Window Seat Weight Reduction Exploration With Nontraditional Seat Geometry

2019 ◽  
Vol 53 (1) ◽  
pp. 107-116 ◽  
Author(s):  
Thomas Trudel ◽  
Karl Stanley
Keyword(s):  
Pressure Vessels ◽  
Scale Model ◽  
Short Term ◽  
Element Analysis ◽  
Design Studies ◽  
Exploratory Testing ◽  
Design Depth ◽  
Strength And Stiffness ◽  
American Society ◽  
Design Pressure

AbstractThis article provides an overview of the design and exploratory testing of a nontraditional submersible window seat design. Typically, window seat geometry is guided by the American Society of Mechanical Engineers-Pressure Vessels for Human Occupancy-1 (ASME-PVHO-1) engineering standard as well as other references by ASME, Stachiw, etc. As viewing area increases, window seat geometry is partly driven by the size of the acrylic window and not solely by the requirements for a hull penetration of equivalent size. The discrepancy in strength and stiffness between the submersible hull materials and acrylic window can result in a window seat that is overbuilt relative to the required hull integrity. This research focuses on nontraditional window seat geometries that decrease weight while performing comparably to designs that conform to the ASME-PVHO-1 standard. A novel window seat is proposed with reductions in window seat weight between 22% and 33%. Design methodology, assumptions, Fine Element Analysis (FEA) results, deviations from the standard, and empirical design studies are summarized in detail. Two scale model windows were tested to their design depth for 102 cycles and showed acceptable signs of wear. FEA constraints were validated using strain gauge and displacement measurements on the conical and low pressure faces of the windows. Short Term Critical Pressure (STCP) testing was conducted in a hydrostatic pressure chamber where the two model windows reached 79% and 86% of their design pressure.

Estimation of Maximum Pressure Stress Intensity in a Welding Tee

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
Martin Blackman
Keyword(s):  
New York ◽  
Empirical Relationship ◽  
Local Stress ◽  
Pressure Vessels ◽  
Maximum Pressure ◽  
Element Analysis ◽  
Pipe Bend ◽  
Process Piping ◽  
American Society ◽  
Pressure Stress

The required thickness of welding tees is neither specified in ASME (2012, “Factory-Made Wrought Buttwelding Fittings,” American Society of Mechanical Engineers, New York, Standard No. B16.9-2012) nor is a clear calculation method provided in codes such as ASME (2016, “Process Piping,” American Society of Mechanical Engineers, New York, Standard No. B31.3-2016). This can lead to uncertainty regarding the pressure capacity of a tee fitting, particularly one that has suffered from erosion or corrosion. Code methods including area replacement (ASME, 2016, “Process Piping,” American Society of Mechanical Engineers, New York, Standard No. B31.3-2016) or pressure-area (ASME, 2015, “Boiler and Pressure Vessel Code Section VIII Division 2,” American Society of Mechanical Engineers, New York, Standard No. BPVC-VIII-2-2015; BSI, 2014, “Unfired Pressure Vessels Part 3: Design,” BSI, London, UK, Standard No. BS EN 13445-3) do not directly account for the effect which the curvature of the crotch region may have on the stress state in the tee. The approach adopted in this work is to liken the geometry of the tee crotch to the intrados of a torus or pipe bend. The shell theory applicable to the torus is adapted for the tee in order to derive a relationship for circumferential membrane stress. An equivalent tube radius is assigned by determining the local radius of shell curvature in the plane passing through the crotch center of the curvature. The actual stresses in the tee crotch are significantly reduced by the adjoining straight portions. This effect is difficult to quantify theoretically and has thus been investigated by means of finite element analysis (FEA)-based assessments. An empirical relationship was then established providing a conservative correlation between the theoretical stresses and the program calculated local stress intensities.

