Abstracts of Vol.37 No.1 in English

Progress and Prospects of High-Frequency Ultrasonic Transducer Techniques

WU Dawei

(State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics Nanjing, 210016, China)

Measurement and Research on Strip Surface Vibration Mark Problem of High Strength Steel in Skin Pass Rolling

LI Hongbo1, WANG Zheng1,3, ZHANG Jie1, JIAN Min2, DING Qi2, LIU Qiang2

(1.School of Mechanical Engineering, University of Science and Technology Beijing Beijing, 100083, China) (2.Wuhan Iron & Steel (Group) Corp. Wuhan, 430083, China) (3.Beijing Aerospace Times Optical-Electronic Co, Ltd. Beijing, 100094, China)

Mechanical Characteristics of Three Support Structures of Flexible SkinSHEN Yuan1, ZHU Hua2, LIU Weidong3, ANG Haisong2(1.Key Laboratory of Vehicle Structural Mechanics and Control, Ministry of Education, Nanjing University ofAeronautics and Astronautics Nanjing, 210016, China) (2.State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University ofAeronautics and Astronautics Nanjing, 210016, China) (3.College of Energy and Electrical Engineering, Hohai University Nanjing, 211100, China)

Damage Prediction Analysis and Verification of the CompositeMaterial Based on LTSA and RVMCUI Jianguo1, ZHANG Wensheng1, QI Yiwen1, YU Mingyue1, PIAO Chunyu2, ZHOU Zhiqiang2(1.School of Automation, Shenyang Aerospace University Shenyang, 110136, China) (2.Shenyang Aircraft Design & Research Institute Shenyang, 110035, China)

Quantitative Diagnosis of Hydraulic Pump Fault Based on Spatial InformationEntropy and Support Vector RegressionWANG Yukui1,2, LI Hongru2, XU Baohua2(1.The Four Stations Department, Air Force Logistics College Xuzhou, 221000, China) (2.The Fourth Department, Ordnance Engineering College Shijiazhuang, 050003, China)

Research for the Smart Micro-Displacement Active Vibration Isolation SystemBased on Fuzzy-PID Control AlgorithmLIANG Sen1, WANG Changsong1, WEI Liming2, LIANG Tianxi2(1.School of Mechanical Engineering, Qingdao Technological University Qingdao, 266033, China) (2.China Academy of Engineering Physics Mianyang, 621900, China)

Research on the Optimization Design Method of Prestress forGiant Magnetostrictive TransducerCAI Wanchong, FENG Pingfa, YU Dingwen(Beijing Key Lab of Precision/Ultra-precision Manufacturing Equipment andControl, Tsinghua University Beijing, 100084, China)

Resonance in Low Frequency Range Induced by Frequency Translation of Flywheel′s Vibration Isolation Using for SatelliteSHEN Junfeng1, ZHOU Chunhua1, YU Zifei1, LIU Zhao2, FENG Shuqing3(1.Shanghai Institute of Satellite Engineering Shanghai, 200240, China) (2.Shanghai Aerospace Control Technology Institute Shanghai, 201109, China) (3.State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University ofAeronautics and Astronautics Nanjing, 210016, China)

Tikhonov Regularization for Operational Transfer Path AnalysisCHENG Wei1,2, LU Yingying2, LU Jiantao2, ZHANG Zhousuo1,2(1.State Key Laboratory for Manufacturing and System Engineering, Xi′an Jiaotong University Xi′an, 710049, China) (2.School of Mechanical Engineering, Xi′an Jiaotong University Xi′an, 710049, China)

Rolling Bearing Fault Feature Extraction Research Based on Application Development of Singular Value DecompositionTONG Shuiguang1, TANG Ning1, CONG Feiyun1, ZHOU Yi1, DONG Guangming2(1.Faculty of Engineering, Zhejiang University Hangzhou, 310027, China) (2.State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University Shanghai, 200240, China)

Modeling and Isolation Efficiency Analysis for Global Flexible Floating Raft Isolation SystemWANG Zhen1, ZHAO Zhigao2, LIU Fang1(1.School of Mechanical Engineering and Automation, Wuhan Textile University Wuhan, 430200, China) (2.Wuhan 2nd Ship Design & Research Institute Wuhan, 430205, China)

Tracked Vehicle Skid Steer Performance Analysis Under the Influence ofthe Centrifugal ForceDONG Chao1, CHENG Kai1, GAO Xueliang2, XI Yuan1, DENG Zhaoyin3(1.School of Mechanical Science and Engineering, Jilin University Changchun, 130022, China) (2.State Key Laboratory of Automotive Simulation and Control, Jilin University Changchun, 130022, China) (3.Changchun Generating Equipment Group Changchun, 130022, China)

Research on Micro-vibrations Testing Platform and CorrespondingCalibration MethodCHEN Jiangpan, CHENG Wei, DONG Jiajun, LI Ming(School of Aeronautic Science and Engineering, Beihang University Beijing, 100191, China)

Fault Diagnosis for Roller Bearing Based on Local Mean Decomposition and Enhanced Envelope SpectrumDU Dongmei, ZHANG Zhao, LI Hong, HE Qing(School of Energy, Power and Mechanical Engineering, North China Electric Power University Beijing, 102206, China)

Cyclic Shock Enhancement by the Combination of Minimum EntropyDeconvolution and Spectral Kurtosis ZHANG Long, HU Junfeng, XIONG Guoliang(School of Mechatronics Engineering, East China Jiaotong University Nanchang, 330013, China)

Analysis of the Effect of Disc Brake System Parameters on Brake ChatterLI Xiaopeng, LI Jiasheng, LI Muyan, WEN Bangchun(School of Mechanical Engineering & Automation, Northeastern University Shenyang, 110819, China)

Mid-spatial Frequency Error Identification of Precision Optical Surface Basedon the Adaptive DT-CWT MethodREN Zhiying1, LIN Youxi1, HUANG Jianmeng1, XIAO Weijun2, GAO Chenghui1(1.School of Mechanical Engineering and Automation, Fuzhou University Fuzhou, 350108, China) (2.Fujian Fuguang Digital Technology Co., Ltd. Fuzhou, 350015, China)

