An integrated multiphysics tribo-multibody-dynamics and 3D subsurface stress framework for high performance constant velocity joints

High performance constant velocity joints (CVJs) operate under extremely harsh contact conditions, including high contact pressures, temperatures, and complex kinematics involving a significant degree of sliding. Comprehensive models capturing the complex interactions between component multibody dynamics, tribology, contact mechanics, and subsurface stress evolution have not been presented to date. This study introduces a novel, validated multiphysics framework that integrates tribological modelling with multibody dynamics and 3D subsurface stress analysis. The results reveal that under low friction conditions dynamic behaviour is largely invariant to in-cycle frictional variations. However, under boundary lubrication regime, friction significantly alters dynamics force distribution, leading to amplification of subsurface stresses. The subsurface stress model quantifies the impact of these, showing that increased friction can indirectly raise subsurface shear stress by up to 30%, drastically reducing fatigue life. The results demonstrate that minimising friction within the joint is crucial for reducing subsurface stresses and extending its operational lifespan. This work provides the first fully coupled tribo-multibody-dynamic and subsurface stress analysis of high-performance CVJs. The framework lays the foundation for development of physics-based digital twins in tribodynamic systems.