scholarly journals Using XFEM to Predict the Damage with Temperature of the Steel Pipe Elbows under Bending and Pressure loading

2020 ◽  
Vol 15 (55) ◽  
pp. 345-359
Author(s):  
Nourddine Hammadi ◽  
Moahmed Mokhtari ◽  
Habib Benzaama ◽  
Kouider Madani ◽  
Abdelkader Brakna ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Calculation ◽  
Internal Pressure ◽  
Structural Damage ◽  
Bending Moment ◽  
Pressure Loading ◽  
Tube System ◽  
Moment Stress ◽  
Calculation Code

The pipes, during their service, are subjected to accumulated loads such as internal pressure and that of the soil. The latter considerably accelerate their damage. In this work, the bending moment stress of API 5L X70 category steel elbows under thermo-mechanical behavior and in the presence of pressure were studied. We used FEM (finite element method) through the numerical calculation code ABAQUS and the XFEM technique for structural damage while using solid elements as a structure. Our objective is to evaluate the response and resistance capacity of the steel elbow by its location in the tube–elbow-tube system under a mixed loading of pressure and moment for all scenarios. It is based on a single standardized dimensioning of the elbow (diameter and thickness). The effect of several parameters has been studied such as the type of loading and the pressure levels, which are clearly conditioned by the level of damage. Numerical damage results are presented by moment-rotation curves. They illustrate the variation in damage as a function of these effects which act simultaneously.

scholarly journals NUMERICAL CALCULATION OF THE VACUUM DEGREE FOR A CORRUGATED WALL

2021 ◽  
Vol 23 (3) ◽  
pp. 9-12
Author(s):  
I.E. Adeyanov ◽  
◽  
M.Y. Alexandrov ◽  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Calculation ◽  
Internal Pressure ◽  
Equivalent Stress ◽  
The Finite Element Method ◽  
Vacuum Degree ◽  
Maximum Equivalent Stress ◽  
Corrugated Wall ◽  
Geometrical Dimensions

The article presents a numerical calculation of the corrugated wall of a transformer under pressure. The permissible degree of evacuation of the wavy transformer tank is determined. The statement of the problem is formulated as follows: to determine the limit of the maximum allowable pressure during the evacuation of the tank with different geometrical dimensions of the corrugation. In this case, the maximum equivalent stress should not exceed the yield point and the walls of the corrugation should not close. Numerical calculation is carried out by the finite element method. This approach to calculating the behavior of a corrugated wall under pressure can be used to determine the maximum allowable internal pressure of the tank.

scholarly journals Structural Damage Identification Based on Integrated Utilization of Inverse Finite Element Method and Pseudo-Excitation Approach

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 606
Author(s):  
Tengteng Li ◽  
Maosen Cao ◽  
Jianle Li ◽  
Lei Yang ◽  
Hao Xu ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Structural Damage ◽  
Damage Identification ◽  
Displacement Measurement ◽  
Engineering Practice ◽  
Position Measurement ◽  
Inverse Finite Element Method ◽  
Pseudo Excitation ◽  
Element Method

The attempt to integrate the applications of conventional structural deformation reconstruction strategies and vibration-based damage identification methods is made in this study, where, more specifically, the inverse finite element method (iFEM) and pseudo-excitation approach (PE) are combined for the first time, to give rise to a novel structural health monitoring (SHM) framework showing various advantages, particularly in aspects of enhanced adaptability and robustness. As the key component of the method, the inverse finite element method (iFEM) enables precise reconstruction of vibration displacements based on measured dynamic strains, which, as compared to displacement measurement, is much more adaptable to existing on-board SHM systems in engineering practice. The PE, on the other hand, is applied subsequently, relying on the reconstructed displacements for the identification of structural damage. Delamination zones in a carbon fibre reinforced plastic (CFRP) laminate are identified using the developed method. As demonstrated by the damage detection results, the iFEM-PE method possesses apparently improved accuracy and significantly enhanced noise immunity compared to the original PE approach depending on displacement measurement. Extensive parametric study is conducted to discuss the influence of a variety of factors on the effectiveness and accuracy of damage identification, including the influence of damage size and position, measurement density, sensor layout, vibration frequency and noise level. It is found that different factors are highly correlated and thus should be considered comprehensively to achieve optimal detection results. The application of the iFEM-PE method is extended to better adapt to the structural operational state, where multiple groups of vibration responses within a wide frequency band are used. Hybrid data fusion is applied to process the damage index (DI) constructed based on the multiple responses, leading to detection results capable of indicating delamination positions precisely.

scholarly journals An Extended Finite Element Method (XFEM) Study on the Elastic T-Stress Evaluations for a Notch in a Pipe Steel Exposed to Internal Pressure

Mathematics ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 507
Author(s):  
K. Yakoubi ◽  
S. Montassir ◽  
Hassane Moustabchir ◽  
A. Elkhalfi ◽  
Catalin Iulian Pruncu ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Extended Finite Element Method ◽  
Research Study ◽  
Extended Finite Element ◽  
T Stress ◽  
Cracked Structures ◽  
Element Method

The work investigates the importance of the K-T approach in the modelling of pressure cracked structures. T-stress is the constant in the second term of the Williams expression; it is often negligible, but recent literature has shown that there are cases where T-stress plays the role of opening the crack, also T-stress improves elastic modeling at the point of crack. In this research study, the most important effects of the T-stress are collected and analyzed. A numerical analysis was carried out by the extended finite element method (X-FEM) to analyze T-stress in an arc with external notch under internal pressure. The different stress method (SDM) is employed to calculate T-stress. Moreover, the influence of the geometry of the notch on the biaxiality is also examined. The biaxiality gave us a view on the initiation of the crack. The results are extended with a comparison to previous literature to validate the promising investigations.

