This work investigates the feasibility of replacing conventional multi-leaf steel springs used in heavy-duty vehicle suspensions with sandwich composite leaf springs and polymeric core designed through a topology optimization framework. The proposed solution targets full interchangeability with existing steel springs, requiring equivalent static stiffness, load-carrying capacity, and dynamic performance, while enabling mass reduction and tailored energy dissipation characteristics. The application considered is a tandem suspension system of a heavy-duty grain semitrailer with a suspended mass of approximately 40 tons. Baseline experimental data obtained from static and dynamic tests of the steel leaf spring are used to define stiffness targets and damping benchmarks. These results indicate that the dominant dissipation mechanism in the steel spring is amplitude-dependent hysteresis associated with interlaminar friction. A density-based topology optimization strategy is formulated to determine the optimal material distribution within a predefined design domain representing the sandwich leaf spring. The optimization problem minimizes structural mass subject to constraints on equivalent static stiffness, admissible stress levels, and dynamic performance indicators. The formulation integrates finite element modelling under large displacement conditions and frequency response analysis. Energy dissipation is incorporated through a hysteretic constitutive model based on complex moduli, implemented via a user-defined material (UMAT) subroutine in Abaqus, enabling the evaluation of energy dissipation. The results show that topology optimization naturally promotes non-uniform material layouts, redistributing stiffness toward high-demand regions and reducing stress concentrations compared to conventional uniform sandwich configurations. The optimized topologies achieve the required global stiffness while improving mass efficiency and enabling controlled tuning of energy dissipation mechanisms. Overall, the study demonstrates that topology optimization provides a systematic and robust framework for designing sandwich composite leaf springs as technically viable substitutes for steel springs in heavy-duty suspensions, offering enhanced lightweight potential, improved stress management, and tunable dynamic behavior.