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Adaptive modification of turbofan engine nonlinear model based on LSTM neural networks and hybrid optimization method

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Chinese Journal of Aeronautics 2022年第9期35卷 314-332页

作者： Yanhua MA xian du Ximing SUN School of Microelectronics Dalian University of TechnologyDalian 116024China Key Laboratory of Intelligent Control and Optimization for Industrial Equipment Ministry of EducationDalian University of TechnologyDalian 116024China School of Control Science and Engineering Dalian University of TechnologyDalian 116024China

An accurate and reliable turbofan engine model which can describe its dynamic behavior within the full flight envelop and lifecycle plays a critical role in performance optimization, controller design and fault diagnosis. However, due to the performance differences caused by the tolerance of engine manufacturing and assembly, and performance degradation during continuously stringent environmental regulations, the model accuracy is severely reduced. In this paper, an adaptive modification method of turbofan engine nonlinear Component-Llevel Model(CLM) based on Long Short-Term Memory(LSTM) Neural Network(NN) and hybrid optimization algorithm is pro-posed. First, a dynamic compensator with a combined LSTM NN architecture is constructed to compensate for the initial error between the experimental data and CLM of a turbofan engine under health condition. Then, a sensitivity analysis approach based on the entropy coefficient and technique for order preference by similarity to an ideal solution integrated evaluation is developed to choose the unmeasurable health parameters to be adjusted. Finally, a parallel hybrid optimization algorithm is developed to complete the adaptive model modification when the performance degrades. The proposed method is verified on a military low-bypass twin-spool turbofan engine, and the experimental results show the effectiveness of the proposed method.

关键词： Hybrid optimization Long short-term memory Model modification and testing Sensitivity analysis Turbofan engines

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Event-based triggering mechanisms for nonlinear control systems

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Science China(Information Sciences) 2020年第5期63卷 119-130页

作者： Yongfeng GAO Ximing SUN xian du Wei WANG Key Laboratory of Intelligent Control and Optimization for Industrial Equipment of Ministry of Education Dalian University of Technology

This study examines triggered implementations of stabilizing controllers for general nonlinear systems. By using perturbation theory and Taylor's theorem, we propose new event-triggering and selftriggering mechanisms for general nonlinear control systems that are not necessarily input-to-state stable with respect to measurement errors. Both mechanisms are presented based on mild conditions and can ensure the uniform ultimate boundedness of the solutions of the resulting closed-loop control systems. The ultimate bounds can be made arbitrarily small by adjusting the design parameters. The effectiveness of the theoretical results is illustrated by simulations.

关键词： nonlinear systems triggered control sampled-data

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An improved high-fidelity adaptive model for integrated inlet-engine-nozzle based on mechanismdata fusion

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Chinese Journal of Aeronautics 2024年第8期37卷 190-207页

作者： Chen WANG Ziyang YU xian du Ximing SUN School of Control Science and Engineering Dalian University of TechnologyDalian 116024China Key Laboratory of Intelligent Control and Optimization for Industrial Equipment Ministry of EducationDalian University of TechnologyDalian 116024China

Nowadays,there has been an increasing focus on integrated flight propulsion control and the inlet-exhaust design for the aero-propulsion *** component-level models are inadequate due to installed performance deviations and mismatches between the real engine and the model,failing to meet the accuracy requirements of supersonic *** paper establishes a quasi-one-dimensional model for the inlet-exhaust system and conducts experimental ***,a mechanism-data fusion adaptive modeling scheme using an Extreme Learning Machine based on the Salp Swarm Algorithm(SSA-ELM)is *** study reveals the inlet model’s efficacy in reflecting installed performance,flow matching,and mitigating pressure distortion,while the nozzle model accurately predicts flow coefficients and thrust coefficients,and identifies various operational *** model’s output closely aligns with typical experimental *** combining offline optimization and online adaptive correction,the mechanismdata fusion adaptive model substantially reduces output errors during regular flights and varying levels of degradation,and effectively handles gradual degradation within a single flight ***,the mechanism-data fusion adaptive model holistically addresses total pressure errors within the inlet-exhaust system and normal shock location *** approach significantly curbs performance deviations in supersonic *** example,at Ma=2.0,the system error impressively drops from 34.17%to merely 6.54%,while errors for other flight conditions consistently stay below the 2.95%*** findings underscore the clear superiority of the proposed method.

