What is Elastic Sliding Bearing

An Elastic Sliding Bearing is a mechanical device that can be used to control the movement of a moving part by elastic means. Its axial bearing surface is made of elastomeric material and supports a disk-like contact surface. The contact surface is made rough so that sliding movements are limited to that surface.

PTFE-coated version

A PTFE-coated version of an elastic sliding bearing has many advantages. Its softer material allows for better load distribution and excellent anti-seizure properties. In addition, this type of bearing can entrap oil in the loaded area. Its properties make it a good option for a variety of applications.

PTFE is a thermoplastic polymer with a low coefficient of friction. It is also chemically inert, and it has a long life. It can also be enhanced by adding additives. It is used in steel and concrete constructions as pipe slides and pipeline saddles.

A PTFE-coated version of an elastic sliding bearing is a good choice for a wide range of applications. It is available in inch and metric sizes and can withstand a wide range of temperatures. It is also corrosion-resistant.

Nonlinear hysteretic model

A nonlinear hysteretic model of an elastic sliding bearing is a model that accounts for the nonlinear performance of an elastic sliding bearing. It can be used to characterize the behavior of an elastic sliding bearing and to predict damage to the bearing. It is based on a simplified Bouc-Wen model that is physically motivated and smooth varying. The model parameters are estimated using sequential nonlinear least-squares estimation.

This mathematical model is able to reproduce the shear-stiffness degradation of a high damping rubber bearing, a steel damper, a viscoelastic damper, and friction interfaces. It also matches experimental results closely.

Analysis of force predictions

Analysis of force predictions for elastic sliding bearings requires the computation of frictional forces in two bodies in contact. Friction generates heat and is distributed in two bodies in contact. This friction is measured by applying the Fourier law of heat conduction in an isotropic solid body. It is also necessary to consider the thermal properties of the bearing components.

For this purpose, an analytical model is developed that represents force-displacement relationships for elastic sliding bearings under constant vertical loading. This model was validated by experimentation. The results showed that the force-displacement relationship is linear, regardless of the loading direction.

Application in seismic isolation system

A significant advantage of seismic isolation is the ability to withstand large earthquake input. This is the case even if the building is not constructed with a highly effective damping mechanism. However, it is important to note that the damping can actually counteract the beneficial effects of the seismic isolation system.

The main limitation of elastomeric bearings is that they have limitations in vertical stiffness, with a design vertical stiffness of approximately 1680 kN/mm for LRB and 1995 kN/mm for NRB. The specimens tested for LRB showed lower values than the limits while those for NRB were higher. The vertical stiffness of the EQS was similar to that of other seismic isolators, and the permanent displacement was less than 70% of the limit value. This fact demonstrates the importance of quality control in the manufacturing of commercial seismic isolators.

Unlike elastomeric systems, sliding systems are able to reduce the amount of lateral energy that a building experiences, thereby lessening the magnitude of a structure's seismic acceleration. One system of seismic isolation that combines sliding bearings and pendulum action is the Friction Pendulum System (FPS). In this system, a wedge slides on a concave surface made of stainless steel or Teflon.

Inspection

In the field of elastic sliding bearing, there are various methods of quality inspection. A vibration-acceleration-based test can diagnose failure in a bearing. However, this method has some shortcomings and is not suitable for small-defect detection, especially under low-speed and low-load conditions. In addition, it is not suitable for online inspection of bearings.

Before performing internal clearance checks, it is necessary to clean the bearing. In addition, new bearings should be removed from packaging. Rust preventative and slushing compound need not be removed from them. The bearing should also be at room temperature before performing a clearance check. Extreme temperatures can affect the results. Also, the bearing should be numbered in order to identify its correct application.

A sliding bearing is composed of two metal plates, commonly made of stainless steel, which slide relative to each other. There is lubricant between the plates to reduce friction and facilitate the sliding motion.