Abstract <p>High-speed railway not only meets the demand for capacity, but also saves energy and reduces emissions, and helps economic development. As the core component of the high-speed electric multiple unit (EMU), the bogie plays the role of bearing, steering, braking, driving, and shock absorption. The bogie side beam is a thick composite structure, which is prone to delamination failure during loading. Prediction of structural delamination by the finite element method can effectively improve the design efficiency. In this paper, a model is established for the short 14T and 16T wheelbase and the lightweight bogie frame structure, and the macroscopic mechanical properties are calculated and predicted. The zero-thickness cohesive element in ABAQUS is used to simulate the delamination damage in the component. Static strength analysis is carried out for the given operation condition, and then the strength of the component is obtained. Due to optimization of the ply design, there is no damage to the bogie under operation conditions. It is illustrated that equivalent modulus theory for composites is suitable for the numerical analysis of delamination damage, and the effective ply design increases the interlayer strength.</p>