Purpose-The rapid development of China’s railway construction has led to an increase in data generated by the high-speed rail(HSR)catenary system.Traditional management methods struggle with challenges such as poor i...Purpose-The rapid development of China’s railway construction has led to an increase in data generated by the high-speed rail(HSR)catenary system.Traditional management methods struggle with challenges such as poor information sharing,disconnected business applications and insufficient intelligence throughout the lifecycle.This study aims to address these issues by applying building information modeling(BIM)technology to improve lifecycle management efficiency for HSR catenary systems.Design/methodology/approach-Based on the lifecycle management needs of catenary engineering,incorporating the intelligent HSR“Model-Data Driven,Axis-Plane Coordination”philosophy,this paper constructs a BIM-based lifecycle management framework for HSR catenary engineering.Findings-This study investigates the full-process lifecycle management of the catenary system across various stages of design,manufacture,construction and operation,exploring integrated BIM models and data transmission methods,along with key technologies for BIM model transmission,transformation and lightweighting.Originality/value-This study establishes a lossless information circulation and transmission system for HSR catenary lifecycle management.Multi-stage applications are verified through the construction of the Chongqing-Kunming High-Speed Railway,comprehensive advancing the intelligent promotion and highquality development of catenary engineering.展开更多
Purpose–Adding an appropriate pre-sag to the geometry of simple catenary systems for electric railways can improve their performance in dynamic interaction with the pantographs of trains operating under them.The valu...Purpose–Adding an appropriate pre-sag to the geometry of simple catenary systems for electric railways can improve their performance in dynamic interaction with the pantographs of trains operating under them.The value of pre-sag can be obtained by empirical approximation or computationally expensive optimisation.This study aims to define a simple but accurate method to determine a suitable pre-sag without dynamic simulations and to find its limitations.Design/methodology/approach–A quasi-static method to determine the ideal value of pre-sag is described based on elasticity variations.It considers variations of the static contact force.The limits of this method are investigated by comparing it to a parametric dynamic simulation study.In the dynamic simulation,an optimal level of pre-sag is identified for each contact force level.The influence of the speed in the dynamic simulation results is expressed in two parameters:the quasi-static influence in the mean contact force and the dynamic influence in the ratio between the vehicle speed and the wave propagation speed in the contact wire.Findings–The comparison between the suggested method and the dynamic simulations shows a high consistency up to a speed limit of around 40%of the wave propagation speed.The best agreement with the dynamic results is achieved by calculating the optimal pre-sag based on the absolute elasticity variation.Practical implications–The simplified approach for determining the pre-sag is valid for low-speed applications,such as suburban railway lines.For these cases,a highly suitable geometry can be obtained with the suggested method,meaning a significantly reduced computational effort.As a case study for this work,the results are applied to a Swedish suburban rail line upgrade case.Originality/value–The static uplift force is added as a varied parameter in dynamic simulations.The shift in system behaviour from low to high dynamics is described,and how the benefits from pre-sag are visible and then disappear.The limit value of the low-dynamics regime is identified to be 40%.展开更多
In this paper,a modeling method for a pantograph-catenary system is put forward to investigate the dynamic contact behavior in space,taking into consideration of the appearance characteristics of the contact surfaces ...In this paper,a modeling method for a pantograph-catenary system is put forward to investigate the dynamic contact behavior in space,taking into consideration of the appearance characteristics of the contact surfaces of the pantograph and catenary.The dynamic performance of the pantograph-catenary system,including contact forces,accelerations,and the corresponding spectra,is analyzed.Furthermore,with the modeling method,the influences of contact wire irregularity and the vibration caused by the front pantograph on the rear pantograph for a pantograph-catenary system with double pantographs are investigated.The results show that the appearance characteristics of the contact surfaces play an important role in the dynamic contact behavior.The appearance characteristics should be considered to reasonably evaluate the dynamic performance of the pantograph-catenary system.展开更多
The paper is aimed at developing an optimized design of the pantograph and catenary system with double pantographs at a speed of 350 km/h for the Wuhan-Guangzhou high-speed railway. First, the pantograph and catenary ...The paper is aimed at developing an optimized design of the pantograph and catenary system with double pantographs at a speed of 350 km/h for the Wuhan-Guangzhou high-speed railway. First, the pantograph and catenary system for the Beijing-Tianjin high-speed railway was analyzed to verify whether its design objective could be fulfilled. It shows that the system is not able to satisfy the requirement of a sustainable running speed of 350 km/h. Then a new scheme for the pantograph and catenary system is proposed through optimization and renovation of the structure and parameters of the pantograph and catenary system, including the suspension type of the catenary, tension of the contact wire, and space between two pantographs. Finally, the dynamic performance of the new system was verified by simulation and line testing. The results show that the new scheme of the pantograph and catenary system for the Wuhan- Guangzhou high-speed railway is acceptable, in which the steady contact between the rear pantograph and the catenary at the space of 200 m can be maintained to ensure the current-collection quality. A current collection with double pantographs at a speed of 350 km/h or higher can be achieved.展开更多
