2018年, 第31卷, 第5期　
刊出日期：2018-10-16

  

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Intelligent Manufacturing Technology
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  IBPSO-Based MUSIC Algorithm for Broken Rotor Bars Fault Detection of Induction Motors

  Pan-Pan Wang, Xiao-Xiao Chen, Yong Zhang, Yong-Jun Hu, Chang-Xin Miao

  Chinese Journal of Mechanical Engineering. 2018, 31(5): 80-80. https://doi.org/10.1186/s10033-018-0279-5

  摘要 ( ) PDF全文 ( )   可视化   收藏

  In spectrum analysis of induction motor current, the characteristic components of broken rotor bars (BRB) fault are often submerged by the fundamental component. Although many detection methods have been proposed for this problem, the frequency resolution and accuracy are not high enough so that the reliability of BRB fault detection is affected. Thus, a new multiple signal classification (MUSIC) algorithm based on particle swarm intelligence search is developed. Since spectrum peak search in MUSIC is a multimodal optimization problem, an improved bare-bones particle swarm optimization algorithm (IBPSO) is proposed first. In the IBPSO, a modified strategy of subpopulation determination is introduced into BPSO for realizing multimodal search. And then, the new MUSIC algorithm, called IBPSO-based MUSIC, is proposed by replacing the fixed-step traversal search with IBPSO. Meanwhile, a simulation signal is used to test the effectiveness of the proposed algorithm. The simulation results show that its frequency precision reaches 10^-5, and the computational cost is only comparable to that of traditional MUSIC with 0.1 search step. Finally, the IBPSO-based MUSIC is applied in BRB fault detection of an induction motor, and the effectiveness and superiority are proved again. The proposed research provides a modified MUSIC algorithm which has sufficient frequency precision to detect BRB fault in induction motors.
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  Ultrasound Imaging of Pipeline Crack Based on Composite Transducer Array

  Shou-Peng Song, Ying-Jie Ni

  Chinese Journal of Mechanical Engineering. 2018, 31(5): 81-81. https://doi.org/10.1186/s10033-018-0280-z

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  Cracks, especially small cracks are difficult to be detected in oil and gas transportation pipelines buried underground or covered with layers of material by using the traditional ultrasonic inspection techniques. Therefore, a new composite ultrasonic transducer array with three acoustic beam incidence modes is developed. The space model of the array is also established to obtain the defect reflection point location. And the crack ultrasound image is thus formed through a series of small cubical elements expanded around the point locations by using the projection of binarization values extracted from the received ultrasonic echo signals. Laboratory experiments are performed on a pipeline sample with different types of cracks to verify the effectiveness and performance of the proposed technique. From the image, the presence of small cracks can be clearly observed, in addition to the sizes and orientations of the cracks. The proposed technique can not only inspect common flaws, but also detect cracks with various orientations, which is helpful for defect evaluation in pipeline testing.
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  Novel Accelerating Life Test Method and Its Application by Combining Constant Stress and Progressive Stress

  Wen-Hua Chen, Fan Yang, Ping Qian, Jun Pan, Qing-Chuan He

  Chinese Journal of Mechanical Engineering. 2018, 31(5): 82-82. https://doi.org/10.1186/s10033-018-0281-y

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  Constant stress accelerated life tests (ALTs) can be applied to obtain a high estimation accuracy of reliability measurements, but these are time-consuming tests. Progressive stress ALTs can yield failures more quickly but cannot guarantee the estimation accuracy of reliability measurements. In this paper, a progressive-constant combination stress ALT is proposed to combine the merits of both tests. The optimal plan, in which the design variables are the initial progressive stress level, the progressive stress ramp rate, the sample allocation proportion of the progressive stress and the constant stress level, is determined using the principle of minimizing the asymptotic variance of the maximum likelihood estimator of the natural log reliable life for the connectors. A comparison between the optimal PCCSALT plan and the CSALT plan with the same sample size and estimation accuracy shows that the test time is reduced by 13.59% by applying the PCCSALT.
Advanced Transportation Equipment
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  Car Fuel Economy Simulation Forecast Method Based on CVT Efficiencies Measured from Bench Test

