Table of Content

25 September 2023, Volume 34 Issue 18

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Analysis and Test on Dynamic Transmission Errors of RV Reducers under Load Conditions

XU Lixin, XIA Chen, YANG Bo

2023, 34(18):  2143-2152.  DOI: 10.3969/j.issn.1004-132X.2023.18.001

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 For the current RV reducer transmission accuracy factory calibration value was detected under no-load conditions, it was difficult to reflect the real accuracy performance under torque loading conditions, in order to effectively reveal the dynamic transmission error characteristics of the RV reducers under the action of the load, a theoretical dynamic model of contact multi-body system of standard RV reducer with two crankshafts was proposed, which took the multi-error factors of geometry and position of key transmission parts into consideration. In order to effectively reveal the dynamic transmission error characteristics of RV reducers under load, during modeling, firstly, the parametric model of the whole reducer was designed and completed for the RV reducer transmission structure characteristics. Secondly, a detailed dynamic contact analysis method was proposed considering involute gear drive of the first stage, cycloidal-pin drive of the second stage, and multiple sets of turning-arm bearings and support bearings. Thus, the dynamic transmission error characteristics of reducer under torque load were discussed taking RV20E as the object. The results show that with the increase of load torque, the transmission error amplitudes of reducer are increasing, but the amplitude growth rate is decreasing. Compared with no-load conditions, the increase of theoretical transmission errors of the reducers under rated torque is as 73.1%, and the increase of experimental transmission errors under rated torque is as 58.9%.

Prediction and Analysis of Cutting Stability Based on Improved Discrete Method

XIE Miao, ZHU Yun, LIU Jie, REN Ze, YANG Zhiyong, LIU Zhixiang, WANG He, MENG Qingshuang

2023, 34(18):  2153-2164，2176.  DOI: 10.3969/j.issn.1004-132X.2023.18.002

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In order to study the influences of multiple interactions among coal and rock and velocity effects on the flutter stability of the cutting head of a cantilever tunneling machine, the physical characteristics of coal and rock, structural parameters of the cutting head, and motion parameters of the cutting head were considered. The functional expressions of the cutting depth of the cutting head and the participating cutting teeth was fitted, and the mechanics characteristic equations of the cutting state for dynamic cutting of the cutting teeth was established. Cutting dynamics models were constructed that included multiple interactions and velocity effects between the cutting head and coal rock based on the mapping relationships between the cutting teeth and the cutting head. An improved discretization method based on Newton Lagrange mixed interpolation was proposed to elucidate the influences of the coupling effect of regeneration effect and velocity effect on the stability of cutting flutter in the cutting states. The superiority of the improved fully discrete method based on mixed interpolation method was demonstrated by comparing with the fully discrete and semi discrete methods. The influences of dynamic parameters of different cutting systems on stability were studied based on the improved fully discrete method. Based on the theory of similarity experiments, a cutting head coal rock system cutting experimental platform was built to simulate the vibrations of the cutting system. The results show that the improved fully discrete method constructed may effectively predict the actual cutting state.

Research on Self-adaptive Chatter Recognition Method for Robotic Milling

JI Yongjian, YAO Licheng,

2023, 34(18):  2165-2176.  DOI: 10.3969/j.issn.1004-132X.2023.18.003

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 Aiming at the problems that the form of robot milling chatters was complex and difficult to identify effectively, a robot milling chatter adaptive identification method was proposed. Firstly, to retain the information that could characterize the robotic milling states, the original vibration signals were separated. Then the difference between the power spectrum entropy was used to characterize the frequency distribution characteristics of vibration signals in different milling states, and the standard deviation of the original signals was used to characterize the time domain characteristics of vibration signals in robotic milling. The three-dimensional feature vector was input to the support vector machine to construct the adaptive recognition model of robotic milling chatters. The model was verified by experiments. The results show that the proposed adaptive chatter recognition model may accurately identify regenerative chatters and low-frequency chatters in robotic milling, and the recognition accuracy of stable, early regenerative chatters, severe regenerative chatters, low frequency chatters and no-load state reaches 93%, which is better than existing methods.

Analysis of Transmission Characteristics of Sun Wheel Root Cracks in Planetary Wheel Gearboxes#br#

SHEN Ziyu, ZHANG Zhai, WANG Youren, LI Hongkun

2023, 34(18):  2177-2185.  DOI: 10.3969/j.issn.1004-132X.2023.18.004

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A centralized parametric model was used to analyze the vibration signal characteristics under two modes of gearbox internal and external meshing respectively, considering the internal excitation of meshing vibrations. Improved time-varying path functions for Gaussian windows and considering time-invariant path functions for gearbox materials were introduced to improve the vibration signal model of the planetary wheel gearbox case surface, and the quantitative influence laws of different transmission paths on the vibration signal modulation phenomenon of the case surface under normal and cracked sun wheel tooth roots were analyzed. The simulation and experimental comparison analysis demonstrate: the sun wheel root cracks mainly affect the side frequency band components of the mesh frequency octave, the model may accurately analyze the frequency, amplitude and side frequency information of the vibration signals under normal gearbox conditions and sun wheel root crack, and may be used for sun wheel root crack fault diagnosis.

