Pneumatic Spring Research Articles

Influence of the geometric parameters of the connecting pipeline on the stiffness and damping of the pneumatic spring suspension at high-speed rolling stock

The study presents investigation is the pneumatic spring suspension system of diesel train DPKr-3. The research aims to estimate the influence of track irregularities on the pneumatic spring dynamic stiffness and its damping coefficient at 170–250 km/h speeds. The pneumatic spring suspension system characteristics were studied using an improved mathematical model of the system ‘rolling stock-track’. The pneumatic spring ‘force-strain’ relations are obtained at different values of the connecting pipeline diameter and length at high speeds. It was determined that increasing a connecting pipeline diameter from 20 to 40 mm and a speed change from 170 to 250 km/h causes decreasing a spring dynamic stiffness. It is shown that at a speed range from 170 to 250 km/h and a connecting pipeline diameter from 20 to 40 mm, a change in a pipeline length from 3 to 6 m does not lead to significant changes in stiffness. It was found that in the range of speeds from 170 to 250 km/h, the damping coefficient has maximum values with a diameter of the connecting pipeline from 25 to 30 mm.

Performance analysis of passive heave compensator operated with inclined piston using analytical method.

When performing operations such as drilling in the ocean, floating platforms undergo vertical motion due to waves, which negatively impacts these operations. So passive heave compensator(PHC) is used to counteract it. In many studies, the analysis of PHC with pneumatic springs has been done. Some of these papers analyzed it using simple second-order differential equations, but there was no case of modeling considering the pneumatic spring installed tilted in the PHC. On the other hand, in some papers, the characteristics were analyzed by numerical methods using multi-body dynamics equations, and it is time consuming. Therefore, in this paper, a second-order ordinary differential equation modeling method for PHC with an inclined pneumatic spring was presented and verified by comparison with the numerical method. Using the model presented in this paper, it is possible to analyze as accurate as conventional analytical methods, and to analyze characteristics faster than numerical methods.

Stiffness model for pneumatic spring with air-diaphragm coupling effect

Stiffness model for pneumatic spring with air-diaphragm coupling effect

INVESTIGATION OF VERTICAL AND HORIZONTAL DEFORMATIONS OF THE PNEUMATIC SPRING OF A HIGH-SPEED MOVING VEHICLE IN THE LIMITS OF THE ARROW OF THE ARROW GEAR

The object of the research is the pneumatic spring of the second stage of the spring suspension of the high-speed rolling stock of the railway. The vertical and horizontal deformations of the pneumatic spring within the scope of the arrow translation are studied. For constructive reasons, two sections of the turnout were chosen, namely the section of the tip of the spikes and the section of the root of the spikes. In order to determine the deformations of the pneumatic spring, a methodology for its full-scale testing has been developed, which includes the use of a test rig that has a rigid metal frame on which the pneumatic spring and measuring equipment are installed. High-frequency potentiometric linear displacement sensors were used to measure vertical and horizontal deformations. In accordance with the developed complex program of field tests, records of vertical and horizontal deformations of the pneumatic spring of the high-speed rolling stock were obtained during the movement of the turn signal in the forward and opposite directions. It was found that the vertical deformations of the pneumatic spring within the range of movement by the arrow transfer in the furrow and anti-furrow directions are greater than the horizontal ones. In addition, in the opposite direction of movement of the test rig, the vertical deformations of the pneumatic spring are larger compared to the opposite direction of movement. It was established that the maximum values of the vertical deformations of the pneumatic spring are within the range of 3.14–5.05 mm in the wool direction and 4.88–5.95 mm in the anti-wool direction. The maximum values of horizontal deformations are within 1.62–2.94 mm and 1.30–2.53 mm, respectively. It was established that the average value of the vertical and horizontal deformations of the pneumatic spring of the high-speed rolling stock within the range of the arrow of the turnout is: for forward motion – 3.85 mm and 2.02 mm, for forward motion – 5,48 mm and 1.82 mm, respectively. The obtained results will make it possible to proceed to the determination of the dynamic characteristics of the pneumatic spring, and at the stage of designing high-speed rolling stock to study its dynamic indicators and traffic safety indicators under different operating conditions.

