• Elastomers and Composites
• /
• v.37 no.3
• /
• pp.151-158
• /
• 2002

An elastomeric bushing which has been considered in this research is a device used in automotive suspension systems to reduce the forte transmitted iron the wheel to the frame of the vehicle. A bushing is modeled at a hollow cylinder which is bonded to a solid metal shaft at its inner surface and a metal sleeve at its outer surface. Lianis constitutive equation for a nonlinear viscoelastic incompressible material is used to model the elastomeric material of the bushing. It is used to derive a force-displacement relation for axial response of the bushing. The displacement dependent force relaxation function for the bushing is obtained from the ramp displacement control tests with an extrapolation method. This is compared with the exact result obtained from the step displacement control test and the results are in very good agreement.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.6 no.3
• /
• pp.190-196
• /
• 2006

In this paper, the nonlinear damping force model is made to identify the properties of the ER damper using higher order spectrum. The higher order spectral analysis is used to investigate the nonlinear frequency coupling phenomena with the damping force signal according to the sinusoidal excitation of the damper. Also, this paper presents an inverse model of the ER damper, i.e., the model can predict the required voltage so that the ER damper can produce the desired force for the requirement of vibration control of vehicle suspension systems. The inverse model has been constructed by using piecewise linear damping force model. In this paper, the fuzzy logic control based on heuristic knowledge is combined with the skyhook control. And it is simulated for a quarter car model. The acceleration of the sprung mass is included in the premise part of the fuzzy rules to reduce the vertical acceleration RMS value of the sprung mass. Then scaling factors and membership functions are tuned using genetic algorithm to obtain optimal performance.

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.415-419
• /
• 2003

An elastomeric bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. A bushing is an elastomeric hollow cylinder which is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation between the load applied to the shaft or sleeve and the relative deformation of elastomeric bushing is nonlinear and exhibits features of viscoelasticity. A load-displacement relation for elastomeric bushing is important for dynamic numerical simulations. A boundary value problem for the bushing response leads to the load-displacement relation which requires complex calculations. Therefore, by modifying the constitutive equation for a nonlinear viscoelastic incompressible material developed by Lianis, the data for the elastomeric bushing material was obtained and this data was used to derive the new load-displacement for radial response of the bushing. After the load relaxation function for the bushing is obtained from the step displacement control test, Pipkin-Rogers model was developed. Solutions were allowed for comparison between the results of Modified Lianis model and those of the proposed model. It is shown that the proposed Pipkin-Rogers model is in very good agreement with Modified Lianis model.

• Proceedings of the KSR Conference
• /
• 2003.10a
• /
• pp.125-130
• /
• 2003

Korean High Speed Train (KHST) designed to operate at 350km/h has been tested on high speed line in JungBu site since it was developed in 2002. The dynamic performances of railway vehicle are generally stability, safety and ride comfort. The stability performance of KHST was proved that it is stable at 400Km/h through Roller Rig test. The safety and ride comfort need to be predicted the capability of it at 350km/h by the on-line test because KHST is testing at 300km/h up to now. Therefor, in this paper, the safety and ride comfort at 350km/h are predicted the performance using the acceleration results at 300kw/h and these results show that the KHST's dynamic performances are very good. Also, it illustrate the two cases occurred the abnormal vibration of KHST during some on-line tests. The first case is that the variation of vertical acceleration of wheel is analyzed when an abrasion occur on wheel. The second case is that the lateral acceleration of wheel, bogie and body are analyzed when the KHST is unstable at high speed. The occurrences of these special phenomena were due to the some faults of the suspension and braking systems and the faults were improved. In present, it is testing with safety.

• Journal of KSNVE
• /
• v.9 no.1
• /
• pp.121-130
• /
• 1999

Generally, A Dynamic Absorber by using Active viscous Damping is highlighted for effective suspension system, such as improved ride comfort and handling in the market. Lately, this system based on the Sky-Hook damper theory is introduced by the name of "Active Dynamic Absorber" to us. This system has an excellent performance in contrast to Passive. Adaptive Dynamic Absorber, besides having low cost components of system, low energy consumption. light weight of system. In this viewpoint. most of car-maker will adopt this system in the near future. For this reason, we developed Dynamic Absorber by using Active viscous Damping which is equipped with continuously variable Dynamic Absorber and Control logic consisting Filter and Estimator. control apparatus of Dynamic Absorber operated by 16-bit microprocessor of high performance. variable device of viscous Damping. G-sensor so on. In this paper. several important points of development procedure for realizing this system will be described with results in which is obtained from experiment by simulation and Full car test in Proving ground. respectively.pectively.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.21 no.4
• /
• pp.333-338
• /
• 2011

