Fracture Mechanics Analysis of Clad Subsea Equipment in Sour HPHT Conditions

2017 ◽  
Author(s):  
Colum Holtam ◽  
Rajil Saraswat ◽  
Ramgopal Thodla
Keyword(s):  
Finite Element ◽  
Fracture Mechanics ◽  
Internal Surface ◽  
Design Guidelines ◽  
Assessment Methods ◽  
Element Analysis ◽  
High Pressure High Temperature ◽  
Failure Assessment ◽  
The Finite Element Analysis

High pressure high temperature (HPHT) design is a significant new challenge facing the subsea sector, particularly in the Gulf of Mexico. API 17TR8 provides HPHT Design Guidelines, specifically for subsea applications. This paper presents the results of a fatigue based fracture mechanics assessment case study conducted on a fully clad subsea HPHT component. The component was assumed to be constructed from F22 low alloy steel internally clad with alloy 625 and exposed to 20ksi (137.8MPa) and 400°F (204°C) internal pressure and temperature. A number of different assessment methods were evaluated as part of this study, including standard failure assessment diagram (FAD) based assessment methods, such as those found in API 579-1/ASME FFS-1 and BS 7910, as well as finite element (i.e. crack mesh) methods. A detailed description of the finite element analysis (FEA) of the uncracked and cracked component is provided. An internal surface flaw assumed to be exposed to sour production fluids was evaluated. The results of the fatigue and fracture assessments are summarized along with the key differences between the assessment methods adopted. The sensitivity of the assessment results to other variables such as welding residual stresses is also discussed.

Effects of Negative Biaxial Loadings and Notch on Failure Assessment Diagrams

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
K. Ragupathy ◽  
K. Ramesh ◽  
D. Hall
Keyword(s):  
Finite Element ◽  
Fracture Mechanics ◽  
Biaxial Loading ◽  
Failure Criteria ◽  
Small Scale ◽  
J Integral ◽  
Element Analysis ◽  
Worst Case ◽  
Failure Assessment ◽  
The Impact

The failure assessment diagram (FAD) is a simplified and robust flaw assessment methodology, which simultaneously connects two dominant failure criteria: linear elastic fracture mechanics on one end and plastic collapse on the other end. This interaction is in the realm of elastic-plastic fracture mechanics. It is popularly known as the R6 approach, which graphically characterizes the impact of plasticity on crack driving force. In recent years, there has been continuous interest in using FADs to assess the failure of cracked structures subjected to biaxial loadings. Biaxiality is defined as the ratio of stress applied parallel and normal to the crack. Some pressure loaded aircraft components operate under negative biaxial ratios up to −0.5. In this paper, a detailed study on FAD was conducted using finite element analysis computed J-integral methods to investigate the effect of biaxial loading using different FAD approaches for geometries with notches. Geometries with a crack that emanates at a fillet region were simulated with various biaxial loading ratios from −0.5 to +0.5 using 2014-T6 material. FAD curves were numerically generated for cracks at notched regions subjected to various biaxial loadings using J-integral values from finite element analyses. These results were compared with standard FAD approaches. All comparison studies were made between uniaxial and biaxial loading cases with FAD curves created using four different crack sizes. Under small scale yielding, this study clearly shows that FAD curves are not influenced by negative biaxial loading at low load (up to 40% of yield strength). It was clearly confirmed that the majority of previously developed analytical FAD curves do not effectively account for notch and plasticity effects due to negative biaxiality. Based on this study, tension normal to the crack and compression parallel to the crack is the worst combination, and it has a very pronounced effect on FAD curve shapes. The standard analytical FAD curves are nonconservative compared with the approach recommended here, particularly under the worst case condition. FAD curves developed are shown to predict lower failure loads as compared with the currently accepted analytical FAD approaches defined in existing standards, e.g., R6 and API 579. The impact of negative biaxial loading can be investigated directly using a J-integral FAD approach but can be compared with ease by plotting both approaches in a FAD format.

On Consistency Relations in Nonlinear Fracture Mechanics

1986 ◽  
Vol 53 (4) ◽  
pp. 834-838 ◽  
Author(s):  
G. J. Rodin ◽  
D. M. Parks
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fracture Mechanics ◽  
Power Law ◽  
Simple Form ◽  
Single Edge ◽  
Element Analysis ◽  
Nonlinear Fracture Mechanics ◽  
Nonlinear Fracture ◽  
The Finite Element Analysis

A simple form of consistency relations between generalized forces and displacements for systems exhibiting power-law behavior is presented. The later discussion focuses on certain details regarding applications of the relations to nonlinear fracture mechanics, emphasizing the finite element analysis of a single edge-cracked strip subjected to remote tension under plane strain conditions.