Semi-Active Suspension Design for Truck Using Pneumatic Spring Joining MR Fluid Damper Based on Neural Networks Controller

<div>In order to modify both stiffness and damping rates according to various road conditions, this research introduces a pneumatic spring in conjunction with a magnetorheological (MR) fluid damper as a single suspension unit for each wheel in the truck. Preventing weight transfer and improving riding comfort during braking, acceleration, and trajectory prediction are the main objectives. A two-axle truck has been used, consisting of three degrees of freedom for the sprung mass, including vertical, pitch, and roll motions, and four degrees of freedom for the unsprung masses, which have been redesigned according to the different types of springs and dampers. Pneumatic-controlled springs, often referred to as dynamic or classic models, replace laminated leaf springs commonly found in vehicles. Additionally, an MR damper replaces a hydraulic double-acting telescopic shock absorber. These models are studied to evaluate the effect of pneumatic spring parameters on truck dynamics. Pneumatic stiffness and the intended damping force are monitored by a recurrent neural network in conjunction with leveling control. This process provides the recommended voltage for the MR damper based on the Signum function damper controller. The performance of the suspension is assessed in the time and frequency domains for both step and random road excitations using vehicle dynamic parameters. Six suspension system configurations are compared with the air spring dynamic model integrated with the MR damper (Model 6), which is recommended as a suspension system for trucks. According to simulation data, when compared to alternative suspension systems, Model 6 significantly enhances both ride comfort and vehicle stability. Model 6 offers improvements in tire workload, truck path, tire–ground contact point during acceleration, braking efficiency, and stopping distance. Compared to previous controlled models, Model 6 also demonstrates zero steady-state offset and zero steady-state error.</div>

Dynamic characteristics analysis of shock absorber based on fluid simulation

Pneumatic spring dampers are extensively utilized within hydraulic systems, and the flow characteristics of the internal oil play a crucial role in determining noise and vibration levels. To validate the mechanical structure's reliability, the shock absorber was simplified and the fluid domain was extracted using a CFD method. The velocity field and pressure field under different conditions were then simulated and analyzed. A finite element model of the flow field was established, and its accuracy was verified by comparing simulation results of gas side pressure with experimental results. According to the working principle of the oil-gas spring, dynamic active surfaces in contact with the main piston and dynamic driven surfaces in contact with the floating piston were defined, determining moving conditions for dynamic grids. The results indicate that as the diameter of flow channels increases, there is a decrease in average pressure drop within the oil chamber (i.e., pressure loss within the flow field). Additionally, as bend angle increases, average pressure drop decreases. However, optimization effects become less significant beyond a certain bend angle.

Method of experimental determination of the effective area of a pneumatic spring of high-speed rolling stock

Method of experimental determination of the effective area of a pneumatic spring of high-speed rolling stock

Multi-Body Model of Agricultural Tractor for Vibration Transmission Investigation

This article analyses vibration transmission on agricultural tractors with the excitation from the road to the driver’s seat. A multi-body model of agricultural tractors created in Adams is presented. The main parts for the investigation of vibration transmission are the tractor body, where the only suspension elements are tyres, the tractor cabin, spring-dampers suspended at the rear and bushings at the front, and the driver seat with its pneumatic spring. A series of measurements were performed, and the model was validated using vertical acceleration values on the tractor body at four different locations. The FTire model (physical FEM-based model) was chosen to describe the behaviour of tyres. The model was created using measured tyre characteristics. Measured characteristics of spring-dampers and front cabin bushings were also implemented. For comfort investigation, ride simulations on ISO 5008 rough roads were performed. The transmission of vibrations in ride simulations was examined. A modal analysis of the linearised model was performed to confirm assumptions of the contribution of suspension elements to overall vibration levels. Finally, three case studies were conducted to better understand the model’s vibration transmission properties.

