Pipeline Vibration Research Articles

Numerical simulation on the effectiveness of using viscoelastic materials to mitigate seismic induced vibrations of above-ground pipelines

Pipeline systems are commonly used to transport oil, natural gas, water, sewage and other materials. They are normally regarded as important lifeline structures. Ensuring the safety of these pipeline systems is crucial to the economy and environment. There are many reasons that may result in the damages to pipelines and these damages are often associated with pipeline vibrations. Therefore it is important to control pipeline vibrations to reduce the possibility of catastrophic damages. This paper carries out numerical investigations on the effectiveness of using viscoelastic materials to mitigate the seismic induced vibrations of above-ground pipelines. The numerical analyses are carried out by using the commercial software package ANSYS. The numerical model of the viscoelastic material is firstly calibrated based on the experimental data obtained from vibration tests of a 1.6m long tubular sandwich structure. The calibrated material model is then applied to the above-ground pipeline system. The effectiveness of using viscoelastic materials as the seismic vibration control solution is investigated. The influences of various parameters, including the constraining arrangement scenarios, the constraining length and angle, the thicknesses of the viscoelastic material and constraining layer are discussed in detail. The influence of earthquake frequency content is discussed as well. Numerical results show that with properly selected viscoelastic materials and constraining layers, the proposed method can be used to effectively mitigate seismic induced vibrations of above-ground pipelines.

The vibration analysis model of pipeline under the action of gas pressure pulsation coupling

Abstract Pipeline vibration is the main factor that makes pipeline system can't work properly. And the pressure pulsation of the air flow is one of the important factors, which causes the gas pipeline vibration. In order to further understand the influence of the pressure pulsation on the pipeline system vibration, the analysis model and calculation method of the pressure pulsation and pipe coupling interaction are established. Taking transferring matrix method to calculate the natural frequency of gas column, and using the stiffness matrix method to obtain the pressure pulsation. According to the interaction force between the pressure pulsation and the pipeline wall, the equation of forced vibration of pipeline is established, which can obtain the variation trends of vibration displacement and velocity of pipeline system. Using field test data to verify the theoretical calculation results, the results of the calculated values and test values are within error limits. The results can provide a theoretical basis for the safety evaluation of oil and gas pipeline, and provide a reference for the pipeline mechanical properties research.

The Vibration Characteristics Analysis of Pipeline Under the Action of Gas Pressure Pulsation Coupling

In order to research the pipeline vibration and prevent the fatigue failure of pipeline, the calculation model and methods for vibration characteristics analysis of pipeline under the action of the gas pressure pulsation and pipeline coupling are presented in this paper. According to the pipeline structure, the pipeline model with different pipe diameters is established. Based on the model and combined with the structure parameters of pipeline, the calculation methods of gas column natural frequency, gas pressure pulsation, and exciting force are built. By these ways, the relationships between the gas column natural frequency and orders, the gas pressure pulsation and orders, and the exciting force and aspect ratio are acquired. Besides, the variable relationships of vibration displacement and velocity of pipeline can be obtained. Comparing the calculated results with the field test values, the calculated results are in agreement with the test values, and the correctness of the calculation model and method is verified. The results show that taking the pressure pulsating and pipe coupling effect account into the vibration analysis of different pipe diameters, which can truly reflect the vibration characteristics of pipeline and possess important reference value for preventing fatigue failure and reducing the vibration of the pipeline.

Research on the vibration band gaps of isolators applied to ship hydraulic pipe supports based on the theory of phononic crystals

According to the theory of phononic crystals, a new isolator applied to ship hydraulic pipe-support with a one-dimensional periodic composite structure is designed, which is composed of metal and rubber. The vibration of the ship hydraulic pipeline can be suppressed by the band gaps (BGs) of the isolator. The band structure and frequency response function of the isolator is figured out by the transfer matrix method and the finite element method respectively. The frequency ranges and width of the BGs can be modulated to obtain the best structure of the isolator by changing the geometrical parameters. The experimental results provide an attenuation of over 20 dB in the frequency range of the BGs, and the results show good agreement with those of the numeric calculations. The research provides an effective way to control the vibration of ship hydraulic pipelines.