Rolling Bearing Faults Diagnostics Based on SPWVD Time-FrequencyDistribution Image Texture FeatureWANG Yaping, XU Di, GE Jianghua, SUN Yongguo, SUI Xiulin(School of Mechanical and Dynamic Engineering, Harbin University of Science and Technology Harbin, 150080, China)

Study of Structural Robustness Analysis Method Based on Seismic ResponseBAO Chao1,3, DU Yongfeng1,2, XU Tianni1, QI Lei1, SONG Xiang1(1.Institute of Earthquake Protection and Disaster Mitigation, Lanzhou University of Technology Lanzhou, 730050, China) (2.Western Center of Disaster Mitigation in Civil Engineering of Ministry of Education,Lanzhou University of Technology Lanzhou, 730050, China) (3.School of Civil Engineering and Hydraulic Engineering, Ningxia University Yinchuan, 750021, China)

Optimal Control of Flexible Beams Under the Action of MovingMass with Constant SpeedLIU Xiaoxiao1, REN Xingmin1, CHEN Hu1, YANG Yongfeng1, DENG Wangqun2, REN Jianting1 (1.School of Mechanics, Civil Engineering and Architecture, Northwestern Polytechnical University Xi′an, 710129, China) (2.China Aviation Powerplant Research Institute Zhuzhou, 412002, China)

Balancing Under All Working Conditions of Rotor Based on ParameterizedTime-Frequency AnalysisHUANG Xin1, ZHOU Jianping1, WEN Guangrui1,2, JIANG Hong1, TAN Yuan1 (1.School of Mechanical Engineering, Xinjiang University Urumqi, 830047, China) (2.The State Key Laboratory of Manufacturing and System, Xi′an Jiaotong University Xi′an, 710049, China)

Degradation Feature Extraction of Hydraulic Pump Based on Improved MF-DFATIAN Zaike, LI Hongru, SUN Jian, XU Baohua(Department of Missile Engineering, Ordnance Engineering College Shijiazhuang, 050003, China)

Strain Modal Method for Damage Detection Based on iFEMYANG Haifeng1, WU Ziyan1, SUN Peng2, ZHANG Kun1(1.School of Mechanics, Civil Engineering and Architecture, Northwestern Polytechnical University Xi′an, 710129, China) (2.School of Computer Science, Northwestern Polytechnical University Xi′an, 710129, China)

Design and Measurement of Dynamic Characteristics of Tall Tower StructureWU Zeyu1, WANG Dongwei2, WANG Fuming3(1.School of Civil Engineering and Communication, North China University of Water Resources and Electric Power Zhengzhou, 450045, China) (2.School of Civil Engineering, Zhengzhou University Zhengzhou, 450000, China) (3.School of Water Conservancy & Environment, Zhengzhou University Zhengzhou, 450000, China)

Measurement Method of Interface Force Between Shaker and Loadfor Swept Sine Vibration TestZHANG Zhong, ZHANG Zhengping, LI Haibo, REN Fang, HAN Li(Science and Technology on Reliability and Environment Engineering Laboratory, Beijing Institute ofStructure and Environment Engineering Beijing, 100076, China)

Design Method of Interference Fits in Automatic Electromagnetic BalancerWANG Renchao1, HU Yong1, ZHOU Tong1, TIAN Guangming1, JING Minqing2, FAN Hongwei2(1.Insititute of System Engineering, China Academy of Engineering Physics Mianyang, 621900, China) (2.School of Mechanical Engineering, Xi′an Jiaotong University Xi′an, 710049, China)

Aero-engine Fault Diagnosis Based on Fuzzy Rough Set and SVMCAO Yuyuan, ZHANG Jian, LI Yanjun, ZHANG Lina(College of Civil Aviation, Nanjing University of Aeronautics and Astronautics Nanjing, 211106, China)

Three-Dimensional Output Behavior of Displacement Sensor ofTwo-Circle Reflective Coaxial Fiber BundleXIE Siying1, ZHANG Xiaodong1,2 (1.School of Mechanical Engineering, Xi′an Jiaotong University Xi′an, 710049, China) (2.Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System,Xi′an Jiaotong University Xi′an, 710049, China)

Feature Extraction of Rolling Bearing Based on CEEMD-WPTWANG Lihua1, TAO Runzhe1, ZHANG Yonghong1, ZHAO Xiaoping2, XIE Yangyang1(1.School of Information and Control, Nanjing University of Information Science & Technology Nanjing, 210044, China) (2.Jiangsu Engineering Center of Network Monitoring, Nanjing University of Information Science & Technology Nanjing, 210044, China)

Acoustic Emission Localization System Based on FBG Sensors and Support Vector MachineZHANG Faye, JIANG Mingshun, SUI Qingmei, LI Dongsheng, CAO Yuqiang, LU Shizeng(School of Control Science and Engineering, Shandong University Jinan, 250061, China)

s of Vol.37 No.1 in English

Progress and Prospects of High-Frequency Ultrasonic Transducer Techniques

WUDawei

(State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics Nanjing, 210016, China)

Abstract With its high spatial resolution and excellent detection capability, high-frequency ultrasound is a valuable tool in clinical studies, biomedical research, and nondestructive testing (NDT) of high value manufacturing (HVM). However, a major bottleneck in further progress is the development of ultrasonic transducers for high-frequency applications. In the paper, we introduce basic principles of ultrasonic transducers and briefly review existing ultrasonic transducer techniques. Following this, we address current technical challenges of high-frequency ultrasonic transducer techniques and provide practical solutions, illustrating our recent efforts to develop state-of-the-art high-frequency ultrasonic transducer arrays. Finally, we discuss the future prospects of high-frequency ultrasonic transducer techniques.

high-frequency ultrasound; ultrasonic transducers; micromachining; piezoelectric devices

Measurement and Research on Strip Surface Vibration Mark Problem of High Strength Steel in Skin Pass Rolling

