Suspension Spring Research Articles

Mechanical characterization and static analysis of fiber based hybrid composite multi leaf spring

This work is to examine the possibility of utilizing a base expense and light weight materials for auto leaf spring suspension application. We contrast existing steel 65Si7 leaf spring and half and half composite leaf spring, for example, Epoxy/E- Glass/Viscose staple fiber (40%:45%:15%) in light of the disfigurement, flexibility, determination, strain energy putting away limit, cost viability and weight minimises. Static examination has been performed to consider the advantages of half and half composite materials for leaf spring suspension models in auto industry and results shows that Epoxy/E-Glass/Viscose staple fiber is the awesome the excess creation. Utilization of Epoxy/E-Glass/Viscose staple fiber (40%:45%:15%) prompts 76.37%weight decrease in leaf spring when contrasted with existing steel 65Si7 leaf spring.

Experimental study on vertical vibration characteristics of medium-low speed maglev vehicle when standing still on steel beams

Levitation stability is the very basis for the dynamic operation of Electromagnetic Suspension (EMS) medium-low speed maglev trains (MSMT). However, self-excited vibration tends to occur when the vehicle is standing still above the lightweight lines, which remains a major constraint to the promotion of medium-low speed maglev technology. In order to study the vertical vibration characteristics of the coupled system of MSMT when it is standing still above lightweight lines, levitation tests were carried out on two types of steel beams: steel beam and active girder of the turnout, with a newly developed maglev vehicle using levitation frames with mid-set air spring. Firstly, modal tests were carried out on the steel beam to determine its natural vibration characteristics; secondly, the acceleration signals and the dynamic displacement signals of the air spring obtained at each measurement point were analyzed in detail in both the time and frequency domains, and the vertical ride comfort was assessed by means of the calculated Sperling index. Subsequently, theoretical explanations were given for the occurrence of self-excited vibration of coupled system from the perspective of the vehicle-to-guideway vibration energy input. Results show that the eigen frequencies of the vehicle on the steel beam and the turnout are 9.65 Hz and 2.15 Hz, respectively, the former being close to the natural frequency of the steel beam while the latter being close to the natural frequency of the air spring suspension system, thus causing the self-excited vibration of the coupled system. It is recommended to either avoid the main eigen frequencies of the coupled system or to increase the damping of the corresponding vibration modes to guarantee a reliable coupled system for its long-term performance. These results may provide valuable references for the optimal design of medium-low speed maglev systems.

Dynamic Modal Analysis of a Passenger Bus: Theoretical and Numerical Studies

The dynamic assessment of a passenger bus is of the highest importance when aiming at high safety standards and low emissions for environmental sustainability. This work studies the dynamic response of a bus considering its modal analysis, for which simple dynamic models were developed for fast determination of the lowest frequencies, mainly arising from the suspension flexibility. In addition, complex natural vibration modes, impossible to determine using simplified models, were calculated via finite element method (FEM) modeling. To study the tire elastic behavior, as the key link between the vehicle and the road, specific deformation models, leading to a stiffness matrix to be combined with that of the vehicle spring suspension at each wheel/axis, were developed. This study aims at proposing a set of mathematical formulations to describe the modal behavior of passenger buses in detail, which could be applicable in any other long vehicle with similar conditions. Two main factors are studied, namely the suspension and the tire deformation effect. An acceptable agreement was verified between the simplified approach and FEM model results for the evaluation of natural frequencies and associated modes.

СОВЕРШЕНСТВОВАНИЕ КОНСТРУКЦИИ РЕССОРНОЙ ПОДВЕСКИ ПРИЦЕПНЫХ АВТОТРАНСПОРТНЫХ СРЕДСТВ

This article presents materials related to the development of a promising design of adaptive tor-sion bar suspension for trailed special and cargo vehicles, both trailers and semi-trailers, designed for the transportation of bulk and general cargo. A number of technical solutions, created at the level of inventions, are proposed, which make it possible to simplify the existing types of spring suspensions, reduce their metal consumption, improve the smoothness of trailed vehicles (TV) and increase their operational reliability due to the operation of suspensions in automatic mode when they overcome micro and macro unevenness of the roadway. Analytical studies were carried out with the development of a design scheme and a methodology for calculating the design of an adaptive torsion spring for static and dynamic strength.

