Fatigue Design Rules in Pressure Vessel Codes Uncertainties and Remaining Open Points

2014 ◽  
Author(s):  
Claude Faidy
Keyword(s):  
Strain Amplitude ◽  
Pressure Vessel ◽  
Material Properties ◽  
Cyclic Strain ◽  
Fatigue Curve ◽  
Fatigue Analysis ◽  
Pressure Vessels ◽  
Life Assessment ◽  
Combination Rules ◽  
Reduction Factors

During the past 30 years the main rules for fatigue analysis of pressure vessels were based on elastic approaches in order to evaluate a cyclic strain amplitude and compare with an S-N fatigue curve for the corresponding material. After review of some rules in different Nuclear and Non Nuclear Codes, like ASME Boiler & Pressure Vessel Code Section III, French RCC-M and RCC-MRx, European Standards EN 13445, the major conservatisms and uncertainties of different rules are discussed. All these Codes propose simple rules to evaluate the strain amplitude based on elastic approaches and simplified correction factors (Ke and Kv), transient combination rules and damage cumulating procedure. In the other hand, the material properties are based on standard fatigue tests done on the material associated to reduction factors to consider some particular effects like scatter, scale, surface roughness, mean stress or environmental effects to transfer them from small specimen to real structures. Concerned components are mainly piping systems. No existing Code covers all the aspects of fatigue with similar conservatisms that can affect the in-service inspection programs and the remaining life assessment of the corresponding components. After the review of different rules, key factors that affect the results and predictions will be identified. Some proposals will be issued to progress in the near future. Finally, a first set of recommendation on fatigue analysis will be presented to improve existing codes on an harmonized way, associated to material properties needed, as fatigue curves associated to reduction factors.

Uncertainties and Margins in Environmental Fatigue Analysis Rules

2014 ◽  
Author(s):  
C. Faidy
Keyword(s):  
Strain Amplitude ◽  
Material Properties ◽  
Cyclic Strain ◽  
Fatigue Curve ◽  
Fatigue Analysis ◽  
Fatigue Tests ◽  
Pressure Vessels ◽  
Life Assessment ◽  
Combination Rules ◽  
Reduction Factors

During the past 30 years the main rules for fatigue analysis of pressure vessels were based on elastic approaches in order to evaluate cyclic strain amplitude and compare with an S-N fatigue curve for the corresponding material. After review of some rules in different Nuclear and Non-Nuclear Codes, like ASME Boiler & Pressure Vessel Code Section III, French RCC-M and RCC-MRx, European Standards EN 13445, the major conservatisms and uncertainties of different rules are discussed. All these Codes propose simple rules to evaluate the strain amplitude based on elastic approaches and simplified correction factors (Ke and Kν), transient combination rules and damage cumulating procedure. In the other hand, the material properties are based on standard fatigue tests done on the material associated to reduction factors to consider some particular effects like scatter, scale, surface roughness, mean stress or environmental effects to transfer them from small specimen to real structures. Concerned components in this paper are mainly piping systems. No existing Code covers all the aspects of fatigue with similar conservatisms that can affect the in-service inspection programs and the remaining life assessment of the corresponding components. After the review of different rules, key factors that affect the results and predictions will be identified. Some proposals will be issued to progress in the near future. Finally, a first set of recommendation on fatigue analysis will be presented to improve existing codes on harmonized way, associated to material properties needed, as fatigue curves associated to reduction factors.

The Fatigue Analysis of Pressure Vessels Based on Workbench

2012 ◽  
Vol 550-553 ◽  
pp. 3082-3087
Author(s):  
Xing Ye Su ◽  
Qin Li ◽  
Hong Mei Wang
Keyword(s):  
Fatigue Failure ◽  
Chemical Industry ◽  
Pressure Vessel ◽  
Petrochemical Industry ◽  
Rapid Development ◽  
Fatigue Analysis ◽  
Pressure Vessels ◽  
Operation Condition ◽  
Key Steps

With the rapid development of petrochemical industry, the operation condition of pressure vessels under the alternating load was increasing and the probability of fatigue failure was also on the rise. As a result, pressure vessel fatigue analysis is gaining the designer's attention. This paper describes the key steps and techniques of the fatigue analysis of pressure vessel based on Workbench platform using the lock hopper of the coal chemical industry as an example.