LIHongbo1,WANGZheng1,3,ZHANGJie1,JIANMin2,DINGQi2,LIUQiang2

(1.School of Mechanical Engineering, University of Science and Technology Beijing Beijing, 100083, China) (2.Wuhan Iron & Steel (Group) Corp. Wuhan, 430083, China) (3.Beijing Aerospace Times Optical-Electronic Co, Ltd. Beijing, 100094, China)

Abstract Strip surface vibration marks often appear on the surface of high strength steel produced by a cold rolling skin pass mill. After several rounds of industrial vibration tests of the roll system and drive system, we conducted time and frequency domain analysis of the vibration signal, calculated the gear-mesh frequency of the drive system, and analyzed the drive system to be the origin of vibration of the rolls system. Then, we set up the three-dimensional finite element model of a six-high skin pass mill and calculated the natural frequency. After comparison with the gear-mesh frequency, we concluded that the meshing impact of the gear box created the forced vibration of the skin pass mill. Finally, we carried out a rolling strategy with rolling speed that avoided the system′s natural frequency vibration zone in industrial production and reduced the strip surface vibration mark of high strength steel by 90%.

Keywords skin pass mill; vibration mark; modal analysis; forced vibration

Mechanical Characteristics of Three Support Structures of Flexible Skin

SHENYuan1,ZHUHua2,LIUWeidong3,ANGHaisong2
(1.Key Laboratory of Vehicle Structural Mechanics and Control, Ministry of Education, Nanjing University of
Aeronautics and Astronautics Nanjing, 210016, China) (2.State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of
Aeronautics and Astronautics Nanjing, 210016, China) (3.College of Energy and Electrical Engineering, Hohai University Nanjing, 211100, China)

Abstract In morphing aircraft, flexible skin bears and passes aerodynamic loads when the wing deforms, so the design of the supporting structure applied to flexible skin directly affects the performance of the morphing aircraft. Three types of cellular support structures that can be applied to the flexible telescopic sandwich skin are called V type, U type and trapezoidal shape. By analyzing the in-plane scale properties of these support structures, we obtained the relationship between the in-plane transverse dimensionless equivalent elastic modulus and the three geometric parameters (shape coefficient k, width coefficient t and height coefficient h). The equivalent elastic modulus decreased with the increase of k or h, and increased with the increase of t. We acquired finite element analysis (FEA) results using ANSYS software, and demonstrated the in-plane mechanical characteristics experimentally. Under the same parameters, the in-plane transverse stiffness of the three kinds of structures from large to small were as follows: V type, U type, and trapezoidal shape, indicating that the trapezoidal cellular type had stronger ability to transform and generated the same deformation with less energy. At the same time, we analyzed the stiffness of the three kinds of structures along surface normals with FEA simulation and compared them with the experimental results. Under the same equivalent aerodynamic load along surface normals, normal displacements of the three kinds of structures in decreasing order were trapezoidal shape, U type, and V type, indicating that the structure with better in-plane scalability had weaker load capacity along surface normals. By measuring the maximum normal displacements of the three structures before and after stretching, we showed that the stiffness of each structure type along surface normals improved greatly after drawing. In the case of generating the same normal displacement, the withstand pressure of the structures increased by an average of 30%～60%.

Keywords morphing wing; flexible skin; honeycomb structure; elastic modulus; finite element analysis (FEA); in-plane tensile; normal deformation

Damage Prediction Analysis and Verification of the Composite
Material Based on LTSA and RVM

CUIJianguo1,ZHANGWensheng1,QIYiwen1,YUMingyue1,PIAOChunyu2,ZHOUZhiqiang2
(1.School of Automation, Shenyang Aerospace University Shenyang, 110136, China) (2.Shenyang Aircraft Design & Research Institute Shenyang, 110035, China)

Abstract This paper proposes an evolution and prediction model of composite structural damage based on the approach of combining local tangent space alignment (LTSA) with relevance vector machine (RVM). In light of the characteristics of composite structural damage, we used a vibration fatigue test to predict structural damage. First, we acquired the health information of the composite structure via multi-sensor decomposed into intrinsic mode function (IMF) by ensemble empirical mode decomposition (EEMD). We then applied Hilbert-Huang transform (HHT) to IMF and obtained corresponding Hilbert marginal energy as the characteristics of each sensor. Second, we made feature fusion in order to obtain the characteristic energy using LTSA, and defined the resulting characteristic energy as the structure of the health index using the DMS method. Finally, regarding the structure of the health index as modeling data, we established a relevance vector machine (RVM) model, and completed the composite structural damage prediction research by predicting the structure of the health index. Results showed that this model can be used effectively to predict structural damage.

Keywords composite material; structural damage prediction; local tangent space alignment (LTSA); relevance vector machine (RVM)

Quantitative Diagnosis of Hydraulic Pump Fault Based on Spatial Information
Entropy and Support Vector Regression

WANGYukui1,2,LIHongru2,XUBaohua2
(1.The Four Stations Department, Air Force Logistics College Xuzhou, 221000, China) (2.The Fourth Department, Ordnance Engineering College Shijiazhuang, 050003, China)

Abstract In order to more accurately realize the purpose of quantitative diagnosis of hydraulic pump faults, we investigated the methods of degradation feature extraction and fault degree diagnosis. We proposed spatial information entropy based on the study of permutation entropy. Then, we analyzed the influence of values variation of partition numbers, embedding dimension and delay time, which were used in the calculation of spatial information entropy, and the conclusion was meaningful for the selection of them. The results obtained by adopting the spatial information entropy algorithm to the simulation signal affirmed the availability and superiority of using spatial information entropy as the degradation feature of pump faults. We extracted the degradation feature set with the spatial information entropy algorithm, considering the nonlinear relationship between the degradation feature and fault degree. We optimized the parameters of the support vector regression machine with a fruit fly optimization algorithm, then used it to realize the quantitative diagnosis of hydraulic pump faults. The analysis results of the practical vibration signal verified that spatial information entropy performed better than did permutation entropy on the degradation state reflection. The results of the diagnosis model demonstrated the improved adaptability of spatial information entropy and the favorable performance of the proposed diagnosis model. The results also demonstrated the better optimizing ability of the fruit fly optimization algorithm compared with traditional algorithms.

