Dealing With Heavy Loads in Large Diameter Piping

2012 ◽  
Author(s):  
Hector Rojas ◽  
Andrey Gutkovsky
Keyword(s):  
Large Diameter ◽  
Operating Conditions ◽  
Configuration Design ◽  
Piping System ◽  
Flow Conditions ◽  
Element Analysis ◽  
Piping Systems ◽  
Molten Sulfur ◽  
Heavy Loads

It is common in a refinery that some piping systems have to handle several flow conditions. However, when a new proposed condition implies the filling of an existing 68″ (1727 mm) line with molten Sulfur, which was initially designed for gas operation, a well thought engineering case study is required to guarantee that no damage will occur under the new operating conditions. This paper covers the procedures employed to qualify the integrity of a 68″ (1727 mm) piping system, initially designed to carry Sulfur vapors and required to handle occasional filling with molten Sulfur due to operational demands. The procedures of reviewing the initial configuration, design of modifications and reinforcements to the piping system and the use of Finite Element Analysis (FEA) in order to qualify several unique support configurations are explained in this paper.

Reduction in Stresses Shown in Piping Programs in Large Diameter Pipe Branch Connections by Applying Flexibilities Computed by Shell Finite Element Analysis

2004 ◽  
Author(s):  
Robert A. Robleto
Keyword(s):  
Finite Element Analysis ◽  
Large Diameter ◽  
Piping System ◽  
Bending Moments ◽  
Straight Pipe ◽  
Element Analysis ◽  
Large Diameter Pipe ◽  
Diameter Pipe ◽  
Piping Systems ◽  
Shell Finite Element

When designing branch connections in low pressure large diameter piping systems as in Figure 1, thicker is not always better. The flexibility factors in ASME B31.3 1 for branch connections do not assist the designer in taking credit for flexibility that may exist in a large diameter intersection. Since the stress intensification factors (SIFs) are relatively high for large diameter piping, many stub-in branch connections will require a pad to meet the code displacement stress limits. In an ASME B31.3 Piping analysis the stiffness of the branch connections is considered to be as stiff as a straight piece of pipe modeled as a beam. This is a simplifying assumption that can lead to expensive conservatism for the component and possibly non-conservatism for nearby equipment especially when large diameter pipe is considered. Branch connection flexibility is often negligible when compared with piping flexibility of straight pipe perpendicular to the deflection and bends which can ovalize under in-plane bending moments. However, studies at KBR show branch connections in large diameter pipe can contribute significant flexibility to a close coupled piping system.

Stress of Large Diameter Piping System Shoe Support

2017 ◽  
Author(s):  
Sadjad Ranjbaran ◽  
Akbar Daneshvar Ghalelar
Keyword(s):  
Failure Modes ◽  
Large Diameter ◽  
Estimation Method ◽  
Beam Theory ◽  
Local Stress ◽  
Accurate Estimation ◽  
Piping System ◽  
Element Analysis ◽  
Piping Systems ◽  
Applied Design

As codes and standards employ the beam theory to evaluate stress in piping systems, large diameter piping is therefore outside the domain of these codes and standards. To investigate any failure modes in these piping systems, more general codes such as ASME Sec. VIII Div.2 must be used. Research has shown that estimating local stress is important near the shoe support tip especially for large diameter piping systems and aboveground pipelines. To evaluate protection against local failure under an applied design load, a more accurate estimation method of ASME Sec. VIII Div.2, part 5 is applied by using elastic-plastic stress analysis procedures. For this purpose, finite element analysis is carried out along with distributed gravity loading and design pressure. Furthermore, parametric FEA studies are conducted on the effect of the ratio of pipe diameter to thickness, as well as the width and wrap angle of shoe support on the local stress of shoe support. The FEA results have been compared to semi-empirical formula for local stress in shoe support developed by AWWA standard.

Creep Life Simulation and Assessment of High Temperature Piping Systems and Components

2012 ◽  
Author(s):  
Brian Rose ◽  
James Widrig
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Temperature ◽  
Creep Behavior ◽  
Material Behavior ◽  
Piping System ◽  
Remaining Life ◽  
Creep Life ◽  
Element Analysis ◽  
Piping Systems

High temperature piping systems and associated components, elbows and bellows in particular, are vulnerable to damage from creep. The creep behavior of the system is simulated using finite element analysis (FEA). Material behavior and damage is characterized using the MPC Omega law, which captures creep embrittlement. Elbow elements provide rapid yet accurate modeling of pinching of piping, which consumes a major portion of the creep life. The simulation is used to estimate the remaining life of the piping system, evaluate the adequacy of existing bellows and spring can supports and explore remediation options.

