Practical Fracture Mechanics Applications to Design of High Pressure Vessels

Author(s):  
T. E. Davidson ◽  
J. F. Throop
Author(s):  
Yu Xu ◽  
Kuao-John Young

Small size longitudinal holes are common in components of high pressure vessels. In fracture mechanics evaluation, longitudinal holes have not drawn as much attention as cross-bores. However, longitudinal holes become critical at certain locations for such assessments because of high stress concentration and short distance to vessel component wall. The high stress concentration can be attributed to three parts: global hoop stress that is magnified by the existence of the hole, local stresses due to pressure in the hole, and crack face pressure. In high pressure vessel design, axisymmetric models are used extensively in stress analyses, and their results are subsequently employed to identify critical locations for fracture mechanics evaluation. However, axisymmetric models ignore longitudinal holes and therefore cannot be used to identify the critical location inside the holes. This paper is intended to highlight the importance of including longitudinal holes in fracture mechanics evaluation, and to present a quick and effective way of evaluating high stress concentration at a longitudinal hole using the combined analytical solutions and axisymmetric stress analysis results, identifying critical locations and conducting fracture mechanics evaluation.


Author(s):  
Shinji Konosu ◽  
Takayasu Tahara ◽  
Hideo Kobayashi

There are numerous instances in which in-service flaws due to various kinds of damage and deterioration are found in equipment as a result of in-service inspections. The proper evaluation of such flaws is extremely important. Fitness-for-Service (FFS) codes, such as ASME B&PV Code Sec. XI and JSME S NA1 for nuclear power generation facilities and BS 7910 and API-RP579 for general industrial facilities, are available. In light of such circumstances, the High Pressure Institute of Japan (HPI) has prescribed its code “Assessment procedure for crack-like flaws in pressure equipment” for conducting quantitative safety evaluations of flaws detected in common industrial pressure components such as pressure vessels, piping, storage tanks, and so on designed and fabricated in accordance with Japanese codes and regulations such as JIS B8265 and High Pressure Gas Safety Law. The FFS code consists of Level 1 assessment (whereby assessment can be conducted without extensive knowledge of fracture mechanics) and Level 2 assessment (which enables more detailed fracture mechanics analyses and is currently being studied). The allowable flaw size is specified in accordance with the plate thickness. The required impact absorbed energies based on material strength, whether or not PWHT has been done and the orientation of the flaw in relation to the weld seam, are also specified. An approximated equation of stress intensity factor for an embedded flaw near the surface has been derived. The re-characterization procedure for assessing an embedded flaw has been clarified. The flaw can be judged to be acceptable if its size is less than that of an allowable flaw and the equipment is to be used at temperatures exceeding the temperature (MAT) at which the material absorbed energy meets the required impact absorbed energy.


2021 ◽  
Author(s):  
Peng Ge ◽  
Zhiping Chen ◽  
Mengjie Liu

Abstract Hydrogen storage cylinders are often used for medium- and short-distance transportation of hydrogen. The presence of hydrogen tends to increase the risk of using the gas cylinders. The alternating stress caused by factors such as hydrogen charging and discharging during the service process of the gas cylinder leads to the expansion of initial cracks inside the cylinder and the final fatigue fracture. At present, the fatigue life calculation of pressure vessels mainly adopts the S-N curve method, however, some steels do not have the S-N curve under the hydrogen environment, it is necessary to use fracture mechanics methods to analyze the fatigue life of gas cylinders in a high-pressure gaseous hydrogen environment. In this work, a method for calculating the fatigue life of fracture mechanics for hydrogen storage cylinders was established according to ASME VIII-3 KD-10. The development of the program was completed by Matlab. An example was given to illustrate the program. Firstly, basic parameters of the material used for the cylinder were obtained. Then, finite element method was used for stress analysis to obtain the fitting curve and the function expression of hoop stress. Finally, fatigue life calculations of high pressure hydrogen storage cylinder were made. The minimum service life of example was predicted to be 40 years. This result is consistent with the good service history of this type of container. This work could contribute to design, safety evaluation of hydrogen storage cylinders.


2019 ◽  
Vol 827 ◽  
pp. 428-433
Author(s):  
Ivo Černý ◽  
Jan Kec

Laser welding is an innovative technology of joining metallic materials. In comparison with conventional arc welding, it has numerous advantages, like high energy of laser beam and high effectiveness, very good reproducibility, possibilities of automation, low energy consumption etc. High pressure vessels and high pressure pipeline industry represent perspective new fields of application. However, since pressure vessels and pipelines are usually operated at conditions of repeated or cyclic loading, an acceptable resistance to fatigue loading of the welds has to be demonstrated. In this contribution, results of an experimental programme aimed at an evaluation of high-cycle fatigue resistance in and near laser welds of a P355 pressure vessel steel are presented and discussed. Particular attention is paid to evaluation of crack initiation mechanisms in connection to laser weld character and welding imperfections. The programme is completed by measurement of fatigue crack growth rates and threshold values in the weld. Results of high-cycle fatigue tests of some groups of specimens were characteristic by a considerable scatter. The reason of the scatter was found in welding defects in some parts of the welds. Fatigue results are discussed also from the viewpoint of fracture mechanics and threshold values of fatigue crack growth.


1987 ◽  
Vol 19 (6) ◽  
pp. 773-779
Author(s):  
A. A. Blyumin ◽  
Yu. I. Zvezdin ◽  
V. A. Ignatov ◽  
B. T. Timofeev ◽  
V. M. Filatov

2014 ◽  
Vol 10 ◽  
pp. 27-31
Author(s):  
R.Kh. Bolotnova ◽  
U.O. Agisheva ◽  
V.A. Buzina

The two-phase model of vapor-gas-liquid medium in axisymmetric two-dimensional formulation, taking into account vaporization is constructed. The nonstationary processes of boiling vapor-water mixture outflow from high-pressure vessels as a result of depressurization are studied. The problems of shock waves action on filled by gas-liquid mixture volumes are solved.


2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Norman L. Newhouse ◽  
George B. Rawls ◽  
Mahendra D. Rana ◽  
Bernard F. Shelley ◽  
Michael R. Gorman

The purpose of this paper is to document the development of ASME Section X Code rules for high pressure vessels for containing hydrogen and to provide a technical basis of their content. The Boiler and Pressure Vessel Project Team on Hydrogen Tanks was formed in 2004 to develop Code rules to address the various needs that had been identified for the design and construction of up to 15,000 psi hydrogen storage vessel. One of these needs was the development of Code rules for high pressure composite vessels with nonload sharing liners for stationary applications. In 2009, ASME approved new Appendix 8, for Section X Code which contains the rules for these vessels. These vessels are designated as Class III vessels with design pressure ranging from 21 MPa (3000 psi) to 105 MPa (15,000 psi) and maximum allowable outside liner diameter of 2.54 m (100 in.). The maximum design life of these vessels is limited to 20 years. Design, fabrication, and examination requirements have been specified, including Acoustic Emission testing at the time of manufacture. The Code rules include the design qualification testing of prototype vessels. Qualification includes proof, expansion, burst, cyclic fatigue, creep, flaw, permeability, torque, penetration, and environmental testing.


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