scholarly journals Developing “Design by Analysis” Methodology for Windows for Pressure Vessels for Human Occupancy

2020 ◽  
Vol 6 (3) ◽  
Author(s):  
Bart Kemper ◽  
Linda Cross
Keyword(s):  
Pressure Vessel ◽  
Large Scale ◽  
Design Method ◽  
Empirical Method ◽  
Pressure Vessels ◽  
Case Review ◽  
Element Analysis ◽  
Engineering Theory ◽  
Operational Variables ◽  
Stochastic Finite Element Analysis

Abstract The ASME pressure vessels for human occupancy (PVHO) codes and standards are engineering standards developed to provide a reliable design method for pressure vessel windows. This empirical method is based primarily on years of government-sponsored testing and development and does not directly use engineering theory. This empirical algorithm makes it challenging to revise without additional large-scale physical testing. The industries using the PVHO code need a way to incorporate advances in material science, manufacturing technology, and overall engineering advances without spending years in code case review. Verification and validation techniques, coupled with stochastic finite element analysis (FEA) to address operational variables, can be the basis for a “design by analysis” method to complement the existing testing requirements to produce a full engineering package consistent with other pressure vessel and pressure vessel component design. A design method sufficiently reliable for PVHO could be used in other applications.

Failure Modes for Acrylic Polymers in Section VIII Pressure Vessels

2021 ◽  
Author(s):  
Bart Kemper ◽  
Guy Richards ◽  
Taylor Nappi ◽  
Veda Thipparthi ◽  
Ana Escobar
Keyword(s):  
Pressure Vessel ◽  
Failure Modes ◽  
Design Method ◽  
Current Method ◽  
Empirical Method ◽  
Pressure Vessels ◽  
Glassy Polymers ◽  
Acrylic Polymers ◽  
Section Viii ◽  
Vessel Material

Abstract Section VIII of the Boiler and Pressure Vessel Code is introducing the use of acrylics as a pressure vessel material. The design method is specified in ASME PVHO-1, Safety Standard for Pressure Vessels for Human Occupancy. The current method relies upon an empirical method developed in the 1960–70’s. It does not use “allowable stress” or other mechanical properties traditionally used to calculate design dimensions, but instead uses a fixed range of dimensions for specific shapes and determines the wall thickness using a curve. Understanding the PVHO-1 design assumptions and typical failure modes is important for a non-PVHO pressure vessel designer using acrylics. An ASME Codes & Standards task group is developing a “design by analysis” method (DBA) for acrylics and other glassy polymers for pressure vessel components. The proposed DBA methodology uses Verification and Validation (V&V) techniques and Finite Element Method (FEM) as the design method framework in order to advance the use of glassy polymers as pressure vessel materials.

Pressure Vessel Optimization Design Based on the Finite Element Analysis

2011 ◽  
Vol 65 ◽  
pp. 281-284 ◽  
Author(s):  
Cai Li Zhang ◽  
Fan Yang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Vessel ◽  
Optimization Design ◽  
Design Method ◽  
Pressure Vessels ◽  
Design Parameters ◽  
Element Analysis ◽  
Quantitative Calculation ◽  
The Finite Element Analysis

According to pressure vessel material waste problem in the traditional design, the finite element technique is used to pressure vessel optimization design in this paper. Firstly, the finite element analysis is applied to carry out stress calculation, and we extracted the related results parameters for following calculation. Then we conducted the quantitative calculation after choosing optimization design method, and got the best design parameters which meet performance indexes. At last, we conducted the optimization design of pressure vessels using this technology. Practical results prove the validity and the practicability of this method in the pressure vessels design.

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.

