AMESim Software Research Articles

Research on evaluation technology for fuel tank inerting system based on task profile

Abstract The flammable and explosive characteristics of aviation fuel have always made the safety of aircraft fuel tanks a focus of attention in the aviation industry. At present, all aircraft test flights in our country require the completion of the evaluation of the fuel tank inerting subsystem, which has put forward clear requirements for the measurement of oxygen concentration in aircraft fuel tanks, and corresponding technical indicators have been developed based on the usage of civil and military aircraft. This article establishes a digital model of the aircraft fuel tank inerting system based on AMEsim software, verifies the accuracy of the model through literature data, and uses the digital model to study the variation law of oxygen concentration in the fuel tank. The temporal variation of oxygen concentration in the gas-phase space of aircraft fuel tanks is analyzed under different nitrogen-rich gas concentrations, nitrogen-rich gas flow rates, fuel tank loading rates, and aircraft descent rates. Based on the temporal variation of oxygen concentration, a reference is provided for formulating flight test methods.

Health assessment method of front landing gear hydraulic retraction and extension system based on GRNN

With the continuous development of civil aircraft health management technology, the status monitoring data of important aircraft systems and components are constantly enriched. The health status of the front landing gear hydraulic retraction system has a great impact on the take-off and landing of the aircraft. Although the system has multi-dimensional monitoring parameters, it is difficult to effectively use the system monitoring data to accurately evaluate its health status. Aiming at the health assessment problem of the front landing gear hydraulic retraction system, this paper builds a simulation model of the system through AMESim software modeling, and studies the influence of the performance changes of hydraulic component parameters on the front landing gear retraction performance. The performance data of the front landing gear retraction actuator at different levels of failure are used as the original data, and the characterization parameters such as retraction time and maximum flow rate are extracted. A health index construction method based on generalized regression neural network (GRNN) is proposed, which can more effectively evaluate the health status of the system. Its effectiveness and accuracy are proved by method comparison.

Study and Experimental Verification on Anti-Disturbance Control Strategy for Electro-Mechanical Servo Systems

With technological advances and industrial upgrading, electro-mechanical actuators (EMAs) have gradually replaced traditional hydraulic actuation systems. During operation, force servo systems inevitably suffer from external force or position disturbances, thus affecting the output performance of the system. Therefore, it is of significant engineering application value to develop EMA anti-disturbance control strategies that exhibit strong robustness and are more easily applicable to engineering practice. In this study, an open-loop transfer function of the system with command signals and disturbance signals as inputs was established based on the nonlinear mathematical models built for the core components of EMAs. To overcome the impact of external position disturbances on the motion performance of the force servo system, a proportional integral derivative (PID) controller was introduced and a high-order transfer function associated with various parameters such as speed and acceleration was derived and obtained as feedforward compensation based on the mathematical model. By incorporating a three-loop PID controller, the impact of external disturbance forces on the motion performance of the position servo system was overcome and the tracking accuracy of the system was also improved. Finally, simulation models were built using AMESim software (AMESim 2020, LMS Imagine.Lab, Roanne, France) and a dual-channel EMA performance testing system was developed. Simulation and test results indicated that both anti-disturbance control methods exhibited strong robustness and excellent anti-disturbance performance, with the control accuracy and dynamic performance almost unaffected by disturbances. This verified the correctness of the single-channel EMA anti-disturbance control strategy and the usability of the simulation model.

Accuracy assessment of the turbomachinery performance maps correction models used in dynamic characteristics of supercritical CO2 Brayton power cycle

