Dynamic Response Studies of Piping-Support Systems

1990 ◽  
Vol 112 (1) ◽  
pp. 39-45 ◽  
Author(s):  
T. Chiba ◽  
R. Koyanagi
Keyword(s):  
Dynamic Characteristics ◽  
Support Systems ◽  
Three Dimensional ◽  
Local Stress ◽  
Integrated Approach ◽  
Piping System ◽  
3 Dimensional ◽  
Piping Systems ◽  
Seismic Loadings ◽  
High Level

Considering the effect of the interaction between piping and support systems in the piping design is a more integrated approach to improve the reliability of piping systems. So, it is important to clarify the dynamic characteristics of the piping and the restraint structure during the seismic events. It may be desirable to investigate the effect of the gap on the response and the local stress of the piping systems. The dynamic characteristics of a simplified piping model with gaps was investigated by the tests and the analysis. Three-dimensional piping model test was performed to estimate the effect of the gap on the response of the piping system. It can be found that the local stress and the stiffness of the piping and the restraint structure under the seismic loadings should be considered in the seismic design. The gap size was not so effective on the response of the 3-dimensional piping system in the high-level response.

Comparison of Failure Modes of Piping Systems With Wall Thinning Subjected to In-Plane, Out-of-Plane and Mixed Mode Bending Under Seismic Load: Computational Approach

2007 ◽  
Author(s):  
Satoshi Tsunoi ◽  
Akira Mikami ◽  
Izumi Nakamura ◽  
Akihito Otani ◽  
Masaki Shiratori
Keyword(s):  
Analytical Model ◽  
Failure Modes ◽  
Experimental Investigations ◽  
Seismic Load ◽  
Piping System ◽  
Wall Thinning ◽  
Piping Systems ◽  
Out Of Plane ◽  
Seismic Loadings ◽  
Local Wall Thinning

The authors have proposed an analytical model by which they can simulate the dynamic and failure behaviors of piping systems with local wall thinning against seismic loadings. In the previous paper [13], the authors have carried out a series of experimental investigations about dynamic and failure behaviors of the piping system with fully circumferential 50% wall thinning at an elbow or two elbows. In this paper these experiments have been simulated by using the above proposed analytical model and investigated to what extent they can catch the experimental behaviors by simulations.

Creep Relaxation Behavior of High-Energy Piping

2000 ◽  
Vol 122 (4) ◽  
pp. 488-493 ◽  
Author(s):  
Raymond K. Yee ◽  
Marvin J. Cohn
Keyword(s):  
Stress Relaxation ◽  
Thermal Loading ◽  
Elevated Temperatures ◽  
Three Dimensional ◽  
Creep Damage ◽  
High Energy ◽  
External Loading ◽  
Piping System ◽  
Dead Weight ◽  
Piping Systems

The analysis of the elastic stresses in high-energy piping systems is a routine calculation in the power and petrochemical industries. The American Society of Mechanical Engineers (ASME) B31.1 Power Piping Code was developed for safe design and construction of pressure piping. Postconstruction issues, such as stress relaxation effects and selection of maximum expected creep damage locations, are not addressed in the Code. It has been expensive and time consuming to evaluate creep relaxation stresses in high energy piping systems, such as main steam and hot reheat piping. After prolonged operation of high-energy piping systems at elevated temperatures, it is very difficult to evaluate the redistribution of stresses due to dead weight, pressure, external loading, and thermal loading. The evaluation of stress relaxation and redistribution is especially important when nonideal conditions, such as bottomed-out or topped-out hangers, exist in piping systems. This paper uses three-dimensional four-node quadrilateral shell elements in the ABAQUS finite element code to evaluate the time for relaxation and the nominal relaxation stress values for a portion of a typical high-energy piping system subject to an ideally loaded hanger or to an overloaded hanger. The stress relaxation results are evaluated to suggest an approximation using elastic stress analysis results. [S0094-9930(00)01304-4]

Simplified Second Stage Creep/Relaxation Analysis of Moderately Complex Spatially Three-Dimensional Piping Systems

1974 ◽  
Vol 96 (3) ◽  
pp. 184-192 ◽  
Author(s):  
G. H. Workman ◽  
E. C. Rodabaugh
Keyword(s):  
Three Dimensional ◽  
Theoretical Development ◽  
Small Displacement ◽  
Piping System ◽  
Stress Strain ◽  
Curved Pipe ◽  
Thermal Change ◽  
Second Stage ◽  
Piping Systems ◽  
Applied Forces

An analysis technique for predicting the second stage creep/relaxation response of moderately complex spatially three-dimensional piping systems is presented herein. The theoretical development of this technique is based on two major assumptions. The first assumption is that at any time the behavior of the piping system can be associated with two components. One is an elastic component which is recoverable, and the other is a creep/relaxation component, which is not recoverable. The second major assumption, the simplifying assumption, is that the creep/relaxation strains due to axial, bending, and torsional loading can be decoupled and strains due to internal pressure can be neglected. Utilizing small displacement linear strain assumptions, the elastic stress-strain and creep/relaxation stress-strain rate laws can be integrated over the pipe’s cross section to yield generalized force-deformation relationships. The method of initial strains associated with the matrix displacement method of structural analysis is now applied to generate the solution of the creep/relaxation problem. This formulation utilizes two distinct types of piping elements. The first is a straight uniform pipe element and the second is a circularly curved pipe element, which incorporates both elastic and creep/relaxation flexibility factors. The end result of this formulation is a digital computer program capable of analyzing spatially three-dimensional piping systems under creep/relaxation conditions that can be represented by a series of straight or circularly curved pipe elements subjected to applied forces, displacements, and/or thermal change. An example analysis is included.