Keywords hydraulic pump; quantitative diagnosis; support vector regression machine; spatial information entropy; fruit fly optimization algorithm

Research for the Smart Micro-Displacement Active Vibration Isolation System
Based on Fuzzy-PID Control Algorithm

LIANGSen1,WANGChangsong1,WEILiming2,LIANGTianxi2
(1.School of Mechanical Engineering, Qingdao Technological University Qingdao, 266033, China) (2.China Academy of Engineering Physics Mianyang, 621900, China)

Abstract In order to isolate the vibration for precision instruments, we present a smart micro-displacement active vibration isolation system that was composed of a piezoelectric ceramic actuator, sensor and controller. Based on the national instruments (NI) data acquisition system and the B&K (Brüel & Kjr) vibration exciter, we built a detailed experimental platform for the micro-displacement active vibration isolation control system. We developed a fuzzy-proportional integral derivative (Fuzzy-PID) control algorithm using laboratory virtual instrumentation engineering workbench (LabVIEW) and applied it to the active vibration control system. We completed the control experimental research under sweep, random and sine excitation signals, and were able to obtain a significant displacement reduction of the active vibration isolation system no matter what the excitation signal was. The results verified the validity of the micro-displacement active vibration isolation system and provided an important theoretical foundation for its design and application to precision instruments and micro-nano equipment.

Keywords smart structure; active vibration isolation; piezoelectric ceramic actuator; fuzzy-proportional integral derivative (Fuzzy-PID) algorithm; micro-displacement control

Research on the Optimization Design Method of Prestress for
Giant Magnetostrictive Transducer

CAIWanchong,FENGPingfa,YUDingwen
(Beijing Key Lab of Precision/Ultra-precision Manufacturing Equipment and
Control, Tsinghua University Beijing, 100084, China)

Abstract In order to improve the performance and amplitude of a giant magnetostrictive transducer, this paper establishes a mathematical model of saturation magnetostrictive coefficient and prestress based on the mechanism of the effect of prestress on a giant magnetostrictive. We put forth the concept of magnetostrictive sensitivity and proposed a theoretical model of magnetostrictive sensitivity, external magnetic field intensity and prestress. In order to maximize the amplitude of the ultrasonic transducer, we selected the optimal prestress with the criteria of the optimal average magnetostrictive sensitivity. The experimental results showed that average magnetostrictive sensitivity exists optimal value with increasing prestress, and maximum ultrasonic amplitude was obtained under a certain magnetic field, thereby verifying the validity of the model of magnetostrictive sensitivity and the feasibility of the optimal prestress method. The proposed model of optimal prestress has guiding significance for the choice of prestress, design, and application of a giant magnetostrictive transducer.

Keywords giant magnetostrictive transducer; prestress; magnetostrictive sensitivity; amplitude

Resonance in Low Frequency Range Induced by Frequency Translation of
Flywheel′s Vibration Isolation Using for Satellite

SHENJunfeng1,ZHOUChunhua1,YUZifei1,LIUZhao2,FENGShuqing3
(1.Shanghai Institute of Satellite Engineering Shanghai, 200240, China) (2.Shanghai Aerospace Control Technology Institute Shanghai, 201109, China) (3.State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of
Aeronautics and Astronautics Nanjing, 210016, China)

Abstract We propose a mechanical model of the vibration isolation system for a satellite flywheel. First, we derived the variation of the natural frequency of the flywheel isolation system under elastic support, considering both the rotation and the precession of the flywheel. The natural frequency of the isolation system was shown to intersect with the dividing frequency related to the spin rate in the low frequency range, which would deduce low frequency resonance. The experiment verified the frequency variation and the resonance at low frequencies. In order to solve the low frequency resonance problem, the damping of the vibration isolation system was increased, and the positive effect was tested and verified.

Keywords flywheel; flywheel vibration isolation; frequency translation; low frequency resonance; micro-vibration

Tikhonov Regularization for Operational Transfer Path Analysis

CHENGWei1,2,LUYingying2,LUJiantao2,ZHANGZhousuo1,2
(1.State Key Laboratory for Manufacturing and System Engineering, Xi′an Jiaotong University Xi′an, 710049, China) (2.School of Mechanical Engineering, Xi′an Jiaotong University Xi′an, 710049, China)

Abstract To overcome the shortcomings of the traditional operational transfer path analysis (OTPA), this paper proposes a novel OTPA model for inverse problems based on Tikhonov regularization through theoretical and experimental analysis. First, we analyzed the theoretical advantages of Tikhonov regularization and provided the basic criteria for determining Tikhonov regularization parameters. We obtained operational data according to changing rotational speeds of the motors and studied the vibration transfer paths of the shell structure by singular value decomposition. Furthermore, we analyzed the errors of total contributions and path contributions for traditional OTPA. Next, we proposed a novel OTPA method based on Tikhonov regularization with Picard conditions and analyzd the effects of regularization parameters. Finally, the comparative study results showed that the proposed method reduced the errors of total contributions, path contributions, and path misjudgment. This study thus provides theoretical references for the monitoring, reduction and control of vibration and noise.

Keywords operational transfer path analysis; Tikhonov regularization; singular value decomposition; Picard condition; vibration & noise reduction and control

Rolling Bearing Fault Feature Extraction Research Based on Application Development of Singular Value Decomposition

TONGShuiguang1,TANGNing1,CONGFeiyun1,ZHOUYi1,DONGGuangming2
(1.Faculty of Engineering, Zhejiang University Hangzhou, 310027, China) (2.State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University Shanghai, 200240, China)

Abstract We propose a slip vector construction method for fault diagnosis that is based on singular value decomposition theory and decomposition matrix frame analysis. Per this method′s guidelines, we introduced the main singular value ratio, maximum eigenvalue reconstruction and optimized filter design methods. We successfully applied the proposed method to the fault feature extraction of rolling bearings. The experimental data analysis results showed that this method has suitably able to extract weak shock fault features. This paper has important implications in intelligent fault diagnosis of rolling bearings in circumstances of strong noise.

