High Temperature Limit Analysis of Pressure Vessels and Piping with Local Wall-Thinning

2017 ◽  
pp. 199-217
Author(s):  
X. Du ◽  
Y. Liu ◽  
J. Zhang
Keyword(s):  
High Temperature ◽  
Limit Analysis ◽  
Temperature Limit ◽  
Pressure Vessels ◽  
High Temperature Limit ◽  
Wall Thinning ◽  
Local Wall Thinning

Plastic Limit Analysis of Piping with Local Wall-Thinning under Elevated Temperature

2016 ◽  
Vol 725 ◽  
pp. 47-52
Author(s):  
Xian He Du ◽  
Ying Hua Liu
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Limit Analysis ◽  
Limit Load ◽  
Plastic Limit ◽  
Wall Thinning ◽  
Plastic Limit Analysis ◽  
Creep Time ◽  
Plastic Limit Load ◽  
Local Wall Thinning

In order to evaluate the safety and integrity of piping with local wall-thinning at elevated temperature, a numerical method for plastic limit load of modified 9Cr-1Mo steel piping is proposed in the present paper. The limit load of piping at high temperature is defined as the load-carrying capacity after the structure has served for a certain time period. The power law creep behavior with Liu-Murakami damage model is implemented into the commercial software ABAQUS via CREEP for simulation, and the Ramberg-Osgood model is modified to consider the material deterioration effect of modified 9Cr-1Mo steel by introducing the creep damage factor into the elasto-plastic constitutive equation. For covering the wide ranges of defect ratios and service time periods, various 3-D numerical examples for the piping with local wall-thinning defects, and creep time are calculated and analyzed. The limit loads of the defected structures under high temperature are obtained through classic zero curvature criterion with the modified Ramberg-Osgood model, and the typical failure modes of these piping are also discussed. The results show that the plastic limit load of piping containing defect at elevated temperature depends not only on the size of defect, but also on the creep time, which is different from the traditional plastic limit analysis at room temperature without material deterioration.

scholarly journals A 4d $$ \mathcal{N} $$ = 1 Cardy Formula

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Joonho Kim ◽  
Seok Kim ◽  
Jaewon Song
Keyword(s):  
Black Holes ◽  
Free Energy ◽  
Asymptotic Behavior ◽  
High Temperature ◽  
Gauge Theory ◽  
Chemical Potential ◽  
Temperature Limit ◽  
Superconformal Index ◽  
High Temperature Limit ◽  
Cardy Formula

Abstract We study the asymptotic behavior of the (modified) superconformal index for 4d $$ \mathcal{N} $$ N = 1 gauge theory. By considering complexified chemical potential, we find that the ‘high-temperature limit’ of the index can be written in terms of the conformal anomalies 3c − 2a. We also find macroscopic entropy from our asymptotic free energy when the Hofman-Maldacena bound 1/2 < a/c < 3/2 for the interacting SCFT is satisfied. We study $$ \mathcal{N} $$ N = 1 theories that are dual to AdS5 × Yp,p and find that the Cardy limit of our index accounts for the Bekenstein-Hawking entropy of large black holes.

scholarly journals Equations of viscous flow of silicate liquids with different approaches for universality of high temperature viscosity limit

2014 ◽  
Vol 8 (2) ◽  
pp. 59-68
Author(s):  
Ana Kozmidis-Petrovic
Keyword(s):  
High Temperature ◽  
Viscous Flow ◽  
Temperature Limit ◽  
High Temperature Limit ◽  
Viscosity Parameter ◽  
General Rules ◽  
Viscosity Limit ◽  
Dependent Parameter ◽  
Silicate Liquids ◽  
The Difference

The Vogel-Fulcher-Tammann (VFT), Avramov and Milchev (AM) as well as Mauro, Yue, Ellison, Gupta and Allan (MYEGA) functions of viscous flow are analysed when the compositionally independent high temperature viscosity limit is introduced instead of the compositionally dependent parameter ??. Two different approaches are adopted. In the first approach, it is assumed that each model should have its own (average) hightemperature viscosity parameter ??. In that case, ?? is different for each of these three models. In the second approach, it is assumed that the high-temperature viscosity is a truly universal value, independent of the model. In this case, the parameter ?? would be the same and would have the same value: log ?? = ?1.93 dPa?s for all three models. 3D diagrams can successfully predict the difference in behaviour of viscous functions when average or universal high temperature limit is applied in calculations. The values of the AM functions depend, to a greater extent, on whether the average or the universal value for ?? is used which is not the case with the VFT model. Our tests and values of standard error of estimate (SEE) show that there are no general rules whether the average or universal high temperature viscosity limit should be applied to get the best agreement with the experimental functions.

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