Towards realistic simulation of two-stroke marine engines: A floating frame approach

This paper presents a novel multi-body simulation framework utilizing the nodal-based Floating Frame of Reference Formulation to realistically model large-bore two-stroke marine engines. The framework employs linear model order reduction to condense finite element models of the crankshaft, shafting system, and housing, and uses specialized deformation modes that efficiently model the fluid-solid interaction in main bearings for time-domain elastohydrodynamic simulations. The framework is implemented in a custom-built multi-body code in MATLAB and the paper explains implementation details allowing other researchers to replicate the approach using the nodal-based Floating Frame of Reference Formulation. Balancing computational efficiency and fidelity, it accurately represents the coupled engine system’s dynamic response. Validated against experimental data from a full-scale four-cylinder test engine, simulated journal orbits and journal misalignments show strong agreement across the engine’s operating range. Evaluation of two case studies, representing distinct engine configurations, compares main journal dynamics and torsional frequency responses, demonstrating the framework’s versatility and robustness in capturing global engine dynamics.