  Yu-Long Lei, Yu-Zhe Jia, Yao Fu, Ke Liu, Ying Zhang, Zhen-Jie Liu

  Chinese Journal of Mechanical Engineering. 2018, 31(5): 83-83. https://doi.org/10.1186/s10033-018-0283-9

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  Researchers face difficulties in studying the effects of driveline efficiency on car fuel economy via bench and road tests because of long working periods, high costs, and heavy workloads. To simplify the study process and shorten test cycles, a car fuel economy simulation forecast method for combining computer simulation forecasting with bench tests is proposed. Taking a continuously variable transmission (CVT) as the research object, a transmission efficiency model based on a bench test is constructed. An optimal economic variogram based on the original CVT variogram, the boundary conditions of vehicle performance, the road conditions and the driving behavior of the driver is generated in the Gear Shift Program (GSP)-Generation module in AVL Cruise. And on this basis a driveline simulation model that can calculate the fuel consumption based on the driveline data of a test car is built. The model is used to forecast fuel consumption and calculate real-time CVT efficiency under different conditions. Contrastive analyses on simulation results and real car drum test results are made. The largest error between simulation results and drum test results in driving cycles is 4.099%, which is 5.449% under constant velocity condition in driver control mode and 4.2% under constant velocity condition in automatic cruise mode. The results confirm the feasibility of the method and the good performance of the driveline simulation model in accurately forecasting fuel consumption. The method can efficiently investigate the effects of driveline efficiency on car fuel economy. Moreover, this research provides instruction for accurately forecasting fuel economy as well as references for studies on the effects of drivelines on car fuel economy.
Intelligent Manufacturing Technology
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  Study of ss-DNA Adsorption and Nano-mechanical Properties on Mica Substrate with Surface Forces Apparatus

  Gui-Bin Shen, Ya-Jing Kan, Min-Hua Chen, Yun-Fei Chen

  Chinese Journal of Mechanical Engineering. 2018, 31(5): 84-84. https://doi.org/10.1186/s10033-018-0286-6

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  Many DNA-based devices need to build stable and controllable DNA films on surfaces. However, the most commonly used method of film characterization, namely, the probe-like microscopes which may destroy the sample and substrate. Surface Forces Apparatus (SFA) technique, specializing in surface interaction studies, is introduced to investigate the effects of DNA concentration on the formation of single-stranded DNA (ss-DNA) film. The result demonstrates that 50 ng/μL is the lowest concentration that ss-DNA construct a dense layer on mica. Besides, it is also indicated that at different DNA concentrations, ss-DNA exhibit diverse morphology: lying flat on surface at 50 ng/μL while forming bilayer or cross-link at 100 ng/μL, and these ss-DNA structures are stable enough due to the repeatability even under the load of 15 mN/m. At the same time, an obvious adhesion force is measured: -6.5 mN/m at 50 ng/μL and -5.3 mN/m at 100 ng/μL, respectively, which is attributed to the ion-correlation effect. Moreover, the atomic force microscopy (AFM) images reveal the entire surface is covered with wormlike ss-DNA and the measured surface roughness (1.8±0.2 nm) also matches well with the film thickness by SFA. The desorption behaviors of ss-DNA layer from mica surface occur by adding sodium salt into gap buffer, which is mainly ascribed to the decreased ion-ion correlation force. This paper employing SFA and AFM techniques to characterize the DNA film with flexibility and stable mechanical ability achieved by ion bridging method, is helpful to fabricate the DNA-based devices in nanoscale.
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  Combined Cellular Automaton Model for Dynamic Recrystallization Evolution of 42CrMo Cast Steel

  Yi-Na Guo, Yong-Tang Li, Wen-Yan Tian, Hui-Ping Qi, Hong-Hong Yan

  Chinese Journal of Mechanical Engineering. 2018, 31(5): 85-85. https://doi.org/10.1186/s10033-018-0284-8

