ANALYSIS OF RESIDUAL STRESS FOR NARROW GAP WELDING USING FINITE ELEMENT METHOD

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2797-2802 ◽  
Author(s):  
CHOON YEOL LEE ◽  
JAE KEUN HWANG ◽  
JOON WOO BAE
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Nuclear Power ◽  
Power Plants ◽  
Large Diameter ◽  
Narrow Gap ◽  
Narrow Gap Welding ◽  
Welding Processes ◽  
Element Method

Reactor coolant loop (RCL) pipes circulating the heat generated in a nuclear power plant consist of so large diameter pipes that the installation of these pipes is one of the major construction processes. Conventionally, a shield metal arc welding (SMAW) process has been mainly used in RCL piping installations, which sometimes caused severe deformations, dislocation of main equipments and various other complications due to excessive heat input in welding processes. Hence, automation of the work of welding is required and narrow-gap welding (NGW) process is being reviewed for new nuclear power plants as an alternative method of welding. In this study, transient heat transfer and thermo-elastic-plastic analyses have been performed for the residual stress distribution on the narrow gap weldment of RCL by finite element method under various conditions including surface heat flux and temperature dependent thermo-physical properties.

scholarly journals CONCEPTION OF REFERENCE BOOKS OF DEFECTS IS IN EQUIPMENT AND PIPELINES OF POWER AND TRANSPORT SYSTEMS

2020 ◽  
Vol 1 (46) ◽  
pp. 387-404
Author(s):  
Kharytonova L ◽  
◽  
Kutsenko O ◽  
Kadenko I ◽  
◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Power Systems ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Transport Systems ◽  
Object Of Study ◽  
Service Inspection ◽  
Element Method

The paper focuses on the one of the persperctive approaches to the increasing of thje safety of Nuclear Power Plants - Flaw Handbook Concept. Object of study - equipment and piping of Nuclear Power Plants. Purpose of study - the description of the Flaw Handbook Concept and the application of the concept for the specific example. Method of the study - numerical procedures of the finite-element method and fracture mechanics. In the modern economics the optimization of the performance and operation of industry and power systems is of the main importance. The Flaw Handbook Concept is considered in the paper. This concept is applied on the nuclear power plants in the leading states with the aim of the optimization of the procedures of in-service inspection and repair. The main steps of the concept are considered and applied for the specific example. An example of Flaw Handbook using is analysed. The results of the paper can be incorporated into the procedures of in-service inspection for the safety-significant equipment and piping. KEYWORDS: FLAW HANDBOOK, BRITTLE FRACTURE, FATIGUE, FINITE-ELEMENT METHOD, SURGE PIPE.

Experimental Investigation on Buckling of Steel Nuclear Containment With Elliptical Head

2016 ◽  
Author(s):  
Keming Li ◽  
Jinyang Zheng ◽  
Zekun Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Internal Pressure ◽  
Nuclear Power ◽  
Power Plants ◽  
Nonlinear Finite Element ◽  
Nonlinear Finite Element Method ◽  
Initial Shape ◽  
Nuclear Containment ◽  
Element Method

Thanks to relative ease of fabrication and erection, steel containments with a torispherical or elliptical head are common in large nuclear power plants with relatively high internal pressure. Buckling failure mode is critical in the design of a steel containment with elliptical head under internal pressure. An experiment on buckling of elliptical head under internal pressure is presented in this paper. A test vessel was designed to provide a substantial margin of safety which permitted testing the head to rupture. The head has a diameter of 4797 mm, radius-to-height ratio of 1.728 and nominal thickness of 5.5 mm. Initial shape and shell displacement measurements of the head were carried out by using 3D laser scanners. The details of the buckling behavior are given. Initial buckling pressure was predicted by nonlinear finite element method considering the measured initial shape of the head. The agreement between the initial experimental buckling pressure and that predicted by the nonlinear finite element method is good. It is very useful in the buckling evaluation and the development of design rules for steel nuclear containment with elliptical head.

scholarly journals Assessment of the Technical Condition of the Emergency Heat Exchanger for the Reactor Plant of the B-320 Type in Order to Extend Its Service Life