A multi-objective optimization model considering both reliability and maintenance cost is proposed to solve the contradiction between reliability and maintenance cost in high-speed railway catenary system maintenance ...A multi-objective optimization model considering both reliability and maintenance cost is proposed to solve the contradiction between reliability and maintenance cost in high-speed railway catenary system maintenance activities.The non-dominated sorting genetic algorithm 2(NSGA2)is applied to multi-objective optimization,and the optimization result is a set of Pareto solutions.Firstly,multistate failure mode analysis is conducted for the main devices leading to the failure of catenary,and then the reliability and failure mode of the whole catenary system is analyzed.The mathematical relationship between system reliability and maintenance cost is derived considering the existing catenary preventive maintenance mode to improve the reliability of the system.Secondly,an improved NSGA2(INSGA2)is proposed,which strengths population diversity by improving selection operator,and introduces local search strategy to ensure that population distribution is more uniform.The comparison results of the two algorithms before and after improvement on the zero-ductility transition(ZDT)series functions show that the population diversity is better and the solution is more uniform using INSGA2.Finally,the INSGA2 is applied to multi-objective optimization of system reliability and maintenance cost in different maintenance periods.The decision-makers can choose the reasonable solutions as the maintenance plans in the optimization results by weighing the relationship between the system reliability and the maintenance cost.The selected maintenance plans can ensure the lowest maintenance cost while the system reliability is as high as possible.展开更多
The fatigue load spectrum and operation life evaluation of key components in the catenary system under the high speed train running condition were investigated.Firstly,based on the catenary model and pantograph model,...The fatigue load spectrum and operation life evaluation of key components in the catenary system under the high speed train running condition were investigated.Firstly,based on the catenary model and pantograph model,the couple dynamic equations of pantograph–catenary were built with the Lagrange’s method;then the dynamic contact force was obtained by the Newmark method at the train speeds of 250,280 and 300 km/h,respectively.Secondly,the finite element model(FEM)of one anchor section’s catenary was built to analyze its transient response under the contact force as train running;then the loading time history of messenger wire base,steady arm,registration tube,oblique cantilever,and straight cantilever were extracted.Finally,the key components’fatigue spectrum was carried out by the rain-flow counting method,and operation life was estimated in consideration of such coefficients,such as stress concentration,shape and dimension,surface treatment.The results show that the fatigue life of the catenary system reduces with the increasing of train speed;specifically,the evaluated fatigue life of the steady arm is shorter than other components.展开更多
Analyzed are the merits and demerits of catenary mooring system and taut mooring system, which are commonly used nowadays. As falling somewhere between these two systems, a new mooring system integrating catenary with...Analyzed are the merits and demerits of catenary mooring system and taut mooring system, which are commonly used nowadays. As falling somewhere between these two systems, a new mooring system integrating catenary with taut mooring is proposed. In order to expound and prove the advantages of this new system, the motion performance of a semi-submersible platform is simulated by employing full time domain coupled analysis method. A comparison of the result of new mooting system with that of taut mooring system shows that the movement of the platform using the new type mooting system is smaller than that using the taut mooring system, which ensures a better working condition. Furthermore, the new mooring system is also compatible with the characteristics of catenary mooting system, which eliminates the requirement of anti-uplift capacity of the anchors.展开更多
This paper presents a non-contact measurement of the realistic catenary geometry deviation in the Norwegian railway network through a laser rangefinder.The random geometry deviation is included in the catenary model t...This paper presents a non-contact measurement of the realistic catenary geometry deviation in the Norwegian railway network through a laser rangefinder.The random geometry deviation is included in the catenary model to investigate its effect on the pantograph–catenary interaction.The dispersion of the longitudinal deviation is assumed to follow a Gaussian distribution.A power spectrum density represents the vertical deviation in the contact wire.Based on the Monte Carlo method,several geometry deviation samples are generated and included in the catenary model.A lumped mass pantograph with flexible collectors is employed to reproduce the high-frequency behaviours.The stochastic analysis results indicate that the catenary geometry deviation causes a significant dispersion of the pantograph–catenary interaction response.The contact force standard deviations measured by the inspection vehicle are within the scope of the simulation results.A critical cut-off frequency that covers 1/16 of the dropper interval is suggested to fully describe the effect of the catenary geometry deviation on the contact force.The statistical minimum contact force is recommended to be modified according to the tolerant contact loss rate at high frequency.An unpleasant interaction performance of the pantograph–catenary can be expected at the catenary top speed when the random catenary geometry deviation is included.展开更多
With the floating structures pushing their activities to the ultra-deep water, model tests have presented a challenge due to the limitation of the existing wave basins. Therefore, the concept of truncated mooring syst...With the floating structures pushing their activities to the ultra-deep water, model tests have presented a challenge due to the limitation of the existing wave basins. Therefore, the concept of truncated mooring system is implemented to replace the full depth mooring system in the model tests, which aims to have the same dynamic responses as the full depth system. The truncated mooring system plays such a significant role that extra attention should be paid to the mooring systems with large truncation factor. Three different types of large truncation factor mooring system are being employed in the simulations, including the homogenously truncated mooring system, non-homogenously truncated mooring system and simplified truncated mooring system. A catenary moored semi-submersible operating at 1000 m water depth is presented. In addition, truncated mooring systems are proposed at the truncated water depth of 200 m. In order to explore the applicability of these truncated mooring systems, numerical simulations of the platform’s surge free decay interacting with three different styles of truncated mooring systems are studied in calm water. Furthermore, the mooring-induced damping of the truncated mooring systems is simulated in the regular wave. Finally, the platform motion responses and mooring line dynamics are simulated in irregular wave. All these simulations are implemented by employing full time domain coupled dynamic analysis, and the results are compared with those of the full depth simulations in the same cases. The results show that the mooring-induced damping plays a significant role in platform motion responses, and all truncated mooring systems are suitable for model tests with appropriate truncated mooring line diameters. However, a large diameter is needed for simplified truncated mooring lines. The suggestions are given to the selection of truncated mooring system for different situations as well as to the truncated mooring design criteria.展开更多