Calculation Method of Pipeline Vibration with Damping Supports Made of the MR Material

Wire damping materials (such as Metal Rubber, MR, or “spring cushion”, etc.) are widely used for protection of a pipeline against vibration. A calculation method for an arbitrary shaped pipeline with damping supports made of the MR material was developed by means of the finite element ANSYS software package. Dependencies of MR support stiffness and energy dissipation coefficient on various parameters (material density, wire diameter, thickness, preliminary static deformation) are obtained as these two characteristics influence the quality of MP supports. An equivalence viscous damping coefficient was obtained on the basis of the equality of the hysteretic loop area for the viscous damping system and dry friction in the wire material. The method takes into account a non-linearity of the MR material by the iteration method. The method allows obtaining a pipeline vibration amplitude and stress in the pipeline for its 3D vibration. Calculation results are proved by experiment with the ARAMIS non-contact measurement system. The error is less than 9%, thus, it is possible to use this method for practical application: placement of pipeline supports and design of these supports parameters. It allows reducing a large experimental work of stress measurement in pipelines during pipeline system design. Any engineer who is able to work with the ANSYS software can use it. It is possible to develop this method for calculation of a pipeline system with many pipelines connected by damping supports.

A new approach to solve the problems of seismic vibrations for periodically nonuniform buried pipelines

The method proposed by E.A. Il’yushina is used to study the longitudinal vibrations of segmented buried pipelines. It is shown that the averaged wave velocity in a periodically nonuniform pipeline is specified by the effective static moduli of the periodicity cell and that, in the case of using a vibration damping material made of rubber or soft metal at joints between pipes, this velocity can be much less than the velocity of longitudinal waves in the main pipe. The last fact makes it reasonable to consider supersonic regimes in the problems of seismic vibrations when the wave velocity in a pipeline is less than the wave velocity in the soil.

Using pipe-in-pipe systems for subsea pipeline vibration control

Pipe-in-pipe (PIP) systems are increasingly used in subsea pipeline applications due to their favourable thermal insulation capacity. Pipe-in-pipe systems consist of concentric inner and outer pipes, the inner pipe carries hydrocarbons and the outer pipe provides mechanical protection to withstand the external hydrostatic pressure. The annulus between the inner and outer pipes is either empty or filled with non-structural insulation material. Due to the special structural layout, optimized springs and dashpots can be installed in the annulus and the system can be made as a structure-tuned mass damper (TMD) system, which therefore has the potential to mitigate the pipeline vibrations induced by various sources. This paper proposes using pipe-in-pipe systems for the subsea pipeline vibration control. The simplification of the pipe-in-pipe system as a non-conventional structure-TMD system is firstly presented. The effectiveness of using pipe-in-pipe system to mitigate seismic induced vibration of a subsea pipeline with a free span is investigated through numerical simulations by examining the seismic responses of both the traditional and proposed pipe-in-pipe systems based on the detailed three dimensional (3D) numerical analyses. Two possible design options and the robustness of the proposed system for the pipeline vibration control are discussed. Numerical results show that the proposed pipe-in-pipe system can effectively suppress seismic induced vibrations of subsea pipelines without changing too much of the traditional design. Therefore it could be a cost-effective solution to mitigate pipe vibrations subjected to external dynamic loadings.

Research of a sleeve connection of the aircraft pipeline under the influence of dynamic loading

The article presents the results of analyzing the dynamic behavior of a prefabricated single-span pipeline with a tube connection on external cone under the influence of kinematic excitation. Five models of pipelines with different conjugation conditions in tube connection on external cone are described. The results have been obtained by using the finite element method and solving a contact problem of deformable body mechanics. At the first stage amplitude-frequency characteristics for the models of pipeline under consideration are constructed. The result shows the dependence of amplitude-frequency characteristics of the pipeline vibrations on the conjugation conditions in the collecting pipe connection. It was found in the process of research that the resonant frequency of the pipeline varies with introducing admissible gaps in the tube connection on external cone. This change may lead to a shift of the resonance frequency of the pipeline in the range of operating frequencies of the structure that may lead to the destruction of the pipeline. The article also reflects the influence of the external dynamic load on the distribution of contact pressure in the prefabricated tube connection on external cone while passing the resonance frequency. This distribution determines the tightness of connections.