The supercritical CO2 Brayton cycle (SCO2BC) has emerged as a promising next-generation power generation technology due to its potential for high thermal efficiency and compact components design. Dynamic modeling of SCO2BC is crucial for understanding and analyzing its performance under design and off-design conditions. Turbomachines are critical components in SCO2BC dynamic models. While turbomachinery components are often modeled using their design-point turbomachinery performance maps (TPM), these maps become less accurate during off-design operations. Despite the existence of various TPM correction methods that ensure model validity, the implementation of the accurate ones within dynamic SCO2BC models remains scarce in the literature. This is crucial as it potentially compromises the accuracy of the obtained results. Therefore, there is a need to investigate the errors in the existing literature TPM correction models (in dynamic SCO2BC simulation) by comparing them against dynamic SCO2BC models employing a highly accurate correction method. Thus, in the current work, the common TPM correction methods from the literature are implemented in SCO2BC dynamic models and compared against a baseline mode, which uses the highly-accurate Pham method (at both the component and cycle levels). To the authors’ knowledge, this is the first work to address this research gap for the SCO2BC dynamic simulations and on both component and cycle levels. Additionally, another novelty is the usage of Simcenter Amesim software to dynamically model the SCO2BC aided with Pham model. Multible dynamic models for both the turbomachines of SCO2BC and the whole cycle are constructed and equipped with the different TPM correction methods found in literature to compare their dynamic behaviour that of Pham model. The Ideal Gas Compressibility factor (IGZ) method demonstrates a better performance than the other tested methods, as it exhibits the lowest discrepancy compared to the Pham model. Many of the other tested methods show significant errors. Furthermore, a popular hybrid correction combining IGZ and Pham (IGZ-Ph) is also investigated. Surprisingly, while seemingly beneficial, this hybrid approach negatively impacts accuracy, even resulting in predictions as if no correction was applied.

Dynamic Simulation Model and Performance Optimization of a Pressurized Pulsed Water Jet Device

Pulsed water jet technology has broad application prospects in the field of rock breaking. The pressurized pulsed water jet (PPWJ) is a new type of pulsed jet that offers high-amplitude pressurization, variable pulse pressure and frequency, and a high energy usage rate. To achieve a more destructive and powerful pulsed water jet, a dynamic simulation model of the device was established by using the AMESim software (v1400) based on the operational principle of PPWJs, and the simulation model was validated against the experimental results. The relationships between the key structural parameters of the PPWJ device and the pulse parameters were quantitatively investigated. The pulse pressure and frequency can be increased by appropriately increasing the nozzle diameter or boost ratio, and the pulse pressure will drop if the nozzle diameter or boost ratio exceeds a threshold value. Increasing the maximum displacement or action area of the piston will increase pulse length while decreasing pulse frequency; a proper match of the maximum displacement or action area of the piston will assure pulse peak pressure. The maximum outer diameter of the piston only affects the pulse frequency. The key structural parameters of the device were optimized on that foundation. Compared to the original device, the optimized device resulted in an increase in pulse frequency and jet output energy, leading to larger diameter and volume of erosion pits at the same stand-off distance and erosion time. The findings of this study offer valuable scientific insights for achieving efficient rock breaking with PPWJ.

SSFLNet: A Novel Fault Diagnosis Method for Double Shield TBM Tool System.

In tunnel boring projects, wear and tear in the tooling system can have significant consequences, such as decreased boring efficiency, heightened maintenance costs, and potential safety hazards. In this paper, a fault diagnosis method for TBM tooling systems based on SAV-SVDD failure location (SSFL) is proposed. The aim of this method is to detect faults caused by disk cutter wear during the boring process, which diminishes the boring efficiency and is challenging to detect during construction. This paper uses SolidWorks to create a complete three-dimensional model of the TBM hydraulic thrust system and tool system. Then, dynamic simulations are performed with Adams. This helps us understand how the load on the propulsion hydraulic cylinder changes as the TBM tunneling tool wears to different degrees during construction. The hydraulic propulsion system was modeled and simulated using AMESIM software. Utilizing the load on the hydraulic propulsion cylinder as an input signal, pressure signals from the two chambers of the hydraulic cylinder and the system's flow signal were acquired. This enabled an in-depth exploration of the correlation between these acquired signals and the extent of the tooling system failure. Following this analysis, a collection of normal sample data and sample data representing different degrees of disk cutter abrasions was amassed for further study. Next, an SSFL network model for locating the failure area of the cutter was established. Fault sample data were used as the input, and the accuracy of the fault diagnosis model was tested. The test results show that the performance of the SSFL network model is better than that of the SAE-SVM and SVDD network models. The SSFL model achieves 90% accuracy in determining the failure area of the cutter head. The model effectively identifies the failure regions, enabling timely tool replacement to avoid decreased boring efficiency under wear conditions. The experimental findings validate the feasibility of this approach.