Oxygen Pressure Aging. Improved Equipment

1938 ◽  
Vol 11 (4) ◽  
pp. 722-727
Author(s):  
L. M. Freeman
Keyword(s):  
Oxygen Pressure ◽  
Pressure Vessel ◽  
Large Scale ◽  
Oxygen Supply ◽  
Pressure Vessels ◽  
Water Bath ◽  
Aging Test ◽  
Constant Temperature Water Bath ◽  
Temperature Water ◽  
Continuous Source

Abstract Since the introduction of the oxygen pressure-aging test by Bierer and Davis, prevailing standard conditions for the test have been 70° C. (158° F.) and 300 pounds per square inch oxygen pressure. Various types of equipment have been used; usually the equipment has consisted of a pressure vessel immersed in a constant-temperature water bath to which is connected an oxygen supply. In the majority of instances the equipment has been difficult to operate and maintain for several reasons: Immersion of pressure vessels in a water bath made handling difficult. Corrosion was a continuous source of trouble, causing “freezing” of cover bolts and making it difficult to obtain a leakproof oxygen seal between cover and vessel. This caused loss of oxygen. Each time the pressure vessel was removed from the bath it was necessary to disconnect the oxygen supply and make the connection again when the test was started. This also caused loss of oxygen. If more than one pressure vessel was connected to the oxygen supply and a safety released, the entire oxygen supply was exhausted. The original pressure vessels were relatively large. Since the use of age resistors on a large scale, smaller units have been desirable in order to decrease migration of age resistors and eliminate erroneous results. Some of these operation difficulties were outlined by Ingmanson and Kemp, who also emphasized the importance of temperature control to obtain reproducible results. It is the purpose of this paper to describe an improved oxygen pressure installation which avoids some of these difficulties.

Finite Element Analysis of Residual Stresses in Threaded End Closures

1991 ◽  
Vol 113 (3) ◽  
pp. 398-401 ◽  
Author(s):  
A. Chaaban ◽  
U. Muzzo
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Bauschinger Effect ◽  
High Stress ◽  
Empirical Method ◽  
Pressure Vessels ◽  
Element Analysis ◽  
High Stress Concentration ◽  
Proof Testing ◽  
Pressure Cycle

Due to the high stress concentration at the root of the first active thread in threaded end closures of high pressure vessels, yielding may occur in this region during the application of the first pressure cycle or proof testing. This overstraining introduces residual stresses that influence the fatigue performance of the vessel. This paper presents a parametric analysis of threaded end closures using elastic and elasto-plastic finite element solutions. The results are used to discuss the influence of these residuals on the estimated fatigue life when the vessel is subjected to repeated internal pressure. A simple empirical method to allow for the Bauschinger effect of the material is also proposed.

Study on the Stress Concentration at the Round Corners of Flat Heads in Pressure Vessels Subjected to Internal Pressure

1996 ◽  
Vol 118 (4) ◽  
pp. 429-433
Author(s):  
H. Chen ◽  
J. Jin ◽  
J. Yu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Intensity ◽  
Stress Concentration ◽  
Internal Pressure ◽  
Pressure Vessel ◽  
Pressure Vessels ◽  
Stress Index ◽  
Element Analysis ◽  
Approximate Formulas

Results from finite element analysis were used to show that the stress index kσ and the nondimensionalized highly stressed hub length kh of a flat head with a round corner in a pressure vessel subjected to internal pressure are functions of three dimensionless parameters: λ ≡ h/dt, η ≡ t/d, and ρ ≡ r/t. Approximate formulas for estimating kσ and kh from λ, η, and ρ p are given. The formulas can be used for determining a suitable fillet radius for a flat head in order to reduce the fabricating cost and to keep the stress intensity at the fillet under an acceptable limit.

The Consequences of Macroscopic Segregation on the Transformation Behavior of a Pressure-Vessel Steel

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
E. J. Pickering ◽  
H. K. D. H. Bhadeshia
Keyword(s):  
Mechanical Properties ◽  
Pressure Vessel ◽  
Large Scale ◽  
Pressure Vessels ◽  
Pressure Vessel Steel ◽  
Vessel Steel ◽  
Chemical Segregation ◽  
Compositional Variations ◽  
Grade 3 ◽  
Kinetics Of