Vibration and Stress Analyses of Positive Displacement Pump Pipeline Systems in Oil Transportation Stations

AbstractIn oil transportation stations, the plunger motion exhibited by positive displacement pumps can cause a great deal of vibration that can influence the secure operations of the equipment and pipelines. If resonance between the equipment and pipelines occurs, their integrity can be compromised, resulting in catastrophic damage. Therefore, both stress analysis and vibration analysis are necessary before a pipeline is formally put into operation. For this study, mechanical models of pipelines and constraints in positive displacement pump pipeline systems, based on theories of stress and vibration in pipelines, were created. Numerical simulations, including stress, modal, and vibration analyses were performed on-site at an oil transportation station in west China. The data were collected, reported, calibrated according to published standards, and then analyzed. The results revealed that the models created were reliable for stress and vibration analyses of pipelines in practical applications and that re...

A Study on the Analysis vibration of fluid flow in ECV

Pipe vibration caused great threat to the safety in production. Strong pipeline vibration will line accessories, especially the joints and pipe fittings etc. pipe joints loosening and rupture, causing serious accidents. By the action of the compressor constant fluid flow within the pipe, this process produces pulsating fluid flow may cause vibration of the pipe, thereby reducing the efficiency of the pipeline, structural vibration induced fatigue, thereby resulting in even piping structural damage. This paper studies on the vibration problems caused by fluid, by analyzing the causes of pipeline vibration and factors affecting pipeline vibrations, FEM (Finite Element Method) analysis of modal and enforced vibration.

Modal Analysis of Axial Vibration of Long Pipeline Delivering Coal Slime in Power Plant

Aiming at the problem of intense vibration of the long pipeline delivering coal slime in the power plant, the finite element model of pipeline is established and modal analysis is carried out by ANSYS. The natural frequency and vibration characteristics of axial vibration are obtained. The vibration characteristics are studied and different pipe segments that produce bigger vibration very easily in operation are determined. Theoretical guidance about pipeline vibration under the external load for further analysis is provided.

Experimental Investigation of the Effect of Splitter Plate Angle on the Under-Scouring of Submarine Pipeline Due to Steady Current and Clear Water Condition

Submarine pipelines are appropriate method for transferring oil, gas and other liquids from the seabed. Free spans may occur due to the natural uneven seabed or by under-scouring. Vortex Induced Vibration (VIV) can happen in such free spans at high Reynolds number. Resonance will occur if the frequency of vortex shedding is close to the pipeline’s natural frequencyleading to its fatigue that can break the pipeline causing economical and environmental losses. In literature, there are different methods for suppressing the vortex shedding and pipeline vibration and consequent scouring under the pipe such as the usage of splitter plates. In this paper, the effect of splitter plate’s angle on the scouring beneath the pipeline is studied experimentally. For this purpose, a new experimental setup is designed and constructed in order to allow for the cylinder to vibrate in both in-line and cross flow directions over an erodible bed. The reduced velocity for the experiments is in the range of 2.45-5.06 with different gap ratios. Experimental results indicate that the relative scour depth is reduced with increasing the ratio of gap to pipe diameter. The relative vibration frequency approaches to a constant value for large gap ratio ( 1<e <2 ) and the pipe does not have more effect on the bed. Therefore, the usage of splitter plate with the angle of 0-30 degrees with the horizon reduces the scouring depth below the mean location of the pipe compared with a pipe without splitter plate. Vice versa, the results were reversed for the pipes which used splitter plates with the angle of 60-90 degrees.

