scholarly journals Data support system for controlling decentralised nuclear power industry facilities through uninterruptible condition monitoring

2018 ◽  
Vol 161 ◽  
pp. 02012 ◽  
Author(s):  
Vladimir Povarov ◽  
Aleksandr Danilov ◽  
Viktor Burkovsky ◽  
Konstantin Gusev
Keyword(s):  
Nuclear Power ◽  
Three Dimensional ◽  
Mechanical Damage ◽  
Maximum Load ◽  
Operating Conditions ◽  
Strained Condition ◽  
Data Support ◽  
Dimensional Finite Element ◽  
System Data ◽  
Three Dimensional Finite Element

The article describes the automated uninterruptible multi-parameter system for monitoring operational vulnerability of critical NPP components, which differs from existing ones by being universally applicable for analysing mechanical damage of nuclear power unit components. The system allows for performing routine assessment of metal structures. The assessment of strained condition of a deteriorating component is based on three-dimensional finite element simulation with calculations adjusted with reference to in-situ measurements. A program for calculation and experimental analysis of maximum load and durability of critical area forms the core of uninterruptible monitoring system. The knowledge base on performance of the monitored components in different operating conditions and the corresponding comprehensive analysis of strained condition and deterioration rates compose the basis of control system data support, both for operating nuclear power units and robotic maintenance and repair systems.

Numerical Modeling of Tube Hydropiercing Using Phenomenological and Micro-Mechanical Damage Criteria

2013 ◽  
Vol 549 ◽  
pp. 172-179 ◽  
Author(s):  
Amir Hassannejadasl ◽  
Daniel E. Green
Keyword(s):  
Experimental Studies ◽  
Three Dimensional ◽  
Equivalent Plastic Strain ◽  
Mechanical Damage ◽  
High Strength ◽  
Dimensional Finite Element ◽  
Steel Dp600 ◽  
Three Dimensional Finite Element ◽  
Jc Model ◽  
Damage Criteria

Hydropiercing is an efficient way of piercing holes in mass produced hydroformed parts with complex geometries. By driving piercing punches radially into a hydroformed and fully pressurized tube, holes will be pierced and extruded into the tube-wall. Recent experimental studies have shown that the formability of advanced high strength steel (AHSS) tubes can be increased with the application of internal pressure. In this study, three-dimensional finite element simulations of a tube hydropiercing process of a dual phase steel (DP600) were performed in LS-DYNA, using phenomenological, micromechanical and combined damage criteria. Damage was included in the numerical analysis by applying constant equivalent plastic strain (CEPS), the Gurson-Tvergaard-Needleman (GTN), and the Extended GTN (GTN+JC) model. In order to calibrate the parameters in each model, a specialized hole-piercing fixture was designed and piercing tests were carried out on non-pressurized tube specimens. Of the various ductile fracture criteria, the results predicted with the GTN+JC model, such as the punch load-displacement, the roll-over depth, and the quality of the clearance zone correlated the best with the experimental data.

Three Dimensional Finite Element Analyses of Welding Residual Stresses of a Repaired Weld

2018 ◽  
Author(s):  
Mingya Chen ◽  
Weiwei Yu ◽  
Fei Xue ◽  
Francis Ku ◽  
Zhilin Chen ◽  
...  
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Nuclear Power ◽  
Power Plants ◽  
Three Dimensional ◽  
Fe Model ◽  
Dimensional Finite Element ◽  
Surge Line ◽  
Line Slope ◽  
Three Dimensional Finite Element

The objective of this study is to correct installation non-conformance of a surge line using the excavation and re-weld method which is widely used in nuclear power plants. The surge line with a backslope was not at the required design level after initial installation. In order to solve the problem, a repairing technology is shown as follows: the weld was successively excavated and welded again while the surge line slope was corrected with the help of jacks. Because many of the degradation mechanisms relevant to power plant components can be accelerated by the presence of welding residual stresses (WRS), the WRS caused by the repairing process need to be studied. In this paper, the WRS simulation technique employed in this project is sophisticated. It utilizes a 3-D finite element (FE) model, and simulates the weld sequencing and excavation. Moreover, the WRS simulation performed in this project not only uses the un-axisymmetric model, but also considers the deformation caused by the external jacking loads. The results show that the repairing process is effective, and strain damage induced by the welding repair is also acceptable.

scholarly journals STAMINA OF A GASKETED BOLTED FLANGED PIPE JOINT UNDER DYNAMIC LOADING

2016 ◽  
Vol 17 (2) ◽  
pp. 137-155
Author(s):  
Muhammad Abid
Keyword(s):  
Three Dimensional ◽  
Operating Conditions ◽  
Axial Loads ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Dynamic Operating ◽  
Critical Components ◽  
Three Dimensional Finite Element ◽  
Bolted Flange ◽  
Pipe Joint

Gasketed bolted flange joints are the most critical components in pipelines for their sealing and strength under operating conditions. Most of the work available in literature is under static loading, whereas in industry, cyclic loads are applied due to the vibrating machinery such as motors, pumps, sloshing in offshore applications and in the ships etc. In this study a three dimensional finite element analysis of a gasketed joint is carried out using a spiral wound gasket under bolt up and dynamic operating conditions (internal pressure, axial and bending) singly and in combination. The cyclic axial loads are concluded relatively more challenging for both the sealing and strength of the joint. Higher magnitudes of loads and frequencies are also observed more challenging to the joints performance.

