A Dynamic Investigation of Piping Systems With a Bolted Flange

2002 ◽  
Author(s):  
William H. Semke ◽  
George D. Bibel ◽  
Sukhvarsh Jerath ◽  
Sanjay B. Gurav ◽  
Adam L. Webster
Keyword(s):  
Dynamic Response ◽  
High Strength ◽  
Mode Shapes ◽  
Piping System ◽  
Resonant Frequencies ◽  
Experimental Procedure ◽  
Piping Systems ◽  
Response Output ◽  
Bolted Flange ◽  
Dynamic Investigation

The dynamic response of piping systems with a bolted flange is analyzed. Experimental and numerical analyses and results are presented and show excellent correlation. An overhanging piping system at various span lengths with a flange at mid-length is used. The testing configuration consists of a standard 2-in. (51 mm) schedule 40 steel pipe and an ANSI B16.5 class 300-pound flange. The presence of a spiral wound wire gasket and high strength flange bolts is also assessed. Included are multiple resonant frequencies and their respective mode shapes for various span lengths and gasket configurations. The experimental procedure utilizes an accelerometer to gather the dynamic response output of the piping system due to an impulse. The resonant frequencies are then determined using a Fast Fourier Transform (FFT) method. The numerical analysis is conducted using the commercial Finite Element (FE) code ANSYS®. Both methods take into account the complex interaction between the flange and gasket and their impact on the entire piping system. The dynamic effects of a bolted flange and gasket on a piping system are critical in their use and a summary of the results for a variety of configurations is presented.

Inelastic Response of Nuclear Piping Subjected to Rupture Forces

1976 ◽  
Vol 98 (2) ◽  
pp. 98-104 ◽  
Author(s):  
J. C. Anderson ◽  
A. K. Singh
Keyword(s):  
Dynamic Response ◽  
Numerical Procedure ◽  
Beam Element ◽  
Piping System ◽  
Curved Beam ◽  
Blow Down ◽  
Curved Beam Element ◽  
Piping Systems ◽  
Support Element ◽  
System 1

A numerical procedure which can be used to evaluate the inelastic dynamic response of piping systems subjected to blow-down forces is described. The following finite elements are used to represent the piping system: (1) bilinear beam element, (2) bilinear curved beam element, and (3) bilinear support element with an initial gap. The method is then used to evaluate the dynamic response of two typical segments of a main steamline.

Main Issues on the Seismic Design of Industrial Piping Systems and Components

2013 ◽  
Author(s):  
Fabrizio Paolacci ◽  
Md. Shahin Reza ◽  
Oreste S. Bursi ◽  
Arnold M. Gresnigt ◽  
Anil Kumar
Keyword(s):  
Seismic Design ◽  
Seismic Analysis ◽  
Experimental Investigations ◽  
Piping System ◽  
Analysis And Design ◽  
Correct Definition ◽  
Component Design ◽  
Piping Systems ◽  
Current Design ◽  
Bolted Flange

A significant number of damages in piping systems and components during recent seismic events have been reported in literature which calls for a proper seismic design of these structures. Nevertheless, there exists an inadequacy of proper seismic analysis and design rules for a piping system and its components. Current seismic design Codes are found to be over conservative and some components, e.g., bolted flange joints, do not have guidelines for their seismic design. Along this line, this paper discusses about the main issues on the seismic analysis and design of industrial piping systems and components. Initially, seismic analysis and component design of refinery piping systems are described. A review of current design approaches suggested by European (EN13480:3) and American (ASME B31.3) Codes is performed through a Case Study on a piping system. Some limits of available Codes are identified and a number of critical aspects of the problem e.g., dynamic interaction between pipes and rack, correct definition of the response factor and strain versus stress approach, are illustrated. Finally, seismic performance of bolted flange joints based on the results of experimental investigations carried out by the University of Trento, Italy, will be discussed.

Dynamic Response of Cracked Cylindrical Shells With Internal Pressure

2002 ◽  
Author(s):  
A. Vaziri ◽  
H. Nayeb-Hashemi ◽  
H. E. Estekanchi
Keyword(s):  
Dynamic Response ◽  
Internal Pressure ◽  
Nodal Point ◽  
Dynamic Responses ◽  
Mode Shapes ◽  
Resonant Frequencies ◽  
Crack Location ◽  
Theoretical Investigations ◽  
Axial Crack ◽  
Internal Pressures

Sub-surface cracks in pipelines with internal pressure may severely affect their dynamic response. The extreme cases of these cracks are when these cracks go through the thickness of the pipes. Dynamic responses of cracked and un-cracked pipes with fixed ends and under various internal pressures were evaluated experimentally and theoretically. In the experimental part, the effects of pipe internal pressure on the resonant frequencies and damping of the pipe were evaluated. In the theoretical part, finite element analyses were performed to find dynamic response of pipes with various crack length and orientation respect to the axis of the pipe. The experimental results showed resonant frequencies of the pipe are little sensitive to the pipe internal pressure. Similar results were obtained from the theoretical investigations. An axial crack had little effect on the pipe resonant frequencies. In contrast, cracks oriented at an angle to the axis of the pipe had a pronounced effect on some of the resonant frequencies of the pipe. This depended on the crack location in a particular mode shapes. For frequencies where the nodal point of the mode shape was located on the crack region, the frequencies were not significantly affected by the presence of the crack in the pipe. Furthermore, it was observed that the pipe internal pressure had little effect on the resonant frequencies of the cracked pipes.