Crosswind Stability of Metro Train on a High-Pier Viaduct under Spatial Gust Environment in Mountain City

To ensure the ride quality of metro system in mountain cities, the characteristics of the wind-train-bridge system with high-piers are studied, and the corresponding safety threshold is calculated in this paper. The improved spatial gust model considering the wind speed-up effect in mountainous terrain and spatial correlation is established. The time series of the wind loads are input to the dynamic system. The finite element method is used to model the bridge and the track, the multi-rigid-body system connected with the suspension spring and the damper is used to model each vehicle in the train. The whole process of the metro train running on the three-span high-pier viaduct is simulated. The study shows that both amplitude and frequency components of fluctuating wind have greater influence than the average wind, which can make the calculation result tend to be conservative and more conducive to analyze the vehicle running performance. Due to the comprehensive effect of the correlation of gust in spatial distribution, different vehicle parameters and aerodynamic coefficient differences, the response of each vehicle is different. The windward side of the high-pier bridge is the conservative calculation condition to evaluate the running performance. The wind barrier weakens the wind resistance of the bridge, but greatly improves the wind environment for the train. Metro train is less sensitive to increased wind speed with the wind barrier, but exceeds the limit under the same condition without any measures. When wind speed reaches 30 and 32 m/s, the ride comfort and running safety cannot be guaranteed respectively. The corresponding value for with single-side and bilateral barrier are 0.063 g and 0.061 g, decrease by 37% and 39% than that without barrier, and the value with two barriers are 0.216 and 0.211, decrease by 73% and 74%.

ANALISIS PENGARUH TEBAL PLAT TERHADAP KARAKTERISTIK MEKANIK PEGAS DAUN PADA PROTOTIPE MOBIL FISH CAR UNEJ (FCU) MUDSKIP

Fish Car Unej (FCU) Mudskip is a car designed with a rural terrain system, especially for fishing transportation. FCU Mudskip uses leaf spring suspension at the rear to support the weight of the vehicle, that is leaning towards the rear. The load of the vehicle is inclined to the rear due to the car carrying system in the form of fish and water. This conveying system can cause leaf spring failure. Therefore, this study aims to determine the value of stress, strain and cycle on leaf springs. Ansys 18.1 software was used to obtain stress, strain, and leaf spring cycle values with a thickness of 7 mm, 10 mm, and 13 mm. The value of stress on leaf springs with thickness 7 is 124,31 x 106 N/m2; thickness 10 mm is 74,92 x 106 N/m2; thickness 13 mm is 48,08 x 106N/m2; the value of strain on leaf springs with a thickness of 7 mm is 0,00075; a thickness of 10 mm is 0,00045; a thickness of 13 mm is 0,00029; Acceptable cycles of leaf springs are 7 mm thick is 69206 cycles, 10 mm is 77833 cycles, and 13 mm thick is 93054 cycles. Leaf springs with a thickness of 13 mm are the most optimal leaf springs because they can receive the most cycles of 93054 cycles, according to the function of leaf springs as vibration dampers.

Strength of Flexible Shell of Pneumatic Springs

The strength for a flexible shell of a vehicle pneumatic spring during movement relative to a rail track has been studied in the paper. The calculation has been carried out using the finite element method implemented in the SolidWorks software environment. For this purpose, 3D drawings of a balloon-type pneumatic spring have been reproduced. A specific feature of the design is that the distance between the upper and lower bottoms in static conditions is unchanged – thanks to the body position regulator, which maintains its constancy relative to the trolley frame. The results obtained have made it possible to conclude that there are certain reserves for the level of stresses, i.e., in addition to the vertical, it is possible to take into account also transverse mutual displacements of the air spring bottoms which will occur when the trolley moves relative to the body. At the next stage, the stresses in the material of the flexible shell are investigated for mutual transverse displacements of the bottoms, which are observed with transverse displacements of the trolleys relative to the body of the vehicle when traveling along curved sections of the track. At the same time, the maximum stresses in the material of the flexible shell of the pneumatic spring are about 11 MPa, even with twice the nominal air pressure and transverse mutual displacements of the bottoms of 40 mm, that is, they are much less than the breaking strength (30 MPa). The carried out researches allow to draw a conclusion that the design and parameters of a flexible shell of a balloon-type air springs ensure its strength under operational loading schemes. Therefore, in order to improve the dynamic qualities of vehicles, it is proposed to use a flexible shell of a pneumatic spring as a component of the spring suspension.

