Vehicle Sprung Research Articles

DEFORMATION OF END CROSSBEAMS OF STEEL BRIDGES RELATED TO SUSTAINABILITY OF BRIDGE JOINTS

Both AASHTO and Eurocode stipulate that the deflection of end crossbeams of bridges must be limited to 5 mm under the influence of frequent traffic loads. After a thorough literature review and survey of data from manufacturers of bridge joints, it must be concluded that the background of this requirement is not really based on facts. Durability of bridge joints certainly does not appear to be the basis. Another valid reason can be the comfort of road user, which is effectively disturbed by driving over bumps and thresholds. Although the road user expects light shocks at the end of a bridge, the acceleration inside the vehicle must be limited. Therefore, the state of a wheel driving over a threshold has been studied, by applying analytical equations taken from literature and extended. These allow a fairly accurate simulation of the state. Force required to cross the threshold produces an acceleration of wheel, which is transmitted to vehicle's sprung chassis. In the latter one finds the acceleration to which persons are subjected. Several values of comfort can be considered. It turns out that 5 mm limit is very conservative, and one could easily allow up to double the end cross beam’s deflection.

DEFORMATION OF END CROSSBEAMS OF STEEL BRIDGES RELATED TO SUSTAINABILITY OF BRIDGE JOINTS

Both AASHTO and Eurocode stipulate that the deflection of end crossbeams of bridges must be limited to 5 mm under the influence of frequent traffic loads. After a thorough literature review and survey of data from manufacturers of bridge joints, it must be concluded that the background of this requirement is not really based on facts. Durability of bridge joints certainly does not appear to be the basis. Another valid reason can be the comfort of road user, which is effectively disturbed by driving over bumps and thresholds. Although the road user expects light shocks at the end of a bridge, the acceleration inside the vehicle must be limited. Therefore, the state of a wheel driving over a threshold has been studied, by applying analytical equations taken from literature and extended. These allow a fairly accurate simulation of the state. Force required to cross the threshold produces an acceleration of wheel, which is transmitted to vehicle's sprung chassis. In the latter one finds the acceleration to which persons are subjected. Several values of comfort can be considered. It turns out that 5 mm limit is very conservative, and one could easily allow up to double the end cross beam’s deflection.

Review on Modeling and Optimization of Electric Vehicle Alloy Wheel

The need for vehicle production now is an increase in vehicle demand at a lower rate. Customers' expectations in terms of longevity, effectiveness, and affordability are increasing tremendously. Automobile wheels constructed of an alloy of aluminium or magnesium metals, or occasionally a combination of the two alloys, are known as alloy wheels. Because they are lighter than steel wheels, alloy wheels are superior to steel wheels for motorcycle driving and handling. Overdesigned vehicle load components increase weight and decrease efficiency. The suspension system supports all of the wheels, which can be changed and adjusted to reduce weight and expense. All of the wheels carry the vehicle's sprung mass. There were already existing alloy components in the reverse-engineered and CAD modelled using CATIA V5 software. Key Words: Composite material, Alloy wheels, Magnesium alloy, Design optimization, weight optimization, stress analysis,

A Model-Based Approach for Setting the Initial Angle of the Drive Axles in a 4 × 4 High Mobility Wheeled Vehicle

This article presents an analysis of the driveline operation of a high-mobility Jelcz 442.32 wheeled vehicle, which uses rigid drive axles connected to drive shafts with two universal joints (another name for the Cardan joints) due to the occurrence of kinematic incompatibility. The conditions for the correct connection of the drive shafts with two universal joints (Cardan joints) were presented, and the kinematic ratio of the complete drive shaft was defined. In the analysis of kinematic incompatibility regarding (but not limited to) the method of loading the vehicle, selected characteristic conditions of vehicle movement and the initial values of the angular setting of the rigid driving axles in relation to the vehicle body were presented. It has been shown that, in the analyzed vehicle, the kinematic incompatibility in the driveline is constantly present, and the value of this incompatibility, represented by the temporary ratio of drive shafts, depends on, among other things, the ways of loading the vehicle, the existing conditions of vehicle movement, and the type of ground. Moreover, the value of the arising kinematic incompatibility was noticed to be highly influenced by the correct manufacturing and assembly of the vehicle springs.