Modal Analysis of Vibrations in Liquid-Filled Piping Systems

1990 ◽  
Vol 112 (3) ◽  
pp. 311-318 ◽  
Author(s):  
M. W. Lesmez ◽  
D. C. Wiggert ◽  
F. J. Hatfield
Keyword(s):  
Modal Analysis ◽  
Transfer Matrix ◽  
Wave Equations ◽  
Axial Stress ◽  
Fluid Pressure ◽  
Mode Shapes ◽  
Piping System ◽  
Long Wavelength ◽  
Piping Systems ◽  
Single Pipe

The motions of liquid-filled pipe reaches in which long wavelength assumptions are valid can be described by Poisson-coupled axial stress waves in the pipe and in the liquid column, and in the piping structure, by torsional and flexural waves. Based on linearized assumptions, a simultaneous solution of the wave equations is presented. Eigenvalues and mode shapes are derived for the variables fluid pressure and displacements, and pipe forces and displacements. The results are assembled into a transfer matrix, which represents the motion of a single pipe section. Combined with point matrices that describe specified boundary conditions, an overall transfer matrix for a piping system can be assembled. Corresponding state vectors can then be evaluated to predict the piping and liquid motion, and the accompanying forces. The results from two experimental piping systems are compared with the ones obtained by the modal analysis method.

Dynamic Response of Coupled Tanks and Piping Systems Under Seismic Loading

2015 ◽  
Author(s):  
Oreste S. Bursi ◽  
Giuseppe Abbiati ◽  
Luca Caracoglia ◽  
Vincenzo La Salandra ◽  
Rocco Di Filippo ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Boundary Conditions ◽  
Seismic Loading ◽  
Coupled System ◽  
Coupled Systems ◽  
Piping System ◽  
Axial Loads ◽  
Industrial Plants ◽  
Piping Systems ◽  
Uncertain Boundary

Dynamic analysis is an integral part of seismic risk assessment of industrial plants. Such analysis often neglects actual boundary conditions or proper coupling between structures of coupled systems, which introduces uncertainty into the system and may lead to erroneous results, e.g., an incorrect fragility curve, in comparison with the actual behaviour of the analyzed structure. Hence, it is important to study the effect of uncertainties on the dynamic characteristics of a system, when coupling effects are neglected. Along this line, this paper investigates the effects of uncertain boundary conditions on the dynamic response of coupled tank-piping systems subjected to seismic loading. In particular, to take into account the presence of the tank as boundary condition for the piping system, two sources of uncertainty were considered: the tank aspect ratio and the piping-to-tank attachment height ratio. Moreover, to model the seismic input, a Filtered White Noise (FWN) characterized by a Kanai-Tajimi spectrum was used. Finally, to study the dynamic interaction of a set of coupled tank-piping systems, the non-intrusive stochastic collocation (SC) technique was applied. It allowed for calculating surface responses of stresses and axial loads of a pair of components of the coupled system with a reduced number of deterministic numerical simulations.

Bolted Flange Joints Under External Moments: An Analysis Using the Compound Gasket Approach for Spiral Wound Gaskets

2007 ◽  
Author(s):  
Trevor G. Seipp ◽  
Christopher Reichert ◽  
Barry Messer
Keyword(s):  
Piping System ◽  
Bending Moments ◽  
Flange Joint ◽  
Pressure Method ◽  
The Past ◽  
External Moment ◽  
Piping Systems ◽  
Bolted Flange ◽  
Design Pressure ◽  
Component Rating

It is common to rate a piping system to its weakest component to maximize flexibility for future operations. In many situations, the bolted flange joint is the lowest rated component. Rating a system for its full flange rating reduces the flange’s capacity to carry external bending moments. In the past, moments on flanged joints have been evaluated by using the concept of equivalent pressure, first presented in the Kellogg Design of Piping Systems. Operating moments are converted to an equivalent pressure. This equivalent pressure is added to the design pressure and compared against a limit. According to conventional practices, the design pressure plus the equivalent pressure must not exceed the rating pressure. Consequently, designing up to the flange rating pressure presents an issue, since no margin is left for the effects of external moments on flange joints. Depending on the circumstances, many designers have compensated by permitting the combined design pressure and equivalent pressure to be as high as twice the flange rating. In this paper, the authors demonstrate a robust methodology to define an appropriate limit for operating moments on bolted flange joints. Using the calculation methodologies of EN-1591-1, the authors calculate the maximum external moment that various classes of standard ASME B16.5 flanges (for Group 1.1 materials) can tolerate over a range of temperatures and present a representative sample. Conclusions are drawn about appropriate limits for moments on flanges and are compared to results using the equivalent pressure method.

scholarly journals High Vibration Problem in Compressor Piping Systems: A Case Study