关键词： Aero-propulsion system Integrated inlet-enginenozzle Component-level model On-board adaptive model Mechanism-data fusion Extreme learning machine

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Simultaneously enhanced thermal conductivity and mechanical performance of carbon nanotube reinforced ZK61 matrix composite

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Journal of Magnesium and Alloys 2024年第7期12卷 2756-2765页

作者： Fanjing Meng Wenbo du xian du Baohong Zhu Ke Liu Shubo Li College of Materials Science and Engineering Faculty of Materials and ManufacturingBeijing University of TechnologyNo.100 Ping Le YuanChaoyang DistrictBeijing 100124China

Alloying seriously deteriorates the thermal conductivity of magnesium(Mg)alloys,thus,restricts their applications in the fields of computer,communication,and consumer *** order to improve the thermal conductivity of Mg alloys,adding carbon nanotube(CNT)combined with aging treatment is proposed in this work,*** the D-CNT(a kind of dispersed CNT)reinforced ZK61 matrix composite via powder metallurgy,and conducting aging treatment to the *** indicate the as-aged ZK61/0.6 wt.%D-CNT composite achieved an excellent thermal conductivity of 166 W/(mK),exhibiting 52.3%enhancement in comparison with matrix,as well as tensile yield strength of 321 MPa,ultimate tensile strength of 354 of MPa,and elongation of 14%.The simultaneously enhanced thermal conductivity and mechanical performance are mainly attributed to:(1)the embedded interface of the D-CNT with matrix and(2)the coherent interface of precipitates with *** is expected the current work can provide a clue for devising Mg matrix composites with integrated structural and functional performances,and enlarge the current restricted applications of Mg alloys.

关键词： Mg matrix composite Carbon nanotube Interface Thermal conductivity Mechanical performance

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Cooling rate controlled basal precipitates and age hardening response of solid-soluted Mg-Gd-Er-Zn-Zr alloy

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Journal of Magnesium and Alloys 2021年第4期9卷 1267-1277页

作者： Jinlong Fu Wenbo du Linyue Jia Yunfeng Wang Xunming Zhu xian du Faculty of Materials and Manufacturing Beijing University of TechnologyBeijing 100124China Weihai Wanfeng Magnesium S&T Development Co.LTD 264200China

The precipitation and age hardening response of the solid-soluted Mg–10Gd–1Er–1Zn–0.6Zr(wt.%)alloy performed by water-quenching(QC),air-cooling(AC)and furnace-cooling(FC)in terms of the volume fraction of precipitates and tensile properties were investigated in present *** indicated the solid-soluted alloy contained stacking faults(SFs)and long period stacking ordered(LPSO)phase on the basal planes regardless of the cooling rate,but a larger volume fraction of the LPSO phase was formed with decreasing in the cooling *** aging,βandβ1 phases precipitated on the prismatic planes,and their number density decreased but mean particle size increased with decreasing in the cooling *** solid-soluted alloys(QC,AC and FC samples)showed no apparent difference in yield strength(YS),but their correspondent peak-aged alloys exhibited sharp difference in hardening *** strongest hardening response took place in the QC sample and showed 82MPa enhancement in YS,which was much larger than that of AC(+26MPa)and FC samples(+5MPa).The reason lies in that the higher cooling rate promotes the precipitation and reduces the average size ofβprecipitate.A novel cooling-rate controlled precipitation model with respect to the correlation of precipitates on basal and prismatic planes was *** this model,the basal precipitates showed a restrictive effect on the growth and/or coarsening ofβprecipitate,and composite precipitates containing theβphase with fine size as well as high area-number density and lower volume fraction of the LPSO phase are preferred to strengthen the Mg–10Gd–1Er–1Zn–0.6Zr alloy.