The comprehensive effect of friction self-excited and modal vibration on polygonal wear of high-speed train wheels

Wheel polygon wear has emerged as a critical issue in the development of high-speed trains in China, but the mechanism underlying its formation remains unknown. The formation mechanism and its effect factors of wheel polygonalization are investigated in depth in this paper using theoretical analysis and numerical simulation. A longitudinal self-excited vibration and vertical modal vibration coupling model of wheel-rail is established, considering the comprehensive effects of wheelset flexibility, vehicle spring mass, and foundation under rail. The critical condition of the system Hopf bifurcation is determined by theoretical analysis, and the longitudinal vibration characteristics of the wheel are studied using numerical simulation. Furthermore, the influence factors on wheel polygonalization are investigated. The research method makes a useful attempt to unify the relevant viewpoints of resonance theory and self-excited vibration theory, and the research results have theoretical guiding significance and engineering reference value for the prediction and suppression of wheel polygonal wear.

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.

INFLUENCE OF VEHICLE SUSPENSION PARAMETERS ON ITS BRAKING PROPERTIES

The paper focuses on the study of the performance of elastic and damping parameters of the car suspension. The problem of arising vibrations of the sprung and unsprung vehicle masses on the braking process is considered. The article presents theoretical models of vehicle braking taking into account the oscillations of the vehicle's sprung masses. The research results will make it possible to establish the relationship between the suspension parameters and the estimated parameters of braking properties, to supplement the "driver - car - road" system, and also to more accurately assess the active safety of vehicles associated with braking dynamics.

Pengaruh Kombinasi Terhadap Kekuatan Material Golok Sulangkar Campuran 10% Pegas 90% Baja SS 400

The manufacture of tools such as machetes in Banten is still widely practiced, machetes are produced from a conventional forging process using a hammer by a blacksmith. Working as a blacksmith in the Banten area, especially in the village of the new village of lightning, was passed down from generation to generation as a traditional blacksmith, but over time the machetes produced by traditional blacksmiths began to be replaced by modern ones machete. The traditional golok of Kampung Baru Village, Petir, consists of two types, the regular machete and the sulangkar golok. The material commonly used by blacksmiths to make machetes is a vehicle spring sheet that is no longer used, while for making machetes, a blacksmith usually combines other materials during forging. The purpose of this study was to determine the differences in the mechanical and micro properties of the two types of golok, Banten cultural heritage. The research was carried out from the start of the search for the material, the manufacturing and forging processes and carried out testing. The results of the hardness test show that the value of the spring material is 423.1 HBW, SS 400 steel material 134.18 HBW, combination material or Sulangkar 735.15 HBW then the data results from the tensile test on steel material SS 400, Spring, Combination or Sulangkar are 442.52 MPa, 1334,60 MPa, 522.81 MPa. The results of the data from the impact test on Spring material, SS 400 steel, Combination or Sulangkar, namely 162 J, 34 J, 88 J. The results of automatic microscope testing and Scanning Electron Microscope (SEM) show the surface of the spring, SS 400 steel and combination materials.

Fault Diagnostics and Prognostics for Vehicle Springs and Stablizer Bar

Vehicle springs and stabilizer bar are critical suspension components impacting vehicle riding and handling experience. Diagnostics and prognostics of springs and stabilizer bar can improve customer perceived quality, reduce repair cost and increase up-time for fleet vehicles. It’s even more important for autonomous vehicles, since there is no human driver to sense fault symptoms. Currently, there is no production solution to automatically diagnose and prognose spring and stabilizer bar failures, and most research work is suffered by various noise factors. In this work, a novel solution based on static ramp test is proposed to isolate and localize spring and stabilizer bar faults. With limited number of longitudinal and lateral acceleration measurements, the solution can quickly and effectively isolate faulty spring, disconnected stabilizer bar, loose bushing and loose end link. The validation results from a MY17 Bolt EV demonstrate the effectiveness and robustness of the proposed solution.

Reliability-based fatigue life of vehicle spring under random loading

Purpose The purpose of this paper is to analyse fatigue-life prediction based on a reliability assessment for coil springs of vehicle suspension systems using different road excitations under random loading. Design/methodology/approach In this study, a reliability assessment was conducted to predict the fatigue life of an automobile coil spring during different road data surfaces. Campus, urban and highway road surfaces were considered to capture fatigue load strain histories using a data acquisition system. Random loadings are applied on top of a coil spring where coil is fixed from down. Fatigue reliability was established as a system of correlated events during the service life to predict the probability of fatigue life using Coffin–Manson, Morrow and Smith–Watson–Topper (SWT) models. Findings Fatigue-life prediction based on a reliability assessment revealed that the Morrow model can predict a safe region of a life data point for the three road surfaces. Highway road data indicated the highest rate of reliability at 0.8 for approximately 1.69 × 105 cycles for the SWT model. Originality/value Reliability assessment of the fatigue life of vehicle coil springs is vital for safe operation. The reliability analysis of a coil spring under random loading excitations can be used for fatigue-life prediction.

