Necessity of applying the concept of the steady state on the numerical analyses of excavation issues: laboratory, field and numerical investigations

Heidarzadeh, Heisam; Kamgar, Reza

doi:10.1080/17486025.2020.1755466

Cited by 14 publications

(6 citation statements)

References 33 publications

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“…There are various numerical methods used for solving engineering problems [26][27][28]. In the present paper, the Finite Element Method (FEM) is used to solve the governing equations.…”

Section: Finite Element Formulationmentioning

confidence: 99%

Finite Element Analysis of Functionally Graded Beams using Different Beam Theories

2020

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The present study deals with buckling, free vibration, and bending analysis of Functionally Graded (FG) and porous FG beams based on various beam theories. Equation of motion and boundary conditions are derived from Hamilton’s principle, and the finite element method is adopted to solve problems numerically. The FG beams are graded through the thickness direction, and the material distribution is controlled by power-law volume fraction. The effects of the different values of the power-law index, porosity exponent, and different boundary conditions on bending, natural frequencies and buckling characteristics are also studied. A new function is introduced to approximate the transverse shear strain in higher-order shear deformation theory. Furthermore, shifting the position of the neutral axis is taken into account. The results obtained numerically are validated with results obtained from ANSYS and those available in the previous work. The results of this study specify the crucial role of slenderness ratio, material distribution, and porosity condition on the characteristic of FG beams. The deflection results obtained by the proposed function have a maximum of six percent difference when the results are compared with ANSYS. It also has better results in comparison with the Reddy formulae, especially when the beam becomes slender. Doi: 10.28991/cej-2020-03091604 Full Text: PDF

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“…There are various numerical methods used for solving engineering problems [26][27][28]. In the present paper, the Finite Element Method (FEM) is used to solve the governing equations.…”

Section: Finite Element Formulationmentioning

confidence: 99%

Finite Element Analysis of Functionally Graded Beams using Different Beam Theories

2020

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“…These data are based on undrained Banding sand in different initial conditions. Next, a series of two-way cyclic triaxial tests on Shahrekord sand [24] has been applied to validate the performance of the modified constitutive model. These data have been presented under different initial conditions (i.e., void ratio and mean effective stress) and different maximum deviatoric stresses in compression and extension.…”

Section: Introductionmentioning

confidence: 99%

“…Several monotonic triaxial data can be found in Ref. [24], based on Shahrekord sand, which are useful for calibrating constitutive models.…”

Section: Introductionmentioning

confidence: 99%

Modification of the Reloading Plastic Modulus in Generalized Plasticity Models for Soil by Introducing a New Equation for the Memory Parameter in Cyclic Loadings

Oliaei,

Kamgar,

Heidarzadeh

et al. 2024

Applied Sciences

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Nowadays, with the widespread supply of very powerful laboratory and computer equipment, it is expected that the analyses conducted for geotechnical problems are carried out with very high precision. Precise analyses lead to better knowledge of structures’ behavior, which, in turn, reduces the costs related to uncertainty of materials’ behavior. A precise analysis necessitates a precise knowledge and definition of the behavior of the constituent materials, which itself requires applying an appropriate constitutive model to show the behavior of materials. Constitutive models used in the generalized plasticity framework are very powerful constitutive models for the simulation of sand behavior. However, the simulation of a cyclic behavior in these models, especially the simulation of the undrained cyclic behavior, is not well-recognized. In this study, in order to eliminate the weakness of generalized constitutive models under cyclic loading, a new equation is presented to substitute the so-called coefficient of the discrete memory factor to consider the loading history in such a way that the plastic modulus is modified during reloading and, as a result, more appropriate predictions of sand behavior are obtained. The performance accuracy of the proposed coefficient was evaluated in accordance with the experimental data. Finally, the results show that after using the modification of the loading history coefficient, predictions of the constitutive model are significantly improved.

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“…Manzari and Yonten [24] presented the numerical implementation of an anisotropic constitutive model for clays, and the simulation effect was verified by field measurements. Using the state parameter and the steady state concept, Heidarzadeh and Kamgar [25] proposed an elastoplasticity constitutive model based on the Duncan-Chang constitutive model, which have been calibrated by experimental results of soil. Qin [26] elucidated the rationality and accuracy of the model by writing a user-defined unsaturated loess constitutive subprogram and performing numerical simulations to compare the static and dynamic triaxial test results.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation on Deformation of the Water-Rich Silt Subsoil under Different Compaction Conditions

Luo,

Kou,

et al. 2024

Electronics

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Determining the deformation trend of silt subsoil under long-term aircraft loading by conventional numerical methods based on finite elements is challenging and poses several limitations. In this study, a boundary surface model for remolded saturated silt considering the influence of the soil dry density was developed, and an explicit integral algorithm with error control was used to incorporate the model into a user-defined material subroutine that the finite element software (ABAQUS 6.14) could call. In this way, the consolidated undrained dynamic triaxial test of a soil unit was established for simulation and model validation, which corroborated that the model could describe the dynamic properties of the saturated silt. Then, a numerical model of the runway with layered compaction and different compaction degrees was also developed to numerically analyze the deformation of the subsoil under cyclic aircraft loading. The results showed that the subsoil deformation increased continuously with the increase of cycle number. However, the deformation rate decreased gradually, and the silt subsoil deformation remained stable after 50 loading cycles. After the same number of loading cycles, the cumulative plastic deformation of the subsoil model with the overall compaction degree of 94% was smaller than that of the model with layered compaction. It was also shown that different aircraft speeds have minimal effect on the cumulative plastic deformation of the subsoil. Nevertheless, the ultimate cumulative plastic deformation is larger, as the loading duration is longer at low aircraft speeds. It indicates that strictly controlling of the compaction degree within a certain range of load influence is imperative in practical engineering, as it reduces the associated costs.

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Necessity of applying the concept of the steady state on the numerical analyses of excavation issues: laboratory, field and numerical investigations

Cited by 14 publications

References 33 publications

Finite Element Analysis of Functionally Graded Beams using Different Beam Theories

Finite Element Analysis of Functionally Graded Beams using Different Beam Theories

Modification of the Reloading Plastic Modulus in Generalized Plasticity Models for Soil by Introducing a New Equation for the Memory Parameter in Cyclic Loadings

Numerical Investigation on Deformation of the Water-Rich Silt Subsoil under Different Compaction Conditions

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