The multi-robot coordinated lifting system is an unconstrained system with a rigid and flexible coupling.The deformation of the flexible rope causes errors in the movement trajectory of the lifting system.Based on the...The multi-robot coordinated lifting system is an unconstrained system with a rigid and flexible coupling.The deformation of the flexible rope causes errors in the movement trajectory of the lifting system.Based on the kinematic and dynamic analysis of the lifting system,the elastic catenary mod-el considering the elasticity and mass of the flexible rope is established,and the effect of the deform-ation of the flexible rope on the position and posture of the suspended object is analyzed.According to the deformation of flexible rope,a real-time trajectory compensation method is proposed based on the compensation principle of position and posture.Under the lifting task of the low-speed move-ment,this is compared with that of the system which neglects the deformation of the flexible rope.The trajectoy of the lifting system considering the deformation of flexible rope.The results show that the mass and elasticity of the flexible rope can not be neglected.Meanwhile,the proposed trajectory compensation method can improve the movement accuracy of the lifting system,which verifies the ef-fectiveness of this compensation method.The research results provide the basis for trajectory plan-ning and coordinated control of the lifting system。展开更多
Steel catenary riser represents the pioneering riser technology implemented in China’s deep-sea oil and gas opera-tions.Given the complex mechanical conditions of the riser,extensive research has been conducted on it...Steel catenary riser represents the pioneering riser technology implemented in China’s deep-sea oil and gas opera-tions.Given the complex mechanical conditions of the riser,extensive research has been conducted on its dynamic analysis and structural design.This study investigates a deep-sea oil and gas field by developing a coupled model of a semi-submersible platform and steel catenary riser to analyze it mechanical behavior under extreme marine condi-tions.Through multi-objective optimization methodology,the study compares and analyzes suspension point tension and touchdown point stress under various conditions by modifying the suspension position,suspension angle,and catenary length.The optimal configuration parameters were determined:a suspension angle of 12°,suspension position in the southwest direction of the column,and a catenary length of approximately 2000 m.These findings elucidate the impact of configuration parameters on riser dynamic response and establish reasonable parameter layout ranges for adverse sea conditions,offering valuable optimization strategies for steel catenary riser deployment in domestic deep-sea oil and gas fields.展开更多
An experimental analysis of the slug-induced vibration(SIV)of a flexible catenary riser with an aspect ratio of 130 is reported in this work.The vibration responses and internal slug flow details at different gas-liqu...An experimental analysis of the slug-induced vibration(SIV)of a flexible catenary riser with an aspect ratio of 130 is reported in this work.The vibration responses and internal slug flow details at different gas-liquid ratios(Q_(g)/Q_(l))and mixture velocities(vm)are non-intrusively and simultaneously captured by high-speed cameras.Both the in-plane and out-of-plane responses of the catenary riser are excited in all considered cases.The slug flow characteristics,including translational velocities,slug lengths,recurrence frequencies,and pressure variations,are analyzed and dis-cussed,as are the dynamic responses of the riser in terms of the amplitudes,space-varying frequency,and modal weight.The dominant modal response based on the root-mean-square amplitude profiles does not match that based on the dominant frequency.Three mode switching types are identified based on the RMS amplitude profiles and the dominant frequency.When vm is small,no mode switching(NMS)is observed in either the in-plane or out-of-plane responses.For mode switching I(MS I),the switching between the first and second modes in the in-plane response is induced by slug flow with different recurrence frequencies in cases of large Q_(g)/Q_(l).However,there is no mode switching in the out-of-plane response.The switching between the first and third modes for the in-plane response and the second and fourth modes for the out-of-plane response(MS II)occurs in cases of relatively high vm and low Q_(g)/Q_(l).展开更多
As oil and gas exploration moves into deeper waters,marine risers are subjected to increasingly complex service conditions,including vessel motions,ocean currents,seabed-soil interactions,and internal flow effects.Thi...As oil and gas exploration moves into deeper waters,marine risers are subjected to increasingly complex service conditions,including vessel motions,ocean currents,seabed-soil interactions,and internal flow effects.This work establishes a dynamic behavior model of steel catenary risers(SCRs)with varying curvatures subjected to internal flow and external currents and considers the effects of pipe-soil interactions on the curvature profile.The governing equation is solved via the generalized integral transform technique(GITT),which yields a semi-analytical solution of a high-order nonlinear partial differential equation.Parametric studies are then performed to analyze the effects of varying curvature on the vibration frequency and amplitude of SCRs.The vibration frequency and amplitude increase with the touchdown angle and hang-off angle,although the effect of the hang-off angle is negligible.Additionally,as the curvature increases along the centerline axis,the position of the maximum amplitude of the SCR moves upward.展开更多
Purpose-As a key structure in the railway power supply system,the overhead catenary pillar carries the entire weight and dynamic load of the contact suspension device and supporting equipment.Its stability and reliabi...Purpose-As a key structure in the railway power supply system,the overhead catenary pillar carries the entire weight and dynamic load of the contact suspension device and supporting equipment.Its stability and reliability are directly related to the operational safety and efficiency of electrified railways.Design/methodology/approach-Regarding the phenomenon of abnormal shedding of coating above the support under the cantilever of the catenary pillar in the track running line,a three-dimensional model is established to analyse the rigid cantilever type catenary and the force analysis of the cantilever part is carried out by using ABAQUS to calculate the contact force of the bow network under different running speeds of the highspeed train.The load is applied at the locator end of the simplified model of the cantilever to get the support reaction force at the connection between the cantilever and the support.Findings-The support reaction force is applied as a load to the three-dimensional model of the pillar support;the stress cloud and the stress extreme value of 86.14 MPa are obtained for the pillar and the support part and the fatigue life of the pillar’s key parts is calculated to be 12.02 years,respectively.Originality/value-The upper part of the lower support of the high-speed rail catenary pillar is subjected to the alternating load transmitted by the bow net,which causes the fretting damage at this position,resulting in the abnormal peeling of the coating on the upper part of the lower support.Through combining the ABAQUS analysis with the structural characteristics and operating conditions of the catenary system,the main causes of component failure are determined.展开更多