Modeling and Experimental Study of Shape Memory Cable Net Structures

PAN Fengqun, JIANG Xiangjun, DU Jingli, LIU Jia, FAN Yesen

2023, 34(18):  2186-2193.  DOI: 10.3969/j.issn.1004-132X.2023.18.005

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In order to solve the problems of reduced surface accuracy caused by space environment during the operation of spaceborne cable net antenna in orbit, a shape memory cable net structure was proposed. The shape memory alloy wires were integrated with the cable net structure to form a shape memory cable net structure. The reflector of the cable mesh structure was adjusted by using the phase transformation characteristics of shape memory alloy to improve the in orbit performance. Experiments were carried out using a 2.2 m cable net structure model under normal temperature and high and low temperature. The experimental results show that the shape memory alloy wires have a relatively stable ability to adjust the surface accuracy of the cable net structures at room temperature. In high and low temperature environments, compared with ordinary cable net, shape memory cable net structure has higher surface accuracy. Shape memory alloy wires have a certain adjustment effect on the reflector of cable net structures.

Design of Double-stage Safety Valves for Hydraulic Support and Experimental Study of Their Rapid Dynamic Load Impact Test

ZHOU Guoqiang, WANG Hui, SONG Yuning, ZHAO Guochao,

2023, 34(18):  2194-2203.  DOI: 10.3969/j.issn.1004-132X.2023.18.006

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In order to improve the impact resistance and stability of the hydraulic supports, a new type of double-stage safety valve combined with a first-stage direct-acting valve with rated flow and pressure of 50 L/min and 45 MPa respectively and a second-stage differential valve with rated flow and pressure of 1000 L/min and 50 MPa respectively was designed. Moreover, a rapid dynamic load impact test system was developed based on the accumulator group, and the pressure dynamic response characteristics of the rapid dynamic load impact test system and the pressure-flow dynamic response characteristics of the double-stage safety valve were obtained by using AMESim and Simulink combined-simulation technology. Finally, a rapid dynamic load impact test bench prototype was established to test the double-stage safety valves. The results show that the rated pressure and flow rate of the second-stage differential valve are about 49.2 MPa and 992 L/min respectively, the opening time is less than 3 ms, the pressure stabilization time is within 1315 ms, and the unloading time is less than 5 ms. The experiments verify that the designed double-stage safety valve has the characteristics of fast unloading speed and excellent impact resistance and the correctness of the rapid dynamic load impact test scheme.


Dynamic Wide Convolutional Residual Network for Bearing Fault Diagnosis Method

QIN Guohao, ZHANG Kai, DING Kun, HUANG Fengfei, ZHENG Qing, DING Guofu,

2023, 34(18):  2212-2221.  DOI: 10.3969/j.issn.1004-132X.2023.18.008

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The ranges of convolutional neural network feature extraction were constrained by the size of the receptive field of the convolutional kernel, and it was difficult for a single-scale convolutional kernel to adequately capture the frequency components of different shocks. A dynamic wide kernels residual network(DWResNet) bearing fault diagnosis method was proposed to solve the above problems which made it difficult to improve the accuracy of bearing fault diagnosis. A wide residual kernel structure to the one-dimensional deep residual network framework was introduced. A parallel two-channel network structure for the feature of bearing faults was constructed. Then, the convolutional kernel was dynamically weighted by the network through an attention mechanism, which was adapted to extract feature information at different scales fully. As a result, effective identification of bearing faults was achieved. Experiments show that the proposed method achieves an accuracy of over 98% for bearing fault diagnosis tasks with different noise levels. Therefore, the dynamic scale weighting mechanism may effectively improve the bearing fault diagnosis, especially in the presence of high noise levels.

Mechanics Property Prediction of Cold Rolled High Strength Steel Coils Based on GBD#br#

TWANG Wei, MA Qianlun, BAI Zhenhua, WANG Ziang

2023, 34(18):  2222-2229.  DOI: 10.3969/j.issn.1004-132X.2023.18.009

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 Based on production data for 1180 MPa level ultra-high strength cold-rolled dual-phase（DP）steel coils, the chemical principal component extraction method based on principal component analysis, the hyper-parameter optimization method combining grid search and cross-validation were studied, and GBDT prediction models of DP steel mechanics properties were established. The predicted results were compared with those of BP neural network models and generalized additive models(GAM). To improve the prediction accuracy of elongation at break, based on the GBDT prediction model with high prediction accuracy, a prediction correction model of elongation at break considering error compensation was established through the model prediction error classification model and the model prediction correction method considering error compensation, and the prediction accuracy of the elongation correction model reaches 94.63% within an absolute error range of ±0.9%. The DP steel property prediction model performs well with good prediction accuracy during online operation, meeting production requirements, and is helpful for online quality monitoring of mechanics properties.