Keywords singular value decomposition; slip vector; feature extraction; rolling bearing; fault diagnosis

Modeling and Isolation Efficiency Analysis for Global Flexible Floating Raft Isolation System

WANGZhen1,ZHAOZhigao2,LIUFang1
(1.School of Mechanical Engineering and Automation, Wuhan Textile University Wuhan, 430200, China) (2.Wuhan 2nd Ship Design & Research Institute Wuhan, 430205, China)

Abstract In order to enhance the precision of the dynamic model of a raft vibration system, this paper introduces the concept of free velocity. We utilized the method of four-end parameters in order to establish the model of raft frame and base. Then, we formulated the dynamic equations of the global flexible floating raft system based on impedance synthesis analysis. We calculated a numerical sample to demonstrate the efficiency and accuracy of the proposed method. Finally, we discussed the influence of the flexibility of the raft frame and the stiffness of the isolators on isolation efficiency.

Keywords floating raft; vibration isolation; flexible; free velocity; four-end parameter; impedance synthesis analysis; vibration level difference

Tracked Vehicle Skid Steer Performance Analysis Under the Influence of
the Centrifugal Force

DONGChao1,CHENGKai1,GAOXueliang2,XIYuan1,DENGZhaoyin3
(1.School of Mechanical Science and Engineering, Jilin University Changchun, 130022, China) (2.State Key Laboratory of Automotive Simulation and Control, Jilin University Changchun, 130022, China) (3.Changchun Generating Equipment Group Changchun, 130022, China)

Abstract Since the traditional tracked vehicle steering mechanical model ignores the influence of centrifugal force, we set up a Caterpillar vehicle steering mathematical model under the influence of the centrifugal force and track slip/slide. The proposed model contributed to the accurate calculation of various performance parameters of the tracked vehicle in the actual steering process on the basis of thorough study on the tracked vehicle steering mechanism. We took a specific tracked vehicle as an example for a numerical solution. The results showed that when considering the influence of centrifugal force, the ground pressure distribution of tracked vehicle presented a trapezoidal shape rather than the uniform distribution demonstrated in traditional theory. The steering performance was also influenced by track slip/slide when the vehicle drove on stickier soil. Finally, the practical test proved the model′s validity. The findings provide a theoretical basis to the design of the crawler, caterpillar vehicles structure optimization and smooth control of the vehicles steering.

Keywords tracked vehicles; centrifugal force; turning radius; slip rat; driving force

Research on Micro-vibrations Testing Platform and Corresponding
Calibration Method

CHENJiangpan,CHENGWei,DONGJiajun,LIMing
(School of Aeronautic Science and Engineering, Beihang University Beijing, 100191, China)

Abstract The micro-vibration generated by the motion equipment on spacecraft significantly influences the imaging quality and pointing accuracy of spacecraft. The key to designing the damping and isolation for the spacraft is the use of precise tests of the micro-vibrations on Earth. We invented two kinds of testing platforms, strain micro-vibrations testing platform (SMTP) and piezoelectric micro-vibrations testing platform (PMTP), to test the micro-vibrations, and proposed accurate calibration methods to achieve high precision for both platforms. Experimental results showed that the testing errors of SMTP and PMTP were within ±1.10% and ±4.94% respectively, and the testing error of SMTP and PMTP of the same micro-vibrations was within ±4.36%.

Keywords micro-vibrations; strain micro-vibrations testing platform; piezoelectric micro-vibrations testing platform; calibration method; testing error

Fault Diagnosis for Roller Bearing Based on Local Mean Decomposition
and Enhanced Envelope Spectrum

DUDongmei,ZHANGZhao,LIHong,HEQing
(School of Energy, Power and Mechanical Engineering, North China Electric Power University Beijing, 102206, China)

Abstract To reduce signal noise, we proposed a kurtosis-skewness screening criteria (KSSC) of local mean decomposition (LMD). We chose the maximal kurtosis or absolute skewness values to reconstruct the signal, then analyzed the de-noising signal using the enhanced envelope spectrum (EES) to obtain the characteristic frequencies. Finally, we used the proposed method to analyze the vibration signals of roller bearings under outer raceway fault, ball fault and inner raceway fault. The signal noise was greatly reduced using the KSSC and EES, indicating promising applications for the diagnosis of all kinds of roller bearing faults.

Keywords local mean decomposition; screening criteria; enhanced envelope spectrum; roller bearing; fault diagnosis

Cyclic Shock Enhancement by the Combination of Minimum Entropy
Deconvolution and Spectral Kurtosis

ZHANGLong,HUJunfeng,XIONGGuoliang
(School of Mechatronics Engineering, East China Jiaotong University Nanchang, 330013, China)

Abstract Localized faults in rolling bearings present in the form of cyclic shocks in vibrations. We proposed the minimum entropy deconvolution (MED) method to enhance the sharp parts of the shocks. Then, the spectral kurtosis (SK) method was employed to eliminate the remaining noise and to further enhance the cyclic impact. Experimental data and field cases verified the effectiveness and merits of the proposed method.

Keywords resonance demodulation; spectral kurtosis; minimum entropy deconvolution; fault diagnosis

Analysis of the Effect of Disc Brake System Parameters on Brake Chatter

LIXiaopeng,LIJiasheng,LIMuyan,WENBangchun
(School of Mechanical Engineering & Automation, Northeastern University Shenyang, 110819, China)

Abstract In order to study the effect of disc brake system parameters on brake chatter, we established a two degrees of freedom kinetic model. We studied the influence of braking initial velocity, braking pressure, system stiffness and damping on the kinetic characteristics of the brake system, using Matlab to perform numerical simulation analysis. We obtained the following conclusions from the displacement curves and phase diagrams: The duration of the viscous phase of the system decreased with increasing brake initial velocity and gradually became stable; when the brake pressure was relatively small, the braking system was in the steady state; as the brake pressure increased, the vibration amplitude of the friction plate and the brake disc increased, as did the vibration intensity; when the damping increased, the friction plate and the brake disc reached the steady state motion in less time from the initial pure sliding motion; the friction plate was able to reach a steady state in a smaller braking stiffness than the brake disc did.

