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20 May 2024, Volume 43 Issue 5 Previous Issue   
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Transportation Infrastructure Engineering
Transportation+Big Data & Artificial Intelligence
Transportation Equipment


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Transportation Infrastructure Engineering

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Joint Action of PBL Connectors and Steel Beam End Bearing in Steel-UHPC Joint Section YANG Jun1, 2, LI Keyang1, 2, ZHOU Jianting1, 2, LENG Jingchen1, 2, ZOU Yang1, 2 2024, 43(5): 1-8.  DOI: 10.3969/j.issn.1674-0696.2024.05.01 Abstract ( )   PDF (7237KB) ( )   The steel-concrete joint section is the core component to connect the steel beam and concrete as a whole, and the force performance of the force-transfer member is very important for the steel-concrete joint section. In order to improve the mechanical properties of the joint section, three groups of deduced tests were carried out, including only the steel beam end bearing, only the PBL connection and the combined action of the above two. The results show that the distribution of final failure cracks in the three groups of specimens is the “figure-eight” distribution on the end face side of the steel beam. The failure mode of the specimens of the steel beam end group (Group D) is mainly the failure of UHPC cracking failure, and that of the specimens of PBL connector group (P group) and combined action group (PD group) is mainly due to the shear failure of the penetrating steel bar. The load-slip curves of the three groups of specimens all include three stages such as elasticity, crack development and yield. And because the penetrating steel bar and UHPC mortise have the effect of inhibiting crack development and improving the ductility of the specimen, the crack development stage of the P group and the PD group specimens is shorter than that of the D group, while the yield stage is longer, and the ductility is better. The load-slip curve is fitted, and the calculation formula of the steel beam end bearing and the bearing capacity of the PBL connector with the slip amount is proposed. The hysteresis slip difference Δsj is introduced, when the Δsj is 0~0.67 mm, the combined action calculation results are biased towards safety. It is calculated that the force transmission ratio of the steel beam end bearing is about 43%, and the force transmission ratio of the PBL connector is about 57%, and the force transmission between the two is basically the same. When UHPC is used as outsourced concrete, it is recommended to use penetrating steel bars with higher bearing capacity to fully utilize the high strength performance of UHPC, so as to improve the bearing capacity of the joint section. References | Related Articles | Metrics

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Quality Evaluation of Bridge Dynamic Monitoring Data Based on EDA Statistical Graph Quantification YIN Pengcheng1, 2, TAN Manlisha3,4, CAO Yangmei1, 2, SHAN Deshan3 2024, 43(5): 9-16.  DOI: 10.3969/j.issn.1674-0696.2024.05.02 Abstract ( )   PDF (3422KB) ( )   Exploratory data analysis (EDA) statistical graphs have been widely used for dynamic data quality assessment in bridge health monitoring. In order to reduce the subjectivity of manually observing statistical graphs, the quantitative analysis of statistical graphs was achieved through an approximation measurement method, and multiple indicators were obtained for rapid quality evaluation of monitoring data. The dynamic response of bridge structures exhibited short-term linear stationary characteristics and approximately followed a normal distribution under the stimulation of the operating environment. Taking the vibration data of a large-span cable-stayed bridge as the research object, sample data histograms and Q-Q plots were firstly plotted. By observing the data distribution characteristics, the data quality was prejudged and determined to be excellent, good, or poor. Subsequently, the sample data histograms and Q-Q plots were quantitatively analyzed by two approximation measure methods, namely KL divergence and cosine similarity, to obtain indicators of the degree to which the data followed a normal distribution. By detecting the global outliers of the sample data through box plots, the proportion of normal data was obtained. The corresponding relationship between the quantified values and the prior quality levels was obtained by statistical analysis. And the data quality evaluation standards were determined by using histogram KL divergence and cosine similarity as the main indicators and box plot normal data proportion as the secondary indicator. Finally, a portion of the data was taken as the validation set to further validate the rationality of each indicator of the proposed method, and the application results of the proposed method in practical engineering were given. References | Related Articles | Metrics