Design of Pressure Vessels for Low-Cycle Fatigue

1962 ◽  
Vol 84 (3) ◽  
pp. 389-399 ◽  
Author(s):  
B. F. Langer
Keyword(s):  
Fatigue Strength ◽  
Pressure Vessel ◽  
Low Cycle Fatigue ◽  
Fatigue Curve ◽  
Pressure Vessels ◽  
Reduction Factor ◽  
Strength Reduction ◽  
Strength Reduction Factor ◽  
The Mean ◽  
Fatigue Evaluation

Methods are described for constructing a fatigue curve based on strain-fatigue data for use in pressure vessel design. When this curve is used, the same fatigue strength-reduction factor should be used for low-cycle as for high-cycle conditions. When evaluating the effects of combined mean and alternating stress, the fatigue strength-reduction factor should be applied to both the mean and the alternating component, but then account must be taken of the reduction in mean stress which can be produced by yielding. The complete fatigue evaluation of a pressure vessel can be a major task for the designer, but it can be omitted, or at least drastically reduced, if certain requirements can be met regarding design details, inspection, and magnitude of transients. Although the emphasis in this paper is on pressure vessel design, the same principles could be applied to any structure made of ductile metal and subjected to limited numbers of load cycles.

Remaining Life Assessment of an External Pressure Vessel in Creep Range and Inspection Findings

2017 ◽  
Author(s):  
Yoichi Ishizaki ◽  
Futoshi Yonekawa ◽  
Takeaki Yumoto ◽  
Teppei Suzuki ◽  
Shuji Hijikawa
Keyword(s):  
Pressure Vessel ◽  
Creep Damage ◽  
External Pressure ◽  
Pressure Vessels ◽  
Life Assessment ◽  
Remaining Life ◽  
Assessment Technique ◽  
Creep Cavity ◽  
Creep Analysis ◽  
Remaining Life Assessment

As widely recognized in the industry, it is important to evaluate the creep damage of an elevated temperature vessel so that the mechanical integrity of the vessel can be achieved through the adequate repair and replacement planning. This is quite straight forward procedure for internal pressure vessels. For an external pressure vessel, it is not easy to assess the creep damage due to the complexity of the creep buckling analysis. Eventually, creep cavity evaluation technique without identifying the correct stress distribution has been used so often. However, due to the uncertainty of the technique itself plus conservative mindset of the inspectors, it tends to leads to an excessive maintenance most of the cases. In order to conduct a reasonable remaining life assessment, it is desirable to use the creep cavity inspection in conjunction with another assessment technique such as FEM creep analysis as stated in API 579-1/ASME FFS-1 10.5.7. In this paper, comprehensive approach with FEM and field inspection such as creep cavity evaluation to reinforce the uncertainty of each method will be demonstrated.

A Comparison of Different Design Codes on Fatigue Life Assessment Methods

2016 ◽  
Author(s):  
Jinhua Shi ◽  
Liwu Wei ◽  
Claude Faidy ◽  
Andrew Wasylyk ◽  
Nawal Prinja
Keyword(s):  
Pressure Vessel ◽  
Task Force ◽  
Fatigue Analysis ◽  
Life Assessment ◽  
Design Codes ◽  
Fatigue Life Assessment ◽  
Analysis Methods ◽  
Section Viii ◽  
Division 2 ◽  
Nuclear Association

Different pressure vessel and piping design codes and standards have adopted different fatigue analysis methods. In order to make some contribution to current efforts to harmonize international design codes and standards, a review of fatigue analysis methods for a number of selected nuclear and non-nuclear design codes and standards has been carried out. The selected design codes and standards are ASME Boiler and Pressure Vessel Code Section III Subsection NB and Section VIII Division 2, EN 12952, EN 13445, EN 13480, PD 5500, RCC-M, RCC-MRx, JSME, PNAEG and R5. This paper presents the initial review results. The results of the study could be used as part of the on-going work of the Codes and Standards Task Force of the World Nuclear Association (WNA) Cooperation in Reactor Design Evaluation and Licensing (CORDEL) Working Group.

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.

Material Requirements for Long-Life Pressure Vessels

1964 ◽  
Vol 86 (4) ◽  
pp. 403-409 ◽  
Author(s):  
B. F. Langer ◽  
W. L. Harding
Keyword(s):  
Plastic Deformation ◽  
Brittle Fracture ◽  
Creep Deformation ◽  
Pressure Vessel ◽  
Material Properties ◽  
Failure Modes ◽  
Pressure Vessels ◽  
Additional Information ◽  
Modes Of Failure ◽  
Long Life

In this paper the authors consider the various possible modes of failure of a pressure vessel intended for long service and show which material properties are of significance in preventing them. The failure modes discussed are (a) plastic deformation and bursting; (b) brittle fracture; (c) fatigue failure; (d) creep deformation and creep rupture; (e) corrosion. The need for additional information in several areas is also noted.

