Numerical Study of Reduction in Vibrations Induced by Water-Pipe System

Abstract

In certain buildings such as synchrotrons and large ground telescopes, strict requirements are stated regarding the vibration levels. Both external and internal vibration sources, for example traffic and indoor water pumps, can have an appreciable effect on the vibration levels in the buildings. The synchrotron research facility MAX IV, which is currently under construction in Sweden, serves as an example case for the analyses. In MAX IV, several water-pipe systems used for cooling purposes will be placed near vibration sensitive equipment. These systems will transmit vibrations, into structural parts of the facility, which could exceed the vibration requirements. Structural modifications of pipe systems are investigated here by means of the finite element method in order to reduce vibration levels in the building. The finite element model employed includes a water-pipe system, adjacent building parts and the underlying soil. The use of fluid-structure interaction is investigated as well as the use of component mode synthesis. This paper focuses on the numerical procedure used as well as the effects on transmitted vibrations by different placements of the pipe supports.Keywords Water-pipe system • Fluid-structure interaction • Component mode synthesis • Vibration reduction • Finite element method IntroductionOccasionally, very strict vibrational requirements are specified for sensitive equipment used in high-tech facilities such as radar towers and synchrotron facilities. Various external and internal vibration sources such as traffic, indoor pumps and human activities can have appreciable effect on the vibration levels in a facility [1].The new synchrotron facility MAX IV (cf. Fig. 42.1) is needed in order to improve research possibilities and to address new scientific challenges. Research fields of particular relevance include those of material science and medicine. In the large ring-shaped building at the MAX IV facility, a beam of electrons is to be controlled by a large number of magnets that are distributed along that building as well as along beam lines that lead electron beams to measurement stations. Since the quality of the measurements obtained is dependent upon the vibration levels of the magnets, very strict requirements are specified regarding the vibration levels in the facility. The vibration requirements regarding vertical displacements of the magnets are especially strict, its being required that these be less than 20-30 nm in RMS per second. At MAX IV, several pipe systems used for cooling purposes, supported by elastic foundations, will be placed near vibration sensitive parts at the facility and thus transmitting vibrations that could exceed the vibration requirements. Literature ReviewVibrations originated from external vibration sources could efficiently be reduced by using wave obstacles such as trenches and shaped landscapes, see, for example [2,3]. The present paper treats reduction in vibrations stemming from an internal vibrations source, namely water-pipe systems.A literature ...

A Fixed Platform Topside Piping System Strength Analysis Under Dynamic Pigging/Slugging Loads

“…CFD analysis is also very difficult (Xiao, 2015). Numerical analysis (Persson, 2015) is reliable and easier to achieve than analytical solution (Santos, 2015). Therefore FEA is a suitable tool for pipe vibration analysis during pigging/slugging process.…”