Construction of Ultrasonic-Stress Inversion Model Based on Distribution States of Coating Materials

KE Qingdi, LUO Junyou, JIANG Shouzhi, HUANG Haihong,

2023, 34(18):  2230-2237.  DOI: 10.3969/j.issn.1004-132X.2023.18.010

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Considering the increasing industrial applications of metal additive manufacturing, it was important to analyze residual stress caused by forming processes and detect residual stress with ultrasonic nondestructive testing, and in coating structure, the complex distribution of materials made the local acoustic elastic characteristics uncertain, resulting in a certain detection errors. Thus, after analyzing the distribution of materials, the stress inversion model of coating structures was proposed. Firstly, the propagation of ultrasound and related ultrasonic signals was analyzed based on the acoustic elasticity theory in variable distributions of materials and stress. Then, considering the forming processes of different coating structural areas in the plasma spray welding additive processes, the distribution of materials in coating structure was discussed. Analyzing the relationship between the acoustic-elastic characteristics and material distribution in bonding area, the stress inversion model of coating structural areas was presented. Finally, the coating structure samples of base material(C45E4) and coating material(Cu) were designed and prepared by plasma spray welding, the ultrasonic testing with tensile/compressive stress was given. Comparing the testing results and calculation ones, the stress inversion model of coating structure is effective. After discussing the feasibility in stress ultrasonic testing, the proposed method is considered as the potential tool in the quality evaluation and monitoring for coating structures.

Research on Topology Optimization and Additive Manufacturing of Automotive Engine Connection Brackets

LIU Yingjie, HU Qiang, ZHAO Xinming, ZHANG Shaoming, HUANG Shuai, WANG Yonghui

2023, 34(18):  2238-2267.  DOI: 10.3969/j.issn.1004-132X.2023.18.011

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The topology optimization and additive manufacturing of automotive engine connecting brackets were studied. Topology optimization module of ANSYS Workbench was used to optimize the connecting brackets of automotive engine air-conditioning compressors, the mass was reduced by about 43.8% and the first-order resonance frequency was increased by about 23%(increase to 255 Hz), and the mechanics properties of the optimized structures were significantly better than those of the original castings. The heat treatment system of aluminum alloy parts made by additive manufacturing was studied, and a better heat treatment system was obtained. The integrated technology of topology optimization and additive manufacturing of the key components of automobile engine was developed.

Collaborative Visualization Analysis of Train Dynamics by Cloud Simulation-driven

WANG Liting, TANG Zhao, LI Rong, GU Zheng, HU Yuwei, LI Yuehong, ZHANG Jiye

2023, 34(18):  2248-2256.  DOI: 10.3969/j.issn.1004-132X.2023.18.012

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To address the challenges of insufficient automation in scene construction, inconvenient multi-role multi-user collaboration, poor analysis timeliness of analysis, and high client hardware requirements in the traditional train dynamics analysis processes, a cloud simulation-driven train dynamics collaborative visualization analysis framework driven by simulation was proposed. A train dynamics simulation and visualization analysis framework, a remote visualization interaction framework, and a solver integration model for real-time analysis were designed. These respectively achieved service-oriented multi-dimensional visualization analysis scene construction, multi-role and multi-group collaborative remote visualization analysis, and efficient module interconnection and node elastic expansion. Based on the proposed framework, a software system was built and validated in the project. The validation results show that the framework and system have outstanding visualization performance and concurrent solving capabilities while ensuring accuracy. The successful applications of the framework also indicate that cloud simulation has great potential for use in train dynamics visualization analysis. 

Bending Load Monitoring and Positioning Method of Long-span Composite Structures

YAN Dongdong, HU Yubo, LANG Lihui, QIN Chengwei, ZHANG Sanmin, LI Yong

2023, 34(18):  2257-2267.  DOI: 10.3969/j.issn.1004-132X.2023.18.013

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 Because of the load monitoring requirements and real-time monitoring problems faced by composite components during service, fiber Bragg grating (FBG) sensors were pasted on the surface of carbon fiber composite materials to measure the strain of carbon fiber composite materials. The bending load size and loading position of carbon fiber composite materials were monitored by establishing theoretical models of strain, load size, and loading position. The method and technical support were provided for overload warning of composite materials in service. The composite components under the bending load, the finite element analysis strain were compared with the theoretically calculated strain to verify the validity of the finite element analysis model, and then the errors between the strain values monitored by the FBG sensor and the theoretically calculated was compared. Finally, the size and position of the bending load subjected to the composite materials were calculated based on the FBG monitoring strain. The results show that under the central load, the maximum error of strain measured by FBG and theoretical calculation value is not more than 16.22%, the maximum error of load size is not more than 10.37%, and the maximum error of load position is not more than 2.83%. Under the action of eccentric 20 mm load, the maximum error of FBG monitoring strain and theoretical calculation value is not more than 10.69%, the maximum error of load size is not more than 13.89%, and the maximum error of load position is not more than 5.70%.