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Continuous Oscillation: Vibrational Effects and Acceptable Frequency Ranges of Small Bore Piping in Field Applications

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Date Issued:
2017
Abstract/Description:
In turbomachinery, a common failure mode is cracking of welds at the equipment and piping connection point. Each incidence of these cracks causes a forced shutdown to perform repairs that cost millions of dollars. This type of failure is predominately seen in small bore piping, which has a nominal diameter of 2 inches and smaller. This thesis addresses the failure prediction analysis of small bore piping, specifically in turbomachinery applications. Performing failure analysis to predict the potential cracking of welds will allow for replacement of the piping during a planned shutdown which in the long term saves money due to costs such as expediting materials, overtime pay, and extended downtime. This analysis uses real-world applications of a chemical plant in Louisiana. The piping analyzed was connected to centrifugal compressors. The data used from these pieces of equipment included the material of construction, the piping schedule, lengths, nominal diameter, and running speeds. Based on research that shows welding the connection point with a full penetration weld greatly increases the life expectancy of the connection, this thesis uses full penetration welds in the analysis. The piping was analyzed using the software ANSYS to perform a finite element analysis, specifically examining the stress due to the induced harmonic forces. It is a common fact that having fewer supports on a vibrating pipe induces greater stresses and strains on the weld connections. Supports installed 12" from the equipment only show one to two ranges of frequencies to avoid compared to the longer piping which has four to five ranges of unacceptable frequencies. Tables are developed to relay acceptable frequencies based on observed stresses of the welds in the model.
Title: Continuous Oscillation: Vibrational Effects and Acceptable Frequency Ranges of Small Bore Piping in Field Applications.
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Name(s): Kasprzyk, Marie, Author
Kauffman, Jeffrey L., Committee Chair
Bai, Yuanli, Committee Member
Gordon, Ali, Committee Member
University of Central Florida, Degree Grantor
Type of Resource: text
Date Issued: 2017
Publisher: University of Central Florida
Language(s): English
Abstract/Description: In turbomachinery, a common failure mode is cracking of welds at the equipment and piping connection point. Each incidence of these cracks causes a forced shutdown to perform repairs that cost millions of dollars. This type of failure is predominately seen in small bore piping, which has a nominal diameter of 2 inches and smaller. This thesis addresses the failure prediction analysis of small bore piping, specifically in turbomachinery applications. Performing failure analysis to predict the potential cracking of welds will allow for replacement of the piping during a planned shutdown which in the long term saves money due to costs such as expediting materials, overtime pay, and extended downtime. This analysis uses real-world applications of a chemical plant in Louisiana. The piping analyzed was connected to centrifugal compressors. The data used from these pieces of equipment included the material of construction, the piping schedule, lengths, nominal diameter, and running speeds. Based on research that shows welding the connection point with a full penetration weld greatly increases the life expectancy of the connection, this thesis uses full penetration welds in the analysis. The piping was analyzed using the software ANSYS to perform a finite element analysis, specifically examining the stress due to the induced harmonic forces. It is a common fact that having fewer supports on a vibrating pipe induces greater stresses and strains on the weld connections. Supports installed 12" from the equipment only show one to two ranges of frequencies to avoid compared to the longer piping which has four to five ranges of unacceptable frequencies. Tables are developed to relay acceptable frequencies based on observed stresses of the welds in the model.
Identifier: CFE0006749 (IID), ucf:51862 (fedora)
Note(s): 2017-08-01
M.S.M.E.
Engineering and Computer Science, Mechanical and Aerospace Engineering
Masters
This record was generated from author submitted information.
Subject(s): small bore piping -- vibration -- Flange -- Socket Weld -- 1 inch diameter -- 2 inch diameter -- Turbomachinery -- Compressor -- Turbine -- carbon steel -- stainless steel -- stress -- endurance limit -- ANSYS -- FEA -- acceptable frequencies -- unacceptable frequencies -- Hz -- rpm -- rotor -- unbalance -- equation of motion -- mode shape -- displacement -- pipe support -- u-bolt -- centrifugal compressor -- 350 Hz -- 20 -- 000 rpm -- Full penetration weld -- socket weld flange -- weld failure -- increase reliability -- vibration technician -- eccentricity -- eccentric mass
Persistent Link to This Record: http://purl.flvc.org/ucf/fd/CFE0006749
Restrictions on Access: public 2017-08-15
Host Institution: UCF

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