Structural Integrity of Flexible Piping Systems Conveying Liquids

2005 ◽  
Vol 128 (3) ◽  
pp. 341-347 ◽  
Author(s):  
Felipe BastosFreitas Rachid
Keyword(s):  
Structural Integrity ◽  
Mathematical Problem ◽  
Nonlinear Partial Differential Equations ◽  
Operator Splitting ◽  
Piping System ◽  
Damage Growth ◽  
Splitting Technique ◽  
Structure Interaction ◽  
Piping Systems ◽  
Fast Transients

This work presents a structural integrity model for piping systems conveying liquids which takes the axial fluid-structure interaction into account. The model is used to numerically investigate the influence of pipe motion on the degradation of the piping when fast transients are generated by valve slam. The resulting mathematical problem is formed by a system of nonlinear partial differential equations which is solved by means of an operator splitting technique, combined with Glimm’s method. Numerical results obtained for an articulated piping system indicate that high piping flexibility may induce a substantial increase in damage growth along the pipes.

The Influence of Pipe Motion on the Integrity of Liquid-Filled Pipes Subjected to Pressure Transients

2005 ◽  
Author(s):  
Felipe Bastos de Freitas Rachid
Keyword(s):  
Partial Differential Equations ◽  
Differential Equations ◽  
Mathematical Problem ◽  
Operator Splitting ◽  
Damage Growth ◽  
Splitting Technique ◽  
Structure Interaction ◽  
Linear Partial Differential Equations ◽  
Piping Systems ◽  
Fast Transients

This work presents a structural itegrity model for piping systems conveying liquids which takes the axial fluid-structure interaction into account. The model is used to numerically investigate the influence of pipe motion on the degradation of the piping when fast transients are generated by valve slam. The resulting mathematical problem is formed by a system of non-linear partial differential equations which is solved by means of an operator splitting technique, combined with a Glimm’s method. Numerical results obtained indicate that high piping flexibility may introduce a substantial increase in damage growth along the pipes.

Frequency Domain Analysis of Vibrations in Liquid-Filled Piping Systems

1999 ◽  
Author(s):  
Zongxia Jiao ◽  
Qing Hua ◽  
Kai Yu
Keyword(s):  
Frequency Domain ◽  
Transfer Matrix ◽  
Fluid Structure Interaction ◽  
Viscous Friction ◽  
Domain Analysis ◽  
Frequency Domain Analysis ◽  
Piping System ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Piping Systems

Abstract In the analysis of liquid-filled piping systems there are Poisson-coupled axial stress waves in the pipe and liquid column, which are caused by the dilation of the pipe. In some conditions the influence of viscous friction that is usually frequency-dependent should not be omitted, which in fact is another kind of coupled form. It directly influences the amplitude of vibration of piping systems to some degree. The larger the viscosity of the liquid is, the greater the influence will be. Budny (1991) included the viscous friction influence in time domain analysis of fluid-structure interaction, but did not give frequency domain analysis. Lesmez (1990) gave the model analysis liquid-filled piping systems without considering friction. If the friction is not included in frequency domain analysis, the vibration amplitude will be greater than that when friction is included, especially at harmony points, cause large errors in the simulation of fluid pipe network analysis, although it may have little influence on the frequency of harmony points. The present paper will give detail solutions to the transfer matrix that represents the motion of single pipe section, which is the basis of complex fluid-structure interaction analysis. Combined with point matrices that describe specified boundary conditions, overall transfer matrix for a piping system can be assembled. Corresponding state vectors can then be evaluated to predict the piping and liquid motion. At last, a twice-coordinate transformation method is adopted in joint coupling. Consequently, the vibration analysis of spatial liquid-filled piping systems can be carried out. It is proved to be succinct, valid and versatile. This method can be extended to the simulation of the curved spatial pipeline systems.

Estimation of Bending Stresses in Piping Systems Subjected to Transient Pressure

2020 ◽  
Author(s):  
Maral Taghva ◽  
Lars Damkilde
Keyword(s):  
Dynamic Analysis ◽  
Static Analysis ◽  
Structural Integrity ◽  
Oil And Gas ◽  
Real Life ◽  
Piping System ◽  
Transient Pressure ◽  
Operational Conditions ◽  
Piping Systems ◽  
Bending Stresses

