Response Surface-Based Design Study of a Relay Lever for a Bus Independent Suspension Steering Mechanism

Mehmet Murat Topaç, Merve Karaca, Mert Atak, Uğur Deryal
126 23


In the scope of this work, mechanical design stages and the structural optimization process of a relay lever that will be used as one of the main load carrying members of a passenger bus multi-link steering system are summarized. In the first stage of the study, design load of the steering mechanism was determined. For this reason, two different methods were used: the bore torque approach and the multibody dynamics (MBD) analysis of the steering mechanism. Therefore, a full-scaled multibody model of the passenger bus was built and analyzed for a chosen critical driving maneuver via Adams/Car™ module of MSC. Adams™ commercial software package. Primary mechanical design of the part was composed with the use of the load model which gives greater reaction forces. Finite element analysis (FEA) of the draft design was also implemented to determine the possible stress concentrated regions. In order to obtain the appropriate relay lever structure which satisfies minimum stress concentration and minimum deformation under the selected design load, a response surface methodology (RSM)-based optimization study was also carried out. Results of the optimization process showed that the final structure of the relay lever satisfies the strength requirements for the chosen critical load case.


Multi-link steering mechanism, Independent front suspension, Multibody dynamics, Mechanical design, Design of experiments, Response surface methodology, Finite element analysis, Optimization, Fatigue

Full Text:



Topaç M. M., Deryal U., Bahar E. and Yavuz G., (2015) " Optimal kinematic design of a multi-link steering system for a bus independent suspension by using response surface methodology", Mechanika, vol.21, pp.404-413

Reimpell, J. (1974). Fahrwerktechnik, Bd.3. Würzburg: Vogel-Verlag.

Montgomery, D. C. (2000). Design and Analysis of Experiments. 5th ed. Hoboken, New Jersey: John Wiley & Sons, Inc.

Park K., Heo S. J., Kang D. O., Jeong J. I., Yi J. H., Lee J. H., Kim, K. W., (2013) " Robust Design Optimization of Suspension System Considering Steering Pull Reduction", International Journal of Automotive Technology, vol.14, pp.927-933

Han H., Park, T., (2004) "Robust optimal design of multi-body systems", Robust optimal design of multi-body systems, vol.11, pp.167-183

Myers, R. H., Montgomery, D. C., Anderson-Cook, C. M. (2009). Response Surface Methodology, Process and Product Optimization Using Design of Experiments. 3rd ed. Hoboken, New Jersey: John Wiley & Sons, Inc.

Rill, G. (2006). Vehicle Dynamics, Lecture Notes. Regensburg: Fachhochschule Regensburg.

Reimpell, J., Stoll, H., Betzler, J. W., (2001). The Automotive Chassis. Warrendale: Society of Automotive Engineers, Inc.

Blundell, M. and Harty, D. (2006). The Multibody Systems Approach to Vehicle Dynamics. London: Elsevier Butterworth – Heinemann.

Roloff, H. and Matek, W. (1972). Maschinenelemente, Normung, Berechnung, Gestaltung. Braunschweig: Friedr. Vieweg + Shn GmbH Verlag.

Yüksel, M. (2003). Malzeme Bilgisi, Malzeme Bilimleri Serisi – Cilt 1. Denizli: TMMOB Makina Mühendisleri Odası. (In Turkish)

Topaç M. M., Günal H. and Kuralay N. S., (2009) "Fatigue Failure Prediction of a Rear Axle Housing Prototype by Using Finite Element Analysis", Engineering Failure Analysis, vol.16, pp.1474-1482

Topaç M. M., Ercan S. and Kuralay N. S., (2012) "Fatigue Life Prediction of a Heavy Vehicle Steel Wheel Under Radial Loads by Using Finite Element Analysis", Engineering Failure Analysis, vol.20, pp.67-79

Subaşı M. and Karataş Ç., (2010) "Relations on The AISI 4140 Steel Hardness and Fatigue Strength", KSU Journal Of Engineering Sciences, vol.13, pp.21-27 (In Turkish with an abstract in English)

Shigley, J. E. and Mischke, C. R. (1989). Mechanical Engineering Design. 5th ed. New York: McGraw-Hill, Inc.

Pilkey, W. D. and Pilkey, D. F. (2008). Peterson’s Stress Concentration Factors. 3th ed. New York: John Wiley & Sons, Inc.

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.

ISSN: 2146-9067