Force and Moment Characteristics of a Rhombi Tessellated Non-Pneumatic Tire

2016 ◽  
Vol 44 (2) ◽  
pp. 130-148 ◽  
Author(s):  
Anand Suresh Kumar ◽  
Ramarathnam Krishna Kumar
Keyword(s):  
Load Distribution ◽  
Three Dimensional ◽  
Element Model ◽  
Operating Conditions ◽  
Lateral Stiffness ◽  
Contact Pressure Distribution ◽  
Static Behavior ◽  
Pneumatic Tire ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

ABSTRACT There has been a recent spate of activities in the design of non-pneumatic tires (NPTs). The validation of a NPT's design is incomplete unless its performance is compared with an equivalent pneumatic tire. Apart from its static behavior, an evaluation of the tire's performance can be done by observing its force and moment (F&M) characteristics. In the present work, an NPT has been designed with an aperiodic rhombi tessellated spoke acting as the load bearing member, where the “unit cell” design is based on the vertical, circumferential, and lateral stiffness offered by the structure. A three-dimensional finite element model has been used to capture the mechanics of load distribution in the spoke, contact patch, and variation of contact pressure distribution when the tire is subjected to different operating conditions. SIMULIA/Abaqus has been used to conduct static loading, acceleration/braking, and cornering analyses. The F&M characteristics have been extracted from these simulations and compared with those of a 165/70R14 passenger car tire. The variation in the vertical and circumferential stiffness based on the spoke geometry has also been highlighted. The use of conventional pneumatic tire's belts to alter the NPT's lateral stiffness, despite the tire behaving like a “bottom loader,” adds uniqueness to the design. The NPT's capability to match the pneumatic tire's performance and the variability observed in the tire's F&M characteristics reiterate the freedom available in NPT design, thus providing the opportunity to have similar tires with varying performance characteristics.

Estimation of Elastic Crack Opening Displacement for Thin Elbows With Circumferential Through-Wall Cracks

2015 ◽  
Author(s):  
Min-Kyu Kim ◽  
Han-Bum Surh ◽  
Min-Gu Won ◽  
Nam-Su Huh ◽  
Moon-Ki Kim ◽  
...  
Keyword(s):  
Crack Opening Displacement ◽  
Nuclear Power ◽  
Crack Opening ◽  
Three Dimensional ◽  
Opening Displacement ◽  
Dimensional Finite Element ◽  
Elastic Crack ◽  
Thin Walled ◽  
Three Dimensional Finite Element ◽  
Leak Before Break

Leak-before-break (LBB) is an important concept that could confirm design and integrity evaluation of nuclear power plant piping. For the LBB analysis, the detective leakage rate should be calculated for a through-wall cracked pipes. For this calculation, the crack opening displacement (COD) calculation is essential. Recently, sodium faster reactor (SFR) which has thin-walled pipes with Rm/t ranged 30–40 was introduced and then the investigation of these thin walled pipes and elbows has received great attention in the LBB evaluation. In this context, the three-dimensional finite element (FE) analyses for thin elbows with circumferential crack under in-plane bending are carried out to investigate the elastic COD values. Finally, the solution for elastic COD which can cover sufficiently thin elbow is successfully addressed.

Dynamic Calculation of Electric Propulsion Motor Tandem Rotors

2022 ◽  
pp. 3-9
Author(s):  
P.P. Gaydzhurov ◽  
G.K. Ptakh
Keyword(s):  
Software Package ◽  
Electric Propulsion ◽  
Three Dimensional ◽  
Calculated Data ◽  
Element Model ◽  
Operating Conditions ◽  
Dynamic Calculation ◽  
Dimensional Finite Element ◽  
Stationary Action ◽  
Three Dimensional Finite Element

The article presents the results of modeling the dynamic response of the tandem rotors of ice-class vessel electric propulsion motors under extreme operating conditions. The loading of rotors by torques in combination with vibration transmitted through the supports to the electric motors is considered as an external non-stationary action. A method for constructing a three-dimensional finite element model of the structure under study by fragmentary assembly has been developed on the basis of the ANSYS Mechanical software package. A scheme of elastic-compliant 3D-links allowing simulating the reciprocating-rotational vibrations of a tandem of rotors is presented. A test example is used to verify the proposed mechanical-mathematical model of the torsion system. Based on the calculated data, the analysis of the dynamic parameters of the tandem rotors is performed for the most unfavorable operating scenarios.

Residual Shank Torque of Bolted Joints: A Numerical Investigation

2019 ◽  
Author(s):  
Stefano Fini ◽  
Massimiliano De Agostinis ◽  
Dario Croccolo ◽  
Giorgio Olmi ◽  
Luca Paiardini ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Element Model ◽  
Operating Conditions ◽  
Torsional Stiffness ◽  
Present Contribution ◽  
Cylindrical Joint ◽  
Analytical Work ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Thick Joint

Abstract During operation, the overall stress state of a screw is a function of the direct stress generated by the axial preload, and the external loads, plus the shear stress due to the residual shank torque. All in all, the higher the residual torque, the lower the direct stress the screw can withstand prior to yielding. The residual shank torque stems from the tightening torque, part of which flows through the shank and it is, only partially, released after wrench removal, thanks to springback phenomena involving both the screw and the joined elements. This phenomenon has been tackled in a previous experimental and analytical work by the authors, which investigated the effect of the stiffness and frictional parameters of the joint on the amount of residual shank torque. Such research was based on a sleevelike specimen, and, in fact, the results were strictly applicable to the case of slender cylindrical joint. The present contribution aims at assessing the effect of the same parameters on the residual shank torque, namely: the ratio between the torsional stiffness of the screw and of the plates, the friction coefficients (underhead and thread). Nonetheless, thanks to a novel three-dimensional finite element model, the parameters have been varied in a much wider range, in order to analyze all the likely operating conditions. The model is capable of predicting the residual shank torque for both the cases of slender and thick joint (plate-like joint). The model has been developed in the Ansys R17 software, but the methodology can be extended to other codes with minimal changes.

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