Abstract Modifications in aged process plants may subject piping systems to fluid transient scenarios, which are not considered in the primary design calculations. Due to lack of strict requirements in ASME B31.3 the effect of this phenomenon is often excluded from piping structural integrity reassessments. Therefore, the consequences, such as severe pipe motion or even rupture failure, are discovered after modifications are completed and the system starts to function under new operational conditions. The motivation for this study emanated from several observations in offshore oil and gas piping systems, yet the results could be utilized in structural integrity assessments of any piping system subjected to pressure waves. This paper describes how to provide an approximate solution to determine maximum bending stresses in piping structures subjected to wave impulse loads without using rigorous approaches to calculate the dynamic response. This paper proposes to consider the effect of load duration in quasi-static analysis to achieve more credible results. The proposed method recommends application of lower dynamic load factors than commonly practiced values advised by design codes, for short duration loads such as shock waves. By presenting a real-life example, the results of improved and commonly practiced quasi-static analysis are compared with the site observations as well as dynamic analysis results. It is illustrated that modified quasi-static solution shows agreement with both dynamic analysis and physical behavior of the system. The contents of this study are particularly useful in structural strength re-assessments where the practicing engineer is interested in an approximated solution indicating if the design criteria is satisfied.

Effects of High Frequency Hydrodynamic Loads on Structural Integrity and Mechanical Operability of Valves

2015 ◽  
Author(s):  
Yigit Isbiliroglu ◽  
Cagri Ozgur ◽  
Evren Ulku ◽  
Nish Vaidya ◽  
Kristofor Paserba
Keyword(s):  
High Frequency ◽  
Structural Integrity ◽  
Energy Content ◽  
Hybrid Approach ◽  
Piping System ◽  
Seismic Loads ◽  
Damage Potential ◽  
Element Analysis ◽  
Piping Systems ◽  
Number Of Cycles

In-line valves are qualified for static as well as dynamic loads from seismic and hydrodynamic (HD) events. Seismic loads are generally characterized by frequency content less than about 33 Hz whereas HD loads may exhibit a broad range of frequencies greater than 33 Hz. HD loads may also result in spectral accelerations significantly in excess of those due to the design basis seismic events. Current regulatory guidelines do not specifically address the evaluation of equipment response to high frequency loading. This paper investigates the response of skid and line mounted valves of piping systems under HD loads by using several independent rigorous finite element analysis solutions for various piping system segments. It presents a hybrid approach for the evaluation of the response of valves to HD and seismic loads. The proposed approach significantly reduces the amount of individual analysis and testing needed to qualify the valves. First, valve responses are evaluated on the basis of displacements since HD loads are generally characterized by high frequencies and small durations. Second, the damage potential of the loads on the valve actuators is represented by the energy imparted to the actuator quantified in terms of Arias intensity. The rationale for using the energy content is based on the fact that damage due to dynamic loading is related not only to the amplitude of the acceleration response but also to the duration and the number of cycles over which this acceleration is imposed.

Forced Convection Flow Through an Unsaturated Wellbore

2003 ◽  
Author(s):  
Maria Laura Martins-Costa ◽  
Roge´rio M. Saldanha da Gama
Keyword(s):  
Nonlinear Partial Differential Equations ◽  
Operator Splitting ◽  
Mixture Theory ◽  
Porous Matrix ◽  
Convection Flow ◽  
Theory Approach ◽  
Splitting Technique ◽  
Nonlinear Hyperbolic System ◽  
Implicit Finite Difference Scheme ◽  
Flow Through

This work studies the dynamics of the filling up of a rigid cylindrical shell porous matrix by a Newtonian fluid and the heat transfer associated phenomenon. A mixture theory approach is employed to obtain a preliminary local model for nonisothermal flows through a wellbore. The mixture consists of three overlapping continuous constituents: a solid (porous medium), a liquid and an inert gas included to account for the compressibility of the mixture as a whole. Assuming the convection flow on radial direction only, a set of four nonlinear partial differential equations describes the problem. Its hydrodynamic part — a nonlinear hyperbolic system — is approximated by means of a Glimm’s scheme, combined with an operator splitting technique, while an implicit finite difference scheme is used to simulate the thermal part.

The Effect of Piping System Non-Linearity on the Unstable Growth of a Circumferential Through-Wall Crack in a Pipe

2003 ◽  
Author(s):  
E. Smith
Keyword(s):  
Cross Section ◽  
Material Properties ◽  
Structural Integrity ◽  
Crack Size ◽  
Instability Criterion ◽  
Piping System ◽  
Linear Elastic ◽  
Piping Systems ◽  
Simple Model System ◽  
Linear Manner

During the last twenty-five years, considerable attention has been given to the structural integrity of steel piping systems, and in particular to the effect of circumferential cracks on their integrity. From a safety perspective, it is important that any crack, say for example a stress corrosion crack or fatigue crack, will not develop into a through-wall crack which will then propagate unstably, thus leading to a guillotine rupture and possibly a pipe whip scenario. One way of guaranteeing that this does not happen is to ensure that unstable growth of a circumferential through-wall crack is unable to occur. An appropriate methodology is based on tearing modulus concepts with the instability criterion being expressed in the form TAPP > TMAT where TAPP is the applied tearing modulus, a measure of the crack driving force, and TMAT is the material tearing modulus, a measure of the material’s crack growth resistance. With a piping system that behaves in a linear elastic manner, TAPP involves only the system’s geometry parameters and the crack size but not the magnitudes of the applied loadings or the material properties of the cracked cross-section; the behaviours of the cracked cross-section and the remainder of the piping system are therefore decoupled. If, however, the system behaves in a non-linear manner say, for example, as a result of excessive deformation arising as a consequence of large deformations, then TAPP also involves the material properties of the cracked cross-section; material and piping system geometry parameters are then not decoupled in the instability criterion. The paper illustrates this point by analysing a simple model system where the non-linearity arises from excessive deformation at a connection.