Performance-Based Analysis of Coupled Support Structures and Piping Systems Subject to Seismic Loading

2015 ◽  
Author(s):  
Oreste S. Bursi ◽  
Fabrizio Paolacci ◽  
Md Shahin Reza
Keyword(s):  
Seismic Design ◽  
Seismic Analysis ◽  
Design Method ◽  
Design Guidelines ◽  
Piping System ◽  
Support Structures ◽  
Limit States ◽  
Piping Systems ◽  
Allowable Stress Design

The prevailing lack of proper and uniform seismic design guidelines for piping systems impels designers to follow standards conceived for other structures, such as buildings. The modern performance-based design approach is yet to be widely adopted for piping systems, while the allowable stress design method is still the customary practice. This paper presents a performance-based seismic analysis of petrochemical piping systems coupled with support structures through a case study. We start with a concept of performance-based analysis, followed by establishing a link between limit states and earthquake levels, exemplifying Eurocode and Italian prescriptions. A brief critical review on seismic design criteria of piping, including interactions between piping and support, is offered thereafter. Finally, to illustrate actual applications of the performance-based analysis, non-linear analyses on a realistic petrochemical piping system is performed to assess its seismic performance.

Modal Reduction Technique for Predicting the Onset of Chaotic Behavior due to Lateral Vibrations in Drillstrings

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
Kathira Mongkolcheep ◽  
Annie Ruimi ◽  
Alan Palazzolo
Keyword(s):  
Finite Element ◽  
Oil And Gas ◽  
Chaotic Behavior ◽  
Large Diameter ◽  
Operating Conditions ◽  
Dynamical Analysis ◽  
Computational Time ◽  
Element Formulation ◽  
Element Analysis ◽  
Lateral Vibrations

Drillstrings used for oil and gas exploration and extraction consist of a drillpipe (slender columns on the order of 3–5 km long), drill collars (DCs) (thick-walled large-diameter pipes), stabilizers (cylindrical elements with short sections and diameter near that of the borehole), and a rock-cutting tool that uses rotational energy to penetrate the soil. Several types of vibrations ensue from these motions and play a major role in added costs resulting from unforeseen events such as abandoning holes, replacing bits, and fishing severed bottom-hole assemblies (BHAs). It is thus of critical importance to understand, predict, and mitigate the severe vibrations experienced by drillstrings and BHA to optimize drilling time while lowering fuel consumption and related emissions of NOX and/or other pollutants. In this paper, we present a dynamical analysis of the behavior of drillstrings due to the violent lateral vibrations (LVs) DCs may experience as a result of rotating drillstrings. The behavior is represented by a system of two coupled nonlinear ordinary equations that are integrated numerically with a finite element analysis based on Timoshenko beam (TB) formulation combined to a modal condensation technique to reduce the computational time. Various nonlinear dynamical analysis tools, such as frequency spectrum, Poincaré maps, bifurcation diagrams, and Lyapunov exponents (LE), are used to characterizing the response. The DC section between two stabilizers is essentially modeled as a Jeffcott rotor with nonlinearity effects included. The model builds on two earlier models for the finite element formulation and the treatment of chaotic vibrations. Nonlinearity appears in the form of drillstring/borehole contact force, friction, and quadratic damping. The DC flexibility is included to allow investigation of bending modes. The analysis takes into account the length of time to steady state, number of subintervals, presence of rigid body modes, number of finite elements, and modal coordinates. Simulations results indicate that by varying operating conditions, a spectrum of behaviors from periodic to chaotic may be observed.

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.

Dynamic Response of a Piping System Under Harmonic Excitations Considering Pipe-Support Friction With Variable Normal Loads

2013 ◽  
Author(s):  
José Argüelles ◽  
Euro Casanova
Keyword(s):  
Equations Of Motion ◽  
Numerical Approach ◽  
Operating Conditions ◽  
Dynamic Loads ◽  
Computational Time ◽  
Integration Scheme ◽  
Piping System ◽  
Harmonic Excitations ◽  
Piping Systems ◽  
Support Surfaces

Dynamic loads in piping systems are mainly caused by transient phenomena generated by operating conditions or installed equipment. In most cases these dynamic loads may be modeled as harmonic excitations e.g. pulsating flow. On the other hand, when designing piping systems under dynamic loads, it’s a common practice to neglect strong nonlinearities such as shocks and friction between pipe and support surfaces, mainly because of the excessive cost in terms of computational time and the complexity associated with the integration of the nonlinear equations of motion. However, disregarding these nonlinearities for some systems may result in overestimated dynamic amplitudes leading to incorrect analysis and designs. This paper presents a numerical approach to calculate the steady-state response amplitudes of a piping system subject to harmonic excitations and considering dry friction between the pipe and the support surfaces, without performing a numerical integration. The proposed approach permits the analysis of three dimensional piping systems where the normal forces may vary in time and is based in the Hybrid Frequency-Time Domain method (HFT). Results of the proposed approach are compared and discussed with those of a full integration scheme, confirming that HFT is a valid and computationally feasible option.

