Stress Analysis of Pipelines With Composite Repairs

2002 ◽  
Author(s):  
Luiz C. M. Meniconi ◽  
Jose´ L. F. Freire ◽  
Ronaldo D. Vieira ◽  
Jorge L. C. Diniz
Keyword(s):  
Experimental Results ◽  
Fiber Reinforced ◽  
Pressure Loading ◽  
Original Design ◽  
Element Analysis ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Repair Systems ◽  
Composite Repairs ◽  
Design Pressure

The repair of corroded pipelines with fiber reinforced composite materials is a well-developed practice in the oil and gas transportation industry. Laboratory hydrostatic burst tests and field practice of several years have shown that these repairs are effective for pipelines with external corrosion defects. This paper deals with laboratory tests carried out to compare the behavior of fiber reinforced composite repairs applied to defects machined in pipeline test specimens. The experimental results were compared to results from Finite Element Analysis (FEA) of the tubes tested. The parameters of FEA were calibrated to this specific problem, beforehand. Some hipotheses were tested during FEA trials to better explain the experimental results. The results indicated that, up to the starting of yielding of the pipe defected region, practically only the elastic pipe stresses equilibrate the pressure loading, due to the steel high Young modulus. After yielding, the composite material starts to work, carrying an important part of the pressure loading increments. Experimental results also showed that the repair systems tested allowed the pipes to achieve the original design pressure before bursting. However, only one of the repair systems was approved in all strength verification tests for both internal and external defects. This system operated for four hours under a hydrostatic pressure test associated to the specified minimum yield strength (SMYS) of the steel and was also able to support ten pressure cycles of the design pressure afterwards, without showing any visual damage.

An Investigation Into the Behaviour of Composite Repaired Pipelines Under Combined Internal Pressure and Bending

2009 ◽  
Author(s):  
Ahmed Shouman ◽  
Farid Taheri
Keyword(s):  
Internal Pressure ◽  
Combined Loading ◽  
Repair System ◽  
Loading Conditions ◽  
Fiber Reinforced ◽  
Defect Region ◽  
Element Analysis ◽  
Composite Repair ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite

The repair of corroded pipelines with fiber reinforced composite materials has gained wide acceptance in the oil and gas transportation industry over recent times. It has been integrated into the ASME B31.4 and B31.8 pipeline codes, along with CSA Z662. A considerable amount of experimental research has been conducted on fiber reinforced composite repaired pipelines with external corrosion defects subject to hydrostatic internal pressure. However, the effects of the internal pressure, thermal loads and geotechnical loads create combined loading conditions on the buried pipeline that need to be considered. This paper aims to address the effectiveness of fiber reinforced composite repair systems on externally corroded pipelines under combined internal pressure and bending. For that, finite element analysis is conducted to examine the effects of various loading conditions on the effectiveness of the fiber reinforced composite repair system. Typical conventional commercially available fiber reinforced composite wrap systems are used for this purpose. Three loading conditions are considered on both conventionally repaired and unrepaired pipes subject to internal pressure, pure bending and combined internal pressure and bending. Results show that up to the stage of yielding of the steel in the defect region, the steel elastic stiffness counteracts most of the stress that is induced by the in-service loading conditions. Once the pipe is loaded beyond the yielding point of its material at the defect region, the composite starts to take effect, thus carrying a significant portion of the applied stresses. Essentially, by comparing the burst pressures of repaired pipes against unrepaired pipes, it is shown that the fiber reinforced composite system restores the minimum specified strength of the pipe to its value before the defects were applied. The results presented in the paper are believed to reveal the response of the wraps subject to realistic combined loading conditions that to our knowledge are nonexistent in open literature.

scholarly journals Multi-Fiber-Reinforced Composites for the Coronoradicular Reconstruction of Premolar Teeth: A Finite Element Analysis

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Raphaël Richert ◽  
Philip Robinson ◽  
Gilbert Viguie ◽  
Jean-Christophe Farges ◽  
Maxime Ducret
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Clinical Success ◽  
Root Anatomy ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Fiber Reinforced Composite ◽  
Risk Of Fracture ◽  
Extreme Stress ◽  
Reinforced Composite

A coronoradicular reconstruction (CRR) has conventionally used a metallic inlay core (MIC) or a single-fiber-reinforced composite (sFRC) but extensive dentin removal can lead to root fracture. We propose herein a multi-fiber-reinforced composite (mFRC) based on a bundle of thin flexible fibers that can be adapted to the root anatomy without removing additional dentin. The aim of this study was to compare the mechanical behavior of the root reconstructed with mFRC, MIC, or sFRC using a finite element analysis (FEA). Models with or without a ferrule effect were created using Autodesk© software and divided into four parts: root, post, bonding composite or cement, and zirconia crown. For both models, extreme stress values (ESV), stress distribution, and risk of fracture were calculated for an oblique force (45°) of 100 N applied to the top of the buccal cusp. Results indicated that mFRC and mFRCG present a lower risk of fracture of the root and of the CRR without ferrule and thus could be valuable alternatives for premolar CRR. Further studies are necessary to evaluate the clinical success of these CRR.