2021 ◽  
pp. 36-43
Author(s):  
Valeriy Konshin ◽  
Mikola Zaiats
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Heat Exchanger ◽  
Nuclear Power ◽  
Power Plants ◽  
Technical Condition ◽  
Operating Conditions ◽  
Preliminary Evaluation ◽  
The Finite Element Method ◽  
Element Method

Extending the life of nuclear power plants in Ukraine during in the super-project period, as in most countries operating nuclear power units, is an accepted strategy and is being implemented practically. In this regard, there is a need for verification calculation of the main elements The calculated analysis of the stress-strain state of the heat exchanger is carried out using the finite element method of power equipment that determine the resource characteristics. The technical condition of the emergency cooling heat exchanger  for the power unit no. 3 of the SUNPP has been evaluated. The analysis of design, technical and operational documentation in the amount of preliminary evaluation of technical condition was performed. Potential mechanisms of wear of heat exchanger elements were determined. The technique of carrying out verification calculations for static, cyclic and seismic stability was described. The emergency cooling heat exchanger calculation model is made in the APM Structure 3D calculation code. The tense-deformed state of the heat exchanger is calculated using the finite-element method of resampling the design region.  The results of the verification calculation of the emergency cooling heat exchanger in the calculated states corresponding to normal operating conditions, hydrotests and under seismic impacts in conditions of the maximum design earthquake were presented.  The correspondence of the actual stresses in the calculation zones of the heat exchanger to the permissible values, specified in the current regulatory documentation was established. The amount of damageability to the heat exchanger elements was determined for the permissible number of load cycles. The cyclical strength of the elements of the emergency cooling heat exchanger, taking into account the period of application equal to 60 years inclusive, is ensured in accordance with the requirements.

Numerical Simulation of Weld Metal by Ultra-Narrow Gap Arc Welding

2011 ◽  
Vol 704-705 ◽  
pp. 728-732
Author(s):  
Li Zhao ◽  
Ke Jie Dai ◽  
Fu Ju Zhang
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Thick Plate ◽  
Welding Residual Stress ◽  
Narrow Gap ◽  
Welding Temperature ◽  
Welding Joint ◽  
Element Method

The ultra narrow gap welding process is suitable to the thick plate, ultra-thick plate welding with the characteristic of highly effective, high quality, low cost, low energy consumption and so on, and is easy to realize the mechanization and the automation. In this paper, the numerical simulation and technical experiment are used to study the form, grow and distribution regulation of the welding temperature field, stress field in welding joint with UNG MAW. Using the calculation to the thickness of 32mm, an example to simulate the magnitude and distribution of the residual stress in welding joint is given. Research shows that it is an effective analysis method to heat process and mechanic behavior in the welding by using finite element method numerical simulation and few experiments. Keywords: UNG MAW, Welding residual stress, Finite element method, Numerical simulation

Numerical Analysis of Residual Stresses and Distortions in Aluminium Alloy Welded Joints

2015 ◽  
Vol 809-810 ◽  
pp. 443-448 ◽  
Author(s):  
Tomasz Kik ◽  
Marek Slovacek ◽  
Jaromir Moravec ◽  
Mojmir Vanek
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Aluminium Alloy ◽  
Thermal Cycle ◽  
Technology Development ◽  
Welding Process ◽  
Simulation Software ◽  
Structure Knowledge ◽  
Welding Processes ◽  
Element Method

Simulation software based on a finite element method have significantly changed the possibilities of determining welding strains and stresses at early stages of product design and welding technology development. But the numerical simulation of welding processes is one of the more complicated issues in analyses carried out using the Finite Element Method. A welding process thermal cycle directly affects the thermal and mechanical behaviour of a structure during the process. High temperature and subsequent cooling of welded elements generate undesirable strains and stresses in the structure. Knowledge about the material behaviour subjected to the welding thermal cycle is most important to understand process phenomena and proper steering of the process. The study presented involved the SYSWELD software-based analysis of MIG welded butt joints made of 1.0 mm thickness, 5xxx series aluminium alloy sheets. The analysis of strains and the distribution of stresses were carried out for several different cases of fixing and releasing of welded elements.

Sign in / Sign up

Export Citation Format

Share Document