It is important that the material used to produce high-integrity pressure vessels has homogeneous properties which are reproducible and within specification. Most heavy pressure vessels comprise large forgings derived from ingots, and are consequently affected by the chemical segregation that occurs during ingot casting. Of particular concern are the compositional variations that arise from macrosegregation, such as the channels of enriched material commonly referred to as A-segregates. By causing corresponding variations in microstructure, the segregation may be detrimental to mechanical properties. It also cannot be removed by any practically feasible heat treatments because of the large scale on which it forms. Here we describe an investigation on the consequences of macrosegregation on the development of microstructure in a pressure-vessel steel, SA508 Grade 3. It is demonstrated that the kinetics of transformation are sensitive to the segregation, resulting in a dramatic spatial variations in microstructure. It is likely therefore that some of the scatter in mechanical properties as observed for such pressure vessels can be attributed to macroscopic casting-induced chemical segregation.

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.

scholarly journals Development of a Design Catalog for Bonded Concrete Overlay Pavements Considering the Regional Characteristics of Korea

2021 ◽  
Vol 13 (17) ◽  
pp. 9876
Author(s):  
Hae-Won Park ◽  
Jin-Seok Seo ◽  
Jae-Hoon Lee ◽  
Jin-Hoon Jeong
Keyword(s):  
Design Method ◽  
Empirical Method ◽  
Climatic Conditions ◽  
Traffic Volume ◽  
Concrete Pavement ◽  
Element Analysis ◽  
Concrete Overlays ◽  
Volume Elastic Modulus ◽  
Bonded Concrete Overlay ◽  
Empirical Design

The design of overlay pavement in Korea, using the American empirical method, does not consider the unique Korean climate, pavement material, and traffic conditions. Therefore, in this study, a mechanistic–empirical design catalog for bonded concrete overlays (BCO) that are appropriate for Korean pavement conditions was developed. First, the thickness of the new pavement slab was determined through the Korean pavement design method, which uses a mechanistic–empirical design program according to the traffic volume of the region with the worst climatic conditions in Korea. Then, finite element analysis models of new jointed concrete and BCO pavements were developed to determine the BCO thickness by adjusting it until the stress–strength ratio of an existing slab of BCO pavement was equal to that of a new concrete pavement slab. By repeating this procedure, a design catalog was developed for the sustainable management of concrete pavement according to the traffic volume, elastic modulus, and thickness of the existing slab after milling. The appropriateness of the BCO thickness predicted by the design catalog was verified by comparing it with that predicted by other design methods.

Investigation on the Effects of Carbon Macro-Segregation of Mechanical Properties Using a Large-Scale Forged Low Alloy Steel for a BWR Reactor Pressure Vessel

2020 ◽  
Author(s):  
Takahiro Hayashi ◽  
Takuya Ogawa ◽  
Rie Sumiya ◽  
Tetsushi Yamaoka ◽  
Shigeaki Tanaka ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Content ◽  
Pressure Vessel ◽  
Material Properties ◽  
Large Scale ◽  
Structural Reliability ◽  
Pressure Vessels ◽  
Reactor Pressure Vessel ◽  
Steel Making ◽  
Reactor Pressure

Abstract Control of carbon macro-segregation in the steel-making process for large steel forgings is of great importance in order to achieve the material properties and structural reliability required for the pressure vessels of nuclear power plant components. It is well known that high carbon content due to carbon macro-segregation can affect the mechanical properties of steels, leading to decreases in ductility and fracture toughness. In this study, possible effects of carbon macro-segregation have been examined using a large-scale forged steel “bottom head dome” of a reactor pressure vessel (RPV) manufactured for a recent BWR. Material testing conducted included chemical analyses, tensile tests and Charpy impact tests. In the center part of the concave disk-shaped forged material, carbon content varied slightly in the material thickness direction within the range of carbon content requirement, as expected from the relationship between the solidification and the resultant segregation process in the cast ingot material and the forging process from the ingot to the dome material. The results of each mechanical test also showed full compliance with the properties required in the code regardless of the carbon content at each of the thickness locations examined. All the tests results demonstrated that with the steel-making technology and practice employed, carbon macro-segregation is well controlled to achieve the required material properties even in large-scale forged materials used in BWRs.

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