New Triaxial Connection Safety Factor for Tubular Design

2021 ◽  
Author(s):  
Malcolm A Goodman

Abstract The API equation for internal leak of API connections is uniaxial since it ignores axial force and external backup pressure. ISO 13679 for qualification of premium connections is biaxial at best. It includes tension/compression but ignores backup pressure for both internal and external leak tests. For tubular design, this paper introduces a new fully triaxial safety factor for threaded connections with dependence on thread shear and hydrostatic pressure. Hydrostatic behavior is modelled with the Mean Normal Stress, and thread shear behavior is modelled with the shear component of the von Mises Stress. A Leak Line for use like the pipe body ellipse is proposed for quick leak assessment. Leak ratings are presented for an example case of 7-in. 35-ppf N80 LTC. The new triaxial safety factor with two connection constants applies to all types of threaded connections, including tubing, casing, and drill pipe, so long as the two constants are evaluated with appropriate but simple physical tests.

2021 ◽  
pp. 1-11
Author(s):  
Malcolm A. Goodman

Summary The American Petroleum Institute (API) equation for internal leak of API connections is uniaxial because it ignores axial force and external backup pressure. The ISO 13679 (2002) standard for qualification of premium connections is biaxial at best. It includes tension/compression but ignores backup pressure for both internal and external leak tests. For tubular design, this paper introduces a new fully triaxial safety factor for threaded connections with dependence on thread shear and hydrostatic pressure. Triaxial hydrostatic behavior is modeled with the mean normal stress, and thread shear behavior is modeled with the shear component of the von Mises stress. A leak line for use like the pipe body ellipse is proposed for quick leak assessment. Leak ratings and correlation with finite element analysis (FEA) results are presented for an example case of a 7-in.35-ppf N80 long-thread-casing (LTC) connection. The new triaxial safety factor with two connection constants applies to all types of threaded connections, including tubing, casing, and drillpipe, so long as the two constants are evaluated with appropriate but simple physical tests.


2020 ◽  
Author(s):  
Lasinta Ari Nendra Wibawa ◽  
Kuncoro Diharjo ◽  
Wijang Wisnu Raharjo ◽  
Bagus Hayatul Jihad

Author(s):  
Armando Félix Quiñonez ◽  
Guillermo E Morales Espejel

This work investigates the transient effects of a single subsurface inclusion over the pressure, film thickness, and von Mises stress in a line elastohydrodynamic lubrication contact. Results are obtained with a fully-coupled finite element model for either a stiff or a soft inclusion moving at the speed of the surface. Two cases analyzed consider the inclusion moving either at the same speed as the mean velocity of the lubricant or moving slower. Two additional cases investigate reducing either the size of the inclusion or its stiffness differential with respect to the matrix. It is shown that the well-known two-wave elastohydrodynamic lubrication mechanism induced by surface features is also applicable to the inclusions. Also, that the effects of the inclusion become weaker both when its size is reduced and when its stiffness approaches that of the matrix. A direct comparison with predictions by the semi-analytical model of Morales-Espejel et al. ( Proc IMechE, Part J: J Engineering Tribology 2017; 231) shows reasonable qualitative agreement. Quantitatively some differences are observed which, after accounting for the semi-analytical model's simplicity, physical agreement, and computational efficiency, may then be considered as reasonable for engineering applications.


Author(s):  
Cho-Pei Jiang ◽  
Ching-Wei Wu ◽  
Yung-Chang Cheng

An integrating optimization procedure is presented to improve the von Mises stress and fatigue safety factor for a handlebar stem system in a bicycle system. The optimization procedure involves uniform design of experiment, Kriging interpolation, genetic algorithm, and nonlinear programming method. Using ANSYS/Workbench software and the ISO 4210 bicycle handlebar stem testing standard, the von Mises stress for the lateral bending test simulation and the fatigue safety factor for the fatigue test simulation is calculated. The von Mises stress and fatigue safety factor are combined into a single and integrated objective function, and Kriging interpolation is then used to create the surrogate model of the integrated objective function. When the integrating optimization procedure is used, the integrated objective function demonstrates that the von Mises stress for the optimized handlebar stem is reduced to 225 MPa and the fatigue safety factor increases to 1.796. This shows that the optimized design increases the strength of the handlebar stem. The proposed technique yields a handlebar stem with an optimized shape.


Author(s):  
Emanuel Willert ◽  
Fabian Forsbach ◽  
Valentin L. Popov

The Hertzian contact theory, as well as most of the other classical theories of normal and tangential contact, provides displacements and the distribution of normal and tangential stress components directly in the contact surface. However, other components of the full stress tensor in the material may essentially influence the material behaviour in contact. Of particular interest are principal stresses and the equivalent von Mises stress, as well as the gradient of the hydrostatic pressure. For many engineering and biomechanical problems, it would be important to find these stress characteristics at least in the contact plane. In the present paper, we show that the complete stress state in the contact plane can be easily found for axially symmetric contacts under very general assumptions. We provide simple explicit equations for all stress components and the normal component of the gradient of hydrostatic pressure in the form of one-dimensional integrals.