Design and Test of Hydraulic Driving System for Undercarriage of Paddy Field Weeder

In response to challenges such as inadequate driving stability and power in traditional weeding machinery, we designed and investigated a hydraulic chassis tailored for paddy field operations. Utilizing SolidWorks and RecurDyn V9R4 software, we obtained linear driving and steering curves to model and simulate the dynamics of the mower chassis. Through the AMESim software, we further modeled and simulated the hydraulic chassis system, focusing on the hydraulic characteristics of the components relevant to its operation. Subsequently, we developed a hydraulic-driven paddy weeder and conducted tests to evaluate the linear deviation and paddy slip rates. Our findings indicate that the designed hydraulic weeder chassis exhibits commendable dynamic performance and driving stability, with the actual average deviation and paddy slip rates measured at 2.61% and 3.59%, respectively. These results underscore the efficacy of our approach in addressing the challenges inherent in traditional weeding machinery and highlight the potential of hydraulic systems in enhancing agricultural operations.

Active control method for fluid borne noise in aerospace fluid systems of variable operation statuses

In the fluid system of aerospace vehicles, the fluid-borne noise (FBN) may induce vibration and damage to components. The FBN may limit the performance of the entire onboard system. To achieve a stable active elimination for the FBN is not easy, for many variable operation statuses exist in practical systems, such as varying-frequency and varying-load status. In this work, an improved feed-forward active control method based on narrowband adaptive notch filters, with an online identification module, is proposed. The algorithm includes three adaptive filters: an adaptive notch filter for producing cancelling signal by using filtered-X least mean square (FXLMS) algorithm, one for online identification to model the real-time secondary path, and an error prediction filter for extracting the precise error for online identification. In the aircraft hydraulic system of high pressure, a so-called relief scheme, also known as the bypass structure, is used for the FNB, controlling an active control valve in the branched line to overflow the main fluid line. The system is modelled with software AMESim for the fluid part and Matlab for the control algorithm. Simulation results show that the control method can performance well in the situations of varying frequency and load. The test rig of a hydraulic system is established, which could change pump speed and fluid pressure. The test results show that more than 90% reduction for a certain frequency can be achieved for stable pressure statuses. And more than 50% reduction is achieved for varying frequency with step changes. As for the load-varying status, the reduction of 82.7% and 65.8% are obtained before and after pressure change. The method proposed is validated to be effective with both numerical and experimental tests.

Performance Simulation Analysis of Synchronous Hydraulic System for Variable-Diameter Threshing Drum

To meet the requirement that the traditional combine harvester can adjust the threshing gap in real time according to different working conditions, a hydraulic driven variable-diameter threshing drum and a synchronous hydraulic system were developed in the early stage. However, the performance of synchronous hydraulic system has not been studied in detail. Therefore, AMESim software was used to simulate and analyze the synchronous hydraulic system to verify its feasibility in this study. The results showed that the synchronization error of synchronous hydraulic system was less than 0.02 mm. When the hydraulic system was self-locking, the position fluctuation of the piston rod of hydraulic cylinder was less than 0.06 mm. When the hydraulic cylinder did not work, the logic valve effectively ensured that the hydraulic oil could directly return to the oil tank, resulting in the minimum energy loss of the system. The flow control valve could regulate the flow rate of the hydraulic system, causing the adjusting speed of the drum diameter can be adjusted. The hydraulic system pressure was determined to be 8 Mpa.

Research on Flexible Braking Control of a Crawler Crane during the Free-Fall Hook Process

Due to the large inertia and strong impact accompanying the free-falling hook process of crawler cranes, it is difficult to meet the demand for flexible and smooth braking control under different weight load conditions. Therefore, this paper takes the free-fall hook system as the research object and combines system operation characteristics and control theory to carry out research on flexible braking control of the free-fall hook system. Firstly, a joint simulation platform of MATLAB (version 2018b) and AMESim (version 2019.1) software is built to theoretically analyze the key components of the free-fall hook system (proportional pressure-reducing valve, winch reducer, and wet clutch). Secondly, a mathematical model of the braking process is established, and the pressure control demand is clarified to analyze the reasons for the existence of dead zones and hysteresis loops in the system. Meanwhile, it is found that the dead zones and hysteresis loops existing in the pressure output of the pressure-reducing valve are the main factors of flexibility with load braking. Then, in this paper, a closed-loop control strategy is formulated based on the automatic adaptation of the braking gear in combination with the fuzzy PID pressure. Finally, the effectiveness of the control strategy proposed in this paper is verified with simulation and experimental testing using the pressure hysteresis loop of the free-fall hook process and the load-braking acceleration as the judging criteria. The results show that the system pressure hysteresis loop is reduced by 50%–60% and the maximum braking acceleration is reduced by 24%–30% under the conditions of 6.44 tonnes and 10.44 tonnes, which improves the accuracy of pressure control and achieves flexible and smooth braking with loads for different tonnages of free-fall hooks.