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Properties of Asphalt Modified by SBR Compound Recycled Rubber Resin ZHAO Zhouqing1, 2, LU Zhenzhen1, LI Jiayu2, LI Fuqiang2 2024, 43(5): 17-23.  DOI: 10.3969/j.issn.1674-0696.2024.05.03 Abstract ( )   PDF (1418KB) ( )   In order to improve the pavement performance of matrix asphalt, combining with the material characteristics of SBR and recycled rubber resin, single modification and pairwise compounding of asphalt were carried out. With reference to the evaluation index of asphalt, the performance of SBR compound recycled modified rubber resin was comprehensively evaluated by using 25 ℃ penetration, softening point, cone penetration, 10 ℃ ductility, rotary viscosity and other tests. The performance differences and influencing factors of modified asphalt with different formulations were explored and compared, and the best compounding scheme was selected out. The research results show that both increasing the content of SBR and recycled rubber resin can improve the high temperature performance of asphalt to some extent. Different sources of SBR have little effect on asphalt properties, but different recycled rubber resins have different effects on asphalt properties. The main reason is that different recycled rubber resin compositions have a significant impact on the performance of asphalt. SBR has a significant improvement effect on the low-temperature performance of asphalt, and a small amount of SBR can significantly enhance the ductility of asphalt. With the increase of SBR content, the softening point of SBR modified asphalt is increased slightly, and the viscosity is also increased accordingly. Compared with SBR, the effect of recycled rubber resin on improving softening point is more significant, with an optimal content of 8%. The optimal solution for this compounding is 3% SBR and 8% recycled rubber resin. References | Related Articles | Metrics

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Experimental Study on Dynamic Characteristics of Silty Clay in Xiong an New Area MA Lina1, SHI Lei1, YANG Bin2, XU Hongxin2, ZHANG Rongling1 2024, 43(5): 24-31.  DOI: 10.3969/j.issn.1674-0696.2024.05.04 Abstract ( )   PDF (1365KB) ( )   To analyze the dynamic characteristics of silty clay in Xiongan New Area, a GDS multifunctional dynamic cyclic triaxial testing system was used to conduct dynamic triaxial tests on the silty clay under 14 working conditions (different confining pressures, consolidation ratios and loading frequencies). The variation rules and relative parameters of dynamic backbone curves, dynamic elastic modulus, dynamic shear modulus and damping ratio under different working conditions were analyzed in depth. The experiment results indicate that: with the increase of dynamic stress amplitude, the dynamic strain shows a nonlinear growth and exists a certain critical dynamic stress value. With the increase of dynamic strain, the dynamic modulus decreases gradually, and the rate of decrease is first fast, then slow, and finally tends to stabilize. As the dynamic shear strain increases, the damping ratio shows nonlinear growth, and the maximum damping ratio does not exceed 0.12. With the increase of confining pressure and consolidation ratio, both the dynamic strength and dynamic modulus increase obviously. The confining pressure and consolidation ratio have little influence on damping ratio and have the characteristics of normalization. As the frequency increases, the dynamic stress amplitude and dynamic elastic modulus increase, but the increase is not significant. Through comprehensive analysis of the influence of three variables on the dynamic characteristics of silty clay in Xiongan New Area, it is concluded that confining pressure has the greatest impact, followed by consolidation ratio and loading frequency. References | Related Articles | Metrics

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Prediction Model of Saltwater Intrusion Distance in the Qinjiang River Estuary XIAO Yi1, LI Dahong2, DENG Jinghong1, XIA Nan1 2024, 43(5): 32-37.  DOI: 10.3969/j.issn.1674-0696.2024.05.05 Abstract ( )   PDF (3918KB) ( )   Pinglu Canal project is an important water transportation infrastructure for China’s “New Western Land and Sea Corridor”, and the Youth Hydro-hub is the most downstream node control hub of the canal. Due to the influence of saltwater upstream in the Qinjiang tidal section, reasonable prediction of saltwater intrusion distance is of great significance for understanding the lifespan of Youth Ship Lock and urban drinking water safety. Based on the measured data of the saltwater intrusion upstream in the Qinjiang River Estuary, a prediction model of saltwater intrusion length in the high tide period considering the estuary geometry, tidal action and runoff process was constructed based on the one-dimensional diffusion steady-state equation for saltwater upstream. Then, the influence of runoff and tidal action on the length of saltwater intrusion length in the Qinjiang River Estuary was analyzed. The obtained main conclusion is that when the upstream inflow is Q<100 m3/s, the saltwater intrusion length in the Qinjiang River Estuary during the high tide period after the Pinglu Canal project is L=10~27 km, with an increase of 4.5 km compared to before the project. When the upstream runoff inflow is Q<20 m3/s, the saltwater in the Qinjiang River Estuary will flow upstream to the bottom of the Youth Ship Lock. During the dry season, the minimum discharge of saltwater from the Youth Hydro-hub must reach 20 m3/s when the tidal range of the river estuary is H0>2.5 m. References | Related Articles | Metrics

