最新刊期
卷 ， 期 6 ， 2022
- 摘要：In respect of large noise interference of wheel tread and insufficient feature fusion of traditional detection algorithms, in order to achieve fast and accurate detection of wheel tread defects, a method for rapid detection of wheel tread defects for YOLO-v5 trains based on residual attention was proposed. First, for the large noise interference, a residual attention noise reduction module was designed to effectively improve the accuracy of model detection, and the Grad-CAM activation mapping technology was used to verify the effect of the residual attention module on reducing noise interference. Secondly, in view of insufficient feature fusion and the model being prone to omission, a feature fusion module of bidirectional feature pyramid was used to efficiently fuse the features extracted by the backbone network, thereby effectively reducing the omission rate. Finally, hundreds of real defect images of wheel treads were collected and contrasted with five classic detection models to verify the superiority of the algorithm. The results show that the algorithm can achieve 77.9% accuracy and 72.3% recall; in addition, the proposed algorithm can detect 125 images per second, and the model weight is only 15.1 MB. The model can quickly and accurately detect such two defects as peeling and sagging, and can be easily applied to the actual real-time defect detection scenario of wheel tread.关键词：defect detection;wheel tread;YOLO-v5;residual attention;bidirectional feature pyramid
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发布时间：2024-08-02 - 摘要：In respect of the fatigue crack failure of the electric locomotive body under the cyclic excitation, the dynamic strain test was carried out on the key parts, and the fatigue life of the locomotive body was researched based on standard loads. Firstly, the body of an electric locomotive was taken as the research object, the dynamic strain test of the key parts was carried out, and the test data were filtered by low-pass filter. Secondly, the rainflow counting was carried out on the filtering results, and the parameters of the welding material at the measuring point were determined based on the IIW (International Institute of Welding) standard. The fatigue crack initiation life of the key parts was calculated according to the Palmgren-Miner linear cumulative damage theory. Then, the body bolsters and the local structure of the underframe of the vertical damper holder were taken as examples, the sub-model of crack propagation simulation of key parts was established, and the load conditions of the sub-model were determined based on the EN 12663 standard. Finally, the initial crack was inserted at the dynamic strain measuring point of the vertical damper, and the fatigue crack propagation life was calculated based on the fracture mechanics, thereby obtaining the fatigue life data of the vertical damper holder of the body. The results show that the fatigue crack initiation life of the vertical damper holder is 6.86×107 km. Under the load conditions required by the EN 12663 standard, the electric locomotive body with an initial semi-elliptical surface crack of 2 mm in half length and 0.8 mm in depth can bear at least 4.18×107 load cycles before it completely loses its bearing capacity. The research results provide reliable test and simulation basis for the necessary improvement of the body structure, as well as a strong guidance and reference value for the evaluating the safety and reliability of the body in locomotive operation.关键词：vehicle engineering;electric locomotive;body;dynamic strain test;damage accumulation;fracture mechanics;crack propagation simulation
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发布时间：2024-08-02 - 摘要：It is imperative to optimize the structure and improve the reliability and stability in the force transmission process of draw-bar for the application on the high speed maglev trains in the 600 km/h operation. Taking the draw-bar used on the 600 km/h high-speed maglev trains as the research object, this paper explored the impacts of lightweight materials and machining errors on their structural stability with the critical bucking load as the index, according to the stability analysis principle, using the Euler’s formula, the eigenvalue buckling analysis method and the finite element method, and in consideration of the material nonlinear factors and machining errors, and accordingly reveals the influence of the lightweight design of the draw-bar on their structural stability. The relevant conclusions were drawn from the simulative analysis as the following. The mechanical properties of materials have a significant effect on the critical bucking load of the draw-bar, and the critical bucking load of the traditional draw-bar made of 42CrMo alloy steel is triple that of the draw-bar made of 6082 aluminum alloy. Machining errors also affect the structural stability, and the critical bucking load decreases from 40.46 kN to 35.45 kN (down 12.4%) for the draw-bar made of 6082 aluminum alloy subject to a machining error of 3 mm. Therefore, the machining precision should be strictly controlled in the design stage; the non-linear buckling analysis method is more suitable for structural stability analysis of the lightweight draw-bar.关键词：high-speed maglev train;draw-bar;stability analysis;eigenvalue buckling;non-linear buckling