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  The dynamic recrystallization (DRX) simulation performance largely depends on simulated grain topological structures. However, currently solutions used different models for describing two-dimensional (2D) and three-dimensional (3D) grain size distributions. Therefore, it is necessary to develop a more universal simulation technique. A cellular automaton (CA) model combined with an optimized topology deformation technology is proposed to simulate the microstructural evolution of 42CrMo cast steel during DRX. In order to obtain values of material constants adopted in the CA model, hot deformation characteristics of 42CrMo cast steel are investigated by hot compression metallographic testing. The proposed CA model deviates in two important aspects from the regular CA model. First, an optimized grain topology deformation technology is utilized for studying the hot compression effect on the topology of grain deformation. Second, the overlapping grain topological structures are optimized by using an independent component analysis method, and the influence of various thermomechanical parameters on the nucleation process, grain growth kinetics, and mean grain sizes observed during DRX are explored. Experimental study shows that the average relative root mean square error (RRMSE) of the mean grain diameter obtained by the regular CA model is equal to 0.173, while the magnitude calculated using the proposed optimized CA model is only 0.11. This paper proposes a novel combined CA model for simulating the microstructural evolution of 42CrMo cast steel, which notably uses a ICA-based grain topology deformation method to optimize the overlapping grain topological structures in simulation.
Advanced Transportation Equipment
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  Numerical Analysis and Verification of the Gas Jet from Aircraft Engines Impacting a Jet Blast Deflector

  Fu-Dong Gao, De-Xin Wang, Hai-Dong Wang, Ming-Ming Jia

  Chinese Journal of Mechanical Engineering. 2018, 31(5): 86-86. https://doi.org/10.1186/s10033-018-0285-7

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  The process of the gas jet from aircraft engines impacting a jet blast deflector is not only a complex fluid-solid coupling problem that is not easy to compute, but also a safety issue that seriously interferes with flight deck environment. The computational fluid dynamics (CFD) method is used to simulate numerically the impact effect of gas jet from aircraft engines on a jet blast deflector by using the Reynolds-averaged Navier-Stokes (RANS) equations and turbulence models. First of all, during the pre-processing of numerical computation, a sub-domains hybrid meshing scheme is adopted to reduce mesh number and improve mesh quality. Then, four different turbulence models including shear-stress transport (SST) k-w, standard k-w, standard k-ε and Reynolds stress model (RSM) are used to compare and verify the correctness of numerical methods for gas jet from a single aircraft engine. The predicted values are in good agreement with the experimental data, and the distribution and regularity of shock wave, velocity, pressure and temperature of a single aircraft engine are got. The results show that SST k-w turbulence model is more suitable for the numerical simulation of compressible viscous gas jet with high prediction accuracy. Finally, the impact effect of gas jet from two aircraft engines on a jet blast deflector is analyzed based on the above numerical method, not only the flow parameters of gas jet and the interaction regularity between gas jet and the jet blast deflector are got, but also the thermal shock properties and dynamic impact characteristics of gas jet impacting the jet blast deflector are got. So the dangerous activity area of crew and equipments on the flight deck can be predicted qualitatively and quantitatively. The proposed research explores out a correct numerical method for the fluid-solid interaction during the impact process of supersonic gas jet, which provides an effective technical support for design, thermal ablation and structural damage analysis of a new jet blast deflector.
Intelligent Manufacturing Technology
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  Thermal Error Compensation of the Wear-Depth Real-Time Detecting of Self-Lubricating Spherical Plain Bearings

  Zhan-Qi Hu, Wei Li, Yu-Lin Yang, Bing-Li Fan, Hai-Li Zhou

  Chinese Journal of Mechanical Engineering. 2018, 31(5): 87-87. https://doi.org/10.1186/s10033-018-0288-4

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  The spherical plain bearing test bench is a necessary detecting equipment in the research process of self-lubricating spherical plain bearings. The varying environmental temperatures cause the thermal deformation of the wear-depth detecting system of bearing test benches and then affect the accuracy of the wear-depth detecting data. However, few researches about the spherical plain bearing test benches can be found with the implementation of the detecting error compensation. Based on the self-made modular spherical plain bearing test bench, two main causes of thermal errors, the friction heat of bearings and the environmental temperature variation, are analysed. The thermal errors caused by the friction heat of bearings are calculated, and the thermal deformation of the wear-depth detecting system caused by the varying environmental temperatures is detected. In view of the above results, the environmental temperature variation is the main cause of the two error factors. When the environmental temperatures rise is 10.3 ℃, the thermal deformation is approximately 0.01 mm. In addition, the comprehensive compensating model of the thermal error of the wear-depth detecting system is built by multiple linear regression (MLR) and time series analysis. Compared with the detecting data of the thermal errors, the comprehensive compensating model has higher fitting precision, and the maximum residual is only 1 μm. A comprehensive compensating model of the thermal error of the wear-depth detecting system is proposed, which provides a theoretical basis for the improvement of the real-time wear-depth detecting precision of the spherical plain bearing test bench.
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  Investigation of Induced Unbalance Magnitude on Dynamic Characteristics of High-speed Turbocharger with Floating Ring Bearings

