Flow-Induced Vibration Screening of a Thermoplastic Composite Pipe Water Injection Jumper

2021 ◽  
Author(s):  
Juan P. Pontaza ◽  
Varadarajan Nadathur ◽  
John L. Rosche
Keyword(s):  
Water Injection ◽  
Operating Conditions ◽  
Thermoplastic Composite ◽  
Flow Induced Vibration ◽  
Element Analysis ◽  
Pipe Water ◽  
Composite Pipe ◽  
Stress Cycling ◽  
High Level ◽  
Steel Piping

Abstract An active subsea field in the Gulf of Mexico has adopted a thermoplastic composite pipe (TCP) water injection jumper for its waterflood upgrade. The jumper assembly is composed of a TCP span attached to steel piping on either end. The TCP spool is lightweight and flexible relative to the traditional steel-only M-shaped subsea jumpers. As such, the flow-induced vibration (FIV) threat from internal fluid flow must be assessed for the intended service. A three-tiered approach is used to assess the level of FIV threat expected in this TCP subsea jumper application. A high-level screening based on widely used industry guidelines indicates a susceptibility to FIV fatigue failure for the steel piping in the TCP jumper assembly. A comprehensive screening based on structural finite element analysis and computational fluid dynamics shows that the vibration levels and stress cycling due to FIV will be acceptable for the intended water injection application and a 30-year design life, when adopting a factor of safety of 10 for subsea service. We evaluate the effect of doubling the length of the steel piping on either end of the TCP span, as a means to increase the overall span of the TCP jumper assembly. Lastly, we draw a comparison between a traditional all-steel M-shaped jumper and the TCP jumper in terms of FIV fatigue life, for the same operating conditions and the same total suspended span.

Flow-Induced Vibration Screening of a Thermoplastic Composite Pipe Water Injection Jumper

2020 ◽  
Author(s):  
Juan P. Pontaza ◽  
Varadarajan Nadathur ◽  
John L. Rosche
Keyword(s):  
Water Injection ◽  
Thermoplastic Composite ◽  
Flow Induced Vibration ◽  
Element Analysis ◽  
Internal Fluid ◽  
Pipe Water ◽  
Composite Pipe ◽  
Internal Fluid Flow ◽  
Stress Cycling ◽  
High Level

Abstract An active subsea field in the Gulf of Mexico has adopted a thermoplastic composite pipe (TCP) water injection jumper for its waterflood upgrade. The TCP spool is lightweight and flexible — relative to the traditional steel-only spool segments used in subsea jumpers. As such, the flow-induced vibration (FIV) threat from internal fluid flow must be assessed for the intended service. A three-tiered approach is used to assess the level of FIV threat expected in this TCP subsea jumper application. A high-level screening based on widely used industry guidelines indicates a high susceptibility to FIV fatigue failure for the steel product in the jumper, with no applicability to the TCP material. A comprehensive screening based on structural finite element analysis and computational fluid dynamics shows that the vibration levels and stress cycling due to FIV will be acceptable for the intended water injection application and a 30-year design life, when adopting a factor of safety of 10 for subsea service.

Flow-Induced Vibration Analysis of a Water Injection System at Elevated Flow Rates of an FPSO

2019 ◽  
Author(s):  
Néstor González Díez ◽  
Juan P. Pontaza ◽  
Oluwaseun M. Awe ◽  
Pieter van Beek ◽  
Can Tümer
Keyword(s):  
Mechanical Response ◽  
Optimization Technique ◽  
Water Injection ◽  
Element Model ◽  
Injection System ◽  
Response Analysis ◽  
Flow Induced Vibration ◽  
Flow Rates ◽  
Screening Analysis ◽  
High Level

Abstract The water injection system of an FPSO active in the Gulf of Guinea is to increase injection capacity to levels that are threatening from a flow-induced vibration perspective, such that hydrocarbon recovery can be accelerated. A three-tier method based on the internal guidelines of the system operator has been employed to assess the level of FIV threat expected from the increase in flow rate. A high-level screening analysis is followed by a more detailed approach, modified in this case by introducing knowledge obtained from field data gathered during a comprehensive measurement campaign aboard the FPSO. In particular, the data has been used to calibrate the finite element model of the mechanical layout of the pipework and associated supporting by making use of an optimization technique. The PSD of the flow excitation has been calibrated to match the measured response of the system, with descriptions of the turbulent excitation introduced in elbows by means of PSD functions available in the open literature. The PSDs, once calibrated, are further scaled to the future flow-rates so that they can be used as input to the mechanical response analysis. Though the high-level screening analysis delivers the conclusion that flow rates should be limited, the detailed analysis proves that the expected vibrations will be acceptable.

