Development and Applications of an Analytical Tool for Piston Ring Design

A comprehensive and robust analytical tool was developed to study three-dimensional (3D) ring-bore and ring-groove interactions for piston rings with either symmetric or asymmetric cross-section. The structural response of the ring is modeled with 3D finite element beam method, and the interfaces between the ring and the bore as well as between the ring and the groove are modeled with a simple asperity contact model. Given the ring free shape and the geometry of the cross-section, this analytical tool can be used to evaluate the ring-bore and ring-groove conformability as well as ring twist angle distribution under different constraints. Conversely, this tool can be used to calculate the free shape to provide the desired ring-bore contact pressure distribution for specific applications. Furthermore, to provide ring designers more insights into the performance of the ring, the capabilities of simulating the ring lapping process and the response of the ring to dynamic loadings and the effect of thermal stresses are included in this analytical tool. Examples are given to demonstrate the capabilities of the tool and complex 3D ring deformation with the support of testing and experimental evidences.