Error Estimation and Mesh Optimization for Finite Element Analysis of Short Fiber Reinforced Composite Materials

1992 ◽  
Author(s):  
H. G. Kim ◽  
Ian R. Grosse ◽  
S. V. Nair
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Mesh Refinement ◽  
Short Fiber ◽  
Matrix Interface ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Fiber Reinforced Composite ◽  
Reinforced Composite ◽  
Fiber Matrix Interface

Abstract Knowledge of internal stress fields in fiber or whisker reinforced composites is crucial to the design, manufacturing and applications of composites. Finite element analysis (FEA) presents the only rigorous approach to a solution of this problem. However, the application of FEA to composites requires careful attention to the geometry of the optimum mesh used in the analysis. Standard energy analysis and mesh refinement procedures have yet to be generalized or extended to the special case of fiber or whisker reinforced non-homogeneous composites. Current automatic mesh generation codes do not provide the optimum mesh for composites. This paper is concerned with the development of a generalized approach for optimal mesh refinement in a short fiber reinforced composite. Optimization procedures are based on the calculation of the error in energy norm for global convergence and the traction differential approach at the fiber/matrix interface for local convergence whereas the mesh refinement strategy is based on the use of elongated elements at the fiber/matrix interface. An isoparametric finite element model that has a periodic hexagonal array of elastic fibers surrounded by an elastic matrix was used in the investigation. It is shown that this approach provides the optimum mesh with a much more rapid convergence than conventional meshes. In this manner converged local solutions can be obtained with significantly lower degrees of freedom than by conventional mesh refinement methods.

3-D Finite Element Analysis of Long Fiber Reinforced Composite Spur Gears

2000 ◽  
Author(s):  
Çağdaş Alagöz ◽  
M. A. Sahir Arıkan ◽  
Ö. Gündüz Bilir ◽  
Levend Parnas
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Spur Gears ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Fiber Reinforced Composite ◽  
Failure Index ◽  
Reinforced Composite ◽  
Processing Module ◽  
Long Fibers

Abstract A method and a computer program are developed for 3-D finite element analysis of long fiber reinforced composite spur gears, in which long fibers are arranged along tooth profiles. For such a structure, the gear is composed of two regions; namely the long fiber reinforced and the chopped fiber reinforced regions. Pre and post-processing modules of the program for the finite element analysis are written in Borland Delphi Pascal 3.0®. ABAQUS® is used for finite element analysis. Main inputs for the pre-processing module of the program are, information on basic gear geometry, gear drive data, material properties and long fiber reinforcement geometry. Finite element meshes are automatically generated and mesh information with other required data are written to a file in the input-file-format of ABAQUS®. Stresses are read from the output file of ABAQUS® by the post-processing module, and color-coded drawings for various stresses and failure index are displayed. For the long fiber reinforced region, failure indexes are calculated by using the tensor polynomial failure criterion. Effects of reinforcing thickness and location of long fibers on gear strength are investigated. Stresses and failure index are calculated for different materials and fiber volume ratios.

Finite Element Analysis of Thermal Residual Stress in Unidirectional Fiber Reinforced Composite

2013 ◽  
Vol 275-277 ◽  
pp. 68-71
Author(s):  
Zhi Luo ◽  
Xiao Long Wang ◽  
Hong Jie Jing ◽  
Heng An Wu
Keyword(s):  
Residual Stress ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Study ◽  
Thermal Residual Stress ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Fiber Reinforced Composite ◽  
Unidirectional Fiber ◽  
Reinforced Composite

During the cooling process of composites after curing, thermal residual stress will be produced due to mismatch of the coefficients of thermal expansion between matrix and reinforcement phases. Thermal residual stress is one of the most important factors that affect the mechanical properties of composite materials. The effect of fiber volume fraction on the distribution of thermal residual stress in unidirectional fiber reinforced composite has been investigated with finite element analysis. The results show an inhomogeneous distribution of thermal residual stress in different regions of composites. The longitudinal stress on the interface between matrix and fiber is the main factor resulting in debonding failure of composites. This numerical study can be of great significance in designing new composites with high performance.

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