This study proposed a novel experimental platform to conduct dynamic loading tests of a truncated model steel catenary riser(SCR)within the touchdown zone(TDZ).The facilities of the platform,including a soil tank,a lo...This study proposed a novel experimental platform to conduct dynamic loading tests of a truncated model steel catenary riser(SCR)within the touchdown zone(TDZ).The facilities of the platform,including a soil tank,a loading system,and a soil stirring system,are introduced in detail.A steel pipe with the same diameter as the in situ SCR has been used in the laboratory tests to investigate the vertical motion of the pipe and the effect of the trench on the lateral motion.As the amplitude of the vertical motion increases,the depth of the trench deepens,the bending moment range increases,and the excess pore water pressure at the bottom of the pipeline first accumulates and then dissipates during loading.The development trend of the trench depth and the influence of the soil strength on the SCR bending moment are also studied.During the test,a seabed trench develops,and its shape is similar to that of the in situ trench.展开更多
Steel catenary risers （SCR） have become an enabling technology for deepwater environments. A comprehensive review was conducted on recent research that examined interactions between deepwater steel catenary risers a...Steel catenary risers （SCR） have become an enabling technology for deepwater environments. A comprehensive review was conducted on recent research that examined interactions between deepwater steel catenary risers and soft clay seabeds. This included the STRIDE （steel risers in deepwater environments） and CARISIMA （catenary riser soil interaction model for global riser analysis） joint jndustry jrogram＇s test data as well as information from existing papers.展开更多
A numerical model of the steel catenary riser(SCR) is built based on the slender rod model. The slender rod model,which describes the behavior of the slender riser in terms of the center line position, can solve the g...A numerical model of the steel catenary riser(SCR) is built based on the slender rod model. The slender rod model,which describes the behavior of the slender riser in terms of the center line position, can solve the geometrical nonlinearity effectively. In a marine environment, the SCR is under the combined internal flow and external loads,such as wave and current. A general analysis considers only the inertial force and the drag force caused by the wave and current. However, the internal flow has an effect on the SCR; it is essential to explore the dynamic response of the SCR with the internal flow. The SCR also suffers the lift force and the fluctuating drag force because of the current. Finite element method is utilized to solve the motion equations. The effects of the internal flow, wave and current on the dynamic response of the SCR are considered. The results indicate that the increase of the internal flow density leads to the decrease of the displacement of the SCR, while the internal flow velocity has little effect on the SCR. The displacement of the SCR increases with the increase of the wave height and period. And the increasing wave period results in an increase in the vibration period of the SCR. The current velocity changes the displacements of the SCR in x-and z-directions. The vibration frequency of the SCR in y-direction increases with the increase of the current velocity.展开更多
This paper presents fatigue characteristic analysis of a deepwater steel catenary riser （SCR） under ambient excitations. The SCR involves complex nonlinear dynamic behaviors, especially at the touchdown point （TDP...This paper presents fatigue characteristic analysis of a deepwater steel catenary riser （SCR） under ambient excitations. The SCR involves complex nonlinear dynamic behaviors, especially at the touchdown point （TDP） where the riser first touches the seafloor. Owing to the significant interaction with soil, the touchdown zone is difficnlt to be modeled. Based on Lumped-Mass method and P-y curve, nonlinear springs are used to simulate the SCR-seabed coupled interaction. In case studies, an SCR＇s dynamic features have been obtained by transient analysis and the structure fatigue assessment has been carried out by S-N approach. The comparative analysis shows that the TDP is the key location where soil-riser interaction rises steeply and minimum fatigue life occurs. Parameters such as ocean environment loads, vessel motions, riser material and geometric parameters are discussed. The results indicate that the vessel motion is the principal factor for the structure fatigue life distribution.展开更多
Rod insulators are vital parts of the catenary of high speed railways(HSRs).There are many different catenary insulators,and the background of the insulator image is complicated.It is difficult to recognise insulators...Rod insulators are vital parts of the catenary of high speed railways(HSRs).There are many different catenary insulators,and the background of the insulator image is complicated.It is difficult to recognise insulators and detect defects automatically.In this paper,we propose a catenary intelligent defect detection algorithm based on Mask region-convolutional neural network(R-CNN)and an image processing model.Vertical projection technology is used to achieve single shed positioning and precise cutting of the insulator.Gradient,texture,and gray feature fusion(GTGFF)and a K-means clustering analysis model(KCAM)are proposed to detect broken insulators,dirt,foreign bodies,and flashover.Using this model,insulator recognition and defect detection can achieve a high recall rate and accuracy,and generalized defect detection.The algorithm is tested and verified on a dataset of realistic insulator images,and the accuracy and reliability of the algorithm satisfy current requirements for HSR catenary automatic inspection and intelligent maintenance.展开更多
To solve the design problem of transformer composed of non-resonant structure in ultrasonic gear-honing, force coupling conditions for moderately thick annular plate （MTAP） and catenary horn are proposed, and the fr...To solve the design problem of transformer composed of non-resonant structure in ultrasonic gear-honing, force coupling conditions for moderately thick annular plate （MTAP） and catenary horn are proposed, and the frequency equations of the transformer, which consist of an MTAP and a catenary horn, are derived based on Mindlin＇s theory. The design parameters of the transformer were obtained by solving the frequency equations with the help of MATLAB, and its mode and frequency were deduced by the modal analysis of finite element method （FEM）, which are consistent with the theoretical design demands. The transformer design can be extended from system with thin annular plate to that with MTAP as the theoretical method by the simulation analysis of various ratios of the thickness to radius.展开更多
基金supported by China Academy of Railway Sciences Foundation(Research on Multi Agent Collaborative Mechanism of Intelligent High Speed Rail System Based on Complex Adaptive System Theory,Grant 2023YJ392).