关键词： Magnesium alloy Long period stacking ordered(LPSO) Stacking faults(SFs) Cooling rate Tensile properties

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Synergistic Effects of Carbon Nanotube(CNT)and Reduced Graphene Oxide(RGO)on Mechanical and Thermal Properties of ZK61 Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第3期37卷 577-585页

作者： Fanjing Meng Wenbo du Ning Ding Jian Sun xian du Ke Liu Shubo Li College of Materials Science and Engineering Faculty of Materials and ManufacturingBeijing University of TechnologyBeijing 100124China

The hybrid of carbon nanotube(CNT)and reduced graphene oxide(RGO)reinforced ZK61 composite was fabricated by a hot extrusion *** with the raw ZK61 alloy and single-reinforced composites,the hybrid-reinforced by RGO+CNT complex exhibited significant enhancements both in mechanical and thermal *** adjusting the proportion of RGO and CNT in ZK61 alloy,the obtained optimum ZK61/(0.06 wt%RGO+0.54 wt%CNT)composite exhibited increase of 25.4%in yield strength,26.5%in ultimate tensile strength,104%in failure strain and 30.4%in thermal conductivity,respectively,in comparison with ZK61 *** superior properties of the nano-hybrid composite are attributed to the synergetic effects of RGO and CNT,leading to a uniform dispersion and integrated structure as well as the enhanced interfacial bonding with *** strengthening ability of RGO and CNT was calculated to quantify their individual contribution to the improvement in mechanical and thermal properties of the ZK61 matrix *** RGO+CNT hybrids provide a promising way to develop Mg matrix composites with impressive performances.

关键词： Mg matrix composite Carbon nanotube Reduced graphene oxide Mechanical performance Thermal conductivity

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Effects of deformation temperatures on microstructures,aging behaviors and mechanical properties of Mg-Gd-Er-Zr alloys fabricated by hard-plate rolling

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Journal of Magnesium and Alloys 2024年第6期12卷 2345-2359页

作者： Ke Liu Dalong Hu Feng Lou Zijian Yu Shubo Li xian du Wenbo du Faculty of Materials and Manufacturing Beijing University of TechnologyBeijing 100124China

In this investigation,a high-strength Mg-12Gd-1.0Er-0.5Zr(wt.%)alloy sheet was produced by hot extrusion(HE)and subsequent hard-plate rolling(HPR)at different *** results indicate that the microstructures of these final-rolled sheets are inhomogeneous,mainly including coarse deformed grains and dynamic recrystallized(DRXed)grains,and the volume fraction of these coarse deformed grains increases as the rolling temperature ***,more DRXed grains can be found in R-385℃sheet,resulting in a smaller average grain size and weaker basal texture,while the biggest grains and the highest strong basal texture are present in R-450℃*** of dynamic precipitation ofβphases which are mainly determined by the rolling temperature are present in these sheets,and its precipitation can consume the content of Gd solutes in the *** a result,the lowest number density ofβphase in R-450℃sheet is beneficial to modify the age hardening ***,the R-450℃sheet displays the best age hardening response because of a severe traditional precipitation ofβ’(more)andβH/βM(less)precipitates,resulting in a sharp improvement in strength,*** tensile strength(UTS)of∼518±17 MPa and yield strength(YS)of∼438±18 ***,the elongation(EL)of this sheet reduces greatly,and its value is∼2.7±0.3%.By contrasting,the EL of the peak-aging R-385℃sheet keeps better,changing from∼4.9±1.2%to∼4.8±1.4%due to a novel dislocation-induced chain-like precipitate which is helpful to keep good balance between strength and ductility.

关键词： Mg-Gd-Er-Zr sheets Age hardening response Precipitates Mechanical properties

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Prediction of hot-rolled strip crown based on Boruta and extremely randomized trees algorithms

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Journal of Iron and Steel Research International 2023年第5期30卷 1022-1031页

作者： Li Wang Song-lin He Zhi-ting Zhao xian-du Zhang School of Mechanical and Power Engineering Shenyang University of Chemical TechnologyShenyang 110142LiaoningChina

The quality of hot-rolled steel strip is directly affected by the strip *** machine learning models have shown limitations in accurately predicting the strip crown,particularly when dealing with imbalanced *** limitation results in poor production quality and efficiency,leading to increased production ***,a novel strip crown prediction model that uses the Boruta and extremely randomized trees(Boruta-ERT)algorithms to address this issue was *** improve the accuracy of our model,we utilized the synthetic minority over-sampling technique to balance the imbalance data *** Boruta-ERT prediction model was then used to select features and predict the strip *** the 2160 mm hot rolling production lines of a steel plant serving as the research object,the experimental results showed that 97.01% of prediction data have an absolute error of less than 8 *** level of accuracy met the control requirements for strip crown and demonstrated significant benefits for the improvement in production quality of steel strip.