Transportation+Big Data & Artificial Intelligence

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Spatial and Temporal Resource Optimization of Shared Overtaking Lane at Linear Bus Stops Based on Bus Priority ZHANG Ruhua, MA Mingdi, CHEN Leiyu, ZHAO Bing, DI Jincan 2024, 43(5): 38-45.  DOI: 10.3969/j.issn.1674-0696.2024.05.06 Abstract ( )   PDF (4531KB) ( )   Limited by urban road red line, many bus stops can only set up linear bus stop, whose platform is prone to cause traffic congestion, queuing, and motor vehicle conflicts. Based on this, an optimization scheme for shared overtaking lane (SOL) sensing signal control was proposed, and the delay level of vehicles before and after sharing overtaking lane was simulated and analyzed by VISSIM software. The research results show that setting up SOL can effectively alleviate traffic congestion, queuing, and motor vehicle conflicts at bus stops. Under the condition of large traffic volume and high bus departure frequency, the level of public transportation service can be effectively improved by setting the linear bus stop with shared overtaking lanes, which ensures priority passage of buses and orderly passage of social vehicles in the upstream section of near road intersections and improves the smoothness and safety of traffic flow. References | Related Articles | Metrics

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Lane Change Point Selection Behavior for Mainline Weaving Vehicles in Urban Continuous Tunnel Weaving Areas WU Lan1, CHEN Yuxin1, CHEN Qian2, ZHAO Yi1, LI Minghao1 2024, 43(5): 46-52.  DOI: 10.3969/j.issn.1674-0696.2024.05.07 Abstract ( )   PDF (2472KB) ( )   Based on the weaving area of urban continuous tunnel, the lane change point selection behavior of weaving vehicles on the mainline was analyzed. Based on the vehicle trajectory data collected in the field, the random forest model was used to analyze the characteristics of the lane change point selection behavior of the mainline vehicle and the influencing factors of the behavior decision. Then, the support vector machine model and the random forest model were used to model and compare the lane change point selection behavior. The research results show that the main factors affecting the selection of lane change points for mainline weaving vehicles are the target vehicle state and the rear vehicle state of the lane, and the accuracy of the lane change decision model established after feature screening is higher. The support vector machine model can better describe the lane change behavior, and the prediction accuracy of the model is not less than 85%. The research results help to describe the lane change point selection behavior more accurately in the simulation model and provide support for the optimization of the weaving area of urban continuous tunnels and the formulation of assisted driving strategies. References | Related Articles | Metrics

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Data-Driven Acceleration Lane Length in Merging Areas of Expressways ZHANG Hang1, MA Baolin1, CHU Zeyu2, LYU Nengchao3 2024, 43(5): 53-60.  DOI: 10.3969/j.issn.1674-0696.2024.05.08 Abstract ( )   PDF (3066KB) ( )   Reasonable design of the length of the acceleration lane can effectively alleviate the frequent traffic bottleneck problem in the expressway merging area. Therefore, a data-driven method was used to study the length of the acceleration lane in the expressway merging area. Firstly, the unmanned aircraft equipment was used to measure the traffic data of the expressway merging zone. The measured data was analyzed from the perspectives of traffic flow characteristics and vehicle convergence behavior, and the driving behavior of vehicles in the merging zone was obtained. Then, according to the characteristics of the traffic flow in the merging zone, the clustering of the dataset was performed. The generative adversarial network (GAN) was used to train car following and lane changing models for vehicles with different merging behaviors in the merging area, which was compared and analyzed with the measured data and the built-in model of SUMO simulation software. Finally, the generative adversarial network model was applied to simulate the traffic environment, and the indicators such as the speed, traffic density and traffic conflict rate were selected to establish the reward evaluation function, so as to obtain the recommended design value of acceleration lane length. The research results show that: through two measures such as early deceleration of mainline vehicles and lane changing towards the inner lane, collaborative lane changing can be achieved to avoid vehicles merging into the ramp. Compared with the built-in model of SUMO software, the generative adversarial network model is closer to the actual situation. The length of the single-lane parallel acceleration lanes obtained by the simulation is recommended to be 280 m, 240 m, and 200 m respectively under the conditions of 100 km/h, 80 km/h, and 60 km/h. References | Related Articles | Metrics

