Machinery Foundations Dynamical Analysis: A Case Study on Reciprocating Compressor Foundation

Stefano Giorgetti,Gabriele Arcidiacono,Alessandro Giorgetti,Reza Tavafoghi Jahromi

doi:10.3390/machines9100228

Abstract

A faulty dynamical interaction between a machine and a foundation can lead to unexpected and dangerous failures, impacting human lives and the environment. Some machines, as reciprocating compressors, have a low rotation speed; this can lead to dangerous frequency for the foundation blocks. For this reason, a careful analysis shall be done during the design phase to avoid the range of the frequency of resonances and low vibration speeds. Designers can approach this problem by relying both on Analytical Theory and Finite Element Analysis. This article compares these methods by studying the dynamical response of different foundation geometries in a case study of a reciprocating compressor foundation. The applicability limits of Analytical theory are explored and an evaluation of the difference in the estimation of natural frequencies of the system using Analytical Theory and Finite Elements Analysis are made for different foundation geometries. The comparison shows similar results until the foundation geometry is rigid; reference geometries limits are provided so that designers can choose which of the methods better suits their type of analysis.

Highlights

Compressors play a fundamental role in industrial plants, where they are given the task of compressing the fluid, and pushing and pressing gasses in piping lines, in vessels and inside the Balance of Plant of the machine
This paper aims to compare Barkan’s rigid body theory and the Finite Element Method (FEM) approach
The softwar foLr, BththeeFsienmiti-eleEnlgethmaenndttAhensaelmyis-iwsidisthSoAf Pth2e0b0a0se©r.ectangle of foundation; DemTbheedmfeonutnddepatthio; n block is modelled by using solid elements

Summary

Introduction

Compressors play a fundamental role in industrial plants, where they are given the task of compressing the fluid, and pushing and pressing gasses in piping lines, in vessels and inside the Balance of Plant of the machine. Barkan’s theory is a methodology where the shallow foundation block is considered a rigid body resting on an elastic half-space, which is the soil. This approach allows designers to obtain dynamical responses such as critical frequencies and maximum displacements of the foundation. Rigid body theory allows for greater sensitivity in the analysis of the results but requires a slower calculation process Another common approach to solving the dynamical study of foundations is the numerical approach [15,16,17,18] and, in particular, the Finite Element Method (FEM). Section 3: Case study, the considered geometry and inputs are described; Section 4: Results and discussion, the original geometry of the foundation is reduced and the results of the different analyses are discussed; Section 5: Conclusion, the main results are summarized, and future developments of the topic are introduced

Materials and Methods

Finite Element Method

The Soil Model and the Dynamical Analysis

Findings

Discussion