Elastoplastic Contact Analysis of Honed Liner and Ring Surface

Cylinder liner scuffing is one of the most critical failure modes in piston ring and cylinder liner assembly, which has become a major engineering bottleneck in the development of high-performance internal combustion engines. Studying the contact characteristics, including the contact pressure, contact area, and stress of the piston ring and the cylinder liner is an important way to understand the surface contact state, and is also of great significance for a reasonable friction couple design, preventing the scuffing failure of friction couple, and improving the economy and reliability of internal combustion engines. Although numerous studies have been conducted on the simulation of rough surface contact and tribological performance of piston rings and cylinder liners, most studies still use GT (Greenwood & Tripp) statistical contact models based on gaussian or exponentially distributed surfaces. The research on the real surface contact model and its contact characteristics of the honing surface of the cylinder liner with compound machining characteristics and obeying the bi-gaussian distribution is not enough, and it cannot reflect the real surface contact state of the friction pair of the piston ring and cylinder liner. In this paper, based on boundary element theory, a numerical simulation analysis method of rough contact elastoplastic contact was established by using fast Fourier transformation and conjugate gradient method. Contact characteristic parameters such as real contact pressure, contact area, elastoplastic deformation and surface stress were used to study the contact evolution of the cylinder liner honing surface under different loads. The results showed that considering the elastoplastic contact model, the contact pressure of the honing surface of the cylinder liner was relatively uniform, indicating that the applied load was uniformly borne by surface asperity; in the non-contact area such as the honing valley, due to the superposition of deformation, the elastic deformation of the non-contact area was not equal to zero, and zero plastic deformation; the load on the honing surface of the cylinder liner had a linear relationship with the contact area, and with the increase of the load, the contact area increased linearly; under low load, the near-surface stress was greater than the subsurface stress inside the material; With the increase of load, the subsurface stress increased and the near-surface stress decreased; under high stress, the surface contact was close to the apparent contact area, and the subsurface stress exceeded the near-surface stress.