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A semi-analytical multi-harmonic balance method on full-3D contact model for dynamic analysis of dry friction systems

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Chinese Journal of Aeronautics 2024年第2期37卷 309-329页

作者： He SUN dayi zhang Yaguang WU Qingyang SHEN Dianyin HU Research Institute of Aero-Engine Beihang UniversityBeijing 100191China School of Energy and Power Engineering Beihang UniversityBeijing 100191China Beijing Key Laboratory of Aero-Engine Structure and Strength Beijing 100191China Sino-French Engineering School Beihang UniversityBeijing 100191China AECC Sichuan Gas Turbine Research Establishment Chengdu 610500China

Dry friction damping structures are widely-used in aero-engines to mitigate *** nonlinear nature of friction and the two-dimensional in-plane motion on the contact interface bring challenges to accurately and efficiently predict the forced response of frictionally damped *** state-of-the-art Multi-Harmonic Balance Method(MHBM)on quasi-3D contact model in engineering cannot precisely capture the kinematics on the friction interface although the efficiency is *** full-3D contact model can describe the constitutive relationship of the interface in a more accurate manner;however,the efficiency and convergence are not guaranteed for large-scale *** this paper,a semi-analytical MHBM on full-3D contact model is *** original Trajectory Tracking Method(TTM)for evaluating the contact force is reformulated to make the calculation more concise and the derivation of the Analytical Jacobian Matrix(AJM)*** on the chain rule of derivation,the AJM which is the core to upgrade the performance is *** a shrouded blade finite element model,the accuracy and efficiency of the proposed method are compared with both the MHBM on full-3D contact model with numerical Jacobian matrix and the MHBM on quasi-3D contact model with *** results show that the AJM improves significantly the efficiency of the MHBM on full-3D contact *** time cost of the proposed method is in the same order of magnitude as that of the MHBM on quasi-3D contact *** also confirm that the full-3D contact model is necessary for the dynamic analyses of shrouded *** one uses the quasi-3D model,the estimation relative error of damping can even reach 31.8%in some *** addition,the AJM also brings benefits for stability *** is highly recommended that engineers use the MHBM on full-3D contact model for the dynamic analysis and design of shrouded blades.

关键词： Dry friction damping Multi-harmonic balance method Trajectory tracking method Jacobian matrix Shrouded blade

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Comparative analysis of DNA-SIP and magnetic-nanoparticle mediated isolation (MMI) on unraveling dimethoate degraders

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Frontiers of Environmental Science & Engineering 2024年第1期18卷 59-69页

作者： Luning Lian Yi Xing dayi zhang Longfei Jiang Mengke Song Bo Jiang School of Energy and Environmental Engineering University of Science&Technology BeijingBeijing 100083China Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants University of Science&Technology BeijingBeijing 100083China National Environmental and Energy Science and Technology International Cooperation Base University of Science&Technology BeijingBeijing 100083China College of New Energy and Environment Jilin UniversityChangchun 130021China Guangzhou Institute of Geochemistry Chinese Academy of SciencesGuangzhou 510640China College of Natural Resources and Environment South China Agricultural UniversityGuangzhou 510642China National Engineering Laboratory for Site Remediation Technologies Beijing 100015China

Microorganisms are crucial in the bioremediation of organophosphorus pesticides. However, most functional microorganisms (> 99%) are yet to be cultivated. This study applied two cultivation-independent approaches, DNA-SIP and magnetic-nanoparticle mediated isolation (MMI), to identify the functional microorganisms in degrading dimethoate in agricultural soils. MMI identified five dimethoate degraders: Pseudomonas, Bacillus, Ramlibacter, Arthrobacter, and Rhodococcus, whereas DNA-SIP identified three dimethoate degraders: Ramlibacter, Arthrobacter, and Rhodococcus. Also, MMI showed higher resolution than DNA-SIP in identifying functional microorganisms. Two organic phosphohydrolase (OPH) genes: ophC2 and ophB, were involved in dimethoate metabolism, as revealed by DNA-SIP and MMI. The degradation products of dimethoate include omethoate, O,O,S-trimethyl thiophosphorothioate, N-methyl-2-sulfanylacetamide, O,O-diethyl S-hydrogen phosphorodithioate, O,O,O-trimethyl thiophosphate, O,O,S-trimethyl thiophosphorodithioate, and O,O,O-trimethyl phosphoric. This study emphasizes the feasibility of using SIP and MMI to explore the functional dimethoate degraders, expanding our knowledge of microbial resources with cultivation-independent approaches.