Variable Material Properties Approach: A Review on Twenty Years of Progress

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Sasan Faghih ◽  
Hamid Jahed ◽  
Seyed Behzad Behravesh
Keyword(s):  
Pressure Vessel ◽  
Material Properties ◽  
Numerical Solutions ◽  
Pressure Vessels ◽  
Large Strains ◽  
The Past ◽  
Axisymmetric Problems ◽  
Distribution Of Stress ◽  
Deformation Modes ◽  
Made In

This paper provides a critical review of the advancements made in the application of the variable material properties (VMP) method over the past two decades. The VMP method was originally proposed in 1997 (Jahed and Dubey, 1997, ASME J. Pressure Vessel Technol., 119(3), pp. 264–273; Jahed et al., 1997, Int. J. Pressure Vessels Piping, 71(3), pp. 285–291) and further developed in 2001 (Parker, 2001, ASME J. Pressure Vessel Technol., 123(3), p. 271) as an elastoplastic method for the analysis of axisymmetric problems. The model was originally developed as a boundary value problem to predict the spatial distribution of stress. However, since 1997, it has been extended to include thermal effects to solve thermomechanical residual stresses; time domain to solve creep of disks and cylinders; finite deformation to solve cylinders under large strains; numerical solutions to make them more efficient; and asymmetric hardening behavior to accommodate nonslip deformation modes. These advancements, made over the past 20 years, are reviewed in this paper, and future trends and frontiers are discussed.

Testing of Fracture Toughness Under Biaxial Loading

2005 ◽  
Author(s):  
Milan Brumovsky ◽  
Dana Lauerova ◽  
Jiri Palyza
Keyword(s):  
Fracture Toughness ◽  
Pressure Vessel ◽  
Biaxial Loading ◽  
Crack Depth ◽  
Pressure Vessels ◽  
Operating Conditions ◽  
Testing Equipment ◽  
Life Assessment ◽  
Biaxial Tests ◽  
Reactor Pressure

Reactor pressure vessels under some special regimes (i.e. pressurized thermal shock) are loaded by a strongly biaxial tensile stresses whose ratio can reach even an opposite value in comparison with normal operating conditions. Pressure vessel integrity as well as its life assessment is performed on the basis of fracture mechanics where normally only uniaxial fracture toughness of materials are used as material inputs. Special biaxial tests on cruciform type specimens with thickness up to 90 mm were tested in Nuclear Research Institute (NRI) Rez - special testing equipment and testing methods including measurements have been developed and realized. Testing equipment with maximum loading up to 1.5 MN allows to reach different biaxial loading ratios between 0 and 2. During tests, carried out mostly at low temperatures, specimens deflections, strains, load and crack opening displacement are measured and then evaluated. In NRI Rez comparative experimental tests on cruciform and beam specimens were performed. The aim of these tests was to examine the effect of crack depth and biaxial loading on fracture toughness for reactor pressure vessel material 15Kh2MFA. For evaluating the tests, the FEM (program SYSTUS) was used. The performed tests confirm shallow crack effect, i.e. increase of fracture toughness for shallow cracks compared to that one of deep cracks. Further, the performed experiments show decrease of fracture toughness of shallow cracks loaded biaxially compared to uniaxial loading of shallow cracks. Quantitatively, the fracture toughness decrease was about 20%.

Unifying Monotonic and Hysteresis Material Properties for Notch Plasticity Analysis under Variable Amplitude Loads

2014 ◽  
Vol 891-892 ◽  
pp. 500-505 ◽  
Author(s):  
Xiao Bo Yu ◽  
Qian Chu Liu ◽  
Chris Wallbrink
Keyword(s):  
Strain Amplitude ◽  
Material Properties ◽  
Present Finding ◽  
High Strain ◽  
Cyclic Strain ◽  
Recovery Process ◽  
Material Behaviour ◽  
Variable Amplitude ◽  
Dog Bone ◽  
Conceptual Consideration

This study was performed in support of accurate notch plasticity analysis under variable amplitude loads. Monotonic and cyclic strain-controlled tests were performed on flat dog-bone coupons machined from 6.35mm thick 7075-T651 aluminium alloy plates. The tests with low-high-low strain amplitude transitions revealed both an instant softening following the high strain amplitude cycle and a gradual recovery during the subsequent low strain amplitude cycles. The transition from monotonic-like to hysteresis-like material behaviour was found to be consistent with an overload induced softening and recovery process. A conceptual consideration is thus proposed to unify the characterisation of monotonic and hysteresis material properties. The implications of the present finding on notch plasticity analysis are also discussed.

Sign in / Sign up

Export Citation Format

Share Document