scholarly journals Methods for Structural Stress Determination according to EN 13445-3 Annex NA – Comparison with other Codes for Unfired Pressure Vessels

2018 ◽  
Vol 165 ◽  
pp. 10003
Author(s):  
Ralf Trieglaff ◽  
Jürgen Rudolph ◽  
Martin Beckert ◽  
Daniel Friers
Keyword(s):  
Pressure Vessel ◽  
Pressure Vessels ◽  
Structural Stress ◽  
Stress Determination ◽  
User Friendliness ◽  
Fatigue Assessment ◽  
Shell Elements ◽  
European Working ◽  
The Status

The European Pressure Vessel Standard EN 13445 provides in its part 3 (Design) a simplified method (Clause 17) and a detailed method for fatigue assessment (Clause 18). Clause 18 “Detailed Assessment of Fatigue Life” is under revision within the framework of the European working group CEN/TC 54/WG 53 – Design methods with the aim of reaching a significant increase in user-friendliness and a clear guideline for the application. This paper is focused on the new informative annex NA ”Instructions for structural stress oriented finite elements analyses using brick and shell elements”. As an essential amendment for the practical user, the determination of structural stress ranges for fatigue assessment of welds is further specified in this new annex. Different application methods for the determination of structural stresses are explained in connection with the requirements for finite element models and analyses. This paper will give a short overview of the proposed approaches of structural stress determination in annex NA of the revised EN 13445-3. It will present the status of the approaches based on the results of fatigue analyses according to EN 13445-3 Clause 18 for different application examples. For verification purposes, the results of the approaches proposed in EN 13445-3 are compared with the results of other pressure vessel design codes for nuclear and non-nuclear application.

Comparison of Methods for Structural Stress Determination According to EN 13445-3 Annex NA

2017 ◽  
Author(s):  
Ralf Trieglaff ◽  
Martin Beckert ◽  
Jürgen Rudolph ◽  
Fabian Hauser
Keyword(s):  
Pressure Vessel ◽  
Working Group ◽  
Structural Stress ◽  
Stress Determination ◽  
User Friendliness ◽  
Fatigue Assessment ◽  
Shell Elements ◽  
European Working ◽  
Detailed Assessment

The European Pressure Vessel Standard EN 13445 provides in its part 3 (Design) a simplified method (Clause 17) and a detailed method for fatigue assessment (Clause 18). Clause 18 “Detailed Assessment of Fatigue Life” is under revision within the framework of the European working group CEN/TC 54/WG 53 - Design methods to reach a significant increase in user-friendliness and a clear guideline for the application. This paper is focused on the new informative annex NA “Instructions for structural stress oriented finite elements analyses using brick and shell elements”. As an essential amendment for the practical user the determination of structural stress ranges for fatigue assessment of welds is further specified in this new annex. Different application methods for the determination of structural stresses are explained in connection with the requirements for finite element models and analyses. This paper will give an overview of the proposed approaches of structural stress determination in annex NA of the revised EN 13445-3. It will present the results of fatigue analyses according to EN 13445-3 Clause 18 from a round robin test with participants of the German working group for different application examples. The estimated structural stress ranges for the proposed approaches of structural stress determination will be compared. This comparison leads to general remarks and open points for the different approaches. Furthermore it is concludes that further comparisons, e.g. with results of other pressure vessel design codes are desirable.

Thermal Fatigue Evaluation Based on the Methods for Structural Stress Determination According to EN 13445-3 Annex NA: Comparison With Other Codes

2018 ◽  
Author(s):  
Ralf Trieglaff ◽  
Martin Beckert ◽  
Jürgen Rudolph ◽  
Daniel Friers
Keyword(s):  
Finite Element ◽  
Thermal Fatigue ◽  
Pressure Vessel ◽  
Structural Stress ◽  
Stress Determination ◽  
User Friendliness ◽  
Shell Elements ◽  
European Working ◽  
Detailed Assessment ◽  
Fatigue Evaluation