关键词： Stable isotope probing(SIP) Magnetic-nanoparticle mediated isolation(MMI) Dimethoate Biodegradation Cultivation-independent approach

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径向可倾瓦轴承静态特性分析

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推进技术 2024年第7期45卷 203-218页

作者：韩院涛张大义赵镇瑶梁智超孙赫张靖煊北京航空航天大学能源与动力工程学院北京100191 北京航空航天大学航空发动机结构强度北京市重点实验室北京100191 复杂航空系统仿真重点实验室北京100076 中国科学院上海高等研究院上海201210

径向可倾瓦轴承具有承载范围大、耐冲击、稳定性好等优点,广泛应用于大型高速旋转机械。为了选用合适参数的轴承,需要对比分析不同参数轴承的静态特性。本文通过有限差分法求解二维Reynolds方程,建立了详细的径向可倾瓦轴承油膜力求解流... 详细信息

径向可倾瓦轴承具有承载范围大、耐冲击、稳定性好等优点,广泛应用于大型高速旋转机械。为了选用合适参数的轴承,需要对比分析不同参数轴承的静态特性。本文通过有限差分法求解二维Reynolds方程,建立了详细的径向可倾瓦轴承油膜力求解流程,在此基础上获得了轴承的流量、功率损耗、温升等静态特性,进而研究轴承关键参数对静态特性的影响规律。结果表明:可倾瓦轴承的承载力随着偏心率增大非线性增大,主要承载瓦的流量减小,功率损耗和油膜温升增大。宽径比和预负荷系数的增大可以提高轴承的承载力,但功率损耗以及油膜温升也增大;瓦块的支点最好置于瓦块中心位置,以提高承载力;瓦块数量增多可使油膜温升降低,但会降低承载能力。提出了非对称可倾瓦轴承,与对称瓦轴承相比,下瓦包角增大20%的非对称轴承,可使承载力提升31%,油膜温升降低16%。

关键词：径向可倾瓦轴承油膜力静态特性关键参数非对称瓦

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基于显式动力学的发动机涡轮组件动态特性仿真与故障分析

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战术导弹技术 2024年第3期 25-31页

作者：陈素荣张家锷于平超蒋科陶玄君张大义北京动力机械研究所北京100074 南京航空航天大学民航学院南京211106 北京航空航天大学能源与动力工程学院北京100191

针对某型发动机高压涡轮叶片断裂导致的低压涡轮组件损伤破坏故障,开展了故障机理研究。在对故障现象进行总结分析的基础上,建立了断裂叶片冲击低压涡轮组件的显式动力学模型,仿真分析了断裂叶片在低压涡轮组件的运动过程、接触特征及... 详细信息

针对某型发动机高压涡轮叶片断裂导致的低压涡轮组件损伤破坏故障,开展了故障机理研究。在对故障现象进行总结分析的基础上,建立了断裂叶片冲击低压涡轮组件的显式动力学模型,仿真分析了断裂叶片在低压涡轮组件的运动过程、接触特征及涡轮叶盘摆动响应。结果表明:高压涡轮断叶飞出后将卡在导向器叶片与涡轮转子间做圆周运动,并与前后各部件发生碰撞接触,这是低压涡轮组件损伤破坏的主要原因;而低压涡轮叶盘在断裂叶片飞入后受其冲击发生摆动,摆动角位移仅有0.005 rad,因而低涡叶片不会与导向器叶片发生碰撞接触造成其损伤。本文分析方法和仿真结果对于类似叶片飞失故障再现具有一定的参考价值。

关键词：叶片飞失显式动力学涡轮组件动态特性故障分析接触特征发动机

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An AuNPs/Mesoporous NiO/Nickel Foam Nanocomposite as a Miniaturized Electrode for Heavy Metal Detection in Groundwater

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Engineering 2023年第8期27卷 199-208页

作者： Boyuan Xue Qian Yang Kaidong Xia Zhihong Li George Y.Chen dayi zhang Xiaohong Zhou State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China National Key Laboratory of Science and Technology on Micro/Nano Fabrication Institute of MicroelectronicsPeking UniversityBeijing 100871China Shenzhen Key Laboratory of Photonic Devices and Sensing Systems for Internet of Things Guangdong and Hong Kong Joint Research Centre for Optical Fiber SensorsShenzhen UniversityShenzhen 518060China College of New Energy and Environment Jilin UniversityChangchun 130021China The Research Institute of Environmental Innovation(Suzhou) Tsinghua UniversitySuzhou 215000China