文摘Purpose-The rapid development of China’s railway construction has led to an increase in data generated by the high-speed rail(HSR)catenary system.Traditional management methods struggle with challenges such as poor information sharing,disconnected business applications and insufficient intelligence throughout the lifecycle.This study aims to address these issues by applying building information modeling(BIM)technology to improve lifecycle management efficiency for HSR catenary systems.Design/methodology/approach-Based on the lifecycle management needs of catenary engineering,incorporating the intelligent HSR“Model-Data Driven,Axis-Plane Coordination”philosophy,this paper constructs a BIM-based lifecycle management framework for HSR catenary engineering.Findings-This study investigates the full-process lifecycle management of the catenary system across various stages of design,manufacture,construction and operation,exploring integrated BIM models and data transmission methods,along with key technologies for BIM model transmission,transformation and lightweighting.Originality/value-This study establishes a lossless information circulation and transmission system for HSR catenary lifecycle management.Multi-stage applications are verified through the construction of the Chongqing-Kunming High-Speed Railway,comprehensive advancing the intelligent promotion and highquality development of catenary engineering.
基金Trafikföorvaltningen Region Stockholm and Trafikverket for funding and supporting this study.
文摘Purpose–Adding an appropriate pre-sag to the geometry of simple catenary systems for electric railways can improve their performance in dynamic interaction with the pantographs of trains operating under them.The value of pre-sag can be obtained by empirical approximation or computationally expensive optimisation.This study aims to define a simple but accurate method to determine a suitable pre-sag without dynamic simulations and to find its limitations.Design/methodology/approach–A quasi-static method to determine the ideal value of pre-sag is described based on elasticity variations.It considers variations of the static contact force.The limits of this method are investigated by comparing it to a parametric dynamic simulation study.In the dynamic simulation,an optimal level of pre-sag is identified for each contact force level.The influence of the speed in the dynamic simulation results is expressed in two parameters:the quasi-static influence in the mean contact force and the dynamic influence in the ratio between the vehicle speed and the wave propagation speed in the contact wire.Findings–The comparison between the suggested method and the dynamic simulations shows a high consistency up to a speed limit of around 40%of the wave propagation speed.The best agreement with the dynamic results is achieved by calculating the optimal pre-sag based on the absolute elasticity variation.Practical implications–The simplified approach for determining the pre-sag is valid for low-speed applications,such as suburban railway lines.For these cases,a highly suitable geometry can be obtained with the suggested method,meaning a significantly reduced computational effort.As a case study for this work,the results are applied to a Swedish suburban rail line upgrade case.Originality/value–The static uplift force is added as a varied parameter in dynamic simulations.The shift in system behaviour from low to high dynamics is described,and how the benefits from pre-sag are visible and then disappear.The limit value of the low-dynamics regime is identified to be 40%.
基金Project supported by the National Natural Science Foundation of China (No.51075341)the National Basic Research Program (973) of China (No.2011CB711105)
文摘In this paper,a modeling method for a pantograph-catenary system is put forward to investigate the dynamic contact behavior in space,taking into consideration of the appearance characteristics of the contact surfaces of the pantograph and catenary.The dynamic performance of the pantograph-catenary system,including contact forces,accelerations,and the corresponding spectra,is analyzed.Furthermore,with the modeling method,the influences of contact wire irregularity and the vibration caused by the front pantograph on the rear pantograph for a pantograph-catenary system with double pantographs are investigated.The results show that the appearance characteristics of the contact surfaces play an important role in the dynamic contact behavior.The appearance characteristics should be considered to reasonably evaluate the dynamic performance of the pantograph-catenary system.
文摘The paper is aimed at developing an optimized design of the pantograph and catenary system with double pantographs at a speed of 350 km/h for the Wuhan-Guangzhou high-speed railway. First, the pantograph and catenary system for the Beijing-Tianjin high-speed railway was analyzed to verify whether its design objective could be fulfilled. It shows that the system is not able to satisfy the requirement of a sustainable running speed of 350 km/h. Then a new scheme for the pantograph and catenary system is proposed through optimization and renovation of the structure and parameters of the pantograph and catenary system, including the suspension type of the catenary, tension of the contact wire, and space between two pantographs. Finally, the dynamic performance of the new system was verified by simulation and line testing. The results show that the new scheme of the pantograph and catenary system for the Wuhan- Guangzhou high-speed railway is acceptable, in which the steady contact between the rear pantograph and the catenary at the space of 200 m can be maintained to ensure the current-collection quality. A current collection with double pantographs at a speed of 350 km/h or higher can be achieved.