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Traffic Flow Anomaly Data Detection Model Based on Improved Isolation Forest Algorithm GONG Xiaoxing, DONG Peixin 2024, 43(5): 61-69.  DOI: 10.3969/j.issn.1674-0696.2024.05.09 Abstract ( )   PDF (2351KB) ( )   For the problem of real-time detection of traffic flow anomaly data, a traffic flow anomaly data detection model based on the combination of improved isolated forest and K-Means++ algorithm was proposed. Firstly, traffic flow sequences were constructed by using traffic flow and traffic flow speed data. Then, the anomaly scoring model of the traffic flow data was constructed by the improved isolated forest algorithm, and the sliding window was constructed by the K-Means++ algorithm to calculate the threshold value of the anomaly scoring, which realized the real-time detection of abnormal values of traffic flow data. Finally, the rationality and feasibility of the proposed model were verified through case study. The research results show that the improved isolated forest method combined with K-Means++ can accurately determine the threshold value of anomaly scoring and then detect the anomalous data. AUC of the proposed model is respectively 29.7% and 5.3% higher than that of the models only considering traffic flow and traditional isolated forest models. Compared with other commonly used LOF, ABOD, and OCSVM methods, AUC of the proposed model has improved. The proposed model has a significant improvement in accuracy and better applicability in detecting abnormal traffic flow data, which can provide traffic condition detection support for traffic management departments and improve traffic management efficiency. References | Related Articles | Metrics

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Car-Following Characteristics of Human-Machine Mixed Driving Traffic Flow in Rainy Weather FU Chenghong, LI Gaowei, GAO Liangpeng 2024, 43(5): 70-77.  DOI: 10.3969/j.issn.1674-0696.2024.05.10 Abstract ( )   PDF (8298KB) ( )   In order to reveal the car-following characteristics of human-machine mixed driving traffic flow in rainy weather, starting from analyzing the impact of rainfall on driving, parameters such as road adhesion coefficient and driving visibility were introduced to improve Gipps safety distance and driving acceleration limitation. Cellular automata models were established for different car following modes, and simulation experiments were designed to explore the car-following characteristics of human-machine hybrid traffic flow under the dual effects of rainfall intensity and permeability. The numerical simulation results show that: the penetration rate on rainy days is positively correlated with traffic capacity, but when the penetration rate is below 0.25, the impact of connected and autonomous vehicle (CAV) on the average speed, critical density, and traffic capacity of mixed traffic flow is limited. When the rainfall intensity is higher than 0.3 mm/min, as the rainfall intensity increases, the car-following degradation of CAV will be exacerbated, which significantly reduces the free speed, critical speed, and traffic capacity of the mixed traffic flow. Under light rain conditions, a penetration rate of about 0.1 can compensate for the loss of traffic capacity caused by rainfall. In the rain intensity range from moderate to heavy rain, for every 0.1mm/min increase of rain intensity, the corresponding increase in penetration rate is 0.1. The traffic capacity of the road section can be restored to a level equivalent to that of pure human-driving traffic flow on sunny days. References | Related Articles | Metrics