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发布时间：2024-08-02 - 摘要：Vehicle-guideway coupling vibration is an important issue in the operation of maglev trains. In this paper, based on a new medium-low speed maglev running mechanism, the vehicle-guideway coupling vibration response was analyzed to determine the rationality of its structure. In order to analyze the vehicle-guideway coupling vibration response of the new maglev train, the vehicle-control-guideway coupling dynamic model was built by using Simpack, Simulink and ANSYS. Numerical simulations of vehicle-guideway coupling dynamic response at different speeds were performed, based on which the dynamic response characteristics of the coupling system and the influence of the speed on the dynamic response law of the coupling system were obtained, and the special response phenomena in response characteristics were analyzed. Results show that, with the increase of the speed, the dynamic responses of the guideway, levitation module, and carbody become more intense. When the speed is 100-120 km/h, resonance exists in the coupling system, both in lateral and vertical directions. In addition, due to the unique structural characteristics of the new levitation bogie, the lateral dynamic response in the middle of the running mechanism is larger than that at the end.关键词：medium-low speed maglev;vehicle-guideway coupling vibration;numerical simulation;new levitation bogie;guideway;dynamic response;track irregularity
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发布时间：2024-08-02 - 摘要：Based on the development and application of passenger car bogies in China, this paper analyzed the characteristics and shortcomings of the bogies of the existing technology platform. In addition, in order to enhance and improve the comprehensive service performance indexes of vehicles, the research on the key technologies of the bogies, such as bearings, wheels, axles and suspensions, for the speed level of 200 km/h was conducted. Based on the reference of the "CRH" and "Fuxing" EMU bogies, trailer bogies for new 200 km/h power centralized EMU were designed, and a strength simulation analysis of key stressed components, an evaluation of weld stress value and a verification of static strength and fatigue strength on test bench were made, which proved that the strength of bogies meets UIC, EN and TB standards. According to the multi-body dynamics modeling, simulation and analysis, the suspension parameters of the bogies are reasonable and all dynamic performance indexes can reach the superior level.关键词：EMU;power centralized;trailer;bogie;200 km/h
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发布时间：2024-08-02 - 摘要：Among the important components on high-speed trains, hollow axles are detected from the inner bore surface for transverse fatigue cracks on the outer surface by the conventional ultrasonic technique, as a measure to ensure the operation safety of high-speed trains. However fatigue cracks cannot be quantified by this conventional technique, making it impossible to identify the next detection cycle of the hollow axle, leaving a safety loophole for the trains. In this study, the shortest path of ultrasonic propagation through the double-layer media was geometrically modeled. Applying the Snell's law and Ferrari’s method, the position was calculated for the incident point of the ultrasonic beam on the interface plane, to enable imaging in the double-layer media by the total focusing method（TFM）. According to the study results, this method can generate the exact solution of the coordinates at the incident point on a linear interface and accurately reconstruct the fatigue crack images. The model improved with additional path calculation and secondary reflection of waveform conversion status, can achieve the real crack quantitative imaging of hollow axles. The results clearly presented the shape and development tendency of cracks, but the diffuse reflection at the crack tip will cause a certain impact on the quantitative.关键词：high-speed train;hollow axle;fatigue crack;total focus method;double-layer media imaging;Snell’s law
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发布时间：2024-08-02 - 摘要：The demand for large passenger capacity of intercity EMU leads to a shorter streamlined train head, the demand for small cross section of the intercity/suburban line tunnel leads to a larger blockage ration of the train passing through the tunnel. The pressure wave and interior pressure fluctuation of the train passing through the tunnel are the prominent problems, which affect the comfort of the passengers. This paper mainly focuses on the pressure wave and interior pressure fluctuation of the intercity EMU passing through the tunnel under the condition of large blockage ratio. Based on the three-dimensional transient compressible RANS equation and the SST k-ω turbulence model, the numerical calculation method of pressure wave of the intercity EMU passing through the tunnel was established using the slip grid technology. The pressure wave characteristics of the train passing through the tunnel were studied for different train speeds and different tunnel diameters. The empirical formula was used to calculate the interior pressure fluctuation under different dynamic tightness coefficients. The computational results show that the pressure wave of the intercity EMU passing through the tunnel is mainly determined by the train speed and the blocking ratio, and the influence of the train speed is more significant. With the increase of the train speed, the interior pressure fluctuations of the passenger compartment area and the driver's cab area are significantly increased. The interior pressure fluctuation of the driver's cab area is greater than that of the passenger compartment area. When the train speed is 160 km/h, the interior pressure fluctuations of the passenger compartment area and driver's cab area reach the good standard when the dynamic tightness coefficient reaches 5 s, for the tunnel diameters of 7.2 m and 7.4 m. When the train speed is 200 km/h, the interior pressure fluctuations of the passenger compartment area and driver's cab area reach the good standard when the dynamic tightness coefficient reaches 8 s, for the tunnel diameters of 7.2 m and 7.4 m.关键词：intercity/suburban EMU;pressure wave;interior pressure fluctuation;blockage ratio;dynamic tightness coefficient