Addressing Shell Mode Vibration in Ducts in Refinery With Computational Models and Field Data

2019 ◽  
Author(s):  
Ishita Chakraborty ◽  
Anup Paul ◽  
Gyorgy Szasz
Keyword(s):  
Computational Models ◽  
Field Measurements ◽  
Operating Conditions ◽  
Flow Induced Vibration ◽  
Element Analysis ◽  
Vibration Data ◽  
Response Data ◽  
Design Changes ◽  
Mode Vibration ◽  
Computational Fluid Dynamics Cfd

Abstract This paper describes the work performed to study the shell mode vibration of a large cross-section flue gas duct. The work involved the collection of field vibration data, as well as predictive computational models associated with finite element analysis (FEA) and computational fluid dynamics (CFD). The goal of this work was to use predictive models to ascertain whether a proposed design change would reduce the vibration levels of the duct under similar operating conditions. The vibration observed in the duct was identified as a flow induced vibration (FIV) which excited the shell modes of the duct walls. This case study serves as an example of using predictive computational models (FEA and CFD), calibrated with vibration response data from field measurements, to represent the real world situation as closely as possible within specified budget and schedule constraints. Such calibrated models can be useful for forecasting the effectiveness of various proposed design changes.

Investigation on the Failures Experienced in Deaerators and Solution Recommendation

2010 ◽  
Author(s):  
Aun Ming Lim ◽  
Simon Yuen
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
Thermal Stresses ◽  
Operating Conditions ◽  
Mode Shapes ◽  
Flow Induced Vibration ◽  
Element Analysis ◽  
Root Cause ◽  
Bottom Side ◽  
Refinery Plant

The internals in the deaerators of a refinery plant were reported to have experienced a series of failures since their installation in 1985. These failures included development of cracks in the floor plates, damage of supports and breakage of fillet welds. Two possible root causes were initially identified; thermal stresses due to transient conditions and flow induced vibration. The former cause was classified as unlikely since the deaerators were always operating on steady-state conditions. No cyclic operating conditions were imposed on these deaerators. Vibrations however posed as the most likely root cause for the series of failures. The refinery plant inspectors reported that vibrations on the deaerators, although have not been measured, could be physically felt. These vibrations appear to be continuous and increase linearly with load. A finite element analysis was performed to determine the natural frequency of the deaerators. Mode shapes predicted from this calculation show that vibrations could have caused the failures of the internals. Furthermore, the lowest natural frequency of the deaerators appeared to fall within the actual vibration frequency on site (∼20 Hz). Although not confirmed, it is highly suspected that the vibration was excited by the flow (low pressure steam). Several repair options were explored to overcome this problem. These options were concentrated in increasing the stiffness of the steam inlet pipe and the deaerator floor. Finite element assessments demonstrated that the current flexible deaerator floor was the reason for the low natural frequency. An option of introducing reinforcement strips to the bottom side of the floor was identified as the best option to increase the natural frequency of the deaerator and this is expected to overcome the vibration problem. Only one vessel was assessed but the results apply to the other vessels since they are similar in design.

scholarly journals Shape Sensing of a Complex Aeronautical Structure with Inverse Finite Element Method

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1388
Author(s):  
Daniele Oboe ◽  
Luca Colombo ◽  
Claudio Sbarufatti ◽  
Marco Giglio
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boundary Conditions ◽  
Strain Field ◽  
Element Analysis ◽  
Inverse Finite Element Method ◽  
Shape Sensing ◽  
Definition Of ◽  
High Level ◽  
Element Method

The inverse Finite Element Method (iFEM) is receiving more attention for shape sensing due to its independence from the material properties and the external load. However, a proper definition of the model geometry with its boundary conditions is required, together with the acquisition of the structure’s strain field with optimized sensor networks. The iFEM model definition is not trivial in the case of complex structures, in particular, if sensors are not applied on the whole structure allowing just a partial definition of the input strain field. To overcome this issue, this research proposes a simplified iFEM model in which the geometrical complexity is reduced and boundary conditions are tuned with the superimposition of the effects to behave as the real structure. The procedure is assessed for a complex aeronautical structure, where the reference displacement field is first computed in a numerical framework with input strains coming from a direct finite element analysis, confirming the effectiveness of the iFEM based on a simplified geometry. Finally, the model is fed with experimentally acquired strain measurements and the performance of the method is assessed in presence of a high level of uncertainty.