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Driving Safety Evaluation Method for Continuous Downhill Section of Mountainous Expressway Based on Longitudinal-Transverse Combination ZHANG Chi1,2, WANG Xiru1, XIANG Yujie3, GAO Yanyang1, RAN Guangjiong4 2024, 43(5): 78-90.  DOI: 10.3969/j.issn.1674-0696.2024.05.11 Abstract ( )   PDF (7851KB) ( )   Subjected to geographical and economic constraints, the construction of mountainous expressways inevitably involves continuous downhill sections, among which the longitudinal-transverse combination section places higher demands on vehicle stability and safety. In order to analyze the driving safety in continuous downhill sections of mountainous expressways, a driving simulation experiment was constructed at a design speed of 80km/h at different positions and under different longitudinal-transverse combination conditions in a continuous downhill section by utilizing the data from a southwestern mountainous expressway. The comprehensive evaluation index was derived according to psychological data of drivers, vehicle speed variation data and lateral deviation data. Subsequently, a correlation analysis between the comprehensive evaluation index and the horizontal curve radius and longitudinal slope was carried out. Then, the threshold value was divided and evaluated through the cumulative frequency graph. A driving safety evaluation method for continuous downhill sections based on longitudinal-transverse combinations was proposed, and based on the proposed evaluation method, the recommended values for the longitudinal-transverse combinations design at the crest, middle, and bottom of slope of the continuous downhill section were proposed. Finally, the proposed evaluation method was applied and validated by taking a certain expressway in the southwestern mountainous region as an example. The research results indicate that the proposed method can serve as an effective reference for evaluating the driving safety of continuous downhill sections of expressways. References | Related Articles | Metrics

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Safety Evaluation of Road Dangerous Goods Transport Vehicle Parking Lot Based on Improved ALARP Risk Matrix ZENG Chao1, 2, LIN Like1, YU Li2 2024, 43(5): 91-98.  DOI: 10.3969/j.issn.1674-0696.2024.05.12 Abstract ( )   PDF (1970KB) ( )   In order to evaluate the safety level of parking lots for dangerous goods transport vehicles and reduce the risk of parking of dangerous goods vehicles, a safety evaluation method of parking lots for dangerous goods transport vehicles based on improved ALARP risk matrix was proposed. Firstly, based on the statistical data of accident cases, a safety risk rating index system for dedicated parking lots for dangerous goods transportation vehicles was constructed through causal analysis, fault tree construction, indicator preliminary selection, and reliability and validity testing. Secondly, combined with Bayesian network, analytic hierarchy method, fuzzy comprehensive evaluation method and improved ALARP risk matrix method, the safety risk evaluation model of dedicated parking lots for dangerous goods transportation vehicles was proposed. Thirdly, on the basis of considering the possibility of known risks and the quantification results of risk losses, the quantitative value and evaluation level of the total risk evaluation of dedicated parking lots were obtained based on the improved LARP risk matrix. Finally, the validation analysis was conducted by taking a dedicated parking lot for dangerous goods transportation vehicles in Chongqing as an example. The validation results show that the evaluation results obtained by the proposed method are highly consistent with the actual situation. References | Related Articles | Metrics

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Influencing Factors on the Use of Bus by Urban Car Users HE Mingwei1, NA Jingli1, ZHU Quan2, XUN Limei1 2024, 43(5): 99-105.  DOI: 10.3969/j.issn.1674-0696.2024.05.13 Abstract ( )   PDF (2634KB) ( )   Guiding car users to use bus can help alleviate urban traffic congestion and promote energy conservation and emission reduction in the transportation field. Using travel survey data for car users in Kunming City, a random forest model was employed to explore the impact of built environment, bus service quality and individual socio-economic attributes on the use of bus by car users. Research indicates that the built environment is the most important factor influencing the use of bus by car users, with a relative importance sum of 53.7%. Road network density, land use mix, residential location, and the number of bus stops are closely related to the use of bus by car users. Individual socio-economic attributes have a relative importance sum of 24.9%, with the family income variable having the highest relative importance (5.2%). The sum of the relative importance of bus service quality is 21.4%, which is convenience (5.8%), comfort (5.6%), reliability (5.2%) and safety (4.8%), respectively. The impact of the built environment on the use of bus by car users is nonlinear, and there are differences in the nonlinear effects between car users with different income levels. The research results contribute to a better understanding of the bus usage behavior by car users, thus the targeted strategies will be adopted to promote their use of buses. References | Related Articles | Metrics