The Influence of Semi-Active Suspension Adjustment on Vehicle Body Pitch Oscillations

Abstract In this paper the relation between semi-active suspension characteristics and vertical oscillations of the vehicle body on road roughness is analysed. During experimental tests, the damping of semi-active suspension was changed while measuring vehicle's sprung and unsprung mass vertical accelerations, pitch rate, which were transformed into a frequency domain for further analysis. The results of the experimental tests were compared to the simulations using the semi-active dynamic model. Validation has shown that model can be used to analyse the influence of semi-active suspension parameters on vehicle oscillations over the entire range of semiactive suspension settings. The comparison of experimental and theoretical simulation showed that semi-active suspension settings have influence on longitudinal oscillations of the sprung mass and it should be estimated in related researches of modern suspension.

High performance structural nano cellulose composites for motor vehicle spring suspension system

High performance structural nano cellulose composites for motor vehicle spring suspension system

Issues with Combining Road Elevation Spectral Models and Vehicle Vibration Response to Estimate Vehicle Dynamic Characteristics

The research presented in this paper focuses on issues associated with the development of an experimental technique to estimate the dynamic characteristics of wheeled vehicles (namely, the frequency response function) using only in-service response data. To validate the approach and eliminate complexities associated with multi-wheel vehicles, a single-wheeled prototype vehicle was designed and commissioned. The vertical vibration acceleration of the prototype vehicle's sprung mass was measured during normal operation. The power spectral density function was computed and used to estimate the frequency response function of the vehicle. A number of experiments using various configurations of the single-wheeled prototype vehicle were undertaken, along with a series of vibration table experiments to provide a comparison with the estimated frequency response functions. The results show that the best estimate of the frequency response function using the vehicle response data provides reasonable agreement with the measured laboratory experiments when the value of the slope of the spectral function is not set to the value suggested by the International Organisation for Standardisation. Another technique was further developed to estimate the value of the pavement spectral slope using only in-service response data; however, this technique does not yield consistent and accurate estimates. Interestingly, the main resonance of the vehicle is in agreement between the vibration table and response data around the sprung mass of all three vehicle configurations when inspected using linear scales (regardless of the variation in the spectral shape of the excitation), although the additional modes (including the unsprung mass) differs for all vehicles. Copyright © 2014 John Wiley & Sons, Ltd.

A multi-stage high-speed railroad vibration isolation system with “negative” stiffness

The intensity of mechanical vibrations generated by a moving train increases at high speeds. Conventional railroad vibration isolation systems are either insensitive or inefficient in the infra-low frequency range, which is the range most hazardous to humans. In this work, an approach for upgrading a multi-stage system for engineers, crew, passengers, and people living near railroads is presented. The approach involves the design of geometrically similar redundant mechanisms with “negative” stiffness that could be compactly inserted into all system stages without degrading structure and safety. The approach is implemented in the design of seat suspensions. Finally, a concept relevant to the design of mechanisms for vehicle spring hangers and track bed elements is discussed in terms of the dimensional analysis.

Investigation into untripped rollover of light vehicles in the modified fishhook and the sine manoeuvres, part II: effects of vehicle inertia property, suspension and tyre characteristics

In this paper, as a continuation of part I of [N. Zhang, G.M. Dong, and H.P. Du, Investigation into untripped rollover of light vehicles in the modified fishhook and the sine manoeuvres, part I: vehicle modelling, roll and yaw instability, Veh. Syst. Dyn. 46 (2008), pp. 271–293], detailed parametric studies are conducted and compared between the fishhook and sine manoeuvres using the presented nine-degree-of-freedom vehicle model, in order to understand the rollover resistance capability of a light passenger vehicle with various parameters. First, effects of driving conditions are studied in the two manoeuvres. Secondly, effects of suspension characteristics are studied, in which the influence of suspension spring stiffness and shock absorber damping, anti-roll bar is discussed. Thirdly, effects of vehicle inertia properties, such as moment of inertia of vehicle sprung mass, sprung mass weight and location of centre of gravity, are investigated. Finally, effects of tyre characteristics are also investigated by altering the scaling factor λ Fz0. An in-depth understanding has been gained on the significant effects of key system parameters on the kinetic performance of vehicles under the fishhook and the sine manoeuvres. Parametric studies show that the combination of step input (fishhook) and frequency input gives a clear indication of the vehicle dynamic stability during cornering.

THEORETICAL AND EXPERIMENTAL INVESTIGATIONS OF THE DAMPING SPRING SUSPENSION TRACTION ROLLING STOCK

The article considers the issues of determining specific parameters of rail vehicle damping. As a result of theoretical and experimental research working formulas for determination of the relative damping coefficient for vehicle spring suspension have been obtained.