关键词： Hot-rolled strip Data improvement Strip crown Feature selection Boruta algorithm Extremely randomized trees algorithm

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Simultaneously Enhanced Thermal and Mechanical Properties of ZK60 Alloy Reinforced by Oriented Graphene Nanoplatelets

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Acta Metallurgica Sinica(English Letters) 2023年第12期36卷 1999-2012页

作者： Baohong Zhu xian du Fanjing Meng Xuefeng Wu Ke Liu Shubo Li Zhaohui Wang Wenbo du Faculty of Materials and Manufacturing Beijing University of TechnologyBeijing100124China

The lamellar and orientational characteristics of graphene nanoplatelets(GNPs)are crucial for reinforcing metal matrix composites,particularly in terms of their thermal *** kinds of GNPs with plane sizes of 6µm and 80µm were respectively used as reinforcements in ZK60 alloy by powder *** oriented distribution of GNPs in the matrix was obtained using a double-pass hot extrusion process,i.e.,a stepped extrusion with two consecutive extrusion ratios(10:1 and 16:1).Reinforced with 0.05 wt%oriented GNPs(80µm),the composite exhibited a tensile yield strength of 257 MPa,ultimate tensile strength of 342 MPa,elongation of 24.7%,and notably enhanced thermal conductivity of 128.3 W(mK)−1 even with refined grain size compared to the ZK60 *** oriented GNPs in the matrix create a favorable path for efficient load and heat transfer,leading to the simultaneously enhancement of mechanical and thermal properties of the GNPs/ZK60 *** work is expected to broaden the application potential of GNPs as highly efficient reinforcements and provide a practical method for fabricating metal matrix composites.

关键词： Graphene Magnesium Orientation Thermal properties Mechanical properties

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Si/TiO_(2) carbon fiber core encapsulated in hierarchical multiple MXene@Co-MoS_(2) shells for constructing a free-standing anode of lithium storage

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Rare Metals 2024年第9期43卷 4222-4233页

作者： xian-ping du Ying Huang Jia-ming Wang Zhen-he Feng Xu Sun MOE Key Laboratory of Material Physics and Chemistry Under Extraordinary Conditions School of Chemistry and Chemical EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Shanghai Institute of Space Power-Sources Shanghai 200245China Ningbo Institute of Northwestern Polytechnical University Ningbo 315103China

Silicon-based(Si-based) materials offer more possibilities for generating new portable electronic devices due to their high specific capacities. However, their inferior electrical conductivity and volume expansion during cycling seriously limit their development. The optimum solution is to select specific materials to establish an exceptionally conductive and volume buffer structure,which can assist Si materials in developing their excellent lithium storage properties. In this study, Si particles were confined in TiO_(2)carbon fibers(TiO_(2)CFs) via electrospinning, after which they were encapsulated with MXene and Co-MoS_(2)(CMS) nanosheets to fabricate hierarchical ST-2@MXene@CMS films. TiO_(2)CF, MXene and CMS were employed to establish a coherent conductive network with one-, two-and three-dimensional electronic pathways to permit the unimpeded flow of electrons inside the electrode material. TiO_(2)CF, MXene and CMS acted precisely as multilayered buffers to ameliorate the volume change of Si particles during cycling. In addition, the CMS nanosheets were involved in lithium storage, contributing to the final electrochemical performance. Ultimately, the ST-2@MXene@CMS films served as free-standing electrodes, avoiding the impact of inactive interfaces on the electrochemical performance and fulfilling the lightweight requirement for new energy storage devices.

关键词： Si particles MXene Co-MoS_(2)nanosheets Hierarchical structure Lithium-ion batteries

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