Keywords braking system; kinetic model; numerical simulation; brake chatter; steady state

Mid-spatial Frequency Error Identification of Precision Optical Surface Based
on the Adaptive DT-CWT Method

RENZhiying1,LINYouxi1,HUANGJianmeng1,XIAOWeijun2,GAOChenghui1
(1.School of Mechanical Engineering and Automation, Fuzhou University Fuzhou, 350108, China) (2.Fujian Fuguang Digital Technology Co., Ltd. Fuzhou, 350015, China)

Abstract This paper proposes an adaptive separation method based on dual tree complex wavelet transform (DT-CWT) according to the polished spherical precision optics surface characteristics. DT-CWT exhibited shift invariance superiority, directional selectivity and limited redundancy, and we intensified its distinguishing ability by introducing the adaptive impact factor during refactoring. Finally, we separated various surface components of the measured polishing optical surfaces effectively and characterized their parameters. Experiments showed that the DT-CWT adaptive separation method was more effective in separation and more convenient for subsequent identification and assessment work, compared with the DT-CWT direct separation method.

Keywords optical components；surface error；dual tree complex wavelet transform；adaptive separation；parametric characterization

Rolling Bearing Faults Diagnostics Based on SPWVD Time-Frequency
Distribution Image Texture Feature

WANGYaping,XUDi,GEJianghua,SUNYongguo,SUIXiulin
(School of Mechanical and Dynamic Engineering, Harbin University of Science and Technology Harbin, 150080, China)

Abstract In order to improve the accuracy of fault diagnosis for rolling bearings, this paper proposes an intelligent fault diagnosis method based on smooth and pseudo Wigner-Ville distribution (SPWVD) time-frequency distribution image texture features. First, we used the SPWVD time-frequency analysis method to process the bearing fault vibration signal. We acquired the time-frequency distribution image, then extracted the texture features from the images for the formation of the rolling bearing fault feature vectors based on certain sensitive texture features. Then, we introduced the fault feature vectors as the input to achieve fault diagnosis of rolling bearings based on the support vector machine (SVM). Finally, we extracted three kinds of feature vectors from the bearing fault data using the SPWVD time-frequency analysis method, Wigner-Ville distribution time-frequency analysis method, and wavelet scale spectrum method, respectively. We acquired the fault diagnosis accuracy of these feature vectors experimentally. The comparison results showed that the performance of the SPWVD time frequency texture fault feature outperformed the two other kinds of feature vectors with the best classification accuracy and sensitivity.

Keywords rolling bearing；fault diagnosis；feature extraction；smooth and pseudo Wigner-Ville distribution；texture feature

Study of Structural Robustness Analysis Method Based on Seismic Response

BAOChao1,3,DUYongfeng1,2,XUTianni1,QILei1,SONGXiang1
(1.Institute of Earthquake Protection and Disaster Mitigation, Lanzhou University of Technology Lanzhou, 730050, China) (2.Western Center of Disaster Mitigation in Civil Engineering of Ministry of Education,
Lanzhou University of Technology Lanzhou, 730050, China) (3.School of Civil Engineering and Hydraulic Engineering, Ningxia University Yinchuan, 750021, China)

Abstract In order to study progressive-collapse resistance robustness of a frame structure, we propose a quantitative analysis method of structural robustness, based on the mechanical characteristics of the frame structure under an earthquake. We verified the correctness and practicability of this method with an example. The results showed that the quality of structural robustness was relative and negatively correlated with the load magnitude. The quantitative analysis method of structural robustness can be used for the structural design scheme selection. The structural robustness can be improved by reducing the member vulnerability coefficient of important columns, protecting the component with a large vulnerability coefficient and importance coefficient, strengthening the connection between members, and ensuring the reliability of the load path under extreme conditions.

Keywords seismic response; structural analysis; random vibration; structural robustness; component importance coefficient; component vulnerability coefficient

Optimal Control of Flexible Beams Under the Action of Moving
Mass with Constant Speed

LIUXiaoxiao1,RENXingmin1,CHENHu1,YANGYongfeng1,DENGWangqun2,RENJianting1
(1.School of Mechanics, Civil Engineering and Architecture, Northwestern Polytechnical University Xi′an, 710129, China) (2.China Aviation Powerplant Research Institute Zhuzhou, 412002, China)

Abstract This paper investigated the optimal vibration control of flexible beams subjected to a moving mass with constant speed. We established the vibration equation of time-variant systems of a moving mass-flexible beam based on the vibration theory of the flexible beam. The model considered the coupling effect between the moving mass and the vibration of the flexible beam. We determined the terminal time instant when the moving mass left the beam and established the free vibration equation of time-invariant systems. Some methods suitable for time-invariant systems would lead to a suboptimal effect when applied to time-variant systems. Consequently, the above problems were analyzed using several control methods. The paper then discussed optimal control results of different actuation solutions. The numerical results indicated that the use of time-varying control strategy was more effective when actuator locations were determined. The optimal results with respect to the performance index were obtained by the state-dependent Riccati equation. For the time-varying system, bang-bang control performed more poorly compared with the bound linear quadratic regulator control in an augmented form, which was optimal corresponding to the performance index.

