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.

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.

Avoid Exchanger Replacement Using Advanced Analysis and Fit for Service Approach

2021 ◽  
Author(s):  
Ibrahim M. Al Awadhi ◽  
Ashok M. Sharma ◽  
Sohail Akhter
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Service Life ◽  
Heat Exchangers ◽  
Structural Integrity ◽  
Design Code ◽  
Element Analysis ◽  
Fit For Purpose ◽  
Design Pressure

Abstract Objective/Scope (25 - 75 word) Shell & Tube Heat exchangers are critical for incessant operation of processing plant. These exchangers may face integrity threats due to reduction in shell thicknesses at Nozzle to Shell Junction below design code requirements. This paper presents the Cost Effective fit for purpose approach utilizing advance Finite Element analysis to explore and recommend the solutions for existing numerous exchangers that are to be safely used even after reported low thickness on account of manufacturing imperfection. Methods, Procedures, Process (75 - 100 word) Reduction in Shell thickness below design value can affect its ability to sustain design pressure & vacuum including nozzle integrity for associated piping loads and service life reduction for exclusion of corrosion allowance. As short-term Mitigation methodology, weld overlay was adopted to restore the areas with lower thickness. For long term solution, fit for purpose review approach was adopted for continued usage of exchangers which involves nozzle load analysis using WRC & FEA based on PAUT thickness data and utilizing actual piping loads, derating of design pressure, comparison of thickness data to establish corrosion rate and service life of exchanger. Results, Observations & Conclusions (100 - 200 words) Thorough Integrity review based on design Code (ASME BPVC Section VIII) and WRC analysis have confirmed that majority of the exchangers have thickness higher than that required to sustain design pressure, vacuum conditions when considered with piping loads acting on nozzles. Thickness data comparison between three (03) year old manual UT and latest Phase array UT confirmed that majority of the exchangers are in clean non-corrosive service thus allowance for corrosion is not required. Where in the nature of exchanger service require corrosion allowance, it is considered in analysis and usage of stiffeners at nozzle to shell intersection and/or on full circumference of shell is recommended to prevent overstress due to piping loads / buckling distortion due to vacuum conditions respectively, based on detailed Finite element analysis (FEA). In order to establish more reliable long-term corrosion rate, next inspection after four (04) years is recommended and impact on integrity can be further evaluated based on the latest data. Change in exchanger nameplate is recommended to consider for design pressure as MAWP and accordingly adjust hydro test pressure followed by R-stamp requirements for rerating and repair. Shell side hydro test is restricted until recommendations are implemented Novel/Additive Information (25 - 75 words) Although conventional approach of replacing complete Shells to meet code requirement would have ensured process safety, performance and structural integrity. However, alternative fit for purpose approach utilizing advanced FEA has not only ensured all these but also led to potential cost saving of multimillion US$. Associated risks of thickness reduction due to corrosion may still be observed, however analysis confirmed structural integrity and safety of heat exchangers with low thicknesses. Accordingly, potential risk is mitigated.

Failure Prediction of Pressure Vessels Using Finite Element Analysis

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Christopher J. Evans ◽  
Timothy F. Miller
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Vessel ◽  
Mechanical Strain ◽  
Pressure Vessels ◽  
Element Analysis ◽  
Failure Pressure ◽  
Location Data ◽  
Failure Point ◽  
Failure Location

This paper investigates using nonlinear finite element analysis (FEA) to determine the failure pressure and failure location for pressure vessels. The method investigated by this paper is to predict the pressure-vessel failure point by identifying the pressure and location where the total mechanical strain exceeds the actual elongation limit of the material. A symmetrically shaped component and a nonsymmetric shaped component are analyzed to determine the failure pressure and location. Data were then gathered by testing each pressure vessel to determine its actual failure pressure. Comparing the FEA results with experimental data showed that the fea software predicted the failure pressure and location very well for the symmetric shaped pressure vessel, however, for the nonsymmetrical shaped pressure-vessel, the fea software predicted the failure pressure within a reasonable range, but the component failed at a weld instead of the predicted location. This difference in failure location was likely caused by varying material properties in both the weld and the location where the vessel was predicted to fail.

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.

Comparison of Different Methodologies for Stress Analysis of Reinforcing Pads

2003 ◽  
Author(s):  
Michael W. Guillot ◽  
Jack E. Helms
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Vessel ◽  
Software Package ◽  
Research Council ◽  
Pressure Vessels ◽  
Element Analysis ◽  
Division 1 ◽  
Section Viii ◽  
Design Requirements

Finite element analysis is widely used to model the stresses resulting from penetrations in pressure vessels to accommodate components such as nozzles and man-ways. In many cases a reinforcing pad is required around the nozzle or other component to meet the design requirements of Section VIII, Division 1 or 2, of the ASME Pressure Vessel Code [1]. Several different finite element techniques are currently used for calculating the effects of reinforcing pads on the shell stresses resulting from penetrations for nozzles or man-ways. In this research the stresses near a typical reinforced nozzle on a pressure vessel shell are studied. Finite element analysis is used to model the stresses in the reinforcing pad and shell. The commercially available software package ANSYS is used for the modeling. Loadings on the nozzle are due to combinations of internal pressure and moments to simulate piping attachments. The finite element results are compared to an analysis per Welding Research Council Bulletin 107 [2].

Fixtures Design for Controlling Distortion of Pressure Vessel During Fabrication

2003 ◽  
Author(s):  
Hee-Tae Lee ◽  
Sang-Beom Shin ◽  
Sung-Hoon Ko
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Vessel ◽  
Integrated Design ◽  
Pressure Vessels ◽  
Design System ◽  
Element Analysis ◽  
Feature Based ◽  
User Friendly ◽  
Component Feature

The purpose of this study is to develop the integrated design system of supports, which are turning roller, dent pad and bracing pipe to control distortion of the pressure vessel. The optimum design condition for each support was established by analytical solution and finite element analysis with simple model and verified by comparing with the results of FEA for actual model. Based on the results, the Window-based computer program was developed using Visual C++. The program supports component feature-based modeling. In addition, user can easily determine the condition of supports and jigs during manufacturing of pressure vessels with user-friendly functions such as the material database of ASME, easy input, and detail output.

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.

An Approach to Derive Primary Bending Stress From Finite Element Analysis for Pressure Vessels and Applications in Structural Design

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
Bingjun Gao ◽  
Xiaohui Chen ◽  
Xiaoping Shi ◽  
Junhua Dong
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Vessel ◽  
Engineering Application ◽  
Pressure Vessels ◽  
Bending Stress ◽  
Element Analysis ◽  
Lack Of Information ◽  
Relationship Of ◽  
The Relationship

An important issue in engineering application of the “design by analysis” approach in pressure vessel design is how to decompose an overall stress field obtained by finite element analysis into different stress categories defined in the ASME B&PV Codes III and VIII-2. In many pressure vessel structures, it is difficult to obtain PL+Pb due to the lack of information about primary bending stress. In this paper, a simple approach to derive the primary bending stress from the finite element analysis was proposed with application examples and verifications. According to the relationship of the bending stress and applied loads or the relationship of the bending stress and displacement agreement, it is possible to identify loads causing primary bending stress for typical pressure vessel structures. By applying the load inducing primary bending stress alone and necessary superposition, the primary bending stress and corresponding stress intensity PL+Pb can be determined for vessel design, especially for axisymmetric problems.

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.

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