Pulsation suppression in a reciprocating compressor piping system using a two-tank element

2017 ◽  
Vol 232 (4) ◽  
pp. 427-437 ◽  
Author(s):  
Quyang Ma ◽  
Zhenhuan Wu ◽  
Guoan Yang ◽  
Yue Ming ◽  
Zheng Xu
Keyword(s):  
Theoretical Model ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Wave Theory ◽  
Damping Coefficient ◽  
Piping System ◽  
Pressure Pulsations ◽  
Surge Tank ◽  
Piping Systems ◽  
Gas Pulsations

Gas pulsations excited by reciprocating compressors could introduce severe vibrations and noise in piping systems. When pulsating gas flows through the reducers, the changes in flow characteristics, such as velocity and damping coefficient, will affect the pressure pulsations. To circumvent these constraints, a two-tank element is introduced to control the gas pulsation that is still strong in the piping system with a surge tank. Installing another surge tank to form a two-tank element is more flexible and costs lower than replacing the original surge tank with a larger one. In this work, a theoretical model based on the wave theory was proposed to study the transferring mechanism of gas pulsations in the pipeline with the two-tank element. By considering the damping coefficient and the Mach number, the distributions of the pressure pulsations were predicted by the theoretical model and agreed with the three-dimensional fluid dynamics transient analysis. Three experiments were conducted to prove that the suppression capability of the two-tank element is as good as that of a single-tank element (surge tank) with the same surge volume. The volume optimization of the two-tank element is implemented by selecting the best allocations of the two tanks’ volumes to achieve larger reductions of pressure pulsations. Assuming that the total surge volume is constant, we found that the smaller the volume of the front tank (near the cylinder) is, the lower the pulsation levels are. The optimized result proves that in some conditions the two-tank element could control pulsations better than the single-tank element with the same surge volume.

The Importance of High Energy Piping Support Maintenance to Enhance System Useful Life

2015 ◽  
Author(s):  
Samuel A. Huff ◽  
John P. Leach ◽  
Daniel S. Vail
Keyword(s):  
High Energy ◽  
Life Extension ◽  
Piping System ◽  
Support Design ◽  
Piping Systems ◽  
Proper Design ◽  
Useful Life ◽  
High Level ◽  
Extension Program

As part of the design basis of any piping system utilized to convey materials, pipe supports are required to ensure those pipes remain in their designed locations and do not overly expand or move due to sustained or occasional loads. These loads represent the total forces and moments in the piping components and as a result create stresses that affect the life of the component. Proper design and maintenance of these supports per the applicable codes and standards provide a reasonable life expectancy for the piping systems. This presentation will review the various codes and standards utilized for both pipe support design and maintenance. A high level overview of what information must be obtained to perform an analysis and meet ASME B31.1 Power Piping code requirements when modifying piping systems will be presented. Specific inputs to system design and computational software including material properties, stress intensification factors (SIF), thicknesses and tolerances, pressures, temperatures, insulation, coatings, the occasional loads, etc. will be discussed. Guidelines will be discussed for determining what piping modifications warrant a full pipe stress analysis to be performed. Recommendations for pipe support maintenance inspections will be provided to facilitate increased life expectancies of subject piping systems. The mandatory requirements of ASME B31.1 Chapter VII will be discussed, as well as recommendations from the non-mandatory appendix. Implementing maintenance programs at existing facilities will be discussed. Step by step recommendations for how to apply these guidelines within a long-term life extension program will be given. Tolerances and general guidelines associated with these programs will also be discussed. Finally, common pipe support failures, what they can affect, and how to look for early indicators of fatigue or failure will be covered.

Elastic-Plastic Analysis of Thick-Walled Toroidal Pressure Vessels

2008 ◽  
Author(s):  
R. Adibi-Asl
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Three Dimensional ◽  
Pressure Vessels ◽  
Toroidal Shell ◽  
Piping System ◽  
Straight Pipe ◽  
Element Analysis ◽  
Process Industries ◽  
Piping Systems

Piping systems in process industries and nuclear power plants include straight pipe runs and various fittings such as elbows, miter bends etc. Elbows and bends in piping systems provide additional flexibility to the piping system along with performing the primary function of changing the direction of fluid flow. Distinctive geometry of these toroidal shell components result in a structural behavior different from straight pipe. Hence, it would be useful to predict the behavior of these components with acceptable accuracy for design purposes. Analytical expressions are derived for stresses set up during loading and unloading in a toroidal shell subjected to internal pressure. Residual stresses in the component are also evaluated. The proposed solutions are then compared with three-dimensional finite element analysis at different locations including intrados, extrados and flanks.

