Hydrostatic equilibrium

About: Hydrostatic equilibrium is a research topic. Over the lifetime, 2451 publications have been published within this topic receiving 62172 citations.

On the nonlinear dynamic model of open‐type constant flow hydrostatic bearings

Abstract: This paper presents experimental and theoretical studies used to assess the dynamic performance of open-type constant flow hydrostatic bearings. A nonlinear dynamic model accounting for the compressibility effect, the squeeze effect, and the hydrostatic effect of hydrostatic fluid for the analytical perdition of the step response is proposed. Moreover, an innovative point-to-point contact step excitation setup is designed. In addition, a test rig is developed to measure the step response of the hydrostatic bearings by removing the imposed displacement within 0.0002 second. The experimental results are in good agreement with the theoretical results. The results show that the maximum dynamic displacement is twice the imposed displacement. Furthermore, the settling time of the step response is related to the inlet flow rate, irrespective of the imposed displacement.

Deformation characteristics of adaptive hydrostatic thrust bearing under extreme working conditions

Abstract: Investigation of the deformation characteristics of adaptive hydrostatic thrust bearings has been performed under extreme conditions, considering the relationship between viscosity and temperature of lubricating oil. A 3D model is generated, including the oil pad, the oil film and friction pairs. The oil film temperature field and the oil cavity pressure field have been calculated based on CFD. According to the lubrication theory and tribology principle, the force deformation, the thermal deformation, the force and thermal coupling deformation have been studied by using workbench simulation software, and the best working condition of adaptive hydrostatic thrust bearing is obtained. The results show that the load causes the table and the base to undergo inward elastic deformation, and the temperature causes them to undergo outward thermal deformation. The two deformations have opposite directions, and the deformations compensate each other. When the load is between 28 and 32t, the possibility of dry friction generated by the friction pair is low. The research results provide a theoretical basis for the stability of adaptive hydrostatic thrust bearings under extreme working conditions.

The weakening effect of hydrostatic pressure on rock mass of different lithology

Abstract: The weakening effect of hydrostatic pressure (P w) on rock mass is an important topic in the field of underground construction. In this article, a new technique is introduced to simulate the mechanical conditions and geological processes of rock mass formation using the MTS815 Rock Mechanics Test System. With this technique, intact rock specimens of marble, sandslate, greenschist, and lamprophyre acquired from rock masses are transformed into rock mass replica specimens with structural planes whose major mechanical characteristics resemble the target rock masses. These replica specimens are subjected to hydro-mechanical interacted tri-axial compression tests to reveal the weakening effect of the hydrostatic pressure on the rock mass. The experimental results show that hydrostatic pressures of 1–4 MPa have a significant effect on the mechanical properties of the rock masses. The internal cohesion c decreased dramatically when the hydrostatic pressure increased; however, the increased pressure had less effect on the internal friction coefficient μ. The deformation modulus decreased when the hydrostatic pressure increased under low confining pressure, but barely changed when the confining pressure rose above 20 MPa. These results have provided an important basis for engineering construction planning and have created a new effective way for laboratory studies of rock mass mechanical properties.