1997 ◽  
Author(s):  
G. Vijaya Kumar ◽  
S. Raghava Chary ◽  
A. Rajamani
Keyword(s):  
Natural Frequencies ◽  
Excitation Frequency ◽  
Mode Shapes ◽  
Piping System ◽  
Mechanical Responses ◽  
Normal Limits ◽  
Piping Systems ◽  
Vibration Problems ◽  
Excitation Frequencies

High vibration problems resulting in damage to supports, instrument stubs etc. have been experienced in many compressor piping systems installed at different fertilizer plants. Investigations aimed at a solution to the problem included vibration measurements on the suction and discharge piping, and mathematical modeling of the piping. The measurements indicated presence of an excitation frequency in the range of 30–35% of the compressor running speed. Dynamic analysis of the piping system showed the presence of natural frequencies coinciding with or very near to the excitation frequencies. This has been further confirmed by impact tests. Analytical mode shapes clearly show that the antinodes match with high vibration zones observed at the site. The mathematical models were used to determine optimum configurations which would separate mechanical responses from excitation frequencies. These modifications have been implemented at site and the piping vibrations are within normal limits.

Dynamic Response of a Pipe Having Bolted Flange Connection With a Gasket

2002 ◽  
Author(s):  
William H. Semke ◽  
George D. Bibel ◽  
Sanjay B. Gurav ◽  
Adam L. Webster ◽  
Sukhvarsh Jerath
Keyword(s):  
Dynamic Response ◽  
Computer Modeling ◽  
Fundamental Frequency ◽  
High Strength ◽  
Bolted Joint ◽  
Pipe System ◽  
Simply Supported ◽  
Flange Connection ◽  
Experimental Values ◽  
Bolted Flange

In this paper the effect of a bolted joint on the dynamic response of a pipe will be presented. The problem is analyzed both experimentally and by computer modeling. Standard 2-in. (51mm) Schedule 40 steel piping with a Class 300 RFWN flange is used. The pipe is used as a simply supported beam at its ends with a 14.5-ft (4.42 m) span. It is connected at the midspan by two flanges, with or without a gasket, and high strength bolts. The gasket used is a flexible spiral wound steel gasket of 0.180in. (4.57mm) thickness. Two values of pre-tensioning, 25,000 psi (172.5 MPa) and 50,000 psi (345 MPa) are used in the high strength bolts connecting the two flanges. Experimental values of fundamental frequency are comparable to the values obtained by computer modeling. It is found that the presence of the gasket and the loading exerted by the bolts on the flanges had very little effect on the fundamental frequency of the pipe system.

Tire Vibrations

1977 ◽  
Vol 5 (4) ◽  
pp. 202-225 ◽  
Author(s):  
G. R. Potts ◽  
C. A. Bell ◽  
L. T. Charek ◽  
T. K. Roy
Keyword(s):  
Natural Frequencies ◽  
Standing Waves ◽  
Resonant Mode ◽  
Mode Shapes ◽  
Resonant Vibrations ◽  
Resonant Frequencies ◽  
Radial Tire ◽  
Analysis Techniques ◽  
Thin Ring ◽  
Good Agreement

Abstract Natural frequencies and vibrating motions are determined in terms of the material and geometric properties of a radial tire modeled as a thin ring on an elastic foundation. Experimental checks of resonant frequencies show good agreement. Forced vibration solutions obtained are shown to consist of a superposition of resonant vibrations, each rotating around the tire at a rate depending on the mode number and the tire rotational speed. Theoretical rolling speeds that are upper bounds at which standing waves occur are determined and checked experimentally. Digital Fourier transform, transfer function, and modal analysis techniques used to determine the resonant mode shapes of a radial tire reveal that antiresonances are the primary transmitters of vibration to the tire axle.

Dynamic Response Analysis of Butt Joint of HTS-A Steel Considering Welding Residual Stresses

2013 ◽  
Vol 423-426 ◽  
pp. 944-950
Author(s):  
Wei Shen ◽  
Ren Jun Yan ◽  
Lin Xu ◽  
Kai Qin ◽  
Xin Yu Zhang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Dynamic Response ◽  
Hot Spot ◽  
Time History ◽  
High Strength ◽  
Simulation Method ◽  
Butt Joint ◽  
Welding Residual Stress ◽  
Response Analysis ◽  
Hull Structure

This paper uses both numerical simulation method and experimental research method to study on welding residual stress of high-strength steel of the cone-cylinder hull. Welding is often accompanied by a larger welding residual stress, which directly affects the safety and service life of the hull structure. In order to obtain the distribution of the welding residual stress, the welding procedure was developed by its parameter language by using FE analysis software in this paper. Then the welding residual stress of hot spot region was measured through X-ray nondestructive testing method, and compared it with simulation results. Finally, considering the residual stress as the initial stress, this paper analyzed dynamic response process of the welding structure under combined actions of the welding residual stress and multiaxial loads, which could more accurately determine the stress of welding structure and the location of fatigue risk point. According to the amplitude of damage parameters and strain time-history curve, we can estimate the fatigue life of structure by selecting the corresponding damage models.

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