Vibroacoustics Analysis of Punching Machine Hydraulic Piping

The reduction of elevated dynamic loads, affecting the elements of the hydraulic drive, is an important task in production equipment maintenance. In case of the hydraulic drive with actuators, remotely located from the power source, the piping defines the working capacity of the whole system. Hence the development of piping vibroacoustic analysis methods appears to be the vital task. The said methods would not only help to define the cause of increased loads, but also permit to develop an adequate design solution without prolonged experimental checks.The article proposes the method of pipeline system vibroacoustics analysis through the example of press-forge unit drain piping. The novelty of this method consists in the use of the fluid pulsation and piping vibration spectra analysis in their correlative comparison with account to the calculated modal parameters of a pipeline.The measurements of working fluid pressure pulsation and pipeline vibration in the vicinity of the breakage locations were carried out. The experimental data spectrum analysis indicated an apparition of intense water-hammer process along with the frequency coalescence of fluid pulsation and pipeline vibration. The resonant vibration amplification, caused by the water-hammer effect, was suggested. The pipeline system mathematical model, allowing to calculate its modal parameters, was derived. The comparison of the modal analysis with the vibroacoustic response confirmed the hypothesis of the pipeline resonant breakdown.The article depicts, that the study of the pipeline system vibroacoustic response, based only on Fourier analysis of the working fluid pulsation and pipeline vibration, is prone to fail the reliable causation of elevated dynamic loads. It is suggested to complement the vibroacoustic response analysis with the modal parameters calculation. The mathematical computation of the modal frequencies and shapes was implemented instead of their experimental observation in order to exclude the undesired signal, introduced with attached mechanical equipment. On top of that, the mathematical computation of the pipeline modal parameters allowed to perform the pipeline modal frequency shift from the water-hammer effect frequency range through cautious relocation of additional supports.

In-Situ Test of Pressure Pipeline Vibration based on Data Acquisition and Signal Processing

Abstract Pipeline vibration of high frequency and large amplitude is an important factor that impacts the safe operation of pumping station and the efficiency of the pumps. Through conducting the vibration in-situ test of pipeline system in the pumping station, we can objectively analyze the mechanism of pipeline vibration and evaluate the stability of pipeline operation. By using DASP (data acquisition &amp; signal processing) in the in-situ test on the 2# pipeline of the third pumping station in the general main line of Jingtaichuan electric-lifting irrigation project in Gansu Province (later known as “the general trunk third pumping station in Jingtai electric project”) and then adopting time-domain analysis and cross-spectrum analysis to deal with collected data, we can acquire the vibration state in different positions of pipeline. Tests have shown that, the application of DASP in the vibration test of pressure pipeline of the pumping station, compared to the traditional test systems, can not only obtain higher test accuracy and efficiency, but can also provide theory basis and technical support for solving the vibration problems of the same-type pipeline operation. It has a good promotion value in the engineering practice.

The Vibroacoustic Characteristics Research of the Gas Pipeline

Technical focus of the research is a discrete throttle valve (DTV) and gas pipeline. An extensive research of vibration and acoustic characteristics of the main pipeline of a gas distribution station was carried out. The acoustic noise power level radiated by the main gas pipeline and it's comparison with the strength criterion were made. The levels of vibration acceleration in different parts of the main gas pipeline were measured. On the basis of experimental data the possible causes of the acoustic-induced vibration are described, and measures for reducing vibration loading of a gas pipeline were proposed.

Numerical solutions of coupling hydraulic transient and axial structural vibration in liquid-filled pipelines by flux vector splitting scheme

Method of characteristics is used widely to solve classical hydraulic transient problems. However, when it is applied to solve coupling hydraulic transient problems, excessive interpolation errors may be introduced into results because of unavoidable multi–wave interpolated calculations. To overcome the disadvantage, a novel finite difference scheme based on Steger–Warming flux vector splitting is proposed. Firstly, flux vector splitting scheme for coupling hydraulic transient model of liquid–filled pipelines is established. Then flux subvectors are discretised by Lax–Wendroff central difference scheme and Warming–Beam upwind difference scheme possessing second order precision in time and space. Finally, according to Rankine–Hugoniot conditions and corresponding boundary conditions, an effective method is developed to solve those points located at the boundaries, which can avoid the problem beyond calculation region induced by using second order discrete technology directly. The numerical simulation shows that the proposed computation scheme has several desirable advantages, such as high precision, excellent capability of capturing the shock waves, without false numerical oscillation, low sensitivity to Courant number and good stability.