The European Pressure Vessel Standard EN 13445 provides in its part 3 (Design) a simplified method (Clause 17) and a detailed method for fatigue assessment (Clause 18) of unwelded and welded components. Clause 18 “Detailed Assessment of Fatigue Life” is under principal revision within the framework of the European working group “CEN/TC 54/WG 53 – Design methods” in order to reach a significant increase in user-friendliness and a clear guideline for the application. This paper is focused on the new recommendations for the thermal fatigue evaluation given in the new informative annex NA “Instructions for structural stress oriented finite element analyses using brick and shell elements”. In this annex NA different application methods for the determination of structural stresses are explained in connection with the requirements for finite element models and analyses. This paper will give a short overview of the proposed approaches of structural stress determination in the new draft annex NA of the revised EN 13445-3 with special recommendations for thermal fatigue evaluation application. This constitutes an extension of the usual and established application of the structural stress approach for welds subjected to mechanical loading conditions. It will present the current state of the approaches based on the results of fatigue analyses according to EN 13445-3 Clause 18 for two different application examples. For validation purposes, these different approaches are compared with the results of Clause 17 of the EN 13445 and other pressure vessel design codes.

Recent Amendments of EN13445-3, Clause 18 and Related Annexes: Detailed Assessment of Fatigue Life

2014 ◽  
Author(s):  
Jürgen Rudolph ◽  
Guy Baylac ◽  
Paul Wilhelm ◽  
John Wintle ◽  
Emilie Buennagel
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Hot Spot ◽  
Structural Stress ◽  
User Friendliness ◽  
Design Data ◽  
Fatigue Assessment ◽  
European Working ◽  
Detailed Assessment

The European Pressure Vessel Standard EN 13445 provides in its part 3 (Design) a simplified method for fatigue assessment (Clause 17) and a detailed method of fatigue assessment (Clause 18). Clause 18 “Detailed Assessment of Fatigue Life” is under revision within the framework of the European working group CEN/TC 54/WG 53 - Design methods. The latest amendments of Clause 18 are to be presented. All these amendments aim at a significant increase in user friendliness and clear guidelines for application. The following items are to be mentioned in particular in that context: • Fatigue assessment of welded components based on structural stress and structural hot-spot stress approaches • Detailed guidelines for determining relevant stresses and stress ranges • Cycle counting proposals. The fatigue assessment of welded components is part of paragraphs 18.6 “Stresses for fatigue assessment of welded components and regions” (determination of relevant stress ranges) and 18.10 “Fatigue strength of welded components” (relevant weld details and revised fatigue curves). The basic rules for unwelded components essentially remain unchanged. Stress analyses for clause 18 are usually based on detailed finite element analyses (FEA). As an essential amendment for the practical user the determination of structural stress ranges for the fatigue assessment of welds is further detailed in the new informative annex NA “Instructions for structural stress oriented finite elements analyses using brick and shell elements”. Here, different applicable methods for the determination of structural stresses are explained in connection with the requirements of the finite element models and analyses. The cycle counting issue is comprehensively treated in the new informative annexes NB “Cycle Counting for a given Load History” and NC “Cycle Counting for Design Data Evaluation” including detailed proposals for implementation in an algorithmic programming framework.

Outline of the Recent Consolidated Revision of EN13445-3, Clause 18 and Related Annexes: Detailed Assessment of Fatigue Life

2019 ◽  
Author(s):  
Jürgen Rudolph ◽  
Guy Baylac ◽  
Ralf Trieglaff ◽  
Rüdiger Gawlick ◽  
Michael Krämer ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Assessment Method ◽  
Structural Stress ◽  
Critical Plane ◽  
Fatigue Assessment ◽  
European Working ◽  
Critical Plane Approach ◽  
Detailed Assessment