Study on the effect of rolling mill dynamic stiffness on coupled vibration of hydraulic machine

The productivity and capacity release of hot-strip rolling is severely limited by pendular vibration. Previous studies on mill vibration have investigated the influence of rolling parameters on vertical vibration; however, the influence of dynamic stiffness compensation factors on vertical vibration has not yet been considered owing to the limitations of modelling methods. Herein, we develop a simulation model of mill liquid–machine coupling with dynamic stiffness compensation using AMESim software. The established simulation model is used to investigate the effect of this dynamic stiffness compensation on mill vertical vibration under conditions of downfeed thickness difference excitation frequency, thickness difference excitation amplitude, thickness difference excitation phase, and dynamic stiffness compensation signal generation hysteresis. Evidently, the impact of the mill stiffness compensation on the mill vertical vibration differs with the thickness of the excitation frequency, and the impact should be discussed according to the excitation frequency segment. The amplitudes of the roll system vibration and incoming thickness difference excitation are essentially linear, whereas the excitation phase does not affect the frequency or amplitude of the mill vibration. The rolling machine stiffness compensation signal hysteresis also has a significant impact on the mill vibration amplitude. Our findings will improve the mechanism of the hot rolling process and suppress droop vibrations.

Development of the simulation model for testing the axial torque distribution in an electric vehicle with the dual-motor layout

BACKGROUND: The market of vehicles using electricity as an energy source demonstrates significant growth. Currently, there are more than twenty million electric vehicles worldwide. Leading manufacturers give the high priority to development of electric transport due to lower vehicle service costs, ease of driving as well as zero emissions in environment and almost complete noiselessness at motion. In addition, using the full-wheel drive in an electric vehicle makes it possible to improve off-road capability, ensures more balanced chassis control, precise following the path and constant accuracy of steering. AIMS: Ensuring increase in vehicle course stability, delivering the maximal torque regarding vehicle motion conditions and slip control in dual-motor layouts of electric vehicles. METHODS: In order to solve the given task, implementation of the special-purpose algorithm of torque distribution between driving axles of an electric vehicle is assumed. The paper presents the development of the simulation model of a vehicle, built in the Simcenter Amesim software and considering dynamic properties and features of the vehicle. This model was implemented into the Labcar hardware-in-the-loop facility. RESULTS: The simulation result is comparison with the data obtained during ground testing of the prototype and confirming the aim of simulation model development, in particular the capability of revision and preliminary setting up the algorithm of torque distribution between driving axles of a vehicle. CONCLUSIONS: Based on the results of the testing of the developed facility, it can be concluded that the developed simulation facility is suitable for solving the simulation tasks including research, debugging and primary calibrations of the algorithm of torque distribution between driving axles of a full-wheel driven electric vehicle. The errors at simulation of operation modes relevant to longitudinal and lateral dynamics of the prototype is no more than 7.5% that complies with the simulation aims.

Design and Analysis of Mechanisms of 7-, 8- and 9-Speed Automatic Transmissions for Vehicle Powertrains

As the core device of engine-driven vehicle powertrains, the automatic transmission (AT) can obtain different output torques and speeds. Designing new mechanisms is the foundation for developing innovative ATs. This paper proposes an innovative design method for 7-speed, 8-speed and 9-speed AT mechanisms based on fractionated planetary gear trains (PGTs) and investigates the performance analysis of the AT mechanisms. Firstly, the detection of symmetric vertices in the PGT graph is studied, and a method for the topologic synthesis of 11-link 2-degree-of-freedom (DOF) fractionated PGTs is proposed. Secondly, the innovative design of 7-speed, 8-speed and 9-speed AT mechanisms is explored, leading to the discovery of two novel 7-speed AT mechanisms, three novel 8-speed AT mechanisms and four novel 9-speed AT mechanisms. Finally, the performance analyses of kinematics, torque, power flow and transmission efficiency of the AT mechanisms are conducted, and AMESim (Simcenter Amesim 2020.1) software is utilized to simulate speed ratios and transmission efficiencies of the AT mechanisms. The analysis and simulation results demonstrate that the nine novel AT mechanisms obtained in this study exhibit excellent overall performances. The speed ratios of each AT mechanism are reasonable, the step ratio is between 1.1 and 1.8, and the transmission efficiency exceeds 0.95. There is no cyclic power, or the cyclic power values are within an acceptable limit.