Investigation of the Influence of a Turnout Cross on Vertical and Horizontal Deformations of a Pneumatic Spring of High-Speed Rolling Stock

Purpose. The aim of the study is to determine the values of vertical and horizontal deformations of the pneumatic spring of high-speed rolling stock during the movement of the test setup along the cross of the switch in the forward and reverse directions. Methodology. To determine the deformations of the pneumatic spring, a special test bench consisting of a pneumatic spring and specialized measuring equipment was developed. The deformations of the air spring in the vertical and horizontal planes were measured using high-frequency potentiometric linear displacement sensors, the signals from which were read using a programmed analog-to-digital converter. To obtain reliable data on the deformations of the air spring, six passes of the test bench were made in the forward and reverse directions of the cross member. Findings. A methodology for dynamic testing of a pneumatic spring of high-speed rolling stock under conditions of movement along the crosshead of a turnout in the forward and reverse directions was developed. The records of vertical and horizontal deformations of the pneumatic spring of high-speed rolling stock under the conditions of movement along the crossover of a switch were obtained. It is established that the deformations of the pneumatic spring in the vertical plane are higher than those in the horizontal plane. The average value of the vertical deformations of the pneumatic spring in the forward direction is 3.15 mm, which is 9.98 % higher than the average value in the opposite direction of the test unit's movement along the cross-section of the switch. In the horizontal direction, this difference in deformation of the air spring is 25.1 %. Originality. For the first time, the vertical and horizontal deformations of the pneumatic spring of high-speed rolling stock under the conditions of movement along the crossbar of a switch were determined, taking into account the direction of movement, forward and reverse. Practical value. Determining the values of deformations of the pneumatic spring will allow to study its dynamic characteristics in different operating conditions of rolling stock, and at the design stage to select the appropriate characteristics of the pneumatic spring suspension system and determine the dynamic and safety indicators of rolling stock.

Design and Development of Combined Mechanical and Pneumatic Valve Spring Remover

A combined mechanical and pneumatic valve spring remover is used to remove or install valve springs from an engine while the cylinder head is mounted on the engine or supported on a workbench (off the head). The designed tool was adjustable and mounted over the cylinder head by a stud. It can operate manually to depress the spring or by using an air compressor for a pneumatic actuator. The model of the tools is done by SOLIDWORK 2021 and we selected the stainless steel AISI grade-304(12) material. Tools were made following the calculations that have been done on valve springs. From the data calculation, the force required to depress the valve spring is 1350 N but the tools were designed to produce 1962.5 N by considering some friction loss. The analysis of the pneumatic system done by ANSYS software shows acceptable results like, Von Mises stress (20.036 MPa), maximum principal stress (26.426 MPa), and the total deformation becomes 1.6029×10-3. The prototype was built, and the test was carried out in time efficiently during the removal or installation of the valve spring on Engine YaMZ-238. The test result shows that to remove 4 springs, the designed tool is very effective to use by optimizing the difference in time savings of an average of 1 minute and 17 seconds when removing the spring valve, and 1 minute and 26 seconds when installing the valve, even when we use it mechanically. The developed valve spring remover has several advantages over the standard C-clamp tools, such as greater precision and accuracy in removing valve springs, reduced labor and time required for the task, and Increased safety with minimal human force.

Design of plastering device of plastering machine

Abstract The plastering machine can effectively improve the plastering efficiency, and the plastering process mainly includes filling the mortar, plastering, floating mortar, and compacting mortar. All of these function is completed by a plastering device. The diversity and complexity of the device increase the production cost and the weight of the whole machine. In order to guarantee the plastering quality and optimize the institution, this thesis designs a plastering device that integrates mortar supply, plastering, surface flattening, and compacting functions. The working process of the plastering mechanism includes upward plastering and downward flattening, mainly achieved by the rotation motion of the hopper. The contour shape of the hopper was designed using the principle of cam mechanism, and the upward plastering and self-locking of the hopper after reaching the top were designed using the principle of connecting rod mechanism. The hopper is supported by two pneumatic springs. The flipping force of the pneumatic springs during the upward plastering and downward plastering processes was analyzed and calculated, which provides the basis for choosing the power of the driving motor.

