scholarly journals Long-Term Creep-Rupture Behavior of Inconel® 740 and Haynes® 282

2014 ◽  
Author(s):  
P. F. Tortorelli ◽  
H. Wang ◽  
K. A. Unocic ◽  
M. L. Santella ◽  
J. P. Shingledecker ◽  
...  
Keyword(s):  
Deformation Behavior ◽  
Microstructural Analysis ◽  
Time Dependent ◽  
Steam Boiler ◽  
Power Law Model ◽  
Inconel Alloy ◽  
Term Creep ◽  
Modified Power Law ◽  
Rupture Behavior

Creep testing and microstructural analysis were used to assess the properties and time-dependent deformation behavior of precipitation-strengthened nickel-based alloys, specifically, Inconel® alloy 740 and Haynes® 282® alloy, for use as pressure components in boilers operating under advanced steam conditions (750°C, >35 MPa). In support of the need for extended service of steam boiler tubing, piping and vessels, the ability of simple Larson-Miller estimates and a modified power-law model (Wilshire et al.) to predict creep lifetimes on the order of 105 hours based on experimental data out to almost 50,000 h was evaluated for these alloys. Even under conservative conditions, both Inconel alloy 740 and Haynes 282 project to have creep lifetimes exceeding 100,000 hours at 750°C and 100 MPa. Paper published with permission.

Creep–rupture model of aluminum alloys: Cohesive zone approach

2014 ◽  
Vol 229 (8) ◽  
pp. 1343-1347 ◽  
Author(s):  
Kyungmok Kim
Keyword(s):  
Aluminum Alloys ◽  
Cohesive Zone ◽  
Rupture Life ◽  
Stress Rupture ◽  
Creep Rupture ◽  
Time Dependent ◽  
Element Analysis ◽  
Rupture Model ◽  
Term Creep

In this article, a creep–rupture model of aluminum alloys is developed using a time-dependent cohesive zone law. For long-term creep rupture, a time jump strategy is used in a cohesive zone law. Stress–rupture scatter of aluminum alloy 4032-T6 is fitted with a power law form. Then, change in the slope of a stress-rupture line is identified on a log–log scale. Implicit finite element analysis is employed with a model containing a cohesive zone. Stress–rupture curves at various given temperatures are calculated and compared with experimental ones. Results show that a proposed method allows predicting creep–rupture life of aluminum alloys.

Height Extrapolation of Wind Data

1985 ◽  
Vol 107 (1) ◽  
pp. 10-14 ◽  
Author(s):  
A. S. Mikhail
Keyword(s):  
Wind Speed ◽  
Power Law ◽  
Wind Data ◽  
Power Law Model ◽  
Short Term ◽  
Shape Factors ◽  
Wind Speeds ◽  
Average Wind ◽  
Modified Power Law

Various models that are used for height extrapolation of short and long-term averaged wind speeds are discussed. Hourly averaged data from three tall meteorological towers (the NOAA Erie Tower in Colorado, the Battelle Goodnoe Hills Tower in Washington, and the WKY-TV Tower in Oklahoma), together with data from 17 candidate sites (selected for possible installation of large WECS), were used to analyze the variability of short-term average wind shear with atmospheric and surface parameters and the variability of the long-term Weibull distribution parameter with height. The exponents of a power-law model, fit to the wind speed profiles at the three meteorological towers, showed the same variability with anemometer level wind speed, stability, and surface roughness as the similarity law model. Of the four models representing short-term wind data extrapolation with height (1/7 power law, logarithmic law, power law, and modified power law), the modified power law gives the minimum rms for all candidate sites for short-term average wind speeds and the mean cube of the speed. The modified power-law model was also able to predict the upper-level scale factor for the WKY-TV and Goodnoe Hills Tower data with greater accuracy. All models were not successful in extrapolation of the Weibull shape factors.

scholarly journals A Coupled Macroscopic and Mesoscopic Creep Model of Soft Marine Soil Using a Directional Probability Entropy Approach