文摘A multi-objective optimization model considering both reliability and maintenance cost is proposed to solve the contradiction between reliability and maintenance cost in high-speed railway catenary system maintenance activities.The non-dominated sorting genetic algorithm 2(NSGA2)is applied to multi-objective optimization,and the optimization result is a set of Pareto solutions.Firstly,multistate failure mode analysis is conducted for the main devices leading to the failure of catenary,and then the reliability and failure mode of the whole catenary system is analyzed.The mathematical relationship between system reliability and maintenance cost is derived considering the existing catenary preventive maintenance mode to improve the reliability of the system.Secondly,an improved NSGA2(INSGA2)is proposed,which strengths population diversity by improving selection operator,and introduces local search strategy to ensure that population distribution is more uniform.The comparison results of the two algorithms before and after improvement on the zero-ductility transition(ZDT)series functions show that the population diversity is better and the solution is more uniform using INSGA2.Finally,the INSGA2 is applied to multi-objective optimization of system reliability and maintenance cost in different maintenance periods.The decision-makers can choose the reasonable solutions as the maintenance plans in the optimization results by weighing the relationship between the system reliability and the maintenance cost.The selected maintenance plans can ensure the lowest maintenance cost while the system reliability is as high as possible.
基金Project(51175383)supported by the National Natural Science Foundation of China(NSF)
文摘The fatigue load spectrum and operation life evaluation of key components in the catenary system under the high speed train running condition were investigated.Firstly,based on the catenary model and pantograph model,the couple dynamic equations of pantograph–catenary were built with the Lagrange’s method;then the dynamic contact force was obtained by the Newmark method at the train speeds of 250,280 and 300 km/h,respectively.Secondly,the finite element model(FEM)of one anchor section’s catenary was built to analyze its transient response under the contact force as train running;then the loading time history of messenger wire base,steady arm,registration tube,oblique cantilever,and straight cantilever were extracted.Finally,the key components’fatigue spectrum was carried out by the rain-flow counting method,and operation life was estimated in consideration of such coefficients,such as stress concentration,shape and dimension,surface treatment.The results show that the fatigue life of the catenary system reduces with the increasing of train speed;specifically,the evaluated fatigue life of the steady arm is shorter than other components.
基金supported by the National Natural Science Foundation of China (Grant No. 51079065)the Science and Technology Support Project Plan of Jiangsu Province (Grant No. BE2010159)A Project Funded by Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Analyzed are the merits and demerits of catenary mooring system and taut mooring system, which are commonly used nowadays. As falling somewhere between these two systems, a new mooring system integrating catenary with taut mooring is proposed. In order to expound and prove the advantages of this new system, the motion performance of a semi-submersible platform is simulated by employing full time domain coupled analysis method. A comparison of the result of new mooting system with that of taut mooring system shows that the movement of the platform using the new type mooting system is smaller than that using the taut mooring system, which ensures a better working condition. Furthermore, the new mooring system is also compatible with the characteristics of catenary mooting system, which eliminates the requirement of anti-uplift capacity of the anchors.
文摘This paper presents a non-contact measurement of the realistic catenary geometry deviation in the Norwegian railway network through a laser rangefinder.The random geometry deviation is included in the catenary model to investigate its effect on the pantograph–catenary interaction.The dispersion of the longitudinal deviation is assumed to follow a Gaussian distribution.A power spectrum density represents the vertical deviation in the contact wire.Based on the Monte Carlo method,several geometry deviation samples are generated and included in the catenary model.A lumped mass pantograph with flexible collectors is employed to reproduce the high-frequency behaviours.The stochastic analysis results indicate that the catenary geometry deviation causes a significant dispersion of the pantograph–catenary interaction response.The contact force standard deviations measured by the inspection vehicle are within the scope of the simulation results.A critical cut-off frequency that covers 1/16 of the dropper interval is suggested to fully describe the effect of the catenary geometry deviation on the contact force.The statistical minimum contact force is recommended to be modified according to the tolerant contact loss rate at high frequency.An unpleasant interaction performance of the pantograph–catenary can be expected at the catenary top speed when the random catenary geometry deviation is included.
基金financially supported by the National Natural Science Foundation of China(Grant No.51379095)
文摘With the floating structures pushing their activities to the ultra-deep water, model tests have presented a challenge due to the limitation of the existing wave basins. Therefore, the concept of truncated mooring system is implemented to replace the full depth mooring system in the model tests, which aims to have the same dynamic responses as the full depth system. The truncated mooring system plays such a significant role that extra attention should be paid to the mooring systems with large truncation factor. Three different types of large truncation factor mooring system are being employed in the simulations, including the homogenously truncated mooring system, non-homogenously truncated mooring system and simplified truncated mooring system. A catenary moored semi-submersible operating at 1000 m water depth is presented. In addition, truncated mooring systems are proposed at the truncated water depth of 200 m. In order to explore the applicability of these truncated mooring systems, numerical simulations of the platform’s surge free decay interacting with three different styles of truncated mooring systems are studied in calm water. Furthermore, the mooring-induced damping of the truncated mooring systems is simulated in the regular wave. Finally, the platform motion responses and mooring line dynamics are simulated in irregular wave. All these simulations are implemented by employing full time domain coupled dynamic analysis, and the results are compared with those of the full depth simulations in the same cases. The results show that the mooring-induced damping plays a significant role in platform motion responses, and all truncated mooring systems are suitable for model tests with appropriate truncated mooring line diameters. However, a large diameter is needed for simplified truncated mooring lines. The suggestions are given to the selection of truncated mooring system for different situations as well as to the truncated mooring design criteria.
基金the National Natural Science Foundation of China(No.51965032)the Natural Science Foundation of Gansu Province of China(No.22JR5RA319)+1 种基金the Science and Technology Foundation of Gansu Province of China(No.21YF5WA060)the Excellent Doctoral Student Foundation of Gansu Province of China(No.23JRRA842).