Abstract The European Pressure Vessel Standard EN 13445 (harmonized Standard acc. to PED 2014/68/EU) provides in its Part 3 (Design) a simplified method for fatigue assessment (Clause 17) and a detailed method of fatigue assessment (Clause 18). While the new revision of Clause 17 has already been adopted, Clause 18 “Detailed Assessment of Fatigue Life” is now available as a consolidated revision in inquiry phase. This major and comprehensive revision has been developed within the framework of the European working group CEN/TC 54/WG 53 – Design methods and constitutes a crucial step towards a modern and user-friendly engineering fatigue assessment method. The overall structure and amendments of Clause 18 are to be presented. All these amendments aim at a significant increase in user friendliness and clear guidelines for application. The following items are to be mentioned in that context: • Fatigue assessment of welded components based on structural stress and structural hot-spot stress approaches, • Detailed guidelines for determining relevant stresses and stress ranges, • Cycle counting proposals in the context of the fatigue assessment method including a critical plane approach. The fatigue assessment of welded components is separated from the fatigue assessment of un-welded parts as it has already been done in previous versions with respective methodological differences. Stress analyses for clause 18 are usually based on detailed finite element analyses (FEA). As an essential amendment for the user, the determination of structural stress ranges for the fatigue assessment of welds is further detailed in a new appropriate annex. Different applicable methods for the determination of structural stresses are explained in connection with the requirements of the finite element models and analyses. The cycle counting issue is comprehensively treated in the context of different design and operation situations (design transients, operational stress-time-histories). The description is detailed towards a critical plane approach. Detailed proposals for implementation in an algorithmic programming framework are given making the described methods ready to use.

Fatigue Assessment of a Weld Joint of a Pressure Vessel

2005 ◽  
Author(s):  
Arturs Kalnins ◽  
Vic Bergsten ◽  
Mahendra Rana
Keyword(s):  
Fatigue Strength ◽  
Internal Pressure ◽  
Weld Joint ◽  
Pressure Vessel ◽  
Structural Stress ◽  
Constant Amplitude ◽  
Fatigue Assessment ◽  
Full Penetration ◽  
Notch Stress ◽  
Number Of Cycles

A full-penetration weld on both sides between a shell and a flat head is evaluated for fatigue strength by four methods, two based on structural stress and two on notch stress. Internal pressure is cycled with constant amplitude. The allowable cycles are calculated by each method. The number of cycles for the same geometry and loading varies widely, ranging from 4,835 to 137,000.

scholarly journals Determination of the Crack Resistance Parameters at Equipment Nozzle Zones Under the Seismic Loads Via Finite Element Method

2018 ◽  
Vol 48 (1) ◽  
pp. 69-75
Author(s):  
Vladyslav Kyrychok ◽  
Vasyl Torop
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Pressure Vessel ◽  
Residual Life ◽  
Pressure Vessels ◽  
Accurate Estimation ◽  
Seismic Loads ◽  
Finite Element Program ◽  
Element Program

Abstract The present paper is devoted to the problem of the assessment of probable crack growth at pressure vessel nozzles zone under the cyclic seismic loads. The approaches to creating distributed pipeline systems, connected to equipment are being proposed. The possibility of using in common different finite element program packages for accurate estimation of the strength of bonded pipelines and pressure vessels systems is shown and justified. The authors propose checking the danger of defects in nozzle domain, evaluate the residual life of the system, basing on the developed approach.

Strength of Thick-Walled Pressure Vessels for Materials With Directional Properties

1962 ◽  
Vol 84 (2) ◽  
pp. 197-202
Author(s):  
A. E. Dapprich ◽  
Joseph Marin ◽  
Tu-Lung Weng
Keyword(s):  
Tensile Stress ◽  
Pressure Vessel ◽  
Anisotropic Material ◽  
Pressure Vessels ◽  
Maximum Pressure ◽  
Closed Solution ◽  
Strain Relation ◽  
Stress Strain Relation ◽  
Cylindrical Pressure Vessel

This paper develops a theory for the determination of the plastic pressure-deformation relation in a thick-walled cylindrical pressure vessel subjected to internal pressure and made of an anisotropic material. In this theory, large or finite strains are considered and a closed solution is found for the pressure-strain relation based on a modified log-log tensile stress-strain relation. Theory is also developed for predicting the maximum pressure which the vessel can withstand.