Determining the effect of additional tank volume and air pressure in the spring on the dynamic indicators of a pneumatic system of spring suspension in high-speed railroad rolling stock

The object of this study is the pneumatic system in the spring suspension of rolling stock under conditions of high-speed movement from 170 to 250 km/h. Based on the thermodynamic model of the pneumatic spring suspension system, the influence of volume of the additional tank and the initial pressure in the pneumatic spring on the nature of change in the spring's dynamic stiffness, energy losses, and damping coefficient was studied. Based on the built "force-deformation" dependences for the pneumatic spring, it was established that the change in the volume of an additional tank has a slight effect on the deformation of the pneumatic spring at different speeds of the high-speed rolling stock. It was established that in the range of rolling stock speeds of 170–250 km/h, the diameter of the connecting pipeline is 30 mm, and the volume of the additional tank is from 30 to 60 l, the maximum change in the dynamic stiffness of the pneumatic spring up to 15.5 % occurs at the pressure in the spring of 6.5 bar. Dependences of energy loss and damping coefficient during the operating cycle of the pneumatic spring suspension system were derived. It was established that an increase in the volume of the additional tank and the initial pressure in the pneumatic spring leads to an increase in the energy loss during the operation cycle of the pneumatic system. The maximum values of the damping coefficient over the entire considered range of variable parameters are 1.16–1.29. It was established that with the volume of the additional tank in the range from 30 to 50 liters, the maximum values of the damping coefficient are observed at a diameter of the connecting pipeline of 25 mm and a speed of movement from 200 to 250 km/h. And with an additional tank volume of 60 liters – with a diameter of 30 mm and a speed of 170 to 250 km/h

AN EXPERIMENTAL STUDY OF THE EFFECT OF AN ADDITIONAL TANK ON THE DEFORMATION OF THE PNEUMATIC SPRING OF HIGH-SPEED RAILWAY ROLLING STOCK

The use of a pneumatic spring suspension system in the second stage of spring suspension of high-speed rolling stock is an integral component of ensuring its permissible dynamic indicators and traffic safety indicators. This work is aimed at researching the deformation characteristics of the rubber-cord shell of the pneumatic spring in the vertical and horizontal directions, taking into account manometric pressure, external load and an auxiliary reservoir. To achieve the goal, a methodology for experimental studies of pneumatic spring deformation was developed using a test rig with an assembled pneumatic spring suspension system, power and measuring equipment. Deformations of the rubber-cord sheath were measured by analog sensors of linear displacements using an analog-to-digital converter and special software. It was established that the effect of the auxiliary reservoir on the amount of vertical deformation of the lower part of the rubber-cord shell does not exceed 3.46 %, which allows us to conclude that the auxiliary reservoir of the pneumatic spring suspension system has a negligible effect on the vertical deformations of the lower part of the rubber-cord shell of the pneumatic spring. The dependences of the deformation of the rubber-cord shell of the pneumatic spring in the horizontal direction on the value of the manometric pressure when the auxiliary reservoir is connected and disconnected are obtained. It was established that in the range of manometric pressure changes of 1.0÷2.5 atm the presence or absence of an auxiliary reservoir has little effect on the amount of deformation of the rubber-cord sheath in the horizontal direction. However, at a pressure of more than 2.5 atm, closing the tap to the auxiliary reservoir leads to significantly greater deformation of the rubber cord shell compared to the deformation when the tap is open and the auxiliary reservoir is turned on. The obtained results regarding the deformation characteristics of the rubber-cord shell of the pneumatic spring will allow us to proceed to the study of the dynamic characteristics of the pneumatic spring, which are necessary when establishing safe conditions for the operation of modern high-speed rolling stock at the stage of its design.