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发布时间：2024-08-02 - 摘要：This paper illustrated the correlations and hierarchical structure among IEC 662864-1: 2016, Railway applications - Rolling stock - Power supply with onboard energy storage system - Part 1: Series hybrid system, IEC 61377: 2016, Railway applications - Rolling stock - Combined test method for traction systems and IEC 61133: 2016, Railway applications–Rolling stock–Testing of rolling stock on completion of construction and before entry into service. IEC 61377:2016 mainly specifies the method of the combined test performed on a ground test bench for traction systems, except for those powered by an energy storage system. IEC 61133:2016 mainly specifies the test method for rolling stock, without covering the detailed test method for the rolling stock powered by an energy storage system. The deficiencies mentioned above are supplemented by IEC 62864-1:2016, which specifies the hybrid power system configuration, as well as the items and methods of the tests performed on a ground combined test bench and rolling stock. This paper contained a detailed analysis covering the system power supply configuration, environmental conditions, functions, system requirements and test items specified in IEC 62864-1:2016, so as to provide a guidance for the implementation of the IEC standards and the formulation of China's national standards.关键词：railway application;hybrid power system;traction system;combined test
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发布时间：2024-08-02 - 摘要：In order to explore the influence of fluctuating cross wind load on the curve passing stability and safety of high-speed train, the three-marshalling train dynamics model was established by using SIMPCAK in this paper. The simulation of pulsating wind aerodynamic load was realized by MATLAB and loaded into the vehicle body centroid. The time / frequency response of the train under wind load was calculated. The line parameters were set with reference to relevant standards, the influence of load curve both inside and outside horizontal wind and the vibration response of vehicles in the marshalling were analyzed. Then, the effects of different superelevation, radius of circular curve, wind attack angle, wind speed and vehicle speed on vehicle safe passage of curve and the corresponding limits were analyzed. The results showed that the pulsating wind was easy to arouse the low frequency vibration of the train structure below 3 Hz. The difference of wind-vehicle parameters leaded to the difference within the train dynamic response in the marshalling, among which the first train T1 was most sensitive to the transverse wind when the wind attack angle α = 60°-90°. In the case of deficient superelevation, the inside wind dominated the lateral response of the vehicle, while in the case of over elevation, the outside wind dominated the lateral response. The decrease of the radius of the circular curve and the increase of the wind speed and the train speed would make the vehicle safety deteriorate rapidly. Under the conditions of speed at 200 km/h, wind speed at 12 m/s and wind direction angle at 90°, the safe radius of the circular curve was 3 800 m. Under the conditions of speed at 200 km/h, wind direction angle at 90° and circular curve at 3 200 m, the maximum wind speed was limited to 25 m/s. Under the conditions of wind angle at 90°, circular curve at 3200 m and wind speed at 12 m/s, the maximum speed was limited to 300 km/h.关键词：fluctuating transverse wind;high-speed train;curve passing performance;operation safety;high-speed railway;simulation;multiple-unit train
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发布时间：2024-08-02 - 摘要：For an engineering train with maximum running speed up to 160 km/h and axle load of 21 t, the brake shoe type, single and double side braking type and wheel diameter were confirmed by analysis in four aspects of braking distance limit, wheel-rail adhesion limit, wheel temperature limit and wheel strength requirement, and the strength of the wheels with the maximum wear was checked under the combined action of thermal load and mechanical load in two braking conditions under the proposed selection scheme. According to the results, for the engineering train with an initial speed at braking application of 160 km/h and 915 mm wheel diameter, the wheel configuration of the M-type powder metallurgy brake shoe and wheel clasp braking can not only meet the requirements of emergency braking distance and no sliding, but also maintain the maximum temperature of wheel tread less than the temperature limit required for service, and exert the maximum stress of the wheels with the maximum wear under the two braking conditions meeting the strength requirements.关键词：finite element;braking distance;wheel-rail adhesion;wheel temperature;strength