Establishing Allowable Nozzle Loads

2011 ◽  
Author(s):  
William Koves ◽  
Elmar Upitis ◽  
Richard Cullotta ◽  
Omar Latif
Keyword(s):  
Finite Element Analysis ◽  
Pressure Vessel ◽  
Heat Exchangers ◽  
Pressure Vessels ◽  
Nozzle Design ◽  
Engineering Project ◽  
Element Analysis ◽  
Design Loads ◽  
External Forces ◽  
Design Pressure

Every engineering project involving the design of pressure equipment, including pressure vessels, heat exchangers and the interconnecting piping requires that the interface loads between the equipment and piping be established for the pressure vessel nozzle design and the limitations on piping end reactions. The vessel or exchanger designer needs to know the external applied loads on nozzles and the piping designer needs to know the limiting end reactions on any connected equipment. However, the final loads are not known until the piping design is completed. This requires a very good estimate of the piping end loads prior to completing the vessel or piping design. The challenge is to develop a method of determining the optimum set of design loads prior to design. If the design loads are too low, the piping design may become too costly or impractical. If the design loads are too high the vessel nozzle designs will require unnecessary reinforcement and increased cost. The problem of the stresses at a nozzle to vessel intersection due to internal pressure and external forces and moments is one of the most complex problems in pressure vessel design. The problem has been studied extensively; however each study has its own limitations. Numerous analytical and numerical simulations have been performed providing guidance with associated limitations. The objective is to establish allowable nozzle load tables for the piping designer and the vessel designer. The loads and load combinations must be based on a technically accepted methodology and applicable to all nozzle sizes, pressure classes, schedules and vessel diameters and thicknesses and reinforcement designs within the scope of the tables. The internal design pressure must also be included along with the 3 forces and 3 moments that may be acting on the nozzle and the nozzle load tables must be adaptable to all materials of construction. The Tables must also be applicable for vessel heads. This paper presents the issues, including the limitations of some of the existing industry approaches, presents an approach to the problem, utilizing systematic Finite Element Analysis (FEA) methods and presents the results in the form of tables of allowable nozzle loads.

Acrylic Plastic Spherical Pressure Hull for 2439 m (8000 ft) Design Depth: Phase I

1987 ◽  
Vol 109 (1) ◽  
pp. 40-47 ◽  
Author(s):  
J. D. Stachiw ◽  
A. Clark ◽  
C. B. Brenn
Keyword(s):  
Phase I ◽  
Scale Model ◽  
Test Plan ◽  
Short Term ◽  
Acrylic Plastic ◽  
Hull Design ◽  
Manned Submersible ◽  
Design Depth ◽  
Different Diameters ◽  
Spherical Pressure

A program has been initiated to provide the oceanographic community with a manned submersible with panoramic visibility for 2439 m (8000 ft) design depth. The first phase of the program is to validate the design of the acrylic plastic pressure hull utilizing model scale spheres with different diameters and thickness to inside diameter (t/Di) ratios. This papers summarizes 1) the criteria used in the design of the acrylic plastic hull for 2439 m (8000 ft) depth, 2) the experimental test plan for validation of the hull design, and 3) the fabrication, and short-term pressurization to destruction of the first scale model with an aluminum hatch. The 457-mm (18-in.) o.d. acrylic sphere with t/Di ratio of 0.2 successfully withstood 1-hr long pressurizations from 0 to 6.9, 13.8, 20.7, 27.6, 34.4 and 41.3 MPa (1000, 2000, 3000, 4000, 5000, and 6000 psi) followed by 1-hr long relaxation periods after each pressurization prior to imploding at 110.2 MPa (16,000 psi) under 4.5 MPa/min (650 psi/min) pressurization. The selected t/Di ratio 0.2 appears to exceed the design depth requirement for 2439 m (8000 ft).