Experimental Study of the Regularities of Deformation of the Rubber Cord Shell of a Pneumatic Spring of High-Speed Rolling Stock

Purpose. The aim of this work is to establish the regularities of deformation of the rubber cord shell in the vertical and horizontal directions in the case of changes in the internal pressure in the pneumatic spring by static experimental studies. Methodology. A static test bench was used to establish the regularities of deformation of the rubber cord shell of a pneumatic spring. Changes in the internal pressure in the pneumatic spring were achieved using a compressor, and the deformation of the rubber cord shell was measured directly by high-frequency potentiometric linear displacement sensors. The deformation of the rubber cord shell of a pneumatic spring in both the vertical and horizontal planes was studied under the condition of changing the internal pressure in the spring in the range from 0 to 5 atm. Findings. Using the designed test bench, a methodology for experimental studies of the deformation of a rubber cord shell with increasing internal pressure in a pneumatic spring was developed. The dependences of the deformation value of the rubber cord casing of a pneumatic spring when the internal pressure changes in the range of 0÷5.0 atm were obtained. It is established that the deformation of the rubber cord casing with an increase in the internal pressure in the pneumatic spring in the horizontal plane is more intense compared to the vertical plane. It is found that the maximum values of deformation of the rubber cord shell of a pneumatic spring in the vertical and horizontal directions are observed at the initial stage of air injection in the range of pressure changes from 0 to 0.5 atm. The polynomial equations describing the deformation dependences of the rubber cord shell of a pneumatic spring were obtained. Originality. The regularities of deformation of the rubber cord casing in the vertical and horizontal planes at different values of the internal pressure in the pneumatic spring were determined by experimental static studies. Practical value. The study of the regularities of deformation of the rubber cord shell will contribute to a more accurate modeling of the operation of the pneumatic spring and a reliable determination of its dynamic performance. This will make it possible to use the dynamic performance of the air spring in the spatial mathematical model of the rolling stock at the design stage, as well as to evaluate its dynamic performance and traffic safety indicators.

The stiffness of elastomeric diaphragm in pneumatic springs

The stiffness of elastomeric diaphragm in pneumatic springs

A novel semi-active control of an integrated chassis and seat quasi-zero stiffness suspension system for off-road vehicles

This article introduces an innovative semi-active suspension system for off-road vehicles, incorporating a quasi-zero stiffness suspension to enhance driver comfort. The system includes a central pneumatic spring, double-acting pneumatic linear actuators for adjustable stiffness, and magnetorheological dampers for controlled damping. Using Lyapunov stability theory, a static output feedback control law is designed to address uncertainties in road profiles, driver body parameters, and actuator saturation, relying on measured variables as feedback. Performance constraints focus on driver head acceleration, suspension displacement, and dynamic tire load. The control law problem is converted into a convex optimization problem with linear matrix inequalities. The new semi-active QZSS system is theoretically tested via Matlab simulations and validated through hardware-in-the-loop testing. Comparative analysis between passive QZSS and the new semi-active QZSS on different roads, and vehicle speeds closely aligns with simulation results, with minor disparities attributable to network discrepancies and signal interruptions. Impressively, the semi-active QZSS system reduces driver head vertical acceleration between 26.53 and 35.0% compared to passive air QZSS, showing potential for significantly improving ride comfort, reducing vibration transfer, and enhancing driver wellbeing with minimal energy requirement.