文摘The multi-robot coordinated lifting system is an unconstrained system with a rigid and flexible coupling.The deformation of the flexible rope causes errors in the movement trajectory of the lifting system.Based on the kinematic and dynamic analysis of the lifting system,the elastic catenary mod-el considering the elasticity and mass of the flexible rope is established,and the effect of the deform-ation of the flexible rope on the position and posture of the suspended object is analyzed.According to the deformation of flexible rope,a real-time trajectory compensation method is proposed based on the compensation principle of position and posture.Under the lifting task of the low-speed move-ment,this is compared with that of the system which neglects the deformation of the flexible rope.The trajectoy of the lifting system considering the deformation of flexible rope.The results show that the mass and elasticity of the flexible rope can not be neglected.Meanwhile,the proposed trajectory compensation method can improve the movement accuracy of the lifting system,which verifies the ef-fectiveness of this compensation method.The research results provide the basis for trajectory plan-ning and coordinated control of the lifting system。
基金financially supported by the National Key Research and Development Program of China(Grant No.2022YFC2806100)the National Natural Science Foundation of China(Grant Nos.U22B20126 and 52374020)+1 种基金Science Foundation of China University of Petroleum,Beijing(Grant No.2462025QNXZ009)Beijing Nova Program(Grant No.20250484913).
文摘Steel catenary riser represents the pioneering riser technology implemented in China’s deep-sea oil and gas opera-tions.Given the complex mechanical conditions of the riser,extensive research has been conducted on its dynamic analysis and structural design.This study investigates a deep-sea oil and gas field by developing a coupled model of a semi-submersible platform and steel catenary riser to analyze it mechanical behavior under extreme marine condi-tions.Through multi-objective optimization methodology,the study compares and analyzes suspension point tension and touchdown point stress under various conditions by modifying the suspension position,suspension angle,and catenary length.The optimal configuration parameters were determined:a suspension angle of 12°,suspension position in the southwest direction of the column,and a catenary length of approximately 2000 m.These findings elucidate the impact of configuration parameters on riser dynamic response and establish reasonable parameter layout ranges for adverse sea conditions,offering valuable optimization strategies for steel catenary riser deployment in domestic deep-sea oil and gas fields.
基金financially supported by the National Natural Science Foundation of China(Grant No.52301338)the Sichuan Science and Technology Program(Grant No.2024NSFSC0968).
文摘An experimental analysis of the slug-induced vibration(SIV)of a flexible catenary riser with an aspect ratio of 130 is reported in this work.The vibration responses and internal slug flow details at different gas-liquid ratios(Q_(g)/Q_(l))and mixture velocities(vm)are non-intrusively and simultaneously captured by high-speed cameras.Both the in-plane and out-of-plane responses of the catenary riser are excited in all considered cases.The slug flow characteristics,including translational velocities,slug lengths,recurrence frequencies,and pressure variations,are analyzed and dis-cussed,as are the dynamic responses of the riser in terms of the amplitudes,space-varying frequency,and modal weight.The dominant modal response based on the root-mean-square amplitude profiles does not match that based on the dominant frequency.Three mode switching types are identified based on the RMS amplitude profiles and the dominant frequency.When vm is small,no mode switching(NMS)is observed in either the in-plane or out-of-plane responses.For mode switching I(MS I),the switching between the first and second modes in the in-plane response is induced by slug flow with different recurrence frequencies in cases of large Q_(g)/Q_(l).However,there is no mode switching in the out-of-plane response.The switching between the first and third modes for the in-plane response and the second and fourth modes for the out-of-plane response(MS II)occurs in cases of relatively high vm and low Q_(g)/Q_(l).
基金financially supported by the National Natural Science Foundation of China(Grant No.52201312).
文摘As oil and gas exploration moves into deeper waters,marine risers are subjected to increasingly complex service conditions,including vessel motions,ocean currents,seabed-soil interactions,and internal flow effects.This work establishes a dynamic behavior model of steel catenary risers(SCRs)with varying curvatures subjected to internal flow and external currents and considers the effects of pipe-soil interactions on the curvature profile.The governing equation is solved via the generalized integral transform technique(GITT),which yields a semi-analytical solution of a high-order nonlinear partial differential equation.Parametric studies are then performed to analyze the effects of varying curvature on the vibration frequency and amplitude of SCRs.The vibration frequency and amplitude increase with the touchdown angle and hang-off angle,although the effect of the hang-off angle is negligible.Additionally,as the curvature increases along the centerline axis,the position of the maximum amplitude of the SCR moves upward.
基金Supported by the State Railway Administration of China(J2022G008).
文摘Purpose-As a key structure in the railway power supply system,the overhead catenary pillar carries the entire weight and dynamic load of the contact suspension device and supporting equipment.Its stability and reliability are directly related to the operational safety and efficiency of electrified railways.Design/methodology/approach-Regarding the phenomenon of abnormal shedding of coating above the support under the cantilever of the catenary pillar in the track running line,a three-dimensional model is established to analyse the rigid cantilever type catenary and the force analysis of the cantilever part is carried out by using ABAQUS to calculate the contact force of the bow network under different running speeds of the highspeed train.The load is applied at the locator end of the simplified model of the cantilever to get the support reaction force at the connection between the cantilever and the support.Findings-The support reaction force is applied as a load to the three-dimensional model of the pillar support;the stress cloud and the stress extreme value of 86.14 MPa are obtained for the pillar and the support part and the fatigue life of the pillar’s key parts is calculated to be 12.02 years,respectively.Originality/value-The upper part of the lower support of the high-speed rail catenary pillar is subjected to the alternating load transmitted by the bow net,which causes the fretting damage at this position,resulting in the abnormal peeling of the coating on the upper part of the lower support.Through combining the ABAQUS analysis with the structural characteristics and operating conditions of the catenary system,the main causes of component failure are determined.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.51879189 and 52071234).
