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
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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

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ISSN: 2146-9067