A Case for New Low Pressure Vessel (LPV) Codes for Design Pressures Below 15 psi (100 kPA)

2021 ◽  
Author(s):  
Barry Millet ◽  
Kaveh Ebrahimi ◽  
James Lu ◽  
Donald Spencer
Keyword(s):  
Pressure Vessel ◽  
Power Plants ◽  
Low Pressure ◽  
Pressure Vessels ◽  
Engineering Practice ◽  
Element Analysis ◽  
Gas Treatment ◽  
Food And Beverage ◽  
Asme Code ◽  
Design Pressure

Abstract Today the ASME Boiler and Pressure Vessel Code Section VIII (ASME Code) covers pressure vessels for design pressure above 15 psi (100 kPa) but not for design pressures below 15 psi. Manufacturers of pressure vessels under 10ft (3048mm) and with design pressure under 15 psi (100 kPa) design to the ASME Code but do not stamp them. The ASME Code is explicit in not allowing this. Manufacturers of low pressure vessels over 10 ft (3048 mm) in diameter, design and built to “good engineering practice” using Finite Element Analysis, the ASME Code, API and the AISC Manual of Steel Construction. This paper provides an overview of these existing codes, standards with their methods for design, fabrication and testing then provides an outline of a Code with two classes of low pressure vessels (LPV). The audience for the smaller pressure vessels would be small batch chemical, pharmaceutical, food, and beverage processing facilities who require small near atmospheric pressure vessels. The audience for the larger pressure vessels would be power plants, refineries, chemical plant, steel mills and concrete plants flue gas treatment and CO2 sequestration of exhaust products.

scholarly journals The Development of Reinforcement Pad Design for Pressure Vessel

2020 ◽  
Vol 8 (5) ◽  
pp. 267-269
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Vessel ◽  
Pressure Vessels ◽  
Element Analysis ◽  
History Of ◽  
American Society

This paper reviews research from difference researchers on pressure vessel component particularly reinforcement pad or repad design. Present study includes the history of pressure vessel and background of famous pressure vessel code American Society of Mechanical Engineers Boiler and Pressure Vessel Code establishment. Purpose of present research is to study the development repad design and the application repad on pressure vessels. Literatures from other researches on various repad design carried out by experimental and finite element analysis were discussed in present study.

Pressure-Resistant Plane Disk Viewports From Allyl Diglycol Carbonate Plastic for Hyperbaric Chambers

1986 ◽  
Vol 108 (4) ◽  
pp. 326-335 ◽  
Author(s):  
J. D. Stachiw ◽  
M. A. Stachiw
Keyword(s):  
Organic Solvents ◽  
Pressure Vessels ◽  
Short Term ◽  
Loss Of Life ◽  
X Ray ◽  
Cyclic Pressure ◽  
Acrylic Plastic ◽  
Plane Disk ◽  
Design Pressure

Acrylic plastic viewports have been used for over 40 yr in pressure vessels for human occupancy without any catastrophic failure resulting in a loss of life. However, there are special applications, such as for example in hyperbaric chambers for medical purposes, where the susceptibility of flexure stressed acrylic plastic to surface crazing and cracking in the presence of common organic solvents contained in antibacterial sprays is a distinct disadvantage. To solve this problem, a search has been initiated for transparent plastics that are not attacked by organic solvents and can be cast economically in thick sections. Allyl diglycol carbonate plastic appears not only to satisfy the foregoing requirement, but also to provide better resistance to abrasion, pitting, and X-ray or gamma irradiation than acrylic plastic. Short-term, long-term, and cyclic pressure testing has been conducted on over one hundred allyl diglycol carbonate plane disk viewports with t/D0 ratio in the 0.06 to 0.4 range and temperature in the 4°C to + 52°C (+40F to 125°F) range. It appears that plane disks cast from allyl diglycol carbonate plastic can perform safely as pressure-resistant viewports in pressure vessels for human occupancy. It is recommended that for such an application their design temperature be limited to under 52°C (125°F), and that their design pressure at 52°C (125°F) design temperature not exceed 4 percent of their (STCP) short-term critical pressure at 24°C (75°F).

scholarly journals Stator Non-Uniform Radial Ventilation Design Methodology for a 15 MW Turbo-Synchronous Generator Based on Single Ventilation Duct Subsystem