2019 ◽  
Vol 16 (03) ◽  
pp. 1842006 ◽  
Author(s):  
Xinyang Cui ◽  
Qingshuai Ren ◽  
Gaoyang Li ◽  
Zihao Li ◽  
Aike Qiao

The stents’ adaptability and safety in realistic and idealized stenotic coronary model were compared to investigate the influence of artery geometry parameter on stent fatigue life. The stents’ fatigue resistance ability was calculated using Goodman diagram, and the cycle to failure, the fatigue life, and the fatigue safety factor (FSF) were analyzed. Although the peak top of the von Mises stress was located at the bending area of crowns, the stress distributions were different in the two models. Considering the safety and accuracy, it is necessary to use a realistic geometric model to calculate the stent fatigue performance.


2021 ◽  
Vol 26 (1) ◽  
pp. 69-78
Author(s):  
Aji Abdillah Kharisma ◽  
Ahmad Fadel Givari ◽  
Irvan Septyan Mulyana

Storage tank adalah alat yang dibutuhkan dalam industri minyak bumi dan gas. Fungsi dari storage tank ialah untuk menyimpan fluida dalam jumlah yang besar. Tangki timbun harus memiliki dinding yang kuat untuk menahan suatu tekanan, maka tangki tersebut tidak mengalami kerusakan. Penelitian ini membahas tentang kekuatan desain fire water storage tank, dari kriteria faktor keamanan, von misses, dan displacement. Metode yang digunakan adalah metode perhitungan actual dan metode analysis simulasi (analysis simulation). Data input desain shell diberi internal pressure sebesar (1 atm) atau (0,101325 MPa), pada hasil simulasi solidworks didapatkan nilai dari von mises stress sebesar (150,49 MPa), safety factor (1,36), dan displacement (5,95 mm). Hasil metode perhitungan aktual didapatkan nilai von mises sebesar (155,245 MPa), safety factor (1,32), dan displacement (4,274 mm). Berdasarkan hasil analisa desain dari storage tank dapat dinyatakan aman digunakan dikarenakan nilai von mises berada dibawah nilai yield strength (205 MPa), safety factor berada pada kisaran (1-10), serta displacement yang tidak terlalu signifikan.


2010 ◽  
Vol 2 (1) ◽  
Author(s):  
Sugiarmadji ◽  
Setiadi

Structural strength analysis on Motor Rocket-168 fins was carried out to determine static stresses due to aerodynamic loadings. Here, 90 mm of the root chord area from leading edge was unclamp (free). The analysis results showed the maximum value of von Mises stress is Q von mises = 42.40 MPa. For 90 mm condition un clamp (free) we obtained the safety factor of the material for fins structures made of Al-Plate is SF=3.39. For 67.5 mm of 90 mm root chord area constrainted at 12456 directions, it was found Qvm equal 11,26 MPa and has higher safety factor. Eigenvalues and eigenvectors of the fins structures. The results showed that the eigenvalues of the fin structures are Q1 equal 198,47 Hz, Q2 equal 616,34 Hz, Q3 equal 1080,97 Hz, Q4 equal 1704,33 Hz, Q5 equal 2386,82 Hz, dan Q6 equal 2770,94 Hz.


2012 ◽  
Vol 510 ◽  
pp. 165-169
Author(s):  
Yong Bai Sha ◽  
Xiao Peng Wan ◽  
Xiao Ying Zhao

This paper presents the structure design, the working principle and the relevant calculation of the mechanical clamping claw of the land rigs automatic arranging drill pipe system. Applying the Generative Structural Analysis module of the CATIA, we can get the Von Mises stress image to show the stress distribution. The finite element analysis provides a simple effective method for the design of the structure of the mechanical clamping claw. Through this device the drill pipe can be transferred automatically and circularly from the rat hole to the pipe racking system and from pipe racking system to the mouth of the well.


2020 ◽  
Vol 2 (2) ◽  
pp. 1
Author(s):  
Mohammad Ihya’ Ulumuddin

Plastik merupakan salah satu bahan baku untuk membuat suatu product plastik yang berguna untuk memenuhi kebutuhan manusia, Selama  pengamatan di PT X terutama dalam proses pembuatan desain molding, di tempat tersebut tidak melakukan analisis desain menggunakan software, oleh sebab itu penulis membuat analisis molding menggunakan software, penelitian ini bertujuan menganalisis kekuatan plate insert cavity pada saat mendapatkan tekanan 160 MPa dari mesin injection untuk mengetahui tegangannya perlu dilakukan analisis memakai software autodesk inventor profesioanl 2017 Pada analisis ini dilakukan studi langsung di PT X Proses analisis diawali dengan membuat desain 3D molding kemudian masuk ke menu stress analysis pada kotak dialog pressure dimasukan data tekanan yang sebesar 160 Mpa, untuk bahan molding yang digunakan untuk analisis adalah stainless steel, setelah data masuk semua bisa langsung dijalankan simulation tegangannya, dari analisis akan diperoleh data tegangan seperti von misess, stress, strain, displacment, .dan safety factor Berdasarkan hasil analisis statis didapat kekuatan molding yaitu nilai von mises stress maksimum adalah 124,2  Mpa, nilai Stress maksimum adalah 118,1 Mpa, nilai displacement maksimum adalah 0,06579 mm, , nilai strain maksimum adalah 6,03 x 10-4, dengan nilai faktor keamanan 2,01 maka faktor kemanan beban pada molding masih aman mengunakan bahan stainless steel.


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