Design of Underground Pipelines under Arbitrary Seismic Loading

On the basis of Hamilton-Ostrogradskiy variation principle a system of equations of linear pipeline vibrations interacting with surrounding soil is derived with appropriate boundary and initial conditions under arbitrary direction of seismic effect. Dynamic problem of underground pipeline is solved by finite difference method of the second order of accuracy with different combinations of boundary conditions under the effect of seismic load on a given law with arbitrary direction. Numerical implementation of the problem is realized.

发电机氢冷管道振动分析研究

发电机氢冷管道振动对发电机及氢冷管道的正常安全运行产生极大的威胁，进而影响整个电厂运行的安全性和可靠性。为了保证发电机的安全运行，有必要对氢冷管道的振动机理进行分析研究。本文分析了管道振动的原因，认为发电机振动传递和管道设计不合理是引起氢冷管道振动的主要原因，并分别从消减管系激振力与改善管系振动特性两方面，提出了控制氢冷管道振动的措施，为电厂发电机氢冷管道振动治理提供了一定的技术支持。 Generator hydrogen-cooled piping vibration produces great threat to the normal and safe operation of generator and hydrogen-cooled pipeline, furthermore affecting the safety and reliability of the power plant. To ensure the normal and safe operation of the generator, it is necessary to make analysis on the mechanism of hydrogen-cooled pipe vibration. This paper has analyzed the causes of pipeline vibrations and finds that generator vibration transmission and unreasonable piping design are the main cause of hydrogen-cooled piping vibration. The suggestion and measures that are piping exciting force reduction and piping vibration characteristics improvement to control hydrogen-cooled piping vibration are given. The study of this paper can provide technical support for hydrogen-cooled piping vibration treatment work in power plant.

Dynamic Analysis of Suspended River Crossing Pipeline

When the long-distance oil pipeline under rivers (referred to as river-crossing pipelines) are damaged by the third-party, they are prone to nudity or left vacant, and the oil pipelines under the action of water flow will cause pipeline failure; and the distance of suspended pipeline is longer than the allowed length will cause the pipeline resonance. In order to avoid pipelines fatigue or broken, suspended pipelines are considered as part of the arc shape, and non-suspended pipelines are considered as the linear shape of the mechanical model with the two ends of the fixed pier synchronous. The study will consider the impact of water flow, buoyancy, the gravity of pipelines and its annexes, bending deformation and bending moment, do the tense calculation for suspended pipelines with external load and the vibration analysis for suspended pipelines under different water flow speeds. The results showed that: the design of river-crossing suspended pipelines not only needs to consider the impact of water flow, buoyancy, the gravity of pipelines and its annexes, bending deformation and bending moment, but also to consider the floating vortex-induced vibration of the suspended pipeline, which should cause pipeline designers, constructors and maintainers’ attention.

Study of Integrity and Interaction of a Non-Buried Marine Subsea Pipeline with Soil

To study the seismic resistance of subsea pipelines, the following item-wise calculations are made for the following exposures:- determining the seismic hazard of the area;- analysis of pipeline integrity and pipeline-soil interaction;- analysis of soil stability along the pipeline route.Assessment of the stressed state of a vibrating subsea pipeline is related to the need to determine the values and basic dependencies of resistance forces (damping, energy dissipation) when exposed to vibrations. Energy dissipation taking place in case of subsea pipeline vibrations is composed of hydrodynamic resistance losses, losses due to resistance in the structural material of a pipeline (insulation coating, lining, concrete coating, ballast) and losses to the soil through supports.