Applicability of Optimal Seismic Design Methodology for Piping Systems Subjected to Seismic Waves With Various Frequency Characteristics

2007 ◽  
Author(s):  
Tomohiro Ito ◽  
Katsuhisa Fujita ◽  
Masashi Michiue
Keyword(s):  
Seismic Design ◽  
Design Methodology ◽  
Seismic Waves ◽  
Structural Integrity ◽  
Frequency Characteristics ◽  
System Model ◽  
Piping System ◽  
Optimal Conditions ◽  
Piping Systems ◽  
Support Devices

In this study, the optimal seismic design methodology which can consider the structural integrity of both piping systems and elasto-plastic support devices are developed. This methodology employs genetic algorithm and can search the optimal conditions such as supporting locations, capacity and stiffness of supporting devices. A lead extrusion damper is treated here as a typical elasto-plastic damper. Numerical simulations are performed using a simple piping system model for the various kinds of seismic waves with different frequency characteristics. As a result, it is shown that the optimal seismic design methodology proposed here is applicable to the seismic design of piping systems supported by elasto-plastic dampers subjected to the seismic waves with various kinds of frequency characteristics.

Fluid-Structure Interaction in Waterhammer Response of Flexible Piping

1986 ◽  
Vol 108 (3) ◽  
pp. 249-255 ◽  
Author(s):  
T. Belytschko ◽  
M. Karabin ◽  
J. I. Lin
Keyword(s):  
Structural Model ◽  
Fluid Structure Interaction ◽  
Added Mass ◽  
Piping System ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Piping Systems ◽  
Thin Walled ◽  
Fully Coupled ◽  
Recovery Procedure

In the waterhammer analysis of piping systems, incompressible (or added mass) representations are generally used in computing the response of the piping. It is shown that this procedure is not necessarily conservative, particularly for thin-walled, flexible piping systems, and that fully coupled fluid-structure solutions can predict higher loads and stresses. A modal recovery procedure which easily permits the representation on the acoustic effects of the fluid to be included in a structural model is also presented. Results are given for both simple models and a piping system from an LMFBR design.

Basic Study on Optimal Design of System Supporting Structures Subjected to Random Inputs Using the Probabilistic Vibration Theory

2012 ◽  
Author(s):  
Atsuhiko Shintani ◽  
Tadashi Nagami ◽  
Tomohiro Ito ◽  
Chihiro Nakagawa
Keyword(s):  
Optimal Design ◽  
Random Vibration ◽  
Structural Integrity ◽  
Piping System ◽  
Basic Study ◽  
Vibration Theory ◽  
Piping Systems ◽  
Random Vibration Theory ◽  
Noise Input ◽  
Supporting Structures

In this paper, we investigate the optimal design of the piping system supported by elasto-plastic damper subjected to the random input based on the random vibration theory. Using proposed optimal design, the structural integrity of both the piping systems and the elasto-plastic supporting devices are considered and the optimal conditions such as the supporting location, the capacity of the supporting devices are searched. Numerical simulations are performed using a simple piping system model for the white Gaussian noise input based on the random vibration theory.

Condensation Water Hammer Calculation as Basis for Better Design

2003 ◽  
Author(s):  
Werner Schnellhammer ◽  
Tilman Diesselhorst
Keyword(s):  
System Design ◽  
Initial Conditions ◽  
Fluid Structure Interaction ◽  
Water Hammer ◽  
Operating Conditions ◽  
Piping System ◽  
System Operation ◽  
Structure Interaction ◽  
Piping Systems ◽  
Pressure Surge

Condensation processes can generate relevant loading on piping systems when large bubbles ore separated vapor volumes are collapsing in a pipe. For prediction of such loads condensation effects in piping systems were modelled and integrated in a pressure surge code for branched systems taking into account fluid structure interaction. From these calculations we get realistic results of condensation water hammer in the piping system. The loads are strongly depending on the initial conditions and operating procedures. By carrying out calculations with the different possible operating conditions the results give the basis to decide which load cases are covered by the system design and where countermeasures have to be taken. These measures may consist of changing the modus of system operation or modifying the system design itself. A typical example is given.

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