Damped rotational vibrations of a long cylinder with a disk in the air flow

We consider the drag and the damped rotational oscillations of a cylinder. The cylinder length-to-diameter ratio is nine. At the upstream end of the cylinder, a disk is mounted coaxially on the leg. The disk reduces the drag of the cylinder. The effect of the disk on damping of oscillations is described by aerodynamic rotational derivatives. Experiment in the wind tunnel is carried out with the flow past a cylinder fixed on an elastic spring suspension. In experiment, the diameter of the coaxial disk, position of axis of rotation and the gap between the disk and the cylinder vary. Deflected from the equilibrium position, the cylinder performs damped oscillations. The dependence of the amplitude of angular oscillations on time is determined by the tensometric method. Aerodynamic coefficients of rotational derivatives are found.

Quad Mass Resonator With Frequency Mismatch of 3 ppm Trimmed by Focused Ion Beam

This paper reports a frequency trimming method for a resonator used in a quad-mass gyroscopes (QMG) by focused ion beam (FIB) etching. The effects of the suspension stiffness, coupling stiffness and mass perturbations on the anti-phase mode resonant frequency were studied theoretically and numerically, proving the effectiveness and merit of the suspension stiffness trimming. The asymmetry caused by the suspension stiffness mismatch was further considered and its effects on frequency and Q-factor were investigated. Then the relationship between the trimming geometry of the suspension springs and the resonant frequency was studied by finite element analysis (FEA). The proposed trimming was demonstrated by using a QMG device fabricated by a standard SOI process. The resonant frequency mismatch was initially about 2810 ppm. After the proposed FIB trimming on the suspension springs, the frequency mismatch decreased to be as small as 3 ppm and the uncertainties do not exceed 75 ppm in the variation of ambient temperature between ±2 K. A slight change of Q-factor was observed in the trimmed axis from 100,000 to 90,000.

Performance of leaf spring suspended axles in model approaches of different complexities

Axles with leaf spring suspension systems are still a popular choice in many commercial vehicles. However, leaf springs are not in perfect conformity to standard multibody vehicle models because they combine guidance and suspension in one single element. Combining standard multibody vehicle models with sophisticated finite element leaf spring models results in rather complex and computing time-consuming solutions. Purely kinematic models, defined by lookup tables or the design kinematics approach, cover only some but not all features of the leaf spring suspension. As shown here, the five-link model, which incorporates a quasi-static solution of the leaf spring compliance, provides a very practical model. It is comparatively lean and provides results of sufficient accuracy in the whole application range.

The Design, Simulation and Fabrication of an Omnidirectional Inertial Switch with Rectangular Suspension Spring.

An omnidirectional inertial switch with rectangular spring is proposed in this paper, and the prototype has been fabricated by surface micromachining technology. To evaluate the threshold consistency and stability of omnidirectional inertia switch, the stiffness of rectangular suspension springs is analyzed. The simulation result shows that the coupling stiffness of the rectangular spring suspension system in the non-sensitive direction is a little more than that in the sensitive direction, which indicated that the omnidirectional switching system’s stability is reinforced, attributed to the design of rectangular springs. The dynamic response simulation shows that the threshold of the omnidirectional inertial switch using the rectangular suspension spring has high consistency in the horizontal direction. The prototype of an inertial switch is fabricated and tested successfully. The testing results indicate even threshold distribution in the horizontal direction. The threshold acceleration of the designed inertial switch is about 58 g in the X direction and 37 g in the Z direction; the contact time is about 18 μs.

Vibration Analysis of a Bus’s Air Spring Suspension Subjected to Random Road Profile

Vehicle dynamics model in type of 1/4 is used for vibration analysis under the effect of random road profile with different grades. The mathematical model to describe the used random road profile is able to change the type of investigated road grades by selecting the corresponding power spectral density parameter of the road grade according to the ISO 8608 standard. Random road profile is ivestigated in the range of frequency domain from 0 to 50 (Hz). The air spring stiffness and the damping coefficience are determined on the basis of reference to the practical vehicle. The variation of relative displacement amplitude of the suspension in the range of investigation domain is small, the air spring stiffness used in the calculation is constant. The obtained results corresponding to different grades of road surface roughness including displacement and acceleration parameters. Relative displacement is a parameter that aims to verify the ability to ensure safe working of the suspension, namely rattle spacing. Acceleration is used to evaluate the vehicle's comfort. Calculation results are analyzed as the basis for evaluating the influence of the air spring stiffness and road surface conditions on the comfort of the vehicle, as the basis for changing the air spring stiffness in accordance with adjusting the pressure of it according to the type of road profile quality.