Keywords moving mass; flexible beam; vibration; optimal control; time-variant system; terminal time

Balancing Under All Working Conditions of Rotor Based on Parameterized
Time-Frequency Analysis

HUANGXin1,ZHOUJianping1,WENGuangrui1,2,JIANGHong1,TANYuan1
(1.School of Mechanical Engineering, Xinjiang University Urumqi, 830047, China) (2.The State Key Laboratory of Manufacturing and System, Xi′an Jiaotong University Xi′an, 710049, China)

Abstract Effectively controlling the vibration amplitude in the rotor system startup process under different speeds is an important measure to ensure the safe operation of rotor systems, whereas the traditional rotor balancing method is based on steady-state response of the rotor with lower frequency of balancing. In light of the shortage of current rotor balancing methods for processing non-stationary data, we proposed a new rotor balancing method under all working conditions that is based on parameterized time-frequency analysis. According to the method, we constructed an appropriate rotation operator based on the rotating frequency and rotated the time-frequency characteristics of the startup signal, which accurately extracted the rotating frequency component. By adding the trial weight and obtaining the transfer matrix under various speeds by means of holobalancing, we achieved rotor balancing under all operating conditions, thus avoiding the shortcoming of the traditional rotor balancing method. Experimental results showed that this method easily and quickly determined the unbalanced weight and unbalanced rotor angle, reduced unbalanced vibration of the rotor system, and shortened the start-times in the balancing process.

Keywords parameterized time-frequency analysis; rotor; startup signal; balancing under all working conditions

Degradation Feature Extraction of Hydraulic Pump Based on Improved MF-DFA

TIANZaike,LIHongru,SUNJian,XUBaohua
(Department of Missile Engineering, Ordnance Engineering College Shijiazhuang, 050003, China)

Abstract To solve the problem that the vibration signals of a hydraulic pump usually appear with nonlinear and a low signal to noise ratio, we devised a degradation feature extraction method based on improved multi-fractal detrended fluctuation analysis (MF-DFA). First, we proposed an improved MF-DFA based on slip window technology to overcome the problem of data partitioning, then used the MF-DFA to calculate four kinds of multi-fractal parameters of a hydraulic pump. We analyzed four parameters and consequently selected the singular indexα0and the width of multi-fractal spectrum Δαas the degradation feature. Finally, the results from analyzing actual data showed that the proposed method effectively recognized the degradation status of the hydraulic pump.

Keywords degradation feature extraction; detrended fluctuations analysis; multi-fractal; hydraulic pump

Strain Modal Method for Damage Detection Based on iFEM

YANGHaifeng1,WUZiyan1,SUNPeng2,ZHANGKun1
(1.School of Mechanics, Civil Engineering and Architecture, Northwestern Polytechnical University Xi′an, 710129, China) (2.School of Computer Science, Northwestern Polytechnical University Xi′an, 710129, China)

Abstract While the strain modal index method is commonly used in damage detection, current damage indices based on strain often need complete measured modes and modal parameters before and after damage, both of which are difficult to obtain in practical engineering. We combined the fiber Bragg grating (FBG) sensor and inverse finite element method (iFEM) in order to reconstruct the global strain field based on measured strain data of limited points. We acquired an approximate complete measured mode based on the global strain field. Thus, the strain modal damage index has a natural advantage in directly making use of strain. Then, we proposed a direct damage detection index based on strain model shape, which could locate damage with only the strain modal data after injury and did not require data before damage. The calculation results showed that the global strain field could be reconstructed quickly based on FBG and iFEM, thus supporting damage detection based on the strain modal method. In the strain modal difference curve, the positive and negative changes occurred at damage locations besides the constrained point, and the mutation degree was slightly different than damage degree, but the pattern was similar. In addition, the proposed direct damage detection index had nothing to do with the model order after regularization. The results of the actual plate experiment also validated the proposed method.

Keywords inverse finite element method; damage detection; strain modal; fiber Bragg grating sensor

Design and Measurement of Dynamic Characteristics of Tall Tower Structure

WUZeyu1,WANGDongwei2,WANGFuming3
(1.School of Civil Engineering and Communication, North China University of Water Resources
and Electric Power Zhengzhou, 450045, China) (2.School of Civil Engineering, Zhengzhou University Zhengzhou, 450000, China) (3.School of Water Conservancy & Environment, Zhengzhou University Zhengzhou, 450000, China)

Abstract In order to meet the equipment work on the building, the natural frequency of a high-rise tower structure should be greater than a certain value. The basic principles of structure frequency adjustment are to reduce the top mass of the structure and improve the bottom stiffness of the system, through the analysis of the fundamental frequency calculation formula and structure deformation curve. Based on the spatial finite element theory, we obtained the frequency and mode shapes of the structure through modal analysis. We used the ambient excitation identification method to test the dynamic property of the radar tower, and used the modal parameter identification method to identify the first three order frequencies, mode shapes and damping ratio of the structure. Then, we introduced modal assurance criteria and a normalized mode difference criterionto analyze and compare the calculated mode and the measured data. The results provided a reliable basis for further accurate predictions of the tower structure dynamic response and frequency adjustment.

Keywords dynamic property; in-situ measurement; modal assurance criteria; normalized mode difference criteria; power spectrum

Measurement Method of Interface Force Between Shaker and Load
for Swept Sine Vibration Test

ZHANGZhong,ZHANGZhengping,LIHaibo,RENFang,HANLi
(Science and Technology on Reliability and Environment Engineering Laboratory, Beijing Institute of
Structure and Environment Engineering Beijing, 100076, China)

Abstract In order to alleviate over-testing in traditional acceleration-controlled vibration tests, we established an electromechanical coupling dynamic model of a shaker system using a combination of structure dynamic and electromagnetic dynamic equations. We obtained the mapping relationship between armature current/voltage and interface force, then proposed an indirect measurement test program of interface force to validate the correctness and effectiveness of the proposed method. This method of interface force was more convenient, in that it avoided the need to change the interface conditions and was a useful supplement to traditional force measurement devices.

