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 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 Characterization Of Ceramic BGA

2004 ◽  
Vol 1 (2) ◽  
pp. 102-107
Author(s):  
Lewis S. Goldmann ◽  
Mukta Farooq
Keyword(s):  
Compressive Loading ◽  
Compressive Force ◽  
Creep Model ◽  
Equivalent Material ◽  
Geometric Stiffening ◽  
The Individual ◽  
Term Creep ◽  
Range Of Values

Long term creep of a ceramic ball grid array (CBGA) solder ball under compressive loading was investigated. An experiment was conducted with two levels of loading and four of temperature. Analysis of the data assumed the composite ball structure could be simulated by an interconnection having the same shape, but of a single equivalent material. Curve fitting determined the stress exponent and activation energy of the equivalent material in the Norton creep model; the values were consistent with the range of values of the individual components available in the literature. Nonlinearity of the change in ball height with time was hypothesized to be due to geometric stiffening, a hypothesis which was confirmed by a simplified model. The model may be used to estimate creep behavior of other ball geometries having the same material set. The final result of this work - a closed form equation describing height decrease as a function of compressive force, temperature and time - can be used to simplify complex modeling of an entire package, and as an aid in designing accelerated thermal cycles which appropriately synchronize solder creep and fatigue.

Unified Viscoplastic Model Coupled With Damage for Evaluation of Creep-Fatigue of Grade 91 Steel

2017 ◽  
Author(s):  
Nazrul Islam ◽  
David J. Dewees ◽  
Tasnim Hassan
Keyword(s):  
Damage Mechanics ◽  
Creep Damage ◽  
Continuum Damage Mechanics ◽  
Creep Model ◽  
Damage Evaluation ◽  
Creep Fatigue ◽  
Grade 91 ◽  
Term Creep ◽  
Grade 91 Steel

A continuum damage mechanics (CDM) coupled unified viscoplasticity model has been developed to predict the creep-fatigue life of modified Grade 91 steel. A tertiary creep model termed MPC-Omega codified in Part 10 of API (and also implemented in the ASME BP&V Code for Grade 22V and more recently Grade 91 Steel) is also employed for creep damage evaluation. As MPC-Omega has a direct relationship with Larson-Miller parameter (LMP) coefficients, creep damage coefficients in the unified constitutive model (UCM) are tied with MPC-Omega coefficients in order to utilize WRC and API 579-1 Grade 91 creep rupture database. The model is validated against long-term creep, LCF, creep-fatigue and TMF experimental responses at T = 20–600°C.

scholarly journals A 3D Creep Model considering Disturbance Damage and Creep Damage and Its Application in Tunnel Engineering

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Geng-Feng Wang ◽  
Fan Sun ◽  
Xiao-Hui Xiong ◽  
Lei He ◽  
Ke-Hong Zhang
Keyword(s):  
Space Dimension ◽  
Creep Damage ◽  
Wave Theory ◽  
Creep Model ◽  
Time Dimension ◽  
Creep Tests ◽  
Railway Tunnel ◽  
Damage Theory ◽  
Term Creep

Based on the Kachanov damage theory and elastic wave theory, considering the long-term creep damage from time dimension and instantaneous disturbance damage from space dimension, we presented a 3D damage creep model and converted it to difference expressions in order to write into the finite difference software FLAC3D. Then, according to the results of creep tests, we conducted parameter inversion of our damage creep model with the help of the particle swarm optimization (PSO) method. Finally, the damage creep model was applied in a railway tunnel project in Yunnan to simulate the tunnel deformation. Compared with the Burgers model and the model considering only creep damage, our model which considers both creep damage and disturbance damage yielded more reasonable results.

Study on the Relationship between Parameters of Deterioration Creep Model of Rock under Different Modeling Assumptions

2011 ◽  
Vol 243-249 ◽  
pp. 2571-2580
Author(s):  
Ming Huang ◽  
Xin Rong Liu
Keyword(s):  
Bulk Modulus ◽  
Evolution Equations ◽  
Three Dimensional ◽  
Creep Model ◽  
Model Parameters ◽  
Three Dimensional Model ◽  
Creep Modulus ◽  
Term Creep ◽  
The Relationship

Based on the analysis to the characteristics of two kinds of rock steady creep curves, the nBurgers model that can describe the uniaxial creep properties of rock is presented. Considering the external influences on rock deformation as instantaneous elastic deterioration defined by the reduction of instantaneous elastic modulus and long-term creep deterioration defined by the reduction of long-term creep modulus, kBurgers model with deterioration is presented too. On this basis, three-dimensional model considering the Poisson’s ratio and Bulk modulus as the constant are established separately, and the relationship between their parameters is obtained. Finally, According to a calculation example, the deterioration evolution of model parameters considering water content changing under the assumption of constant bulk modulus is analyzed. In addition, the deterioration evolution equations of instantaneous elastic and long-term creep under the assumption of constant bulk modulus are obtained. It is verified that conversion relationships of model parameters are reasonable.

Statistical reinterpretation of the long term creep behaviour of the Ismetpasa segment of North Anatolian Fault, Turkey

2021 ◽  
pp. 228947
Author(s):  
Gokhan Gurbuz ◽  
Caglar Bayik ◽  
Saygin Abdikan ◽  
Kurtulus Sedar Gormus ◽  
Senol Hakan Kutoglu
Keyword(s):  
Creep Behaviour ◽  
North Anatolian Fault ◽  
Term Creep

scholarly journals Experimental and Analytical Study on Creep Characteristics of Box Section Bamboo-Steel Composite Columns under Long-Term Loading

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 983
Author(s):  
Shixu Wu ◽  
Keting Tong ◽  
Jianmin Wang ◽  
Yushun Li
Keyword(s):  
Load Level ◽  
Experimental Results ◽  
Creep Model ◽  
Composite Column ◽  
Composite Columns ◽  
Creep Coefficient ◽  
Creep Characteristics ◽  
Section Size ◽  
Steel Composite

To expand the application of bamboo as a building material, a new type of box section composite column that combined bamboo and steel was considered in this paper. The creep characteristics of eight bamboo-steel composite columns with different parameters were tested to evaluate the effects of load level, section size and interface type under long-term loading. Then, the deformation development of the composite column under long-term loading was observed and analyzed. In addition, the creep-time relationship curve and the creep coefficient were created. Furthermore, the creep model of the composite column was proposed based on the relationship between the creep of the composite column and the creep of bamboo, and the calculated value of creep was compared with the experimental value. The experimental results showed that the creep development of the composite column was fast at first, and then became stable after about 90 days. The creep characteristics were mainly affected by long-term load level and section size. The creep coefficient was between 0.160 and 0.190. Moreover, the creep model proposed in this paper was applicable to predict the creep development of bamboo-steel composite columns. The calculation results were in good agreement with the experimental results.

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