The Accepting of Pipe Bends With Ovality and Thinning Using Finite Element Method

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
AR. Veerappan ◽  
S. Shanmugam ◽  
S. Soundrapandian
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Cross Sections ◽  
Pressure Ratio ◽  
Empirical Relationship ◽  
The Finite Element Method ◽  
Element Method

Thinning and ovality are commonly observed irregularities in pipe bends, which induce higher stress than perfectly circular cross sections. In this work, the stresses introduced in pipe bends with different ovalities and thinning for a particular internal pressure are calculated using the finite element method. The constant allowable pressure ratio for different ovalities and thinning is presented at different bend radii. The allowable pressure ratio increases, attains a maximum, and then decreases as the values of ovality and thinning are increased. An empirical relationship to determine the allowable pressure in terms of bend ratio, pipe ratio, percent thinning, and percent ovality is presented. The pipe ratio has a strong effect on the allowable pressure.

Elastic and elastic-plastic finite element analysis of hollow tubes with axisymmetric internal projections under combined axial and pressure loading

2001 ◽  
Vol 36 (4) ◽  
pp. 373-390 ◽  
Author(s):  
S. J Hardy ◽  
M. K Pipelzadeh ◽  
A. R Gowhari-Anaraki
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Internal Pressure ◽  
Plastic Material ◽  
Axial Loading ◽  
Material Model ◽  
Pressure Loading ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Applied Loading

This paper discusses the behaviour of hollow tubes with axisymmetric internal projections subjected to combined axial and internal pressure loading. Predictions from an extensive elastic and elastic-plastic finite element analysis are presented for a typical geometry and a range of loading combinations, using a simplified bilinear elastic-perfectly plastic material model. The axial loading case, previously analysed, is extended to cover the additional effect of internal pressure. All the predicted stress and strain data are found to depend on the applied loading conditions. The results are normalized with respect to material properties and can therefore be applied to geometrically similar components made from other materials, which can be represented by the same material models.

Finite Element Analysis of the Forging Process for Half-Shaft Bushing

2009 ◽  
Vol 16-19 ◽  
pp. 1248-1252
Author(s):  
Chun Dong Zhu ◽  
Man Chun Zhang ◽  
Lin Hua
Keyword(s):  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Numerical Calculation ◽  
Two Dimensional ◽  
Element Analysis ◽  
Forging Process ◽  
Die Life ◽  
Dimensional Finite Element ◽  
Forging Force

As an important forged part of an automobile, the inner hole of the half-shaft bushing must be formed directly. However, the process requires many steps, and how the forging, or deformation, is spread over the production steps directly affects the die life and forging force required. In this paper, the three steps involved in directly forging a half shaft bushing's inner hole are simulated using the two-dimensional finite element method. Further more, we improve the forging process. From numerical calculation, the improved necessary forging force is found to be only half the original force, and the die life is doubled.

Effects of Scatter in Bolt Preload of Pipe Flange Connections With Gaskets on Sealing Performance

2003 ◽  
Author(s):  
Toshiyuki Sawa ◽  
Mitsuhiro Matsumoto ◽  
Satoshi Nagata
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Control Method ◽  
Torque Control ◽  
Stress Distributions ◽  
Flange Connection ◽  
Gas Leakage ◽  
Bolt Preload ◽  
Sealing Performance

It has been well known that a scatter in axial bolt forces of pipe flange connections tightened by the torque control method is substantial. It is necessary for evaluating the sealing performance of the pipe flange connections with the gaskets subjected to intemal pressure to know the contact gasket stress distributions due to the scatter of the axial bolt forces in the connections tightened by the torque control method. This paper deals with the leakage of the pipe flange connections with a spiral wound gasket and that with a compressed sheet gasket tightened by the torque control method. The scatter in the axial bolt forces was measured in the experiments. The contact gasket stress distributions at the interfaces of the pipe flange connections with the gaskets were calculated under the measured axial bolt forces by using elasto-plastic finite element method (FEM) taking into account hysteresis and non-linearity in the stress-strain curves of the gaskets. The effects of the scatter in the axial bolt forces tightened by the torque control method on the gas leakage were also examined by using the actual pipe flange connections. As the result, a difference in an amount of gas leakage measured was found to be substantial between our study and PVRC procedure. By using the calculated contact gasket stress distributions under the internal pressure and the results of the leakage tests, the sealing performance was evaluated. It is found that the sealing performance is worse in the actual pipe flange connection than that evaluated by PVRC procedure.

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