Three-Dimensional Nonlinear Simulation of Piston Ring Installation, Dynamics, and Wear

Abstract A three-dimensional nonlinear finite element model for compression rings has been developed to simulate the ring's installation within the liner and the ring dynamics over an engine cycle. Any ring free shape and cross-section may be specified. Straight beam elements were employed to represent the ring's internal stiffness and inertial properties, while the contact interaction at the liner and groove interfaces was modeled over a fine grid. The large-displacement nonlinearity arising from the ring installation procedure is addressed using a co-rotational beam element formulation. Using this approach, the predicted end gap is within the manufacturer's specification after installation and is also cross-verified against a commercial solid-element model. The model was then used to simulate the static twist, ring dynamics, and progressive wear of the ring face and ring side surfaces. The predicted wear profiles are in good agreement with the experimentally observed results, and the twist variation around the ring's circumference also aligns with the worn profile traces. The influence of thermal loads on the ring-liner contact and dynamic stresses is discussed. Finally, an iterative process is developed to update the free shape geometry, yielding a more circumferentially uniform contact pressure at the running face. This modeling approach can be used to assess the effect of varying ring and groove geometries on contact interactions, wear, cycle dynamics, and stresses.