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发布时间：2024-08-02 - 摘要：When a railway vehicle is running on the track, it is inevitable that it will pass through the twisted track caused by factors such as track superelevation, twist warp, rail gaps, turnouts and geometric irregularity of track. When a vehicle passes through a twisted track on a minimum plane radius curve at low speed, the risk of derailment increases. However, there is no standard method for assessment of safety against derailment on a twisted track in China at present. Therefore, in this paper, the method for assessment of safety against derailment on a twisted track stipulated in the EN 14363 standard was researched. A city vehicle was taken as an example, and the assessment was made based on three methods specified in the standard. For method 1, the wheel lift was required to be measured on a twisted track and a plane curve with R150 m, and the wheel lift of no more than 5 mm shall be regarded as the assessment limit. For method 2, the vertical wheel-rail force was required to be measured on the straight section of the twisted track, and the lateral wheel-rail force of the outer wheel to be measured at R150 m on a plane curve. The ratio Y/Q of the lateral wheel-rail force to the vertical wheel-rail force on the outer rail side of the curve shall be calculated according to the formula, and the value of Y/Q not exceeding 1.2 shall be regarded as the assessment limit. For method 3, the slewing resistance coefficient was required to be measured on the test bench and the rate of wheel load reduction to be measured on the twisted track. The slewing resistance coefficient not exceeding 0.1 and the rate of wheel load reduction not exceeding 0.6 shall be regarded as the assessment limit. The results show that compared with method 1 and method 2, method 3 results in the worst track twist, and the maximum vertical displacement of the wheel during the track twist is 80.1 mm. For a vehicle, the wheel load reduction increases when the vehicle passes through the twisted track due to the fact that the vertical stiffness of the secondary system increases nearly 10 times in the deflated condition of the air spring. The deflated condition of the air spring results in a lower ability to adapt to the twisted track compared with the inflated condition, and the maximum limit ratio is 98%. For the convenience of simulation and test comparison, it is recommended that when assessing the safety against derailment on the twisted track according to EN 14363, method 2 should be used. That is, the vertical wheel-rail force shall be measured on the straight section while the lateral wheel-rail force measured at R150 m.关键词：twisted track;safety;EN 14363;simulation
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发布时间：2024-08-02
Railway Rolling Stock
- 摘要：The traction drive system and auxiliary power system are two core subsystems of urban rail transit trains. In order to improve their operational reliability, this paper proposed an online fault diagnosis and early warning system based on massive data information regarding external fault symptoms, operational environment, faults and so forth, carried out the data analysis and field investigation on the existing maintenance mode of these two subsystems, and summarization on their requirements of fault diagnosis and early warning. Considering that their fault characteristics information is complicated and fuzzy, the long short-term memory (LSTM) neural network model was built to realize fault early warning, and the fuzzy expert diagnosis method was used to realize fault diagnosis in the current study. Consisting of an onboard network system, onboard data processing center and ground big data platform, this online system can automatically generate fault data, push early warnings, fault diagnosis results output and troubleshooting suggestions, obviously improving train availability and maintenance efficiency. According to the field test results, this system can push early warnings in case of any abnormality of most fault items and locate faults of the two subsystems, thus optimizing the maintenance procedure and improving the maintenance efficiency.关键词：urban rail transit train;traction drive system;auxiliary power system;intelligent operation and maintenance;fault diagnosis;fuzzy expert diagnosis;LSTM
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发布时间：2024-08-02 - 摘要：According to the complexity of electromagnetic interference of traction system of high-speed EMU, and in combination with the design of the vehicle system, the EMI coupling paths of traction system were analyzed. Based on the equivalent interference source method, a calculation model for the common-mode interference of the system was established. The high-frequency test and modeling of the EMU traction system and the simulation prediction of the interference current were completed, and the accuracy of the theoretical model was verified by the measured results. Finally, according to the analysis of the influencing factors of electromagnetic interference of traction system, an interference suppression method was proposed, and the effectiveness of each suppression measure was verified by simulation or test.关键词：high-speed EMU;traction system;electromagnetic interference;high-frequency modeling;interference suppression