  Guang-Fu Bin, Yuan Huang, Shuai-Ping Guo, Xue-Jun Li, Gang Wang

  Chinese Journal of Mechanical Engineering. 2018, 31(5): 88-88. https://doi.org/10.1186/s10033-018-0287-5

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  Due to operational wear and uneven carbon absorption in compressor and turbine wheels, the unbalance (me) vibration is induced and could lead to sub-synchronous vibration accidents for high-speed turbocharger (TC). There are very few research works that focus on the magnitude effects on such induced unbalance vibration. In this paper, a finite element model (FEM) is developed to characterize a realistic automotive TC rotor with floating ring bearings (FRBs). The nonlinear dynamic responses of the TC rotor system with different levels of induced unbalance magnitude in compressor and turbine wheels are calculated. From the results of waterfall and response spectral intensity plots, the bifurcation and instability phenomena depend on unbalance magnitude during the startup of TC. The sub-synchronous component 0.12×caused rotor unstable is the dominant frequency for small induced unbalance. The nonlinear effects of induced unbalance in the turbine wheel is obvious stronger than the compressor wheel. As the unbalance magnitude increases from 0.05 g·mm to 0.2 g·mm, the vibration component changes from mainly 0.12×to synchronous vibration 1×. When unbalance increases continuously, the rotor vibration response amplitude is rapidly growing and the 1×caused by the large unbalance excitation becomes the dominant frequency. A suitable un-balance magnitude of turbine wheel and compressor wheel for the high-speed TC rotor with FRBs is proposed: the value of induced un-balance magnitude should be kept around 0.2 g·mm.
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  Design of Lattice Structures Using Local Relative Density Mapping Method

  Guo-Hua Song, Shi-Kai Jing, Fang-Lei Zhao, Ye-Dong Wang, Hao Xing, Long-Fei Qie

  Chinese Journal of Mechanical Engineering. 2018, 31(5): 89-89. https://doi.org/10.1186/s10033-018-0289-3

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  In order to solve the problem of substantial computational resources of lattice structure during optimization, a local relative density mapping (LRDM) method is proposed. The proposed method uses solid isotropic microstructures with penalization to optimize a model at the macroscopic scale. The local relative density information is obtained from the topology optimization result. The contour lines of an optimized model are extracted using a density contour approach, and the triangular mesh is generated using a mesh generator. A local mapping relationship between the elements' relative density and the struts' relative cross-sectional area is established to automatically determine the diameter of each individual strut in the lattice structures. The proposed LRDM method can be applied to local finite element meshes and local density elements, but it is also suitable for global ones. In addition, some cases are considered in order to test the effectiveness of the LRDM method. The results show that the solution time of the LRDM is lower than the RDM method by approximately 50%. The proposed method provides instructions for the design of more complex lattice structures.
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  Active Damping of Milling Vibration Using Operational Amplifer Circuit

  Bashir Bala Muhammad, Min Wan, Yang Liu, Heng Yuan

  Chinese Journal of Mechanical Engineering. 2018, 31(5): 90-90. https://doi.org/10.1186/s10033-018-0291-9

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  The problem of chatter vibration is associated with adverse consequences that often lead to tool impairment and poor surface finished in a workpiece, and thus, controlling or suppressing chatter vibrations is of great significance to improve machining quality. In this paper, a workpiece and an actuator dynamics are considered in modeling and controller design. A proportional-integral controller (PI) is presented to control and actively damp the chatter vibration of a workpiece in the milling process. The controller is chosen on the basis of its highly stable output and a smaller amount of steady-state error. The controller is realized using analog operational amplifier circuit. The work has contributed to planning a novel approach that addresses the problem of chatter vibration in spite of technical hitches in modeling and controller design. The method can also lead to considerable reduction in vibrations and can be beneficial in industries in term of cost reduction and energy saving. The application of this method is verified using active damping device actuator (ADD) in the milling of steel.
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  A Local Region Molecular Dynamics Simulation Method for Nanoscale Sliding Contacts