Analysis and design of the optimal radius gap of the piston pair

The axial piston pump plays a crucial role as a power component in the hydraulic system. As one of the important friction pairs, the piston pair has a significant influence on the mechanical and volumetric efficiency of the axial piston pump, where the gap of the piston pair has a considerable effect on the lubrication and overall efficiency of the piston. However, there are a few studies on the gap of the piston pair and there is a lack of relevant theoretical support for the design of the gap of the piston pair, especially when the piston has spin motion. To tackle this problem, we propose a CORG (critical and optimal radius gap) design method for the gap of the piston pair based on the critical radius gap and the optimal radius gap. Specifically, we first provide a theoretical proof for the existence of the critical radius gap. Then, considering that the piston has spin motion, we analyze the power loss of the piston pair and define the leakage power loss and viscous dissipation power loss according to the physical meaning. Meanwhile, the minimum value of the total power loss of a single piston pair is taken as the optimization metric of the piston pair, and we further propose the optimal radius gap. Then, by combining the critical radius gap and the optimal radius gap of the piston pair, we propose the CORG design method for the radius gap of the piston pair and obtain a dimensionless CORG constant that should be satisfied in the design of the radius gap of the piston pair. In framework of the CORG design method, it can not only ensure that the total power loss of a single piston pair is minimized but also prevent the volumetric efficiency of the piston pair from being too low. Finally, the simulation model of the piston pair is built by AMESim software, and the correctness of the theoretical calculation results are further verified by comparing the simulation results with the theoretical calculation results. The CORG design method can further provide theoretical references for the design of the piston pair.

Analysis of influencing factors on vibration characteristics of electro-hydraulic vibration cutting system

The cutting process of the cantilever tunneling machine mainly generates excitation through the cutting motor or the hydraulic cylinder driven by the hydraulic system. Regardless of the driving method, the frequency width of the excitation system is limited, difficult to control, and the excitation effect is poor. Therefore, in order to improve excavation efficiency, the excitation system parallel to the original cutting and rotating system is designed. Based on the excitation characteristics caused by alternating fluid flow, the core component of the excitation system, hydraulic exciter, is designed, and the dynamics and dynamic characteristics of the excitation system are analyzed. Based on AMESim software, analyze the impact of factors such as pump displacement, excitation frequency, and pipeline parameters on the operational performance of the electro-hydraulic vibration cutting system, and conduct experimental verification by building a cutting test bench. The experimental results show that as the inner diameter of the pipeline increases, the fluctuation at the acceleration turning point decreases in each cycle and approaches the peak faster. As the excitation frequency increases, the cutting acceleration of the electro-hydraulic excitation cutting system decreases first and then increases, verifying the accuracy of the simulation results. In the experiment, it was found that the acceleration transformation range of the cutting head of the excitation system is the smallest and most stable when the excitation frequency is 30 Hz. In order to verify that the excitation frequency of 30 Hz is the optimal frequency, further contact force tests were conducted on the cutting teeth. It was found that when the hydraulic excitation system adds a 30 Hz excitation frequency, the contact force on the cutting teeth is the smallest. It is more conducive to reducing the damage and wear of the cutting head, and the cutting effect of the cutting head is more obvious. The research results are beneficial for improving the cutting performance of the electro-hydraulic excitation cutting system, providing theoretical support for the selection of cutting parameters for excavation machinery and hydraulic excitation, and improving the existing theoretical system for active excitation cutting vibration analysis of excavation machines.

Modeling of the Cooling of the Batteries of Electric Vehicles Using the Cabin Air Conditioning System

In this study, a simulation on management of battery temperature, which is a significant problem for electric vehicles, has been made. Battery temperatures can reach up to 50 oC if not checked during quick charging and discharging processes. Such situation shortens the lifetime of battery and also increases the temperature inside the cabin. More importantly, they can be dangerous. LMS Amesim software and WLTC driving cycle have been used for the simulation. Three battery packages have been used in simulations. Temperature of the battery have been checked at three different ambient temperatures (25 oC, 30 oC, 35 oC). During the test, it has been enhanced to keep the battery temperature below 35 oC under all conditions. Air-conditioner of the vehicle has been used to cool the batteries. When the temperature increased, the air-conditioner automatically checked the operating cycle of the compressor and cooled the batteries by means of constant air flow. In conclusion, the simulation has kept the battery temperature at desired level at ambient temperatures of 25 oC and 30 oC. At ambient temperature of 35oC, battery temperature increased up to 35.2oC.