Studying the diagrams “force - deformation” of a pneumatic spring of a modern rolling stock at increased speeds

The research object is a pneumatic spring of a modern rolling stock. Using a two - mass calculation scheme, the diagrams “force-deformation” of a pneumatic spring are designed at driving speed of 160-200 km/h and high-speed driving of 201-250 km/h. It is determined that when the diameter of the connecting pipeline is changed from 20 to 35 mm, the inclination angle of the diagram “force - deformation” of the pneumatic spring is changed at speed driving from 32 degrees up to 57 deg.; at high-speed driving from 30 deg. up to 48 deg. It is proposed to determine a pneumatic spring operation coefficient using the forms of the designed diagrams “force - deformation.” Studying the specified coefficient in the speed range from 160 to 250 km/h, and the connecting pipeline diameter from 20 to 35 mm showed that the values of the pneumatic spring operation coefficient vary from 0.089 to 0.24, and the dependencies are nonlinear. Using the pneumatic spring operation coefficient will make it possible to further evaluate the pneumatic spring suspension system operation depending on the operating conditions of the railway vehicle.

Numerical and analytical method of calculation of dynamic strength of modernized air springs for high-speed electric trains

The article presents a new design of a pneumatic suspension device for the high-speed electric train “AFROSIAB”, Uzbekistan. The authors developed a numerical-analytical method for the calculation of dynamic strength of modernized pneumatic springs for high-speed electric trains; an algorithm and a program for the Mathcad 15 programming environment were built. The design given in the article is protected by the Patent of the Republic of Uzbekistan for invention No. IAP 04632 [1].

Synthesis of an electromechanical system of body tilt and recuperation of vibration energy for a high-speed electric train

This paper considers issues related to the undercarriage system of a high-speed electric train with body inclination and a vibration recovery system. The main suspension systems of the electric train body, which are currently used, were investigated. The existing shock absorption systems and alternative approaches and solutions for increasing the speed characteristics of electric rolling stock have been highlighted. A basic problem of these suspension systems was put forward, which is the lack of the possibility of recovery of oscillations, as well as the complexity of systems for tilting the body. The main dimensional and power parameters of the proposed promising shock absorber are presented. The characteristics of basic parameters of the electromechanical shock absorber were compared with those of a pneumatic spring shock absorber. A simulation model of a high-speed electric train with an electromechanical shock absorber was built in the MATLAB Simulink environment. The main units of the simulation model were defined and described, owing to which it is possible to simulate the inclination of the body to a given angle and the simulation of vibration energy recovery. Based on the results of simulating the operation of an electromechanical shock absorber as part of the undercarriage of the electric locomotive, it was determined that the synthesis of this system makes it possible to tilt the body by 5 degrees in 2 seconds. It is also stated that the proposed system makes it possible to reduce the vibrations of the electric train body by 2 times, and to recover 84 W/h of vibration energy. The body tilt results are predetermined by the speed of the mechanism due to the absence of a compressor set used in the pneumatic system. The scope of application of the vibration damper also includes the automotive field, subject to additional research into the form, amplitude of road surface vibrations and changes in overall parameters in accordance with the requirements

Performance benchmarking of an ultra-low vibration laboratory to host a commercial millikelvin scanning tunnelling microscope

Ultra-low temperature scanning tunnelling microscopy and spectroscopy (STM/STS) achieved by dilution refrigeration can provide unrivalled insight into the local electronic structure of quantum materials and atomic-scale quantum systems. Effective isolation from mechanical vibration and acoustic noise is critical in order to achieve ultimate spatial and energy resolution. Here, we report on the design and performance of an ultra-low vibration (ULV) laboratory hosting a customized but otherwise commercially available 40 mK STM. The design of the vibration isolation consists of a T-shaped concrete mass block (∼55t), suspended by actively controlled pneumatic springs, and placed on a foundation separated from the surrounding building in a ‘room-within-a-room’ design. Vibration levels achieved are meeting the VC-M vibration standard at >3 Hz, reached only in a limited number of laboratories worldwide. Measurement of the STM’s junction noise confirms effective vibration isolation on par with custom built STMs in ULV laboratories. In this tailored low-vibration environment, the STM achieves an energy resolution of 43 μeV (144 mK), promising for the investigation and control of quantum matter at atomic length scales.