced DRX(TDRX),while the discontinuous DRX(DDRX)prevails when extruded at 330℃(E330)and 370℃(E370).For all three kinds of alloys,a decrease in extrusion temperature results in enhanced strength without a significant loss of ductility.Notably,the E300 alloy demonstrates outstanding comprehensive mechanical properties,with a yield strength of 325 MPa,an ultimate tensile strength of 365 MPa,and an elongation of 10.2%.Numerous blocky Mg14Nd2Y with size of~100 nm is formed within elongated grains,which contributes to the increased strength of E300 alloy.Additionally,the high-density of I1 stacking faults and fine blocky precipitates within elongated grains enhance ductility.
基金financially supported by the National Key Research and Development Program of China(Grant No.2023YFB4005401)the National Natural Science Foundation of China(Grant Nos.52574432 and 52425401)+2 种基金the National Natural Science Foundation of China(Grant No.52204386)the Key R&D and Achievement Transformation Plan(Grant No.2025YFHH0096)the Foundation of Heilongjiang Province,China(Grant No.JQ2023E003)。
摘要The high operating temperatures and sluggish kinetics of Mg-based hydrogen storage materials(HSMs)are urgently being addressed.In this work,a novel Mg-Ni-Ga HSM with dual-phase synergistic catalysis is developed,including the fishbone-like Mg3Ni2Ga1 catalytic phase and the Mg2Ni phase with stacking faults(SFs).The spheroidization of Mg grains is inhibited by the pinning effect of the Mg3Ni2Ga1 phase,and the high-energy Mg grain boundaries are obtained.High-density SFs are induced in the Mg2Ni phase via Ga dissolution.It is worth noting that Mg94.5Ni5Ga0.5 alloy absorbs 0.37 wt%H2 merely at 25℃,and absorbs 2.71 wt%H2 at 150℃ under even 0.1 MPa.The dehydrogenation activation energy is significantly decreased from 81.86 kJ mol-1 in Mg95Ni5 alloy to 67.68 kJ mol-1.The room temperature and low-pressure hydrogenation performance are achieved through these multiphase synergistic catalysis:H2 molecule dissociation facilitated by the Mg3Ni2Ga1 phase,hydride nucleation promoted by high-energy Mg grain boundaries,additional rapid diffusion channels for H atoms,and the enhanced"hydrogen pump"effect provided by the Mg2Ni phase with SFs structure.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51704138)
摘要Rolling bearings are important central components in rotating machines, whose fault diagnosis is crucial in condition-based maintenance to reduce the complexity of different kinds of faults. To classify various rolling bearing faults, a prognostic algorithm consisting of four phases was proposed. Since stacked denoising auto-encoder can be filtered, noise of large numbers of mechanical vibration signals was used for deep learning structure to extract the characteristics of the noise. Unsupervised pre-training method, which can greatly simplify the traditional manual extraction approach, was utilized to process the depth of the data automatically. Furthermore, the aggregation layer of stacked denoising auto-encoder(SDA) was proposed to get rid of gradient disappearance in deeper layers of network, mix superficial nodes’ expression with deeper layers, and avoid the insufficient express ability in deeper layers. Principal component analysis(PCA) was adopted to extract different features for classification. According to the experimental data of this method and from the comparison results, the proposed method of rolling bearing fault classification reached 97.02% of correct rate, suggesting a better performance than other algorithms.