Research on Dynamics of Vehicle Height Adjustment for Automobile with Double-Wishbone ECAS

This paper addresses the problem of dynamics of vehicle height adjustment for automobile with Double-wishbone electronically-controlled air suspension (ECAS) under considering the effects of suspension geometry and kinematics. The model of vehicle height adjustment consists of air spring model and suspension dynamics model. The air spring model was derived by thermodynamic theory for variable-mass gas charge/discharge system. The suspension dynamics model was formulated by kinematics analysis and dynamics modeling of double-wishbone suspension. Then, the influence of suspension geometry and kinematics on the model of vehicle height adjustment was quantitatively analyzed through simulation. Finally, Simulink-Adams co-simulation results show the accuracy of the model.

Selection of rational kinematic and geometric parameters of the "steering drive — suspension" system of the modernized wheeled vehicle

The issues of the consistency of the steering kinematics with the suspension kinematics of the modernized wheeled vehicle are considered. The influence of the geometric and kinematic parameters of the steering gear is analyzed. The results of a full factorial experiment with the determination of the rational parameters of the steering gear and the suspension are presented. Keywords: steering gear, consistency, longitudinal thrust, leaf spring suspension, controllability, vector of closed contours. ali_boy76@mail.ru

On the issue of choosing vertical and horizontal connections in a bogie for freight cars of high-speed trains

To increase the competitive advantages of rail freight transportation, the long-term development program of the Russian Railways provides for an increase in the speed of freight trains. The design speed of freight cars currently operating on the railway network is mainly 120 km/h, and the permitted speed is limited to 90 km/h. One of the possible solutions to the problem is the introduction of freight cars with an increased speed. At JSC “VNIIZHT” and JSC “VNIKTI”, work is being carried out on the selection of structures, the development of safety requirements, theoretical and experimental studies of freight traffic at increased speeds. In 2017—2018 at the Belorechenskaya—Maikop high-speed test range of the North Caucasian Railway, specialists of JSC “VNIIZHT” carried out running tests of a prototype of a platform car for transporting containers with a design speed of 160 km/h, developed by JSC “VNIKTI”. In the design of the platform car, a bogie is used, which is an analogue of the bogie of trailed cars of electric trains ED4 and ED9, with the selection of the stiffness of the springs in the spring suspension steps to comply with the difference in the level of the automatic coupler from the rail head in the “container” and “gross” modes. Analysis of the results of running tests allows determining the ways to improve the design of the bogie. To select design solutions for the purpose of ensuring safety, a review of the studies of domestic scientists aimed at studying the dynamic properties of railway rolling stock with various designs of the carriage part was carried out. Tests were carried out on prototypes of rolling stock having different elastic-dissipative connections in the “body-bogie-wheelsets” system. Based on the results of the analysis, design solutions have been determined that allow achieving satisfactory dynamic qualities for a freight car at a speed of up to 140 km/h. The adopted design solutions were tested on the basis of the results of theoretical studies of the dynamic properties of a platform car with a new bogie, carried out by the method of computer simulation. Increasing the flexibility of the spring suspension and the horizontal connection of the body with the bogie made it possible to improve the dynamic qualities of freight cars. To assess the safety during certification, it is required to develop a standard that would take into account the design features of car bogies, designed for increased speed.

Research of the Vertical Dynamics of the Supporting Structures of Freight Cars Made of Round Pipes

Purpose. This study is aimed at determining the vertical dynamics of supporting structures of freight cars made of round pipes. Methodology. Mathematical modeling of the dynamic loading of the supporting structures of the main types of freight cars made of round pipes (gondola car, covered car, flat car, hopper car) was carried out. The studies were carried out in a plane coordinate system – the XZ plane. At the same time, it was taken into account that the car is moving in an elastic-viscous track so that the reactions of the track are proportional to both its deformation and the rate of this deformation. The studies were carried out for the case of empty cars. The joint inequality is described by a periodic function. The calculation was performed at a speed of 80 km/h. Differential equations of motion were solved in the MathCad software package using the Runge-Kutta method. Findings. Based on the mathematical modeling of the dynamic loading of the supporting structures of cars made of round pipes, the main indicators of their dynamics were obtained: accelerations acting on the supporting structures in the mass center, forces acting in the spring suspension of bogies, dynamics coefficients. For gondola car, covered car, and hopper car, the acceleration at the mass center of the supporting structure is within 0.4 g, and for a flat car – 0.5 g. It was found that the obtained indicators of the dynamics of cars made of round pipes are within the permissible limits. The accelerations acting on the supporting structures of cars made of round pipes are almost the same as those obtained for prototype cars. At the same time, the motion of cars is assessed as "excellent" for gondola car, covered car, and hopper car and "good" for flat car. Originality. Mathematical modeling of the dynamic loading of the supporting structures of cars from round pipes was carried out and the main indicators of their dynamics were obtained. Practical value. The research carried out will contribute to the creation of recommendations for the design of supporting structures of freight cars of round pipes, and can also be useful developments in the creation of innovative car designs.

