scholarly journals Finite element method investigation of geometrical influences of adhesive and patch in the safety for 90° elbow piping system

2019 ◽  
Vol 13 (4) ◽  
pp. 5973-5987
Author(s):  
Ibrahim Gadi ◽  
Madjid Meriem-Benziane ◽  
B. Bachir Bouiadjra
Keyword(s):  
Finite Element Method ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Piping System ◽  
Composite Patch ◽  
Circumferential Crack ◽  
Pipeline Safety

Piping system elbow study is the most important part in all fields of hydrocarbons transportation which presents the behaviour of circumferential crack at elbow extrados. The effect of geometry of adhesive and patch in the crack elbow is important in pipeline safety. This study shows the details for along the direction of the circumferential elbow crack by three dimensional (FEM) which is used to determine the stress intensity factor at 90° elbow for two cases: firstly, without patch and secondly, repaired with composite patch. This method allows to predict the behaviour of cracked elbow through the analysis of crack propagation under the internal different pressures taking into consideration the operating conditions. The geometry and nature of composite patch proved   that the increase of patch thickness leads to decrease the SIF from 7 MPa.m1/2 to 6.15 MPa.m1/2. It can be concluded that the repairing by composite materials leads to reduce the stress intensity factor with patch which not only can augment the lifetime of pipeline but also decreasing the costs and the pollution.

Research on the Stress Intensity Factor of the Cracks in the Spherical Shell

2015 ◽  
Vol 757 ◽  
pp. 25-28
Author(s):  
Fei Chen ◽  
Ying Juan Yue ◽  
Cui Ping Zhang ◽  
Hai Xia Du
Keyword(s):  
Finite Element Method ◽  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Spherical Shell ◽  
Vessel Wall ◽  
Three Dimensional ◽  
Surface Cracks ◽  
Abaqus Software

Three models including scheme A, B and C of the semicircular or crescent surface cracks, and two ones including scheme D and E of elliptical inner cracks in the vessel wall in three-dimensional are estabished with ABAQUS software. The values of the crack tip of the stress intensity factor are calculated and compared with the empirical results based on BS 7910 standard. The results show that scheme C and D are better, which provide a new method for the modeling and simulation of three-dimensional components containing cracks with finite element method.

scholarly journals Numerical analysis of surface cracks repaired with single and double patches of composites

2017 ◽  
Vol 52 (8) ◽  
pp. 1113-1120 ◽  
Author(s):  
Inés Iváñez ◽  
Matías Braun
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Depth ◽  
Three Dimensional ◽  
Composite Patch ◽  
Dimensional Finite Element ◽  
Patch Repairs ◽  
Maximum Stress Intensity ◽  
Three Dimensional Finite Element

In this work, the performances of circular single- and double-sided composite patch repairs are compared by computing the maximum stress intensity factor of a repaired surface crack. The three-dimensional finite-element method is used to calculate the stress intensity factor along the crack. The effects of the crack depth, composite patch thickness and patch material on the stress intensity factor variation are highlighted. The obtained results show that the selection of single- or double-sided patches depends on both the crack depth and patch thickness.

Stress Intensity Factor for Repaired Circumferential Cracks in Pipe With Bonded Composite Wrap

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
F. Benyahia ◽  
A. Albedah ◽  
B. Bachir Bouiadjra
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Fracture Criterion ◽  
Three Dimensional ◽  
Element Analysis ◽  
Composite Systems ◽  
Bonded Composite ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The use of composite systems as a repair methodology in the pipeline industry has grown in recent years. In this study, the analysis of the behavior of circumferential through cracks in repaired pipe with bonded composite wrap subjected to internal pressure is performed using three-dimensional finite element analysis. The fracture criterion used in the analysis is the stress intensity factor (SIF). The obtained results show that the bonded composite repair reduces significantly the stress intensity factor at the tip of repaired cracks in the steel pipe, which can improve the residual lifespan of the pipe.

Application of Extended Finite Element Method (XFEM) to Stress Intensity Factor Calculations

2015 ◽  
Author(s):  
Do-Jun Shim ◽  
Mohammed Uddin ◽  
Sureshkumar Kalyanam ◽  
Frederick Brust ◽  
Bruce Young
Keyword(s):  
Finite Element Method ◽  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Degrees Of Freedom ◽  
Extended Finite Element Method ◽  
Partition Of Unity ◽  
Extended Finite Element ◽  
Element Method

The extended finite element method (XFEM) is an extension of the conventional finite element method based on the concept of partition of unity. In this method, the presence of a crack is ensured by the special enriched functions in conjunction with additional degrees of freedom. This approach also removes the requirement for explicitly defining the crack front or specifying the virtual crack extension direction when evaluating the contour integral. In this paper, stress intensity factors (SIF) for various crack types in plates and pipes were calculated using the XFEM embedded in ABAQUS. These results were compared against handbook solutions, results from conventional finite element method, and results obtained from finite element alternating method (FEAM). Based on these results, applicability of the ABAQUS XFEM to stress intensity factor calculations was investigated. Discussions are provided on the advantages and limitations of the XFEM.

General Method for Optimizing Composite Patch Repairs

2015 ◽  
Vol 1120-1121 ◽  
pp. 670-674
Author(s):  
Abdelmadjid Ait Yala ◽  
Abderrahmanne Akkouche
Keyword(s):  
Mechanical Properties ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Optimization Problem ◽  
Composite Patch ◽  
Matlab Program ◽  
Patch Repairs ◽  
Selection Of ◽  
General Method

The aim of this work is to define a general method for the optimization of composite patch repairing. Fracture mechanics theory shows that the stress intensity factor tends towards an asymptotic limit K∞.This limit is given by Rose’s formula and is a function of the thicknesses and mechanical properties of the cracked plate, the composite patch and the adhesive. The proposed approach consists in considering this limit as an objective function that needs to be minimized. In deed lowering this asymptote will reduce the values of the stress intensity factor hence optimize the repair. However to be effective this robust design must satisfy the stiffness ratio criteria. The resolution of this double objective optimization problem with Matlab program allowed us determine the appropriate geometric and mechanical properties that allow the optimum design; that is the selection of the adhesive, the patch and their respective thicknesses.

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