Derivation to Calculate Pipe Collapse Performance using a Combined Loading Equivalent Grade Accounting for Axial Stress, Internal Pressure, Bending and Torsion

2021 ◽  
Author(s):  
Jean-Guillaume Besse
Keyword(s):  
Yield Strength ◽  
Internal Pressure ◽  
Closed Form ◽  
Axial Stress ◽  
Combined Loading ◽  
Collapse Pressure ◽  
Form Equation ◽  
Analytical Derivation ◽  
Von Mises ◽  
Performance Calculation

Abstract This paper proposes a new analytical derivation to incorporate bending and torsion into collapse calculation, further pushing the already existing approach of combined loading equivalent grade proposed in API TR 5C3 (2019) Clause 8.4.6 Eq. (42) for axial stress and internal pressure (identical to ISO TR 10400 Clause 8.4.7) used to calculate a differential collapse pressure. This new derivation is also based on Hencky-von Mises maximum distortion criterion. The interest of developing such combined loading equivalent grade is to enable the use of the four collapse types described in Clause 8 i.e., Yield Strength, Plastic, Transition and Elastic. The formulae are adapted to a closed-form equation similar to current Eq. (42), enabling pipe collapse performance calculation. Newly derived formulae are checked against a size governed by yield strength collapse to verify consistency. The restrictions regarding collapse performance under compression are discussed.

Partially Plastic Thick-Walled Cylinder Theory

1952 ◽  
Vol 19 (2) ◽  
pp. 133-140
Author(s):  
M. C. Steele
Keyword(s):  
Internal Pressure ◽  
Experimental Evidence ◽  
Closed Form ◽  
Strain Hardening ◽  
Axial Stress ◽  
Quantitative Comparison ◽  
Stress Strain ◽  
Von Mises ◽  
Walled Cylinder

Abstract Previous theories for partially plastic thick-walled cylinders under internal pressure are reviewed. A quantitative comparison is given for (a) compressibility versus incompressibility of material, and (b) von Mises’ versus Tresca’s theory of failure. The former reveals that deflections at the outside and bore surfaces agree closely, although considerable percentage differences may be found in the axial stresses and strains. Large differences (except for the axial stress) are found in comparing the two theories of failure. Based on the comparison and available experimental evidence, a theory is presented in closed form to include the Hencky stress-strain relations, incompressibility, and Ludwik’s strain-hardening function.

Yield Pressure Measurements and Analysis for Autofrettaged Cannons

2002 ◽  
Author(s):  
John H. Underwood ◽  
David B. Moak ◽  
Michael A. Audino ◽  
Anthony P. Parker
Keyword(s):  
Residual Stress ◽  
Yield Strength ◽  
Yield Criterion ◽  
Axial Stress ◽  
Design Procedure ◽  
Pressure Vessels ◽  
Pressure Measurements ◽  
Strain Rate Effects ◽  
Axial Residual Stress ◽  
Von Mises

Yield pressure corresponding to a small permanent OD strain was measured in quasi-static laboratory tests of autofrettaged ASTM A723 steel cannon pressure vessels. Yield pressure was found to be a consistent ratio of the yield strength measured from specimens located in close proximity to the area of observed yielding. Yield pressure measurements for dynamic cannon firing with typically a 5 ms pressure pulse duration gave 14% higher yield pressures, attributed to strain rate effects on plastic deformation. Calculated Von Mises yield pressure for the laboratory test conditions, including the Bauschinger-modified ID residual stress and open-end vessel conditions, agreed with measured yield pressure within 3–5%. Calculated yield pressure was found to be insensitive to the value of axial residual stress, since axial stress is the intermediate value in the Von Mises yield criterion. A description of yield pressure normalized by yield strength was given for autofrettaged A723 open-end pressure vessels over a range of wall ratio and degree of autofrettage, including effects of Bauschinger-modified residual stress. This description of yield pressure is proposed as a design procedure for cannons and other pressure vessels.

Yield Pressure Measurements and Analysis for Autofrettaged Cannons

2003 ◽  
Vol 125 (1) ◽  
pp. 7-10 ◽  
Author(s):  
John H. Underwood ◽  
David B. Moak ◽  
Michael J. Audino ◽  
Anthony P. Parker
Keyword(s):  
Residual Stress ◽  
Yield Strength ◽  
Yield Criterion ◽  
Axial Stress ◽  
Design Procedure ◽  
Pressure Vessels ◽  
Pressure Measurements ◽  
Strain Rate Effects ◽  
Axial Residual Stress ◽  
Von Mises

Yield pressure corresponding to a small permanent OD strain was measured in quasi-static laboratory tests of autofrettaged ASTM A723 steel cannon pressure vessels. Yield pressure was found to be a consistent ratio of the yield strength measured from specimens located in close proximity to the area of observed yielding. Yield pressure measurements for dynamic cannon firing with typically a 5-ms pressure pulse duration gave 14% higher yield pressures, attributed to strain rate effects on plastic deformation. Calculated Von Mises yield pressure for the laboratory test conditions, including the Bauschinger-modified ID residual stress and open-end vessel conditions, agreed with measured yield pressure within 3–5%. Calculated yield pressure was found to be insensitive to the value of axial residual stress, since axial stress is the intermediate value in the Von Mises yield criterion. A description of yield pressure normalized by yield strength was given for autofrettaged A723 open-end pressure vessels over a range of wall ratio and degree of autofrettage, including effects of Bauschinger-modified residual stress. This description of yield pressure is proposed as a design procedure for cannons and other pressure vessels.

