Finite Element Analysis of a Mono Composite Leaf Spring of Lightweight Vehicles for Reducing Fuel Consumption

Abstract

Conventional steel leaf springs are the primary suspension system for the road vehicles. However, they are very heavy and account for 10-20% of the unsprung weight of the vehicle. Though, there is a possibility of reducing this weight in order to improve fuel economy. Hence, this thesis investigates the properties of CFRP, E – Glass, Technora H and BFRP leaf springs for lightweight vehicles through FEA of ANSYS software. The model is designed based on the design specifications acquired from Toyota Tacoma SR 2020 model. As such, Technora H leaf spring became the lightest leaf spring with 5.44 kg saving up to 73% of leaf spring weight of conventional steel leaf spring. In addition, all of the alternative leaf springs provide better fuel economy than the conventional steel leaf spring with Technora H offering the best fuel economy at 8.68 km/liter saving 44 liters of fuel per year that estimated at 3451 Birr per year. Moreover, the natural frequency for the first and second mode of transverse vibration for composite leaf springs are higher than the conventional leaf spring, with Technora H having highest first and second transverse natural frequency of 1179.8 Hz and 2482.3 Hz, respectively. Similarly, the amplitude of the transverse vibration of composite leaf springs are lower than that of conventional steel leaf spring, with Technora H having lowest amplitude of the transverse vibration of 0.000294 mm. This indicates that, the composite material, particularly Technora H, exhibit much lower vibration amplitudes, indicating better vibration isolation. Furthermore, all of the alternative leaf springs have a higher safety factor than the conventional steel leaf spring with E – Glass having highest safety factor of 3.77. Thus, MCLS have low weight, low fuel consumption, high safety factor, high transverse natural frequency, and low transverse vibration amplitude than conventional steel leaf springs. Therefore, MCLS can replace conventional steel leaf spring for the benefit of weight reduction and better fuel economy.