2021 ◽  
Vol 9 (2) ◽  
pp. 224
Author(s):  
Cuiying Zhou ◽  
Guangjun Cui ◽  
Wanyi Liang ◽  
Zhen Liu ◽  
Lihai Zhang
Keyword(s):  
Deformation Behavior ◽  
Morphological Characteristics ◽  
Particle Orientation ◽  
Creep Model ◽  
Critical Parameters ◽  
Structural Failure ◽  
External Pressures ◽  
Term Creep ◽  
Marine Soil

To mitigate the risk of structural failure in coastal engineering caused by soft marine soil creep, this study presents a coupled macroscopic and mesoscopic creep model of soft marine soil to predict long-term deformation behavior of the soil. First, the mesoscopic characteristics of soft marine soil (e.g., pore, particle, and morphological characteristics) under different external pressures were obtained using a scanning electron microscope. Then, both the mesoscopic and macroscopic characteristics of soil were quantified using directional probability entropy and then used as inputs to develop the model. The model predictions agree with the experimental data. In addition, the experimental results indicate linear negative correlations between porosity and pore ratio with stress—the relationships between the fractal dimension of pore distribution and probability entropy of particle orientation under stress are generally nonlinear. Further, results of sensitivity analysis indicate that the probability entropy of particle orientation is one of the most critical parameters governing long-term creep deformation behavior of soft marine soil.

scholarly journals Correction to: Long-Term Creep-Rupture Behavior of Alloy Inconel 740/740H

2021 ◽  
Author(s):  
M. Render ◽  
M. L. Santella ◽  
X. Chen ◽  
P. F. Tortorelli ◽  
V. Cedro
Keyword(s):  
Creep Rupture ◽  
Term Creep ◽  
Rupture Behavior

scholarly journals Time-Dependent Analysis of Precast Segmental Bridges

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Gian Felice Giaccu ◽  
Davide Solinas ◽  
Bruno Briseghella ◽  
Luigi Fenu
Keyword(s):  
Time Dependent ◽  
Long Term Effects ◽  
Model Code ◽  
Dependent Behavior ◽  
Model Code 2010 ◽  
Fiber Reinforcements ◽  
Segmental Bridges ◽  
Term Creep ◽  
Over Time

AbstractPrestressed segmentally constructed balanced cantilever bridges are often subjected to larger deflections than those predicted by calculations, especially for long-term effects. In this paper, the case of modular balanced cantilever bridges, which are prestressed segmental bridges obtained through a repetition of the same double cantilever, is investigated. The considered bridges are two typical cases of modular balanced cantilever both subjected to large deformations during their lifetime. In this case, due to the unusual employed static scheme, creep deflections indefinitely evolve over time particularly at the end of the cantilevers and in correspondence with the central joint. These remarkable deflections cause discomfort for vehicular traffic and in certain cases can lead to the bridge collapse. Important extraordinary maintenance interventions were necessary to restore the viability of the bridges and to replace the viaduct design configuration. To this aim, the static schemes of the structures were varied, introducing new constraints, new tendons, and carbon fiber reinforcements. In the present work, time analysis was performed to compare the time-dependent behavior of the bridge according to two different creep models, the CEB-FIP Model Code 2010 and the RILEM Model B3, with the real-time-dependent behavior of the bridge observed during its lifetime. The two different employed models exhibit different behaviors in terms of displacements and bending moments acting on the bridge. Interesting considerations are made on their reliability in simulating the long-term creep effects that evolve indefinitely over time. Moreover, retrofitting techniques have been proposed and modeled to predict their effectiveness in reducing time-dependent deflections.

Long-Term Creep-Rupture Behavior of Alloy Inconel 740/740H

2021 ◽  
Author(s):  
M. Render ◽  
M. L. Santella ◽  
X. Chen ◽  
P. F. Tortorelli ◽  
V. Cedro
Keyword(s):  
Creep Rupture ◽  
Term Creep ◽  
Rupture Behavior
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