DESAIN DAN ANALISIS KEKUATAN TANGKI FIRE WATER STORAGE TANK TIPE FIX CONE ROOF KAPASITAS 1500 KL DENGAN PERHITUNGAN AKTUAL DAN SIMULASI SOFTWARE

2021 ◽  
Vol 26 (1) ◽  
pp. 69-78
Author(s):  
Aji Abdillah Kharisma ◽  
Ahmad Fadel Givari ◽  
Irvan Septyan Mulyana
Keyword(s):  
Yield Strength ◽  
Internal Pressure ◽  
Safety Factor ◽  
Storage Tank ◽  
Water Storage ◽  
Von Mises Stress ◽  
Data Input ◽  
Simulation Data ◽  
Water Storage Tank ◽  
Von Mises

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.

scholarly journals Numerical Study of The Effect of Wall Thickness and Internal Pressure on Von Mises Stress and Safety Factor of Thin-Walled Cylinder for Rocket Motor Case

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Lasinta Ari Nendra Wibawa
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Internal Pressure ◽  
Wall Thickness ◽  
Axial Stress ◽  
Rocket Motor ◽  
Von Mises Stress ◽  
Element Analysis ◽  
Maximum Hoop Stress ◽  
Von Mises

The rocket motor is an important part of rockets. The rocket motor works using the pressure vessel principle because it works in an environment with high pressure and temperature. This paper investigates the von Mises stress that occurs in thin-walled cylinders and safety factors for rocket motor cases due to the influence of the wall thickness and internal pressure. Dimensions of the cylinder length are 500 mm, outer diameter is 200 mm, and cap thickness is 30 mm. The wall thickness is varied 6, 7, 8, and 9 mm, while the internal pressure is varied 8, 9, and 10 MPa. Stress analysis is performed using the finite element method with Ansys Workbench 2019 R3 software. The simulation results show that the maximum von Mises stress decreases with increasing wall thickness. The maximum von Mises stress increases with increasing internal pressure. The material has a safety factor higher than 1.25 for all variations in wall thickness and internal pressure. It means that the material can withstand static loads. The verification process is done by comparing the results of finite element analysis with analytical calculations for maximum hoop stress and maximum axial stress with a fixed boundary condition. The results of maximum hoop stress and maximum axial stress using finite element analysis and analytical calculations are not significantly different. The percentage of errors between analytical calculations and finite element analysis is less than 6 percent.

A computational and experimental assessment of the pipeline stress state under bending load and internal pressure

2021 ◽  
pp. 114-126
Author(s):  
A. A. Ignatik
Keyword(s):  
Plastic Deformation ◽  
Stress State ◽  
Internal Pressure ◽  
Central Region ◽  
Pipe Wall ◽  
Combined Loading ◽  
Von Mises Stress ◽  
Bending Load ◽  
Stress Zone ◽  
Von Mises

Main pipelines are subjected to a complex of loads during operation. Monitoring of the stress state of the pipeline wall is necessary for performing strength calculations and evaluating the pipeline reliability.The article is devoted to the method of computational and experimental study of the stress state of a pipe under a bending load and combined action of a bending load and internal pressure.The experiments have been carried out on a laboratory bench. The object of the study is a pipe that has the following characteristics: an outer diameter of 325 mm, a wall thickness of 8.5 mm and steel grade of "14XGS". Electrical resistance strain gages were used to measure the strain of the pipe wall. Formulas for calculating the stress state components of the pipe wall in the elastic-plastic deformation stage are proposed. It is given formulas for calculating the stress state components of the pipe wall in the elastic-plastic deformation stage. Plots of hoop and longitudinal stresses as well as von Mises stress are obtained for the case of bending load on the pipe and the case of combined loading under bending and internal pressure. The areas of maximum values of von Mises stress where the transition to the limiting state is most likely have been determined.When only the bending load is applied, the maximum von Mises stress zone is observed on the lower area of the pipe in its central region. When combined loading under bending and internal pressure, the maximum von Mises stress zone is observed on the lateral area of the pipe in its central region.

Leakage Prediction in Mechanical Seals Under Hydrostatic Operating Condition

2007 ◽  
Author(s):  
S. Elhanafi ◽  
K. Farhang
Keyword(s):  
Closed Form ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Rough Surfaces ◽  
Mechanical Seals ◽  
Operating Condition ◽  
Form Equation ◽  
Macro Scale ◽  
The Mean

This paper considers leakage in mechanical seals under hydrostatic operating condition. A contact model based on the Greenwood and Williamson contact of rough surfaces is developed for treating problems involving mechanical seals in which both the micron scale roughness of the seal face and its macro scale profile are used to obtain either a closed-form equation or a nonlinear equation relating mean plane separation to the mass flow rate. The equations involve the micron scale geometry of the rough surfaces and physical parameter of the seal and carriage. Under hydrostatic condition, it is shown that there is an approximate closed-form solution in which mass flow rate in terms of the mean plane separation, or alternatively, the mean plane separation in terms of the leakage mass flow rate is found. Equations pertaining to leakage in nominally flat seal macro profile is considered and closed form equation relating to leakage flow rate to pressure difference is obtained that contain macro and micron geometries of the seal.

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