This paper describes the design process of floor damping material optimization to reduce structure borne noise. This process uses finite element analysis(FEA) along with experimental techniques to complement each other. The objective of this approach was to develop an optimized damping material application layout and thickness at the initial design stage. The first step is to find the sensitivity areas of vehicle body without damping material applied using FEA. In order to determine the high vibration areas of the floor panel, the velocity was measured using a scanning laser vibrometer from 20 Hz to 300 Hz. To excite the floor panel vibration, shaker was placed at the front suspension attachment point. The second step is the optimization process to determine the light weight solution of damping material. The design guideline of damping material was suggested that the lightweight solution was verified using test result of road noise. Design engineer could efficiently decide the design variable of damping material using parameter analysis results in early design stage.

• Journal of the Korean Society for Precision Engineering
• /
• v.22 no.11 s.176
• /
• pp.118-124
• /
• 2005

An automotive bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. A bushing is a hollow cylinder, which is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation between the force applied to the shaft and the relative deformation of a bushing is nonlinear and exhibits features of viscoelasticity. In this paper, an automotive bushing is regarded as nonlinear viscoelastic incompressible material. Instron 8801 equipment was used for experimental res earch and ramp-to-constant displacement control test was used for data acquisition. Displacement dependent force relaxation function was obtained from the force extrapolation method and expressed as the explicit combination of time and displacement. Pipkin-Rogers model, which is the direct relation of force and displacement, was obtained and comparison studies between the experimental results and the Pipkin-Rogers results were carried out.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.9 no.4
• /
• pp.148-156
• /
• 2001

Brake judder, one of low Sequency vibrations in brake system is determined by the excitation of Brake Torque Variation (BTV). The largest contributor to BTV is disc thickness variation. In this study, the static loads of brake torque at Suspension Mounting Points (SW) are obtained by the quasi-static analysis using DADS. The dynamic loads with frequency of BTV at SW are derived from correlation between forced vibration analysis with static loads and brake test results. And the accelerations at steering wheel were analyzed by forced vibration analysis with dynamic loads using commercial finite element program MSC/NASTRAN so that vibration characteristics of vehicle due to brake judder were investigated. Reliability of analysis results was verified through comparing the brake test results. Also, a parametric study with natural frequencies of frame, such as the 1st torsional mode and 1st bending mode, was conducted to reduce vibration amplitudes. As a result we could detect frame natural frequency conditions to improve vibration characteristics and obtained the frame model to reduce vibration amplitude.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.703-708
• /
• 2002

An elastomeric bushing is a device used in automotive suspension systems to reduce the load transmitted from the wheel to the frame of the vehicle. A bushing is an elastomeric hollow cylinder which is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation between the load applied to the shaft or sleeve and the relative deformation of Elastomeric bushing is nonlinear and exhibits features of viscoelasticity. A load-displacement relation fur elastomeric bushing is important fur dynamic numerical simulations. A boundary value problem for the bushing response leads to the load-displacement relation which requires complex calculations and is hence unsuitable. Therefore, by modifying the constitutive equation for a nonlinear viscoelastic incompressible material developed by Lianis, the data fur the elastomeric bushing material was obtained and this data was used to derive the new load-displacement relation fur radial response of the bushing. After the load relaxation function for the bushing is obtained from the step displacement control test, Pipkin-Rogers model was developed. Solutions were allowed for comparison between the results of Modified Lianis model and those of the proposed model. It is shown that the proposed Pipkin-Rogers model is in very good agreement with Modified Lianis model.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.15 no.4
• /
• pp.83-93
• /
• 2007

This paper represents the development of 3-axises loadcell for measuring the side-force of suspension module of MPV(Multi Purposed Vehicle). The side force causes the failure of damper, such as leakage. The loadcell was developed using strain gauges, and the Wheastone bridge circuit to compensate for the cross-talk between the each axises and the measurement error by temperature. Structure analysis of loadcell was accomplished with FEM(Finite Element Method) to optimize the location of strain gages. The design optimization for important factors that have an effect on performance of loadcell was accomplished by using DOE(Design of Experiment). Loadcell was produced and successfully tested, showing good sensitivity and low cross-talk. The cross-talk of the developed loadcell is bellow 5%. The load history was measured at proving ground. The maximum side-force, the longitudinal force, and vertical force of MPV are 4.2 kN, 8.0 kN, and 17.0 kN, respectively, at Belgian road.