Some computational aspects of elastic‐plastic large strain analysis

Nagtegaal, J. C.; Jong, J. E. De

doi:10.1002/nme.1620170103

Cited by 136 publications

(44 citation statements)

References 10 publications

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“…Mogu se koristiti 8-čvorni ili 9-čvorni elementi s 5 ili 6 stupnjeva slobode u svakom čvoru. Šesti stupanj slobode (rotacijska krutost oko normale na srednju plohu ljuske) dodan je prema Kozuliću [8]. Korišteni model materijala ponajprije je namijenjen modeliranju ljuski od konstrukcijskog čelika, uz pretpostavku elastoplastičnog ponašanja [5].…”

Section: Model Za Konstrukcijuunclassified

Modelling fluid and shell structure interaction by combined finite element method and particle method

Kusić¹

2017

Zajednički Temelji 2017 - Peti Skup Mladih Istraživača Iz Područja Građevinarstva I Srodnih Tehničkih Znanosti - Zbornik Radova

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SažetakU ovome radu je prikazan numerički model za međudjelovanje konstrukcije i tekućine u uvjetima dinamičkog opterećenja. Model se zasniva na pristupu sa zasebnim rješenjima, pri čemu se za analizu konstrukcije koristi model zasnovan na metodi konačnih elemenata (eng. Finite element method -FEM), a za analizu tekućine model zasnovan na metodi hidrodinamike izglađenih čestica (eng. Smoothed particle hydrodynamics -SPH). Modelom je moguće opisati glavne nelinearne značajke konstrukcije: tečenje (popuštanje) u tlaku i vlaku i razvoj plastič-nosti. Moguće je adekvatno simulirati i osnovne nelinearne karakteristike tekućine: stišljivost, viskoznost i turbulenciju. Numerički testovi provedeni pomoću razvijenog numeričkog modela prikazuju njegovu pouzdanost i mogućnost primjene. Provjera modela izvršena je na primjeru rezultata numeričkih i eksperimentalnih rezultata iz literature. Ključne riječi: 3D numerički model, interakcija, FSI, FEM, SPHModelling fluid and shell structure interaction by combined finite element method and particle method Abstract Numerical model for the fluid structure interaction under dynamic loading is presented in this paper. The partitioned approach applied involves the use of the finite element method (FEM) for the analysis of structure, while the smoothed particle hydrodynamics (SPH) is used for the analysis of fluid. The model can be used to describe main nonlinear characteristics of the structure: flow (yield) under compression and tension, and increase in plasticity. It is also possible to simulate basic nonlinear characteristics of the fluid (compressibility, viscous flow, and turbulence). Numerical tests performed using the developed numerical model show its reliability and application. The model is validated using the numerical and experimental results from literature.

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Section: Model Za Konstrukcijuunclassified

Modelling fluid and shell structure interaction by combined finite element method and particle method

Kusić¹

2017

Zajednički Temelji 2017 - Peti Skup Mladih Istraživača Iz Područja Građevinarstva I Srodnih Tehničkih Znanosti - Zbornik Radova

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“…This method is usually referred to as the "1/4" point singularity technique [15]. It is applied by using eight-node quarter of the edge length, and the edge opposite the crack is kept straight.…”

Section: Fracture Mechanicsmentioning

confidence: 99%

Criteria for Crack Deflection-Penetration in EBC Coated Ceramics: A Parametric Study

Abdul-Aziz

Bhatt

Grady

2015

Mechanics of Advanced Materials and Structures

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This article discusses results obtained from a parametric study to analytically evaluate the impingement of a crack at the interface of an environmental barrier coating (EBC) and a monolithic Silicon nitride (Si 3 N 4 ) layered ceramics substrate. The study establishes a correlation that leads to determine if the crack is arrested or advanced by either penetrating or deflecting along the EBC/substrate interface. A finite-element-based fracture mechanics methodology is utilized to perform these calculations. Critical parameters determining penetration-deflection conditions in relation to EBC's physical characteristics, such as porosity level, voids, and mini cracks, are determined for a single layer and multi-layered coating system coordinating the interactions between the EBCs (Mullite, Mullite mixture, Silicon nitride, etc.) and the substrate structure. Results showing thermo-mechanical stresses and stress/strain energy release relations with respect to crack penetration-deflection are presented and discussed as the crack is advanced. = stress at the interface r and = radial distance and the polar angle f ij ( ) = angular distribution of the singular stress field = defines the strength of stress singularity ␣ and ␤ = Dundurs bi-material parameters E' j = E j is for plane stress E' j = E j /(1 -j ) for plane strain (1 and 2 denote the material) = shear modulus [MPa] G d = (material 1) is the strain energy release rate associated with the "deflected" crack or adhesive failure G p = (material 2) is the strain energy release rate associated with the "penetrated" crack (or cohesive failure of adjacent material) G pc = cohesive or penetrated fracture energy G dc = adhesive or deflected fracture energy, respectively K 1 and K 2 = stress intensity factors for the interface crack ε = a function of material constants Keywords