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Ideal Transmission Ratio Control Strategy and Optimization of the Steering-by-Wire System YAN Chunli, WANG Yunsheng 2024, 43(5): 106-112.  DOI: 10.3969/j.issn.1674-0696.2024.05.14 Abstract ( )   PDF (4275KB) ( )   In order to design the steering-by-wire system that met the requirements of handling stability, an ideal transmission ratio control strategy that could adapt to different vehicle speed conditions was proposed. Based on the transmission ratio with constant steady-state yaw rate gain, three speed ranges such as low-speed range, medium-speed range and high-speed range were set. Based on the constant steady-state yaw rate gain in parameter fitting and constant steering gain control method, the ideal transmission ratio of low-speed range and medium-speed range was designed. Considering the influence of nonlinear factors such as friction characteristics in the high-speed range, fuzzy control was used to design the ideal transmission ratio of the steering-by-wire system. And the effectiveness of the ideal transmission ratio control strategy designed at different vehicle speeds was analyzed through Carsim and Simulink simulations. The research results show that in the low-speed range, the steering motion characteristics of the vehicle are significantly improved, enhancing the vehicles steering sensitivity. In the medium-speed range, the vehicles steering response follows well and responds faster. In the high-speed range, the steering stability of the vehicle during driving is significantly improved. References | Related Articles | Metrics

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Segmented Pose Estimation Method for Vehicle Steering State during Parking LI Chenxu1, JIANG Haobin2, MA Shidian2, HOU Tong1 2024, 43(5): 113-123.  DOI: 10.3969/j.issn.1674-0696.2024.05.15 Abstract ( )   PDF (4088KB) ( )   In order to solve the problem that nonlinear factors of steering system affected the accuracy of vehicle pose estimation during parking, a segmented pose estimation method based on vehicle steering state was proposed to improve the accuracy of vehicle pose estimation during automatic parking. Firstly, the error sources of the vehicle kinematic trajectory prediction positioning method were analyzed through experiments, and the influence of nonlinear factors in the steering process on the accuracy of vehicle pose calculation during parking was determined. Secondly, the segmented pose estimation model based on vehicle steering state was designed. LSTM was used to classify the steering state in real time, the hybrid model was trained separately for pose estimation, and posterior correction on the classification results and pose estimation results were carried out. Then, the data set of vehicle transverse and longitudinal displacement under parking condition was constructed. The data set was used for training the established model and offline testing. Finally, Python was used to build an online test platform to test the pose estimation of the proposed model, and a comparative experiment was carried out. The test results show that the European distance error of the vehicle can be controlled within 10 cm and the heading angle error can be controlled within 1° during parking through the proposed method. The segmented pose estimation method based on vehicle steering state can effectively improve the accuracy of vehicle pose estimation during parking and has relatively higher real-time performance and better robustness. References | Related Articles | Metrics

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Rolling Bearing Life State Recognition Based on Deep Convolutional Autoencoder and Multi-scale Residual Shrinkage Network PAN Xuejiao1, 2, DONG Shaojiang2, ZHOU Cunfagn2, XIAO Jiafeng2, SONG Kai3 2024, 43(5): 124-132.  DOI: 10.3969/j.issn.1674-0696.2024.05.16 Abstract ( )   PDF (3434KB) ( )   Aiming at the difficulty of early fault identification and accurate evaluation of degradation performance of rolling bearings, the life state identification method based on deep convolutional autoencoder (DCAE) and multi-scale residual shrinkage network (MSRSN) for the rolling bearings was proposed. Firstly, in order to obtain clear fault characteristic frequency and frequency multiplier, the original data samples were converted into the envelope spectrum input deep convolutional autoencoder to realize the automatic extraction and expression of bearing life state features, and the multidimensional scaling (MDS) algorithm was used to reduce the life state features to obtain low-dimensional features. Then the Euclidean distance (ED) between samples in the low-dimensional feature space was calculated, which was the evaluation index of bearing performance degradation. Secondly, in order to comprehensively extract the bearing performance degradation characteristics, an improved multi-scale residual shrinkage network recognition model was proposed, and a new activation scheme combining ReLU and DropBlock regularization was developed to enhance the noise resistance of the model. Finally, the proposed method and the comparison method were applied to the bearing life experiment data. The experiment results show that the proposed performance degradation evaluation index can accurately identify the starting point of bearing performance degradation and describe the trend of bearing degradation. The improved multi-scale residual shrinkage network recognition model can accurately identify the bearing life state with an average recognition rate of 91.75% in the SSNR=-4~6 dB environment. The practicability and effectiveness of the proposed method are verified. References | Related Articles | Metrics