Localization simulation of forming-induced residual stresses of composite using prescribed boundary

2021 ◽  
pp. 073168442094118
Author(s):  
Qi Wu ◽  
Hongzhou Zhai ◽  
Nobuhiro Yoshikawa ◽  
Tomotaka Ogasawara ◽  
Naoki Morita
Keyword(s):  
Residual Stresses ◽  
Representative Volume Element ◽  
Computational Cost ◽  
Volume Element ◽  
Thermoplastic Composite ◽  
Structural Deformation ◽  
Element Analysis ◽  
Micro Scale ◽  
Representative Volume ◽  
Localization Approach

A novel localization approach that seamlessly bridges the macro- and micro-scale models is proposed and used to model the forming-induced residual stresses within a representative volume element of a fiber reinforced composite. The approach uses a prescribed boundary that is theoretically deduced by integrating the asymptotic expansion of a composite and the equal strain transfer, thus rendering the simulation setting to be easier than conventional approaches. When the localization approach is used for the finite element analysis, the temperature and residual stresses within an ideal cubic representative volume element are precisely simulated, given a sandwiched thermoplastic composite is formed under one-side cooling condition. The simulation results, after being validated, show that the temperature gradient has an impact on the local residual stresses, especially on the in-plane normal stress transverse to the fiber, and consequently, influences the structural deformation. This newly designed localization approach demonstrates the advantages of enhanced precision and reduced computational cost owing to the fast modeling of the finely meshed representative volume element. This is beneficial for a detailed understanding of the actual residual stresses at the micro-scale.

Vibration Spectra as a Feedback for Controlling Multicylinder Engine Performance

1992 ◽  
Vol 3 (2) ◽  
pp. 176-192
Author(s):  
T.W. Abou-Arab ◽  
M. Othman ◽  
Y.S.H. Najjar
Keyword(s):  
Engine Speed ◽  
Engine Performance ◽  
Feedback System ◽  
Operating Conditions ◽  
Flow Induced Vibration ◽  
Vibration Spectra ◽  
Parametric Studies ◽  
Vibration Pattern ◽  
Engine Components ◽  
Heat And Fluid Flow

Increasing requirements for vehicle confort, economy and reliability lead some investigators to consider the relationships between the mechanical vibrations with the heat and fluid flow induced vibration and noise in a more accurate manner. This paper describes the variation of the vibration phenomena associated with the motion of some engine components under different operating conditions. The measured vibration spectra indicates its capability in predicting symptoms of early engine failures, hence, expediting their control using a suitable feedback system. Parametric studies involving the effect of air-fuel ratio, ignition timing and engine speed on the vibration pattern are also carried out. These studies indicate that the amplitude of vibration decreases as the speed increases then increases again after certain engine speed. The effect of ignition system characteristic on the induced vibration are obtained and the correlation between the developed power and the engine dynamics over a range of operating conditions are discussed.

Research on the Structural Performance of Large-Tonnage Gantry Crane

2013 ◽  
Vol 823 ◽  
pp. 247-250
Author(s):  
Jie Dong ◽  
Wen Ming Cheng ◽  
Yang Zhi Ren ◽  
Yu Pu Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Theoretical Calculations ◽  
Complex Structure ◽  
Early Period ◽  
Operating Conditions ◽  
Structural Performance ◽  
Gantry Crane ◽  
Element Analysis ◽  
Design And Manufacture

Because of the huge lifting weight and complex structure of large-tonnage gantry crane and in order to effectively design and review it, this paper aims to carry out a research on its structural performance based on the method of theoretical calculation and finite element analysis. During the early period of design, the method of theoretical calculations is adopted, and after specific design it comes the finite element analysis, so as to get the results of analysis under a variety of operating conditions, which illustrates that the structural design and review of large-tonnage gantry crane based on theoretical calculations and finite element are feasible, and also verifies that the method of finite element is an effective way to find a real dangerous cross-section, thus providing the basis for the design and manufacture of the crane structure.

Proving the Labeled Interval Calculus for Inferences on Catalogs

1990 ◽  
Author(s):  
Walid Habib ◽  
Allen C. Ward
Keyword(s):  
Mechanical Design ◽  
Formal System ◽  
Constraint Propagation ◽  
Operating Conditions ◽  
Manufacturing Processes ◽  
Entire System ◽  
High Level Language ◽  
Design Problems ◽  
High Level ◽  
Interval Constraint

Abstract The “labeled interval calculus” is a formal system that performs quantitative inferences about sets of artifacts under sets of operating conditions. It refines and extends the idea of interval constraint propagation, and has been used as the basis of a program called a “mechanical design compiler,” which provides the user with a “high level language” in which design problems for systems to be built of cataloged components can be quickly and easily formulated. The compiler then selects optimal combinations of catalog numbers. Previous work has tested the calculus empirically, but only parts of the calculus have been proven mathematically. This paper presents a new version of the calculus and shows how to extend the earlier proofs to prove the entire system. It formalizes the effects of toleranced manufacturing processes through the concept of a “selectable subset” of the artifacts under consideration. It demonstrates the utility of distinguishing between statements which are true for all artifacts under consideration, and statements which are merely true for some artifact in each selectable subset.

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