Keywords electromechanical coupling model of shaker; interface force; swept sine vibration test；force-limited

Design Method of Interference Fits in Automatic Electromagnetic Balancer

WANGRenchao1,HUYong1,ZHOUTong1,TIANGuangming1,JINGMinqing2,FANHongwei2
(1.Insititute of System Engineering, China Academy of Engineering Physics Mianyang, 621900, China) (2.School of Mechanical Engineering, Xi′an Jiaotong University Xi′an, 710049, China)

Abstract In order to satisfy the demand of on-line automatic balance of a grinding wheel and motor spindle, we introduced an on-line automatic balance system and designed an automatic electromagnetic balancer. We conducted a study on the design method of interference fits in an automatic electromagnetic balancer based on the finite element method. The simulation results demonstrated that the interference tolerance fit for this automatic electromagnetic balancer was between 4μm and 16 μm. We made automatic electromagnetic balancers with an interference tolerance of 5 μm, which satisfied the demand of on-line automatic balance. Finally, we conducted experiments to test the function of the automatic electromagnetic balancer at 1 834 r/min. The experimental results showed that the unbalance-induced vibration could decrease by at least 80%.

Keywords automatic electromagnetic balancer; multi-layer interference fits; interference tolerance; rotating speed

Aero-engine Fault Diagnosis Based on Fuzzy Rough Set and SVM

CAOYuyuan,ZHANGJian,LIYanjun,ZHANGLina
(College of Civil Aviation, Nanjing University of Aeronautics and Astronautics Nanjing, 211106, China)

Abstract With the development of the aviation industry, methods for aero-engine fault diagnosis have become increasingly intelligent and accurate. In this paper, we proposed a method that combines fuzzy clustering, rough sets and support vector machine (SVM). First, a fuzzy C-average clustering algorithm was applied to discretize the continuous data. Then, we used the knowledge discovery theory of rough set to reduce the decision table under the premise of keeping the table′s attribute and dependencies between conditions attributes unchanged. We used the SVM to study samples to obtain the optimal hyper-plane decision function. Finally, we used the diagnosis faults based on these characteristics for the data processing of small samples. The instance validation results of the aero-engine performance parameters showed that our method had improved ability to diagnosis aero-engine faults and could greatly shorten operation time without affecting the diagnostic rate. Thus, the proposed algorithm is both practical and accurate.

Keywords aero-engine; fault diagnosis; fuzzy clustering; rough set; support vector machine

Three-Dimensional Output Behavior of Displacement Sensor of
Two-Circle Reflective Coaxial Fiber Bundle

XIESiying1,ZHANGXiaodong1,2
(1.School of Mechanical Engineering, Xi′an Jiaotong University Xi′an, 710049, China) (2.Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System,
Xi′an Jiaotong University Xi′an, 710049, China)

Abstract Based on the characteristics of failures inside an aero-engine turbine, we introduced a three-dimensional fiber-optic tip clearance measuring method using the displacement sensor of a two-circle reflective coaxial fiber bundle. Next, we built a three-dimensional modulation function for the sensor when there was radial clearance and inclination in both the axial and circumferential directions of the reflector. We also built a compensation algorithm for the overlapping area between the receiving fiber and light spot, and a correction algorithm of average light intensity on the surface of the virtual image of the receiving fiber. Then, we obtained the simulation results of the three-dimensional modulation function when the reflector was parallel or declining relative to the probe, and compared them with the experimental results. Finally, we simulated output behavior with different design parameters of the sensor. We concluded that the newly built three-dimensional modulation function of the two-circle reflective coaxial fiber bundle not only reproduced the real output behavior of the sensor, but also provided theoretical guidance in the design process of the fiber-optic probe based on any measuring requirement for three-dimensional displacement.

Keywords three-dimensional tip clearance; fiber-optic displacement sensor; two-circle reflective coaxial fiber bundle; three-dimensional displacement measurement; light intensity compensation

Feature Extraction of Rolling Bearing Based on CEEMD-WPT

WANGLihua1,TAORunzhe1,ZHANGYonghong1,ZHAOXiaoping2,XIEYangyang1
(1.School of Information and Control, Nanjing University of Information Science & Technology Nanjing, 210044, China) (2.Jiangsu Engineering Center of Network Monitoring, Nanjing University of
Information Science & Technology Nanjing, 210044, China)

Abstract Rolling bearings are one of the most widely used and most easily damaged components in mechanical equipment. Extracting the vibration signal of the rolling bearing can give us a better grasp of the equipment′s operational state. In practical applications, traditional wavelet package transform (WPT) due to a defect itself MALLAT algorithm cannot accurately extract the characteristic frequency of the signal. Complementary ensemble empirical mode decomposition (CEEMD) can effectively restrain the mode mixing problem, but cannot completely avoid it. In order to accurately diagnose rolling bearing defects, we propose the WPT-CEMMD feature extraction method, based on CEEMD and WPT. Combining the the two methods could not only effectively solve the problem of mode mixing after CEEMD decomposition, but also eliminate the influence of the spurious frequency component and frequency aliasing after WPT treatment. Both simulations and a case of the working frequency of extraction demonstrated the efficacy of the proposed method.

Keywords rolling bearing; wavelet package transform; complementary ensemble empirical mode decomposition; feature extraction

Acoustic Emission Localization System Based on FBG Sensors
and Support Vector Machine

ZHANGFaye,JIANGMingshun,SUIQingmei,LIDongsheng,CAOYuqiang,LUShizeng
(School of Control Science and Engineering, Shandong University Jinan, 250061, China)

Abstract We constructed an acoustic emission (AE) localization system for aluminum alloy plate using fiber Bragg grating (FBG) sensor network and edge filtering, then used the wavelet transforms and support vector classifiers algorithm to identify acoustic emission localization. We explored the relationship between the AE region and signal characteristic according to the acoustic emission test on the divided area. On the basis of signal wavelet decomposition, we proposed the AE region identification method, which is based on the vibration energy calculated by a reconstructed signal using approximation coefficients and detail coefficients. Then, we built a multi-classification support vector machine whose input was vibration energy of the reconstructed signal and output was the AE region. The experimental results showed that for a 180 AE area identification test on a 400 mm×400 mm×2 mm aluminum alloy plate, a 176 AE region identification test was entirely accurate, which indicated accuracy at 97.78% and on a 30 mm×30 mm regional location.

Keywords fiber Bragg grating; acoustic emission regional location; multi-classification support vector machine; wavelet decomposition and reconstruction; signal characteristic extraction