Elastoplastic stress and strain predictions for axisymmetric pressure vessel bodies under transient thermal loads

1996 ◽  
Vol 31 (2) ◽  
pp. 81-89 ◽  
Author(s):  
N Adinarayana ◽  
R S Alwar
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Steam Turbine ◽  
Pressure Vessel ◽  
Thermal Loading ◽  
Pressure Vessels ◽  
Approximate Methods ◽  
Valve Body ◽  
Transient Thermal

Evaluation of localized peak strains at stress concentration zones under transient thermal loading is essential for the determination of low cycle fatigue life of a number of pressure vessels like steam turbine components and reactor vessels. Finite element analysis is a powerful technique but there are some difficulties in using the method for inelastic analysis of large-sized components. Several investigators have proposed approximate methods to determine inelastic strains at notches and other stress concentration zones from elastically calculated stress distributions. The accuracy of three of these methods, namely the Neuber rule, the Molski-Glinka rule and GLOSS analysis under thermal loading for axisymmetric pressure vessel bodies was investigated. A parametric study with geometry and material parameters as variables was carried out for three sizes of spheres with nozzles for the determination of peak strains and stresses under transient thermal loading using thermoelastoplastic finite element analyses and also by approximate methods. The same analyses have also been carried out for a steam turbine valve body for the same thermal loading, which is normally encountered by the valve body under start-up conditions. It has been found that GLOSS analysis is more accurate and the use of approximate methods has been recommended, especially for preliminary analyses in the development of new components.

The Validity of Rector�s Circular Letter on the Covid-19 Pandemic

2020 ◽  
Vol 7 (1) ◽  
pp. 126 ◽  
Author(s):  
Fradhana Putra Disantara
Keyword(s):  
Legal Theory ◽  
Legal Issues ◽  
State Universities ◽  
Ministry Of Education ◽  
Conceptual Approach ◽  
State Of Emergency ◽  
Circular Letter ◽  
The Status ◽  
The Government

This study aims to analyze the relevance of the �health emergency� status to the existing legal theory and condition as well as to identify the validity of the Circular Letter of the Rector of State Universities. To this end, this study applied the statute and conceptual approach. The study was conducted by inventorying primary and secondary legal materials to obtain a proper and critical review of the legal issues under study. The results showed that the determination of the �health emergency� status by the government was inappropriate due to the uncertainty of the regulations issued by the government to determine the current condition. Thus, the status of the COVID-19 pandemic is a �legal emergency� status. Further, the Rector�s policy through the Circular Letter is valid judicially, sociologically, and philosophically. The determination of the �legal emergency� status can be done by issuing a Perppu without a �state of emergency� from the President. Finally, it is suggested to firstly get an approval from the Ministry of Education and Culture regarding the issuance of the Rector�s Circular Letter. Besides, further study is needed as this study was conducted during the COVID-19 pandemic.�Keabsahan Surat Edaran Rektor Perguruan Tinggi dalam Pandemi Covid-19Tujuan dari penelitian ini adalah untuk menganalisa relevansi status �darurat kesehatan� dengan teori hukum dan kondisi yang ada dan keabsahan atas Surat Edaran Rektor Perguruan Tinggi Negeri. Metode yang digunakan dalam penelitian ini adalah statute approach dan conseptual approach. Penelitian dilakukan dengan menginventarisasi bahan hukum primer dan sekunder, guna mendapatkan kajian yang seyogianya dan telaah kritis terkait isu hukum. Hasil penelitian menyatakan penetapan status darurat kesehatan oleh pemerintah kurang tepat, dikarenakan tidak menentu-nya peraturan yang dikeluarkan oleh pemerintah untuk menetapkan kondisi saat ini. Sehingga, status pandemi COVID-19 merupakan status darurat hukum. Kebijakan rektor melalui Surat Edaran adalah absah secara aspek yuridis, sosiologis, dan filosofis. Penetapan darurat hukum cukup dilakukan dengan menerbitkan Perppu tanpa pernyataan darurat dari Presiden. Saran peneliti adalah di perlukan persetujuan pada Kementerian Pendidikan dan Kebudayaan terkait terbitnya Surat Edaran Rektor, dan dibutuhkan penelitian lebih lanjut dikarenakan penelitian ini dilakukan pada masa COVID-19 yang bersifat temporal.�

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