Results From Dynamic Tests and Analyses of a Medium Diameter LMFBR Piping System

1986 ◽  
Vol 108 (3) ◽  
pp. 330-333
Author(s):  
G. A. Schott ◽  
G. M. Hulbert ◽  
C. F. Heberling
Keyword(s):  
Seismic Design ◽  
Large Diameter ◽  
Piping System ◽  
Fast Breeder Reactor ◽  
Test Results ◽  
Dynamic Tests ◽  
Test Program ◽  
Piping Systems ◽  
Seismic Tests ◽  
Medium Diameter

This paper presents results and observations from dynamic tests and analyses performed on an 8-in. (0.20-m) diameter, thin-walled piping system. The piping system is a scaled representation of a Liquid Metal Fast Breeder Reactor (LMFBR) large diameter piping loop. Prototypic piping restraints were employed, including mechanical snubbers, rigid struts, pipe hangers and nonintegral pipe clamps. Snap-back, sine-sweep and seismic tests were performed for various restraint configurations and piping conditions. The test results are compared to analytical predictions for verification of the methods and models used in the seismic design of LMFBR piping systems. Test program conclusions and general recommendations for piping seismic analyses are presented along with a discussion of test and analysis results.

Simplified Seismic Response Analysis Method Using Reduced Model of Piping System

2018 ◽  
Author(s):  
Michiya Sakai ◽  
Ryuya Shimazu ◽  
Shinichi Matsuura ◽  
Ichiro Tamura
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Seismic Response ◽  
Degrees Of Freedom ◽  
Response Analysis ◽  
Piping System ◽  
Element Analysis ◽  
Mass System ◽  
Piping Systems ◽  
Low Degrees

In the seismic response analysis of piping systems, finite element analysis is performed with analysis method guidelines [1]–[4] established based on benchmark analysis. However, since it takes a great deal of effort to carry out finite element analysis, a simplified method to analyze the seismic response of complex piping systems is required. In this research, we propose a method to reduce an equivalent spring-mass system model with low degrees of freedom, which can take into account the main mode of the complicated piping system. Simplified seismic evaluation is carried out using this spring mass system model with low degrees of freedom, and the accuracy of response evaluation is confirmed by comparison with finite element analysis.

B31.1 Compliant Design of CFRP Buried Piping Systems

2015 ◽  
Author(s):  
Neda Stoeva ◽  
Timothy M. Adams ◽  
Tomas Jimenez ◽  
Scott Arnold ◽  
John Uhland
Keyword(s):  
Carbon Fiber ◽  
Composite System ◽  
Large Diameter ◽  
Material Behavior ◽  
Piping System ◽  
Service Water ◽  
Piping Systems ◽  
Cfrp Composite ◽  
Welded Pipe ◽  
Fiber Fabric

This paper presents the implementation of a Carbon Fiber Reinforced Polymer (CFRP) composite system as a long term replacement for a non-safety, non-seismic, non-QA, low pressure service water buried pipeline. The existing pipeline (to be replaced) consists of approximately 1800 feet of large diameter (primarily 54in.), carbon steel, spiral wound, seam welded pipe, which was built and installed using AWWA standards, but is maintained in accordance with the B31.1 Power Pipe Code [1]. The CFRP pipe installation is to be done as an internal repair, and designed to comply with ASME B31.1 as a stand-alone pipe (pressure boundary). In lieu of using the limited evaluation of PCC-2 [2], which is focused on local repairs; a complete design evaluation of the entire piping system to B31.1-2010 is conducted, which is consistent with and acceptable under PCC-2. Since B31.1 does not provide detailed guidance on the design of buried piping systems, the criteria presented in this paper use the base design requirements of B31.1 adjusted to include applied soil and surcharge loads. The selected CFRP repair is the TYFO® Fiberwrap® system which consists of a carbon fiber fabric (CFRP, TYFO SCH-41-2X), and glass fiber fabric (GFRP/dielectric barrier, TYFO SHE-51A), saturated with epoxy. This composite system is built up of unidirectional CFRP layers; thus, the presented design approach also considers anisotropic material behavior, and evaluates the hoop and axial loads and capacities separately. The criteria are presented for plants considering alternative repair and replacement techniques for buried and above ground non-safety pipes.

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