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2760
Author(s):  
Ruiye Li ◽  
Peng Cheng ◽  
Hai Lan ◽  
Weili Li ◽  
David Gerada ◽  
...  
Keyword(s):  
Finite Element ◽  
Temperature Distribution ◽  
Design Methodology ◽  
Large Scale ◽  
Synchronous Generator ◽  
Axial Direction ◽  
Scale Model ◽  
Element Analysis ◽  
Axial Temperature ◽  
Ventilation Duct

Within large turboalternators, the excessive local temperatures and spatially distributed temperature differences can accelerate the deterioration of electrical insulation as well as lead to deformation of components, which may cause major machine malfunctions. In order to homogenise the stator axial temperature distribution whilst reducing the maximum stator temperature, this paper presents a novel non-uniform radial ventilation ducts design methodology. To reduce the huge computational costs resulting from the large-scale model, the stator is decomposed into several single ventilation duct subsystems (SVDSs) along the axial direction, with each SVDS connected in series with the medium of the air gap flow rate. The calculation of electromagnetic and thermal performances within SVDS are completed by finite element method (FEM) and computational fluid dynamics (CFD), respectively. To improve the optimization efficiency, the radial basis function neural network (RBFNN) model is employed to approximate the finite element analysis, while the novel isometric sampling method (ISM) is designed to trade off the cost and accuracy of the process. It is found that the proposed methodology can provide optimal design schemes of SVDS with uniform axial temperature distribution, and the needed computation cost is markedly reduced. Finally, results based on a 15 MW turboalternator show that the peak temperature can be reduced by 7.3 ∘C (6.4%). The proposed methodology can be applied for the design and optimisation of electromagnetic-thermal coupling of other electrical machines with long axial dimensions.

A Study on Fatigue Life Evaluation of Pressure Vessel Made of ASME SA240-316L Material Using Numerical Analysis

2019 ◽  
Vol 893 ◽  
pp. 1-5 ◽  
Author(s):  
Eui Soo Kim
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Pressure Vessel ◽  
Life Prediction ◽  
Pressure Vessels ◽  
Physical Damage ◽  
Element Analysis ◽  
Internal Damage ◽  
Life Evaluation ◽  
Fatigue Life Evaluation

Pressure vessels are subjected to repeated loads during use and charging, which can causefine physical damage even in the elastic region. If the load is repeated under stress conditions belowthe yield strength, internal damage accumulates. Fatigue life evaluation of the structure of thepressure vessel using finite element analysis (FEA) is used to evaluate the life cycle of the structuraldesign based on finite element method (FEM) technology. This technique is more advanced thanfatigue life prediction that uses relational equations. This study describes fatigue analysis to predictthe fatigue life of a pressure vessel using stress data obtained from FEA. The life prediction results areuseful for improving the component design at a very early development stage. The fatigue life of thepressure vessel is calculated for each node on the model, and cumulative damage theory is used tocalculate the fatigue life. Then, the fatigue life is calculated from this information using the FEanalysis software ADINA and the fatigue life calculation program WINLIFE.

Stress Analysis and Structure Optimization for the Opening Flat Cover of Pressure Vessels

2012 ◽  
Vol 538-541 ◽  
pp. 3253-3258 ◽  
Author(s):  
Jun Jian Xiao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Concentration ◽  
Stress Analysis ◽  
Structure Optimization ◽  
Pressure Vessels ◽  
Secondary Stress ◽  
Element Analysis ◽  
Primary Stress ◽  
Flat Cover

According to the results of finite element analysis (FEA), when the diameter of opening of the flat cover is no more than 0.5D (d≤0.5D), there is obvious stress concentration at the edge of opening, but only existed within the region of 2d. Increasing the thickness of flat covers could not relieve the stress concentration at the edge of opening. It is recommended that reinforcing element being installed within the region of 2d should be used. When the diameter of openings is larger than 0.5D (d>0.5D), conical or round angle transitions could be employed at connecting location, with which the edge stress decreased remarkably. However, the primary stress plus the secondary stress would be valued by 3[σ].

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