Hydrostatic guideways are used as an alternative to contact bearings due to high stiffness and high damping in heavy machine tools. To improve the dynamic characteristic of bearing structure, the dynamic modeling of the hydrostatic guidway should be accurately known. This paper presents a "mass-spring-Maxwell" model considering the effects of inertia, squeeze, compressibility and static bearing. To determine the dynamic model coefficients, numerical simulation of different cases between displacement and dynamic force of oil film are performed with fluent code. Simulation results show that hydrostatic guidway can be taken as a linear system when it is subjected to a small oscillation amplitude. Based on a dynamic model and numerical simulation, every dynamic model's parameters are calculated by the LevenbergMarquardt algorithm. Identification results show that "mass-spring-damper" model is the most appropriate dynamic model of the hydrostatic guidway. This paper provides a reference and preparation for the analysis of the dynamic model of the similar hydrostatic bearings.

Purpose This paper aims to present a simplified method to predict the pressure of the recess, no matter whether the tilt center coincides with the geometric center of the hydrostatic journal bearings. Design/methodology/approach To validate the effectiveness of the presented model, computational fluid dynamics (CFD) method and experimental method are performed in this study. Findings By comparing the CFD results and the experimental results, the pressure of the recess is related to the tilt direction, the tilt center, the width of the land and the circumferential angle of the land. Originality/value The mathematic model requires equivalent resistance of land edge – tilt position, tilt direction, tilt angle and the thickness of oil film instead of any digital iteration. Furthermore, a novel experimental apparatus including a circular hydrostatic bearing called ball bearing is designed to study the tilt effect produced by manufacturing error and offset load force on the pressure of the recess.

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Based on the measured distribution law of humidity field, according to the humidity stress field theory, the coupling of the humidity field and the ground stress field is realized, and the humidity field is systematically analyzed. Under the conditions, the influence of the expansion of surrounding rock, lining, buried depth, height-span ratio and horizontal pressure coefficient on the deformation of the surrounding rock of the roadway, the general law of the surrounding rock deformation of the swelling rock roadway is obtained. The results show that the five factors have a certain impact on the approaching amount of the two sides of the surrounding rock and the approaching amount of the roof and floor of the swelling rock roadway, but the degree of influence is different. The order of factors affecting the approach of two sides is lining > expansibility > buried depth > horizontal pressure coefficient > height-span ratio; The order of factors affecting the approach of roof and floor is lining > expansibility > height-span ratio > horizontal pressure coefficient > buried depth. The research results provide valuable suggestions and references for the selection of reasonable support schemes and related design and construction of swelling rock roadways.