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Measurement of Dynamic Properties of Automotive Shock Absorbers for NVH
ISSN: 0148-7191, e-ISSN: 2688-3627
Published May 17, 1999 by SAE International in United States
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This paper describes a project on the dynamic characterization of automotive shock absorbers. The objective was to develop a new testing and analysis methodology for obtaining equivalent linear stiffness and damping of the shock absorbers for use in CAE-NVH low- to- mid frequency chassis models. Previous studies using an elastomer test machine proved unsuitable for testing shocks in the mid-to-high frequency range where the typical road input displacements fall within the noise floor of the elastomer machine. Hence, in this project, an electrodynamic shaker was used for exciting the shock absorbers under displacements less than 0.05 mm up to 500 Hz. Furthermore, instead of the swept sine technique, actual road data were used to excite the shocks. Equivalent linear spring-damper models were developed based on least-squares curve-fitting of the test data. The type of road profile did not influence the stiffness and damping values significantly for the range of amplitudes and frequencies considered. Finally, sensitivity of the vehicle level responses to the shock absorber rate change was studied, to finalize whether or not an upgrade to the existing shock absorber test procedure is necessary.
CitationRao, M., Gruenberg, S., and Torab, H., "Measurement of Dynamic Properties of Automotive Shock Absorbers for NVH," SAE Technical Paper 1999-01-1840, 1999, https://doi.org/10.4271/1999-01-1840.
- Duym S., Stiens R., and Reybrouck K., “Evaluation of Shock Absorber Models,” Vehicle System Dynamics, Vol. 27, pp. 109-127, 1997.
- Lang H.H., “A Study of the Characteristics of Automotive Dampers at High Stroking Frequencies,” Ph.D. Thesis, University of Michigan, 1977.
- Morman K., et. al, “A Model for the Analysis and Simulation of Hydraulic Shock Absorber Performance, Part I- Theoretical Development (SR-83-043), Part II- Parameter Identification and Model Validation Studies (SR-86-61), Ford Motor Company Research Staff Reports.
- Reybrouck K., “A Non Linear Parametric Model of an Automotive Shock Absorber,” SAE Paper No. 940869, Vehicle Suspension and System Advancements, SP-1031, pp. 79-86, 1994.
- Karadayi R., and Masada G.Y., “A Nonlinear Shock Absorber Model,” Proc. of the Symposium on Simulation and Control on Ground Vehicles and Transportation Systems, pp. 149- 165, 1986.
- Alanoly J., Kuber P., Rubio-Ratton C., “Large Deflection Non-Linear Component Models for Durability Simulation,” Proc. 7th Worldwide Vehicle Dynamics Conference, Ford Motor Co., Dearborn, MI, Oct. 1993.
- Cafferty S., Worden K. and Tomlinson G., “Characterization of Automotive Shock Absorbers Using Random Excitation,” Proceedings of Institute of Mechanical Engineers, Part D- Journal of Automobile Engineering, Vol. 209, pp. 239-248, 1995.
- Belingardi G. and Campanile P., “Improvement of the Shock Absorber Dynamic Simulation by the Restoring Force Mapping Method,” Proc. of the 15th International Seminar on Modal Analysis and Structural Dynamics, Leuven, Belgium, pp. 441-454, 1990.
- Duym S., Schoukens J., and Guillaume P., “A Local Restoring Force Surface Method,” Proc. 13th IMAC, Nashville, Tennessee, pp. 1392-1399, 1995.
- Surace C., Worden K., and Tomlinson G. R., “On the Non-linear Characteristics of Automotive Shock Absorbers,” Proceedings of Institute of Mechanical Engineers, Part D- Journal of Automobile Engineering, Vol. 206, pp. 3-16, 1992.