Heavy metals,notably Pb2+and Cu^(2+),are some of the most persistent contaminants found in *** monitoring of these metals,which relies on efficient,sensitive,cost-effective,and reliable methods,is a *** present a nanocomposite-based miniaturized electrode for the concurrent measurement of Pb2+and Cu^(2+)by exploiting the electroanalytical technique of square wave *** also propose a facile in situ hydrothermal calcination method to directly grow binder-free mesoporous Ni O on a three-dimensional nickel foam,which is then electrochemically seeded with gold nanoparticles(Au NPs).The meticulous design of a low-barrier Ohmic contact between mesoporous Ni O and Au NPs facilitates target-mediated nanochannel-confined electron transfer within mesoporous Ni *** a result,the heavy metals Pb2+(0.020 mg.L^(-1)detection limit;2.0–16.0 mg.L^(-1)detection range)and Cu^(2+)(0.013 mg.L^(-1)detection limit;0.4–12.8 mg.L^(-1)detection range)can be detected simultaneously with high ***,other heavy metal ions and common interfering ions found in groundwater showed negligible impacts on the electrode’s performance,and the recovery rate of groundwater samples varied between 96.3%±2.1%and 109.4%±0.6%.The compactness,flexible shape,low power consumption,and ability to remotely operate our electrode pave the way for onsite detection of heavy metals in groundwater,thereby demonstrating the potential to revolutionize the field of environmental monitoring.

关键词： AuNPs Mesoporous NiO Miniaturized electrode Heavy metal ions Groundwater Square wave voltammetry

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Ecological Barrier Deterioration Driven by Human Activities Poses Fatal Threats to Public Health due to Emerging Infectious Diseases

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Engineering 2022年第3期8卷 155-166页

作者： dayi zhang Yunfeng Yang Miao Li Yun Lu Yi Liu Jingkun Jiang Ruiping Liu Jianguo Liu Xia Huang Guanghe Li Jiuhui Qu School of Environment Tsinghua UniversityBeijing 100084China Key Laboratory of Drinking Water Science and Technology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China

The coronavirus disease 2019(COVID-19)and concerns about several other pandemics in the 21st century have attracted extensive global *** emerging infectious diseases threaten global public health and raise urgent studies on unraveling the underlying mechanisms of their transmission from animals to *** numerous works have intensively discussed the cross-species and endemic barriers to the occurrence and spread of emerging infectious diseases,both types of barriers play synergistic roles in wildlife *** far,there is still a lack of a complete understanding of viral diffusion,migration,and transmission in ecosystems from a macro *** this review,we conceptualize the ecological barrier that represents the combined effects of cross-species and endemic barriers for either the natural or intermediate hosts of *** comprehensively discuss the key influential factors affecting the ecological barrier against viral transmission from virus hosts in their natural habitats into human society,including transmission routes,contact probability,contact frequency,and viral *** the significant impacts of human activities and global industrialization on the strength of the ecological barrier,ecological barrier deterioration driven by human activities is critically analyzed for potential *** climate change can trigger and expand the range of emerging infectious diseases,and human disturbances promote higher contact frequency and greater transmission *** addition,globalization drives more transmission routes and produces new high-risk regions in city *** review aims to provide a new concept for and comprehensive evidence of the ecological barrier blocking the transmission and spread of emerging infectious *** also offers new insights into potential strategies to protect the ecological barrier and reduce the wide-ranging risks of emerging infectious diseases to public health.

关键词： Emerging infectious diseases Virus Ecological barrier

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Investigation on nonlinear lateral-torsional coupled vibration of a rotor system with substantial unbalance

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Chinese Journal of Aeronautics 2020年第6期33卷 1642-1660页

作者： Jie HONG Pingchao YU Yanhong MA dayi zhang School of Energy and Power Engineering Beihang UniversityBeijing 100083China Collaborative Innovation Center of Advanced Aero-Engine Beihang UniversityBeijing 100083China Beijing Key Laboratory of Aero-Engine Structure and Strength Beijing 100083China

Substantial unbalance may be caused by fan blade off during the operation period of gas turbine engines,and related dynamic problems are very critical to the safety design of rotor system in *** article aims to understand lateral-torsional coupled vibration of the rotor system with substantial *** governing equation of a modified unbalanced rotor system is established based on Lagrangian ***,a mathematical analytical method is proposed in which a linear approximation is derived and the Floquet theory and Hill’s method are incorporated,from which the modal characteristics of the unbalanced rotor are *** modal characteristics of the unbalanced rotor system are revealed comprehensively for the first ***,the relation between the modes and responses of the unbalanced rotor is discussed in *** results show that the lateral vibration and torsional vibration of the unbalanced rotor are coupled through the inertial terms in the governing *** to the coupling,veering and lock-in phenomena occur between the frequencies of the forward whirl mode and the torsional ***,lock-in can lead to a kind of principal *** regard to the response of the unbalanced rotor,both natural vibration components and enforced vibration components appear in the lateral response,while only natural vibration components appear during torsional ***,natural vibration components play a crucial role in the response within the principal instability region and cause divergence of the vibration amplitudes in the lateral and torsional directions.