  Rui-Ting Tong, Geng Liu, Tian-Xiang Liu

  Chinese Journal of Mechanical Engineering. 2018, 31(5): 91-91. https://doi.org/10.1186/s10033-018-0292-8

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  Computational efficiency and accuracy always conflict with each other in molecular dynamics (MD) simulations. How to enhance the computational efficiency and keep accuracy at the same time is concerned by each corresponding researcher. However, most of the current studies focus on MD algorithms, and if the scale of MD model could be reduced, the algorithms would be more meaningful. A local region molecular dynamics (LRMD) simulation method which can meet these two factors concurrently in nanoscale sliding contacts is developed in this paper. Full MD simulation is used to simulate indentation process before sliding. A criterion called contribution of displacement is presented, which is used to determine the effective local region in the MD model after indentation. By using the local region, nanoscale sliding contact between a rigid cylindrical tip and an elastic substrate is investigated. Two two-dimensional MD models are presented, and the friction forces from LRMD simulations agree well with that from full MD simulations, which testifies the effectiveness of the LRMD simulation method for two-dimensional cases. A three-dimensional MD model for sliding contacts is developed then to show the validity of the LRMD simulation method further. Finally, a discussion is carried out by the principles of tribology. In the discussion, two two-dimensional full MD models are used to simulate the nanoscale sliding contact problems. The results indicate that original smaller model will induce higher equivalent scratching depth, and then results in higher friction forces, which will help to explain the mechanism how the LRMD simulation method works. This method can be used to reduce the scale of MD model in large scale simulations, and it will enhance the computational efficiency without losing accuracy during the simulation of nanoscale sliding contacts.
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  High Resolution Clinometers for Measurement of Roll Error Motion of a Precision Linear Slide

  Yuki Shimizu, Satoshi Kataoka, Wei Gao

  Chinese Journal of Mechanical Engineering. 2018, 31(5): 92-92. https://doi.org/10.1186/s10033-018-0294-6

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  This paper proposes a new method for measurement of the roll error motion of a slide table in a precision linear slide. The proposed method utilizes a pair of clinometers in the production process of a precision linear slide, where the roll error motion measurement will be carried out repeatedly to confrm whether the surface form errors of slide guideways in the linear slide are sufciently corrected by hand scraping process. In the proposed method, one of the clinometers is mounted on the slide table, while the other is placed on a vibration isolation table, on which the precision linear slide is mounted, so that infuences of external disturbances can be cancelled. An experimental setup is built on a vibration isolation table, and some experiments are carried out to verify the feasibility of the proposed method.
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  Controlling Roll Temperature by Fluid-Solid Coupled Heat Transfer

  Jing-Feng Zou, Li-Feng Ma, Guo-Hua Zhang, Zhi-Quan Huang, Jin-Bao Lin, Peng-Tao Liu

  Chinese Journal of Mechanical Engineering. 2018, 31(5): 93-93. https://doi.org/10.1186/s10033-018-0293-7

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  Currently, when magnesium alloy sheet is rolled, the method of controlling roll temperature is simple and inaccurate. Furthermore, roll temperature has a large influence on the quality of magnesium alloy sheet; therefore, a new model using circular fluid flow control roll temperature has been designed. A fluid heat transfer structure was designed, the heat transfer process model of the fluid heating roll was simplified, and the finite difference method was used to calculate the heat transfer process. Fluent software was used to simulate the fluid-solid coupling heat transfer, and both the trend and regularity of the temperature field in the heat transfer process were identified. The results show that the heating efficiency was much higher than traditional heating methods (when the fluid heat of the roll and temperature distribution of the roll surface was more uniform). Moreover, there was a bigger temperature difference between the input and the output, and after using reverse flow the temperature difference decreased. The axial and circumferential temperature distributions along the sheet were uniform. Both theoretical calculation results and numerical simulation results of the heat transfer between fluid and roll were compared. The error was 1.8%-12.3%, showing that the theoretical model can both forecast and regulate the temperature of the roll (for magnesium alloy sheets) in the rolling process.