Monitoring Crack Propagation of High Pressure and High Temperature Components by Multi-Physics Numerical Analysis Approach

2017 ◽  
Author(s):  
Hamid R. Ahmadi Moghaddam ◽  
Pierre Mertiny
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Numerical Analysis ◽  
Crack Propagation ◽  
Interaction Analysis ◽  
Analysis Approach ◽  
High Temperature Component ◽  
Sensor Device ◽  
Temperature Component ◽  
High Temperature Components

The safety of high pressure and high temperature components is paramount, and therefore, developing effective and reliable methodologies to improve the prediction of crack propagation is an important task. The present paper describes and demonstrates a multi-physics numerical analysis approach for assessing crack propagation using a sensor device. This method employs a coupled structural-thermal-electric analysis in conjunction with a thermal-fluid-structure interaction analysis to study the structural health of a high pressure and high temperature component.

Hydrogen-Induced Mechanical Losses in Oxygen-Free Copper

2012 ◽  
Vol 184 ◽  
pp. 122-127 ◽  
Author(s):  
Mykola Ivanchenko ◽  
Yuriy Yagodzinskyy ◽  
H. Hänninen
Keyword(s):  
High Temperature ◽  
Internal Friction ◽  
Oxygen Content ◽  
Hydrogen Atoms ◽  
Internal Friction Peak ◽  
Exponential Factor ◽  
Hydrogen Charging ◽  
High Temperature Component ◽  
Temperature Component ◽  
High Temperature Components

Two oxygen-free copper grades with purity of 99.99 % were studied by means of free decay inverted torsion pendulum at the temperature range of 90 – 300 K and frequencies of 0.5 – 2 Hz. One copper grade was oxygen free electrolytically refined copper with oxygen content of 1.2 wt. ppm. The other one was oxygen-free phosphorous-alloyed grade with oxygen content less than 5 wt. ppm and phosphorous content of 30 – 70 wt. ppm. Electrochemical hydrogen charging induces a complex internal friction peak in the studied copper grades. The observed internal friction peak has a relaxation origin with apparent activation enthalpy and pre-exponential factor for the oxygen-free grade of 0.276 ± 0.002 eV and 10-11.59 ± 0.08 s, respectively. The internal friction peak can be fitted by three broadened Debye peaks (P1, P2 and P3) with activation enthalpies and pre-exponential factors of 0.248 ± 0.003 eV and 10-11.4 ± 0.4 s; 0.297 ± 0.004 eV and 10-11.8 ± 0.2 s; 0.36 ± 0.04 eV and 10-12.7 ± 1.4 s, respectively. Phosphorous doping markedly reduces the height of the observed peak. It was also shown that prior deformation by tension suppresses high-temperature components of the complex internal friction peak. Mechanism of relaxation is presumably caused by interaction of H – H pairs (low-temperature component, peak P1), interaction of hydrogen atoms with dislocations (P2) and interaction of hydrogen with impurities (high-temperature component, peak P3). Absorption of hydrogen in the studied copper grades during electrochemical hydrogen charging was confirmed by the thermal desorption method.

Analytical Expression of Elastic Follow-Up Factors in Fully-Plastic Situation for Creep-Fatigue Damage Assessment of High Temperature Components

2016 ◽  
Author(s):  
Terutaka Fujioka
Keyword(s):  
High Temperature ◽  
Theoretical Background ◽  
Element Analysis ◽  
Simple Method ◽  
High Temperature Component ◽  
Creep Fatigue ◽  
Temperature Component ◽  
High Temperature Components ◽  
Life Consumption

To assess creep-fatigue life consumption in a high temperature component, strain ranges and stress relaxation histories are needed to be estimated. Inelastic finite element analysis may provide these structural responses. Performing inelastic FEA is, however, usually costly, and thus simple elastic FEA-route methods to estimate these are preferred to in some practical cases. A simple method employed in a design code for the Japanese proto-type fast breeder reactor uses an elastic follow-up factor, and is applicable for components subjected to cyclic secondary stresses. A cantilever model was employed to illustrate theoretical background for this method, and lead to a default value of three for gross elastic follow-up factor for the simplicity and conservatism. Validity of this method, however, has never been confirmed theoretically for general conditions of geometry, loading, and material properties. This paper describes characteristics of the factor based on theoretical investigations of a generally-shaped component subjected to a displacement-controlled loading. Some supporting numerical examples are shown by performing elastic-plastic FEA of a notched cylinder.

Estimation of Frictional Coefficient between Punch and Billet at Back-Stroke in Backward Can Extrusion Test of Steel

2018 ◽  
Vol 767 ◽  
pp. 248-255
Author(s):  
Kazuhito Asai ◽  
Kazuhiko Kitamura ◽  
Keisuke Goto ◽  
Nobukazu Hayashi
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Numerical Analysis ◽  
Frictional Coefficient ◽  
Expansion Ratio ◽  
Coated Steel ◽  
Forward Stroke ◽  
High Pressure High Temperature ◽  
The Coefficient Of Friction ◽  
Surface Expansion

A backward can extrusion test provides severe tribological conditions because high pressure, high temperature, and large surface expansion ratio affect the lubricant. During the forward stroke these conditions intensify with increasing cup depth of the extruded workpiece; additionally, the back-stroke force during retraction of the punch rises to a significant level under a poor-lubricated condition. This study estimates the coefficient of friction μp between punch and workpiece during the back-stroke by combining experiments using conventional soap-phosphate coated steel and numerical analysis by FEM. The values of μp were estimated to be 0.09 and 0.03 in case of small and large workpiece depth, respectively. Friction decreased with elevating temperature.

High temperature component design

1985 ◽  
Vol 87 ◽  
pp. 365-371
Author(s):  
H.-J. Seehafer ◽  
M. Becker ◽  
E. Bodmann
Keyword(s):  
High Temperature ◽  
High Temperature Component ◽  
Component Design ◽  
Temperature Component

scholarly journals ASCA SIS X-ray Observations of the Wind Blown Bubble NGC 6888

1997 ◽  
Vol 166 ◽  
pp. 425-428
Author(s):  
Matthias Wrigge ◽  
You-Hua Chu ◽  
Eugene A. Magnier ◽  
Yuichi Kamata
Keyword(s):  
Heat Conduction ◽  
High Temperature ◽  
Spectral Resolution ◽  
Surface Brightness ◽  
Contact Discontinuity ◽  
Plasma Component ◽  
Central Temperature ◽  
X Ray ◽  
High Temperature Component ◽  
Temperature Component

AbstractWe present ASCA SIS observations of the wind-blown bubble NGC 6888. Because the ASCA SIS is sensitive to higher energy photons and has a higher spectral resolution compared to the ROSAT PSPC, we are able to detect a T ≈ 8×106 K plasma component besides the T ≈ 1.5×106 K component known from previous PSPC observations. The existence of a high-temperature component, the observed limb-brightened X-ray surface brightness profile, and the observed level of X-ray surface brightness cannot be satisfactorily explained by currently available models. Reducing heat conduction at the contact discontinuity may raise the central temperature and produce a limb-brightening; however, the expected X-ray surface brightness is still considerably higher than the observed surface brightness.

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