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“…A mixed isotropic-kinematic hardening model defines subsequent yield surfaces. The Mises yield surface is given by (22) where ts' is the deviatoric part of the shifted stress vector t s , R is the radius of the yield surface in deviatoric stress space, and Ep is the effective plastic strain. R is related to the effective tensile stress Y by (23) The shifted stress ts is given by (24) where t is the current Cauchy stress on the unrotated configuration and tb is the backstress on the unrotated configuration which locates the center of the yield surface (for isotropic hardening, tb = 0).…”

Section: Plasticity Rate Equationsmentioning

confidence: 99%

“…The predicted Cauchy stresses oscillate in an unrealistic manner (a12 actually reverses sign). Nagtegaal and de Jong [22] noted such stress oscillations with kinematic hardening in elasto-plasticityfor a material which strain hardens monotonically in tension. Atluri [2] later showed that similar oscillations exist for isotropic hardening unless the elastic strains are vanishingly small.…”

Section: Introductionmentioning

confidence: 95%

A large strain plasticity model for implicit finite element analyses

Healy

Dodds

1992

Computational Mechanics

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Annual:11-1-89 to 12-31-90 14.The theoretical basis and numerical implementation of a plasticity model suitable for finite strains and rotations are described. The constitutive equations governing J2 flow the0!y' are formulated using strainsstresses and their rates defined on the unrotated frame of reference. Unhke models based on the classical J aumann (or corotational) stress rate, the present model predicts physically acceptable responses for homogeneous deformations of exceedingly large magnitude. The associated numerical algorithms accommodate the large strain increments that arise in finite-element formulations employing an implicit solution of the global equilibrium equations. The resulting computational framework divorces the finite rotation effects on . Consequently, all of the numerical refinements developed previously for small-strain plasticity (radial return with subincrementation, plane stress modifications, kinematic hardening, consistent tangent operators) are utilized without modificatIOn. Details of the numerical algorithms are provided including the necessary transformation matrices and additional techniques re9.uired for finite deformations in plane stress. Several numerical examples are presented to illustrate the realIstic responses predicted by the model and the robustness of the numerical procedures. ABSTRACTThe theoretical basis and numerical implementation of a plasticity model suitable for finite strains and rotations are described. The constitutive equations governing J2 flow theory are formulated using strains-stresses and their rates defined on the unrotated frame of reference. Unlike models based on the classical Jaumann (or corotational) stress rate, the present model predicts physically acceptable responses for homogeneous deformations of exceedingly large magnitude. The associated numerical algorithms accommodate the large strain increments that arise in finite-element formulations employing an implicit solution of the global equilibrium equations. The resulting computational framework divorces the finite rotation effects on strain-stress rates from integration of the rates to update the material response over a load (time) step. Consequently, all of the numerical refinements developed previously for small-strain plasticity (radial return with subincrementation, plane stress modifications, kinematic hardening, consistent tangent operators) are utilized without modification. Details of the numerical algorithms are provided including the necessary transformation matrices and additional techniques required for finite deformations in plane stress. Several numerical examples are presented to illustrate the realistic responses predicted by the model and the robustness of the numerical procedures.-ii - ACKNOWLEDGMENTS

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Some computational aspects of elastic‐plastic large strain analysis

Cited by 136 publications

References 10 publications

Modelling fluid and shell structure interaction by combined finite element method and particle method

Modelling fluid and shell structure interaction by combined finite element method and particle method

Criteria for Crack Deflection-Penetration in EBC Coated Ceramics: A Parametric Study

A large strain plasticity model for implicit finite element analyses

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