关键词： Instability Lateral-torsional coupled vibration Lock-in phenomenon Modes Unbalanced rotor

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Bending and vibration of a discontinuous beam with a curvic coupling under different axial forces

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Frontiers of Mechanical Engineering 2020年第3期15卷 417-429页

作者： Heng LIU Jie HONG dayi zhang School of Energy and Power Engineering Beihang UniversityBeijing 100191China State Key Laboratory of Laser Propulsion and Application Beijing Power Machinery InstituteBeijing 100074China

The transverse stiffness and vibration characteristics of discontinuous beams can significantly differ from those of continuous beams given that an abrupt change in stiffness may occur at the interface of the *** this study,the equations for the deflection curve and vibration frequencies of a simply supported discontinuous beam under axial loads are derived analytically on the basis of boundary,continuity,and deformation compatibility conditions by using equivalent spring *** equation for the deflection curve is solved using undetermined coefficient *** normal function of the transverse vibration equation is obtained by separating *** differential equations for the beam that consider moments of inertia,shearing effects,and gyroscopic moments are investigated using the transfer matrix *** deflection and vibration frequencies of the discontinuous beam are studied under different axial loads and connection spring *** show that deflection decreases and vibration frequencies increase exponentially with increasing connection spring ***,both variables remain steady when connection spring stiffness reaches a considerable ***,an experimental study is conducted to investigate the vibration characteristics of a discontinuous beam with a curvic coupling,and the results exhibit a good match with the proposed model.

关键词： discontinuous beam bending stiffness transverse vibration axial loads gyroscopic moments

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Modal characteristics analysis for a flexible rotor with non-smooth constraint due to intermittent rub-impact

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Chinese Journal of Aeronautics 2018年第3期31卷 498-513页

作者： Jie HONG Pingchao YU dayi zhang Zhichao LIANG School of Energy and Power Engineering Beihang University Collaborative Innovation Center of Advanced Aero-Engine Beihang University

Intermittent rub-impact, during which the contact between rotor and stator is characterized by a ‘‘bouncing＂ or intermittent type of behavior, is one of the most common rubbing forms in rotating machinery. When the intermittent rub-impact occurs, the non-smooth constraint, which is the phenomenon that the system stiffness changes with respect to the state of contact and noncontact, will appear. The paper aims at discovering the possible effects of the non-smooth constraint on the flexible rotor＇s modal characteristics by theoretical and experimental methods. The qualitative description for non-smooth constraint is given for the intermittent rub-impact process, and the dynamic modeling for a rotor system with non-smooth constraint is carried out. Meanwhile, the analysis method is developed by Floquet theory and Hill＇s method to obtain the rotor＇s modal characteristics. The results reveal that the non-smooth constraint produced by the intermittent rubimpact will increase the modal frequencies and critical speeds of the rotor system *** to the time-varying features of the constraint stiffness, the modal frequencies for the intermittent rub-impact rotor present fluctuant changes with the increase of rotation speed, which is different from the general linear rotor system. The non-smooth constraint is possible to lead the rotor＇s instability, and the rotor＇s instable regions can be expanded significantly for the increase of average constraint stiffness, constraint amplitude and contact time ratio. Non-smooth constraint could also expand the resonance speed and resonance sideband of the rotor system, which sometimes results in amplitude jump phenomenon.

关键词： Flexible rotor Intermittent rub-impact Instabifity Modal characteristics Non-smooth constraint

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Experimental investigation on dynamic response of flat blades with underplatform dampers

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Chinese Journal of Aeronautics 2019年第12期32卷 2667-2678页

作者： dayi zhang Bin GAO Jie HONG Jianwei FU Xiangyun GE School of Energy and Power Engineering Beihang UniversityBeijing 100083China Beijing Key Laboratory of Aero-Engine Structure and Strength Beijing 100083China Collaborative Innovation Center of Advanced Aero-Engine Beihang UniversityBeijing 100083China

One test rig with three blades and two Under-Platform Dampers(UPDs) is established to better understand the dynamical behavior of blades with UPDs. A pre-loaded spring is used to simulate the centrifugal load acting on the damper, thereby achieving continuous adjustment of the pressing load. UPDs with different forms, sizes and materials are carefully designed as experimental control groups. Noncontact measurement via a laser Doppler velocimeter is employed and contact excitation which is performed by an electromagnetic exciter is adopted to directly obtain the magnitude of the excitation load by a force sensor mounted on the excitation rod. Particular attention is paid to the influence of the contact status of the contact surfaces, e.g. the pressure-sensitive paper is used to measure the effective contact area of the UPDs. The experimental variables are selected as the centrifugal force, the amplitude of the excitation force, the damper mass, the effective contact area, and the damper material. The Frequency Response Function(FRF) of the blade under different experimental parameters is obtained by slow frequency sweep under sinusoidal excitation to study the influence of each parameter on the dynamic characteristics of the blade and the mechanism analysis is carried out combined with the experimental results.

关键词： Effective contact area Forced response Friction Test rig Turbo machinery Underplatform dampers

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