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发布时间：2024-08-02 - 摘要：This paper proposed a method to control neutral section passing based on the signal fusion of catenary voltage amplitude and phase, from a study on the neutral section passing process and optimal closing time for the vacuum circuit breaker on high-speed EMUs, to solve the downsides of the traditional control method for neutral section passing, i.e. a long vacuum circuit breaker disconnection duration and serious power loss. This method focused on the judgment whether a high-speed EMU has passed a neutral section depending on changes in the catenary voltage amplitude and phase. In order to verify the effectiveness of the proposed method, a semi-physical test was performed. Based on the test results, any changes in the catenary voltage amplitude and phase occurring when an EMU enters an electrified section can be quickly and effectively identified using the proposed method, so that the vacuum circuit breaker can be closed effectively ahead of time the EMU passes a neutral section, reducing the neutral section passing duration by more than 25%. Confronting the deficient railway capacity in China and the complicated track conditions, the method proposed in this paper can effectively reduce the power loss in the process of neutral section passing, so as to improve the efficiency of railway operation and relieve the traffic pressure during the peak period of passenger transportation, exhibiting a promising engineering application prospects.关键词：high-speed EMU;neutral section passing;neutral section auto-passing;catenary voltage and phase;information fusion;high-speed train
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发布时间：2024-08-02 - 摘要：Due to the mechanism of the TTDP (Train Topology Discovery Protocol), network nodes cannot meet the application requirements of all fault recovery scenarios in the status of inauguration inhibition, including multi-node fault recovery scenarios when multiple intermediate nodes are lost or one end node is included in multiple lost adjacent nodes. Therefore, in this paper, a new node fault recovery method was designed to solve this problem and achieve full compatibility with the standard TTDP. The storage of network configuration information was realized by adding a special storage unit with an independent power supply. The node equipment was improved by setting up the node fault preparation (writing the network configuration information to the special storage unit during the initialization), identification (matching the topology count values of adjacent nodes), and recovery (calling the network configuration information of the special storage unit) processes, so as to realize the fault recovery of the Ethernet train backbone (ETB) node in the special scenario. The proposed fault recovery scheme was verified by simulation test, which confirms the effectiveness and feasibility of the method.关键词：train topology discovery protocol (TTDP);Ethernet train backbone (ETB);inauguration inhibition;fault recovery
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发布时间：2024-08-02
Electric Traction and Control
- 摘要：In order to adapt to the continuous growth of freight traffic volume, the heavy haul railways have undergone the transportation capacity upgrading and transformation. The co-phase and bilateral power supply technologies can be adopted to cancel the phase breaks along the line and effectively improve the traction power supply capacity. A power supply transformation scheme suitable for the interconnected co-phase power supply traction network of heavy haul railway was put forward in this paper, and such a scheme can meet the needs of grid-based power supply of the traction network and continuous operation of the locomotive. Moreover, due to the fact that the existing protection and tripping/reclosing scheme could not satisfy the safety requirements for the interconnected co-phase power supply system, based on the operation characteristics of the interconnected co-phase traction network and the locomotive, the sectionalized protection and fault self-recovery strategies for traction network were proposed to realize the fault-oriented safety of traction network and ensure the minimum outage interval of traction network with fault. Finally, the simulation results verified the accuracy and effectiveness of the scheme. This scheme can provide important support for the interconnected co-phase power supply transformation for heavy haul railway, and plays a positive role in ensuring the safe transportation of goods.关键词：heavy haul railway;co-phase power supply;traction network;segmented power supply;fault self-recovery
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发布时间：2024-08-02 - 摘要：With the development of the power facilities across China, the underground stray current becomes more and more non-negligible as a source of hazard to electrical facilities, buried pipelines and other equipment, so it is extremely urgent to carry out an in-depth study of stray current. In the current study, a dynamic model of stray current sources was established according to the traction characteristics of the DC traction system for rail transit, and an algorithm to position underground stray current sources was proposed based on the propagation law of electromagnetic wave on the ground. The positioning method was verified by building a simulation model of dynamic diffusion of stray current along metros, in combination with the case analysis at a metro station in Shanghai, in which some geographical locations were selected and ground potentials were measured on site. The calculated coordinates using the stray current positioning algorithm are almost coincident with the actual interference source positions, including the measurement errors and the influence of the surrounding environment, etc., which demonstrates the feasibility of this method in the research on positioning of stray current interference sources in engineering practice.关键词：stray current;rail transit;positioning;simulation model;traction power supply;urban rail transit