Optimization Research on the Heat Transfer Capacity of an Aircraft Fuel Thermal Management System

The thermal management system (TMS) for aircraft fuel is a critical component of integrated TMSs in aircraft. As such, its optimal design is necessary to ensure the efficient completion of flight missions. This study presents the model building of a numerical simulation model for the fuel TMS, with the objective of minimizing fuel return flow. Sensitivity analysis was performed using variance analysis. The genetic algorithm was utilized for the optimization of the model building, taking into consideration the system’s geometric structure and performance parameters, which include the pipe length, the ram air-fuel HX’s efficiency, and the ram air’s volume flow rate in the ram air cooling subsystem, as design variables. The optimization solution for system design variables yielded a design scheme with the highest working efficiency for the fuel TMS. In this paper, the genetic algorithm in AMEsim software is adopted, which can also effectively optimize the design parameters and achieve the optimization objective. Compared with the original TMS structure, the heat dissipation capacity of the fuel TMS is improved and reduced the return fuel flow by 67.4% after the optimization of system structure parameters.

Design of Hydrostatic Power Shift Compound Drive System for Cotton Picker Experiment

To meet the working performance demand of cotton pickers, a hydrostatic power shift composite drive system design is proposed. This study aims to enhance the driving function of the cotton picker in various working conditions and improve its adaptability by combining a hydrostatic speed control system with a mechanical power shift structure. To achieve this, a single variable pump + double variable motor closed circuit is adopted. By adjusting the pump and motor displacement in stages, the driving speed of the cotton picker can be optimized for different working conditions. Additionally, the power shift mechanism is employed to increase the speed range and improve the transmission efficiency, enabling higher speeds to be achieved. Firstly, the main components of the composite drive system were calculated and selected, and then AMESim software was used for modeling and simulation analysis, and the results are as follows: When the cotton picker starts and picking operation stage variable displacement pump + fixed displacement dual motor speed control, the highest driving speed is 8.5 km/h. During the field and road transport operation stage fixed displacement pump + variable displacement dual motor speed regulation, the highest speed of 14.5 km/h was achieved in the field. When transferring to the road, the instant mechanical power shift speed and, the highest speed on the road was up to 27.5 km/h. Finally, the field experiment and speed ratio analysis of the drive system was conducted, and the average error of the experimental speed measurement was 0.588%. The speed ratio matching was in line with the design expectation. The results show that the hydrostatic power shift composite drive system designed in this study has good driving adaptability and can effectively meet the functions of cotton picker field picking, transport operation and road transportation in transit, which provides theoretical support for the design of cotton picker chassis drive system.

Accurate Modeling, Operation Laws and Commutation Timing Matching for Concrete Pumping Systems

The pump system is the heart of the concrete pump truck, and its main function is to deliver high-pressure concrete into the pipeline through the reciprocating motion and cooperation of the main cylinder and the distribution valve driven by the swing cylinder. However, there are currently problems, such as unclear pumping operation rules and mismatched commutation timing, that result in poor pumping efficiency and short life of wear parts such as spectacle plates and cutting rings. To address above problems, based on AMEsim software and system test data, this thesis establishes an accurate simulation model of the pump system with more than 90% precision. Based on this model, the simulation reveals the operating rules of the main cylinder and the swing cylinder during the pumping process; draws the commutation timing diagram of the pumping system; clarifies that the commutation timing has four characteristics: sequential, hysteresis, coupling and cyclic; and proposes an optimization scheme for the commutation timing, i.e., reducing the relief pressure of the main cylinder and shortening the swing time of the distribution valve. The proposed optimization has been proven in the market and significantly improved the life of wearing parts by more than 90%. This study provides technical reference for the structure and parameter optimization of concrete pumping systems.

The Research on Performance Characteristics of the Sliding Relief Valve

Based on the software AMESim, this paper introduced the operating principle and established the system models of relief valves. The effects on dynamic characteristics under the different parameters, including the number of overflow orifices, overflow orifice diameter and spring stiffness, were analyzed by the AMESim batch processing method. This paper compared and analyzed the curves and summarized the parameters which affect the performance characteristics of the relief valves. The result helps optimize the structure parameters and improve the performance characteristics of the relief valves.