Design of a Copolymer-Reinforced Composite Material for Leaf Springs Inside the Elastic Suspension Systems of Light-Duty Trucks

Abstract

The growing demand for passenger comfort and environmental protection, as well as reducing fuel consumption and exhaust emissions, drives the search for new, high-performance materials. Composite leaf springs, applied as part of elastic suspension systems and with the advantages of being strong and lightweight, with a high load-carrying capacity, are a possible method with which to achieve those goals. In this study, an epoxy thermoset was blended with 10–50 wt.% polysulfide rubber and reinforced with 10 wt.% alumina powder. The characteristics of the copolymer composite blend were studied by performing ASTM mechanical tests, including tensile strength, impact strength, hardness, and damping ratio tests. The experimental outcomes showed that increasing the proportion of polysulfide rubber caused a reduction in the maximum tensile strength, modulus at fracture, natural as well as damped frequency, and hardness, whereas a significant improvement was observed in impact strength, logarithmic decrement, and the damping ratio. Reinforcement with alumina powder caused a meaningful increase in the maximum tensile strength and natural frequency, with a good improvement in deformation strength. Impact strength and the damping ratio were maximized when alumina powder was increasingly added. This increase was contrary to what occurred for the hardness, which decreased upon reinforcement. Statistical methods, altering the design of the experiments, and linear regression were used to optimize the composite mixture for manufacturing leaf springs. Finally, the model was validated using analysis of variance and probability plots (normal distribution). The regression equations of tensile and impact strength, hardness, and damping ratio test results proved composite suitability for the application of leaf springs under representative loading and operating conditions. Finite element analysis of the composite material was performed using SolidWorks Simulation 22 Mechanical software. ANSYS 2022 R1 was used to study the mechanical properties of the leaf spring model fabricated from the proposed composite material. The finite element analysis results showed a significant reduction in the weight of leaf springs, with very good mechanical properties, including the tensile and impact strength, hardness, and damping ratio, when using the proposed copolymer-reinforced composite material.