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发布时间：2024-08-02 - 摘要：The varying number and location of traction substations along urban rail transit system lines, the time-varying characteristics of the DC traction power supply system network structure caused by continuous operation of trains, the DC traction network connectivity along the whole lines, are the critical technical bottlenecks in the mathematical modeling for the DC traction power supply system. Based on node-admittance network equation theory, a self-adaptive real-time dynamic mathematical modeling approach of the DC traction power supply system for the urban rail transit system was put forward. Firstly, the nodes which include both ends of all traction substations along the whole line and trains were sequenced automatically at any train operation moment, according to the given rules, such nodes were then sequenced according to position coordinates and stored in the node array, and the node-admittance network equation of the DC traction power supply system was generated according to the node array and input parameter files in a self-adaptive, real-time and dynamic pattern, and then solved. The scientificity and correctness of the proposed approach was verified through simulation and experimental study.关键词：urban rail transit;traction power supply;mathematical modeling;time-varying network;node-admittance network equation;self-adaptive
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发布时间：2024-08-02
Railway Electrification
- 摘要：As a kind of power semiconductor field-controlled self-shutdown electronic device, IBGT has become an irreplaceable component in new energy vehicle energy conversion, motor driving and high-voltage power switching units. While the electrical and electronic systems present a trend towards a smaller size, higher switching frequency and higher rated voltage, how to better guarantee the performance and reliability of the IGBT module to keep abreast with the improved performance has gradually become a hot spot of research among experts and scholars. This paper reviewed the various heat dissipation technologies on the IGBT module in recent years, and focused on analyzing the status quo of the heat pipe type heat dissipation from different angles of view, and summarized the existing heat dissipation means, to offer a reference for scholars to further study and make breakthrough in the IGBT module heat dissipation.关键词：IGBT;heat dissipation technology;heat pipe type heat dissipation;heat transfer enhancement;power semiconductor device
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发布时间：2024-08-02 - 摘要：As a key component of electric locomotives, the traction converter works for the DC to AC energy conversion through a large power insulated gate bipolar transistor (IGBT), thus exerting control over starting, braking and speed regulation of the AC traction motor. Its reliability is directly related to the operational safety of electric locomotives. Since the solder layer failure is one of the main failure modes of IGBT modules, it is very important to clarify the solder layer defect evolution law, for the sake of reliability of IGBT modules. In this paper, the solder layer of an IGBT module was firstly scanned by CT before and after putting into service of the electric locomotive. The statistical results showed that the number of solder layer voids in the IGBT module with different service mileages was in line with the Poisson distribution, of which the variance (λ) had a mapping relationship with the service mileage of the devices. Secondly, a multi-physical field simulation model of IGBT modules for electric locomotives was established, based on the statistical distribution law of voids and considering the initial defects, and the evolution inducements and law of random voids were studied by means of the strain mathematical description on the upper and lower surfaces of the solder layer. Finally, the relationship among void distribution, size and evolution rate was generated according to the energy-based fatigue lifetime model, which provided a basis for guiding optimal design and active maintenance of the devices.关键词：high power IGBT module;void distribution;void evolution;multi-physical field finite element simulation, electric locomotive
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发布时间：2024-08-02 - 摘要：Using sintering silver paste as an interconnect material for packaging can give full play to the advantages of wide bandgap semiconductors in device applications and improve the reliability of devices. By analyzing the microstructure, mechanical properties and failure modes of the pressureless silver paste sintering joints, the microstructure evolution rule of the pressureless silver paste sintering joints at different temperatures was systematically researched. The influence of sintering temperature and substrate metallization type on the connection performance and reliability of sintered silver was obtained. When the sintering temperature was 250 ℃, the shear strength of the pressureless sintering joints at the silver interface reached more than 60 MPa. The shear strength of the pressureless sintering joints at the gold interface was the highest at 200 ℃. Increasing the temperature would cause the atoms at the interface of sintered silver and gold to diffuse too fast, resulting in a decrease in the bonding strength of the interface. Due to the severe oxidation and the cracks at the interface, the shear strength of pressureless sintering joints at the copper interface was much lower than that of joints at silver and gold interfaces.关键词：sintering silver paste;pressureless sintering;shear strength;surface metallization;fracture mode
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发布时间：2024-08-02
High-power Devices
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