An Element Splitting Algorithm for Crack Propagation

2011 ◽  
Vol 90-93 ◽  
pp. 2277-2281 ◽  
Author(s):  
Zhao Bin Su ◽  
Zong Xi Cai ◽  
Yi Lan Kang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fracture Mechanics ◽  
Crack Propagation ◽  
Crack Path ◽  
Crack Tip ◽  
Splitting Algorithm ◽  
Element Analysis ◽  
The Finite Element Analysis

A new algorithm is presented for the finite element analysis of fracture mechanics. The algorithm allows crack propagation in any direction, and guarantees the crack path smoothly. This is achieved by tracking the path of the crack tip and by introducing a new remeshing method. Examples show that this algorithm is efficient for 2D problems.

Interactive Graphics for the Analysis of Tires

1985 ◽  
Vol 13 (3) ◽  
pp. 127-146 ◽  
Author(s):  
R. Prabhakaran
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Approximate Solutions ◽  
Interactive Graphics ◽  
Element Analysis ◽  
Analysis Process ◽  
Physical Problems ◽  
The Finite Element Analysis ◽  
Analysis Computer ◽  
Discretization Technique

Abstract The finite element method, which is a numerical discretization technique for obtaining approximate solutions to complex physical problems, is accepted in many industries as the primary tool for structural analysis. Computer graphics is an essential ingredient of the finite element analysis process. The use of interactive graphics techniques for analysis of tires is discussed in this presentation. The features and capabilities of the program used for pre- and post-processing for finite element analysis at GenCorp are included.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

Use of the Finite Element Analysis Method in Pedodontics

2018 ◽  
Vol 55 (4) ◽  
pp. 666-675
Author(s):  
Mihaela Tanase ◽  
Dan Florin Nitoi ◽  
Marina Melescanu Imre ◽  
Dorin Ionescu ◽  
Laura Raducu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Model ◽  
Analysis Method ◽  
Ansys Software ◽  
Concentrated Force ◽  
Element Analysis ◽  
Finite Element Analysis Method ◽  
The Finite Element Analysis ◽  
Solid Type

The purpose of this study was to determinate , using the Finite Element Analysis Method, the mechanical stress in a solid body , temporary molar restored with the self-curing GC material. The originality of our study consisted in using an accurate structural model and applying a concentrated force and a uniformly distributed pressure. Molar structure was meshed in a Solid Type 45 and the output data were obtained using the ANSYS software. The practical predictions can be made about the behavior of different restorations materials.

A necessary modification for the finite element analysis of cracked members detection, construction, and justification

2013 ◽  
Vol 83 (7) ◽  
pp. 1087-1096 ◽  
Author(s):  
A. Ranjbaran ◽  
H. Rousta ◽  
M. O. Ranjbaran ◽  
M. A. Ranjbaran ◽  
M. Hashemi ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Cracked Members

Modeling and experimental verification on directivity of an electret cell array loudspeaker

2012 ◽  
Vol 24 (3) ◽  
pp. 326-333 ◽  
Author(s):  
Yu-Chi Chen ◽  
Wen-Ching Ko ◽  
Han-Lung Chen ◽  
Hsu-Ching Liao ◽  
Wen-Jong Wu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Digital Control System ◽  
Analysis Model ◽  
Cell Array ◽  
Element Analysis ◽  
Finite Element Analysis Model ◽  
The Finite Element Analysis ◽  
Directivity Characteristics

We propose a model to give us a method to investigate the characteristic three-dimensional directivity in an arbitrarily configured flexible electret-based loudspeaker. In recent years, novel electret loudspeakers have attracted much interest due to their being lightweight, paper thin, and possessing excellent mid- to high-frequency responses. Increasing or decreasing the directivity of an electret loudspeaker makes it excellent for adoption to many applications, especially for directing sound to a particular area or specific audio location. Herein, we detail a novel electret loudspeaker that possesses various directivities and is based on various structures of spacers instead of having to use multichannel amplifiers and a complicated digital control system. In order to study the directivity of an electret loudspeaker based on an array structure which can be adopted for various applications, the horizontal and vertical polar directivity characteristics as a function of frequency were simulated by a finite-element analysis model. To validate the finite-element analysis model, the beam pattern of the electret loudspeaker was measured in an anechoic room. Both the simulated and experimental results are detailed in this article to validate the various assertions related to the directivity of electret cell-based smart speakers.

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