文摘This study proposed a novel experimental platform to conduct dynamic loading tests of a truncated model steel catenary riser(SCR)within the touchdown zone(TDZ).The facilities of the platform,including a soil tank,a loading system,and a soil stirring system,are introduced in detail.A steel pipe with the same diameter as the in situ SCR has been used in the laboratory tests to investigate the vertical motion of the pipe and the effect of the trench on the lateral motion.As the amplitude of the vertical motion increases,the depth of the trench deepens,the bending moment range increases,and the excess pore water pressure at the bottom of the pipeline first accumulates and then dissipates during loading.The development trend of the trench depth and the influence of the soil strength on the SCR bending moment are also studied.During the test,a seabed trench develops,and its shape is similar to that of the in situ trench.
文摘Steel catenary risers （SCR） have become an enabling technology for deepwater environments. A comprehensive review was conducted on recent research that examined interactions between deepwater steel catenary risers and soft clay seabeds. This included the STRIDE （steel risers in deepwater environments） and CARISIMA （catenary riser soil interaction model for global riser analysis） joint jndustry jrogram＇s test data as well as information from existing papers.
基金financially supported by the Fundamental Research Funds for the Central Universities(Grant No.201861036)the National Natural Science Foundation of China(Grant No.51279187)+1 种基金the Science and Technology Major Project of Shandong Province(Grant No.2015ZDZX04003)the Key Research and Development Program of Shandong Province(Grant No.2018GHY115045)
文摘A numerical model of the steel catenary riser(SCR) is built based on the slender rod model. The slender rod model,which describes the behavior of the slender riser in terms of the center line position, can solve the geometrical nonlinearity effectively. In a marine environment, the SCR is under the combined internal flow and external loads,such as wave and current. A general analysis considers only the inertial force and the drag force caused by the wave and current. However, the internal flow has an effect on the SCR; it is essential to explore the dynamic response of the SCR with the internal flow. The SCR also suffers the lift force and the fluctuating drag force because of the current. Finite element method is utilized to solve the motion equations. The effects of the internal flow, wave and current on the dynamic response of the SCR are considered. The results indicate that the increase of the internal flow density leads to the decrease of the displacement of the SCR, while the internal flow velocity has little effect on the SCR. The displacement of the SCR increases with the increase of the wave height and period. And the increasing wave period results in an increase in the vibration period of the SCR. The current velocity changes the displacements of the SCR in x-and z-directions. The vibration frequency of the SCR in y-direction increases with the increase of the current velocity.
基金supported by the National Natural Science Foundation of China(Grant No.50739004)
文摘This paper presents fatigue characteristic analysis of a deepwater steel catenary riser （SCR） under ambient excitations. The SCR involves complex nonlinear dynamic behaviors, especially at the touchdown point （TDP） where the riser first touches the seafloor. Owing to the significant interaction with soil, the touchdown zone is difficnlt to be modeled. Based on Lumped-Mass method and P-y curve, nonlinear springs are used to simulate the SCR-seabed coupled interaction. In case studies, an SCR＇s dynamic features have been obtained by transient analysis and the structure fatigue assessment has been carried out by S-N approach. The comparative analysis shows that the TDP is the key location where soil-riser interaction rises steeply and minimum fatigue life occurs. Parameters such as ocean environment loads, vessel motions, riser material and geometric parameters are discussed. The results indicate that the vessel motion is the principal factor for the structure fatigue life distribution.
基金supported by the National Natural Science Foundation of China(Nos.51677171,51637009,51577166 and 51827810)the National Key R&D Program of China(No.2018YFB0606000)+2 种基金the China Scholarship Council(No.201708330502)the Fund of Shuohuang Railway Development Limited Liability Company(No.SHTL-2020-13)the Fund of State Key Laboratory of Industrial Control Technology(No.ICT2022B29),China。
文摘Rod insulators are vital parts of the catenary of high speed railways(HSRs).There are many different catenary insulators,and the background of the insulator image is complicated.It is difficult to recognise insulators and detect defects automatically.In this paper,we propose a catenary intelligent defect detection algorithm based on Mask region-convolutional neural network(R-CNN)and an image processing model.Vertical projection technology is used to achieve single shed positioning and precise cutting of the insulator.Gradient,texture,and gray feature fusion(GTGFF)and a K-means clustering analysis model(KCAM)are proposed to detect broken insulators,dirt,foreign bodies,and flashover.Using this model,insulator recognition and defect detection can achieve a high recall rate and accuracy,and generalized defect detection.The algorithm is tested and verified on a dataset of realistic insulator images,and the accuracy and reliability of the algorithm satisfy current requirements for HSR catenary automatic inspection and intelligent maintenance.
基金Supported by the National Natural Science Foundation of China (50975191)the Innovation and Entrepreneurial Projects for College Students of Taiyuan (110148050)
文摘To solve the design problem of transformer composed of non-resonant structure in ultrasonic gear-honing, force coupling conditions for moderately thick annular plate （MTAP） and catenary horn are proposed, and the frequency equations of the transformer, which consist of an MTAP and a catenary horn, are derived based on Mindlin＇s theory. The design parameters of the transformer were obtained by solving the frequency equations with the help of MATLAB, and its mode and frequency were deduced by the modal analysis of finite element method （FEM）, which are consistent with the theoretical design demands. The transformer design can be extended from system with thin annular plate to that with MTAP as the theoretical method by the simulation analysis of various ratios of the thickness to radius.