Analysis of Helical Suspension Spring for Different Material Using Finite Element Method

There is tough competition in the automobile industry to reduce the weight and optimize the characteristics of suspension system. In this paper discussion about analysis of helical suspension spring carried out. Helical suspension spring analyzed for different material like steel, carbon fiber composite, Kevlar fiber composite. To get the higher stiffness to weight ratio composite material are used. Spring Geometry is modeled in CATIA software and another hand it is analyzed in ANSYS Workbench under different loading condition.

Neuro-fuzzy fatigue life assessment using the wavelet-based multifractality parameters

This study aims to establish a fatigue life predictive model based on multifractality of road excitations using neuro-fuzzy method to assess the durability of suspension spring. Traditional durability analysis in time domain is complicated and time-consuming due to the needs of large data amount. Thus, it is an idea to adopt an adaptive neuro-fuzzy inference system (ANFIS) for relating the performance of coil spring to the multifractal properties of road excitations, giving a meaningful fatigue life prediction. Different membership function numbers were tested to obtain the optimum membership function number. During the data training process, the checking data was used to test the trained model each Epoch of training for overfitting detection. As a result, the Morrow-based fatigue life prediction model was found to give the most suitable result with three membership functions. The SWT-based model needed five membership functions due to nonlinear properties in the SWT-based fatigue life data. Training process of Morrow-based-ANFIS was stopped at Epoch 8 given its lowest checking root-mean-square-error of 0.6953. SWT-based model recorded a higher error of 0.7940. The neuro-fuzzy models gave accurate fatigue life predictions with 96 % of the data distributed within the acceptance boundary, hence, contributing to an acceptable assessment of coil spring fatigue life based on load multifractality. This study had shown a nonlinear relationship between road multifractality and durability performance of coil spring. Multifractality had been proven an important feature to characterise various road excitations for durability prediction.

Characterization of low‐acceleration, long‐duration horizontal events using a spring suspension straight delivery box truck

AbstractA field measurement study, using a combination of controlled and uncontrolled phases, examined low‐acceleration, long‐duration events occurring during over‐the‐road truck transport. A field data recorder equipped with a DC‐based triaxial accelerometer was employed for this study to capture the steady‐state nature of these event types. The field data recorder was rigidly mounted to the trailer chassis to record lateral and longitudinal events of interest. The controlled phase recorded normal and aggressive braking events and traversing a roundabout to fundamentally quantify the behaviour of the vehicle. For the controlled phase, average decelerations of 0.27 and 0.45 g were reported for normal and aggressive braking events, respectively. Lateral accelerations from traversing a roundabout were on average 0.40 g. The uncontrolled field measurement study, which evaluated the transport vehicle over 13 days, reported average longitudinal decelerations and lateral accelerations of 0.29 and 0.34 g, respectively. The rise times associated with these events were also reported. The jerk was calculated based on the rise times for the controlled and uncontrolled phases and compared to currently available test procedures. For both project phases, composite test profiles were developed based on field‐measured levels. The resulting composite test profiles can be utilized to evaluate the load stability of a unit load system travelling through this distribution channel.

Designing and Analyses of Leaf Spring Suspension System Using Creo Parametric 2.0

This paper presents various aspects of Leaf Spring suspension system,its Analysis and Design. A suspension system isolates the vehicle from wheel and road vibration and absorbs most of the shock. In this paper a design as well as analysis has been done of aLeaf spring suspension system. For the research, designing has been done in Creo Parametric 2.0 software. Different design parameters have been reviewed and optimization of the major parameters is shown as given by research that affects suspension over Creo Parametric 2.0 Software. At last, the results have been displayed with various graphs.