Fatigue Evaluation Method for Piping System Based on Total Input Energy and One-Cycle Momentary Input Energy

2019 ◽  
Author(s):  
Michiya Sakai ◽  
Ichiro Tamura ◽  
Shinichi Matsuura ◽  
Ryuya Shimazu ◽  
Yohei Ono ◽  
...  
Keyword(s):  
Fatigue Damage ◽  
Evaluation Method ◽  
Three Dimensional ◽  
Piping System ◽  
Damage Evaluation ◽  
Input Energy ◽  
Energy Evaluation ◽  
Total Input ◽  
Seismic Loadings ◽  
Fatigue Evaluation

Abstract In this study, the fatigue damage evaluation of seismic loadings was proposed and applied to an elbow of a three-dimensional simple piping system. The energy evaluation method was employed, focusing on energy balance of the total input energy and energy absorption of the piping system. Moreover, the concept of one-cycle momentary input energy was used for counting the loading cycle. Fatigue damage evaluation of the piping system was performed according to the maximum response of the elbow from the experimental results. The fatigue evaluation results were compared with the shaking test results of the piping system. Moreover, they were determined to be within the factor of 2 range, and were demonstrated to be applicable.

Noncontact Three-Dimensional Laser Measuring Device for Tracheoscopy

2002 ◽  
Vol 111 (9) ◽  
pp. 821-827 ◽  
Author(s):  
Andreas Müller ◽  
Mario Schubert ◽  
Eggert Beleites
Keyword(s):  
Unsolved Problem ◽  
Laser Light ◽  
Three Dimensional ◽  
Correlation Coefficients ◽  
Distortion Correction ◽  
Tracheal Lumen ◽  
Registration System ◽  
Measuring Device ◽  
3 Dimensional ◽  
High Level

Luminal dimension measurements are still an unsolved problem in endoscopy. The goal of our study was to develop a 3-dimensional (3-D) measuring device for endoscopic applications. For this purpose, a fiber probe projecting a ring of laser light (laser diode, 675 nm) was integrated in a position registration system. Software was developed for image analysis, distortion correction, and export of data for 3-D display. Experimental evaluation of measuring accuracy employing plastic tubes and 15 postmortem pig trachea preparations with artificial stenosis indicated a high level of method precision (Pearson's correlation coefficients, r = 0.99 for normal tracheal lumen and r = 0.97 for high-grade stenosis; p < .0001). Our clinical experience with the technique in 10 patients with tracheal stenosis revealed no side effects and encourages us to recommend this method for other endoscopic applications. The method enhances our 3-D grasp of endoscopically examined lesions.

Wave Propagation and Attenuation in Piping Systems

1986 ◽  
Vol 108 (4) ◽  
pp. 441-446 ◽  
Author(s):  
Shiran Nanayakkara ◽  
N. Duke Perreira
Keyword(s):  
Wave Propagation ◽  
Three Dimensional ◽  
Piping System ◽  
Transmission Matrix ◽  
Two Dimensional ◽  
Longitudinal Vibrations ◽  
Bending Vibrations ◽  
Piping Systems ◽  
Modes Of Vibration ◽  
Computational Errors

Results of an investigation on wave propagation in two-dimensional fluid-filled piping systems is reported. This phenomenon is studied by first developing a model for the transmission of solid-borne and fluid-borne vibrations in fluid-filled piping system elements, such as bends and straight sections. The aforementioned model, which is represented by an element transmission matrix, is used to determine the transfer and point impedances between the motion and forces of both the pipe and the fluid at any point within the element. It allows for longitudinal vibrations in the fluid, and longitudinal and bending vibrations in the solid portion of the system. The effects of both shear strains and rotary inertia within the pipe are included, while the effects of fluid flow and radial or angular modes in the fluid are neglected. Computer results for two-dimensional piping systems with modes of vibration in the plane of the pipes are considered. This method which is exact, except for possible computational errors, can be easily extended to the three-dimensional case.

Fatigue Damage Estimation in a Three-Dimensional Piping System Under Seismic Loadings

2014 ◽  
Author(s):  
Tadahiro Shibutani ◽  
Izumi Nakamura ◽  
Akihito Otani
Keyword(s):  
Fatigue Damage ◽  
Seismic Wave ◽  
Three Dimensional ◽  
Seismic Loading ◽  
Piping System ◽  
Damage Estimation ◽  
Element Analysis ◽  
System A ◽  
Seismic Loadings ◽  
Line Elements

This study introduces an approach by which to estimate fatigue damage in a three-dimensional piping system under seismic loadings. A hybrid piping system simulator consisting of detailed elbow/tee models and piping line elements was constructed in order to estimate fatigue damage in the piping system. A dynamic non-linear finite element analysis with modified seismic wave inputs was carried out in order to calculate the entire strain profile of the piping system. Fatigue damage due to seismic loading was calculated by Miner’s rule since seismic wave contains several amplitudes of total strain ranges. Several tests reported in previous papers were used in order to verify the validity of the proposed approach for fatigue damage estimation.

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