Modeling to Predict Rollover Threat of Tractor-Semitrailers

Summary A predictive model to determine a rollover threat index associated with tractor-semitrailers is proposed. The purpose of this model is to predict the rollover threat sufficiently in advance of the actual event so as to enable the driver to react accordingly. The predictive model is established using simple roll-plane models of the vehicle sprung and unsprung masses in conjunction with online vehicle parameter identification. Using this predictive model, the predicted Load Transfer Ratio (LTR) for the trailer axle can be determined as the rollover threat index. The proposed predictive model and the associated parameter-identification algorithm are verified using a 12-degree-of-freedom vehicle model. It is shown that the identified parameter values are close to the actual ones used in detailed simulation study. Similarly it is shown that the predicted values of the LTR are close to the simulated ones, and hence the proposed approach is potentially suitable as the basis for application in rollover threat assessment.

Design of a vibration isolation actuator for automotive seating systems - Part II: Controller design and actuator performance

The ride quality of passenger/light-duty and off-road vehicles depends heavily on the suspension system which isolates the occupants from road surface disturbances. This passive system approach provides acceptable results but does not offer an ideal solution for applications where the occupants may be subjected to prolonged vibrations on rough roads and/or off-road driving. One strategy has been the design of semi-active and active suspension systems to attenuate vibrations between the vehicle's sprung and unsprung masses. An alternative concept is the placement of vibration isolation systems in the passenger compartment between the vehicle floor and seating system. In this paper, controllers are designed and evaluated for the semi-active hydraulic and active electromechanical hydraulic actuators. A series of four model-free and model-based control strategies are presented for each actuator to attenuate road vibrations transmitted to the occupant's lower and upper torso. The controller designs include relative, proportional-integral, variable structure system, and optimal control. Representative numerical results for the integrated chassis, seat, occupant, actuator, and control algorithms are discussed and metrics introduced to quantify the performance gains available with each configuration. The semi-active and active actuator designs provide a 27% and 35% reduction in the driver's head acceleration, respectively, when compared with the passive seating system.

Characterization of errors in cirrus simulations from a cloud resolving model for application in ice water content retrievals

Data available from the Atmospheric Radiation Measurement-Unmanned Aerospace Vehicle (ARM-UAV) Spring 1999 experiment are used in this study to estimate errors in cirrus simulations from a 3D Cloud Resolving Model (CRM). The performance of the model, heritage of the CSU Regional Atmospheric Modeling System (RAMS) is assessed by direct comparison of modeled and observed fields. Results show that the CRM succeeds in placing the cloud at approximately the correct altitude, but consistently overestimates the Ice Water Content (IWC). A statistical approach is introduced and applied to quantify average model bias under the assumption of bias-free observations. An error covariance matrix associated with simulated fields is also computed, and used to identify model strengths and deficiencies. Model fields are then used in the context of an optimum estimation retrieval of IWC from a combination of radar and radiometric observations. The retrieval is based on the knowledge of an a priori profile and relative error covariance to ensure algorithm convergence and stability. RAMS average Ice Water Content, corrected for the bias, and the related error covariance matrix derived in this study are used to provide this a priori information to the retrieval.

GOES 10 cloud optical property retrievals in the context of vertically varying microphysics

An optimal estimation approach is applied to the physical retrieval of single‐layer cloud optical properties (optical depth and effective radius) using multispectral imager channels on the western Geostationary Operational Environmental Satellite (GOES 10). The retrieval includes diagnostic information pertaining to uncertainty and dependence on a priori assumptions required by the forward model. Satellite retrievals of 0.65‐μm cloud optical depth and effective radius (micrometers) for marine stratocumulus (in both drizzle and drizzle‐free conditions) during the CloudSat Antecedent Validation Experiment and tropical cirrus during the Atmospheric Radiation Measurement (ARM)‐Unmanned Aerospace Vehicle spring flight series are examined together with data from the NASA/Jet Propulsion Laboratory Airborne Cloud Radar (ACR), the ARM Cloud Detection Lidar, and the Colorado State University Scanning Spectral Polarimeter (SSP) instruments. Optical depths are found to be consistent between GOES and SSP after taking into account the degradation of responsivity in GOES channel 1. Colocated ACR/GOES observations support past evidence that passive satellite detection of drizzle size droplets (in terms of a significant positive bias in the retrieved effective radius) may be possible under certain conditions. The ability of a dual lidar/radar active observing system to provide independent information over different cloud particle size regimes is illustrated and speaks to the vertical variability of cloud microphysics. The GOES estimate of effective radius was found to be more representative of the upper 0.5 km of the cirrus clouds examined.