Structural Weight and Stiffness Optimization of a Midibus Using the Reinforcement and Response Surface Optimization (RSO) Method in Static Condition

Hailemichael Solomon Addisu,Ermias Gebrekidan Koricho,Angelos Markopoulos

doi:10.1155/2022/6812744

Abstract

Midibuses are medium-sized buses widely used for transportation purposes in Asia and Africa. However, most midibuses are locally built and indirectly regulated through inspecting the end product (finished bus) during licensing for the public transport business in Ethiopia. Due to lack of engineering analysis and testing, low stiffness and overweight of midibus were compromised. This research was aimed at analyzing and optimizing the midibus structure using the reinforcement and response surface optimization (RSO) method for pure bending and torsion loading cases. Results show that the maximum deformation occurred at the roof section of the original structure during both loading cases. Furthermore, the reinforcement design was found by replacing the cross section and layouts of structural members and adding reinforcements for the most suitable location of the original structure. Response surface optimization with the multiobjective genetic algorithm (MOGA) method in ANSYS DesignXplorer was performed on the reinforced structure to maximize the bending and torsional stiffness with reduced weight. The bending stiffness of the reinforced and optimized structure increased by 41.65% (1911.4 N/m) and 10.02% (651.7 N/m), respectively. In addition, the torsional rigidity or stiffness of the bus structure was improved by 12.56% (173.31 Nm/deg) via reinforcement design. Moreover, the torsional stiffness of the optimized (RSO) model was increased by 3.29% (51.07 Nm/deg). Reinforcement design was effectively reduced by 5.23% of the structure’s weight. Moreover, the RSO method has also decreased the weight of the reinforced structure by 2.64%.

Highlights

Structural optimization mainly focuses on determining the optimal size and shape of the structure by the iterative approach [1]
This research facilitates the static analysis of a midibus structure using numerical methods (ANSYS)
The obtained results of static strength analysis and optimization can be summarized as follows: (i) In the baseline model, the maximum deformations occurred at the roof luggage and the top of rear frames for all loading conditions except the pure torsion case

Summary

Introduction

Structural optimization mainly focuses on determining the optimal size and shape of the structure by the iterative approach [1]. The response surface optimization combined with the MOGA (multiobjective genetic algorithm) optimization algorithm can develop the multiobjective optimization of the design parameters to obtain the optimal solution for static stiffness and weight of the structure. Ismail et al [11] focused on the response surface optimization (RSO) method to obtain a better optimal design in the static structural analysis of a three-dimensional bike crank arm. According to Gauchia and Diaz and Zhong et al [12, 13] showed that a genetic algorithm (GA) is a well-matched optimization approach to reduce the weight and increase the torsional stiffness in very complex problems. Previous research shows that the strength parameters of the bus superstructure and structural optimization for lightweight design are crucial during experimental and numerical studies

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Conclusion