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Incrementally linear constitutive model. Nonlinear solution procedure

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Hello everyone,

My doubt is related with the obtenion of the true stress when using incrementally linear constitutive models (hypoelastic models). These models, alternatively to total stress strain models, related increment of strain and increment of stress. The predicted stress is obtained by adding to the previous stress the stress increment obtained by using the tangent matrix. By using total stress-strain models it is clear that the true stress is obtained by substituting the current strain into the constitutive equation. How do we do this for hypoelastic models?

sunbohua's picture

Exact solution of Qian equation of slender toroidal shells

In 1979 Qian Weichang studied the slender toroidal shell systematically and derived a called Qian’s equation, then obtained a series solution with the expression of continued fractions. But Qian did not mention if the series solution can be converted to a well-known special functions. In this paper, a linear transformation has been introduced, which will transfer the equation into a Mathieu equation, whose solution can be expressed in terms of Mathieu functions. This study has revealed a intrinsic relationship between the Qian’s solution and the Mathieu solutions.

sunbohua's picture

Dimensional analysis and applications (invited article)

The paper gives a systematical introduction on dimensional analysis (DA), and proposes a six-steps on how to use the dimensional analysis, the universality of the DA will be shown by some typical examples, such as, point blast, pipe flow and a small sphere moving through a viscous fluid.

published: Physics and Engineering, Vol 26, No.6, pp.11-20, 2016. Invited article, in Chinese)

karelmatous's picture

A review of predictive nonlinear theories for multiscale modeling of heterogeneous materials

Since the beginning of the industrial age, material performance and design have been in the midst of innovation of many disruptive technologies. Today’s electronics, space, medical, transportation, and other industries are enriched by development, design and deployment of composite, heterogeneous and multifunctional materials. As a result, materials innovation is now considerably outpaced by other aspects from component design to product cycle. In this article, we review predictive nonlinear theories for multiscale modeling of heterogeneous materials.

PolyFEM: Obtaining polygonal mesh from structured T3 Mesh

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Hello,

I am developing a solver implemeting Polygonal Finite Element Method (PolyFEM). Currently my code can handle n-gons with nmax=6 (hexgon).

I am trying to test the code with comlex geometries for which I need to obtain polygonal meshes. PolyMesher developed by Dr Paulino's group can obtain polygonal mesh using voronoi doagrams but the code doesn't provide control over the maximum number of edges of a polygon in mesh and ends up creating octagons etc. Hence I am thinking of using a code which can convert a structured  T3 mesh into hexagonal mesh.

mohsenzaeem's picture

Quantitative phase-field crystal modeling of solid-liquid interfaces for FCC metals

This work deals with the quantification and application of the modified two-mode phase-field crystal model (M2PFC; Asadi and Asle Zaeem, 2015) for face-centered cubic (FCC) metals at their melting point. The connection of M2PFC model to the classical density functional theory is explained in this article. M2PFC model in its dimensionless form contains three parameters (two independent and one dependent) which are determined using an iterative procedure based on the molecular dynamics and experimental data.

bohrapankaj's picture

Why Natural Frequency of Functionally Graded Material Plate decreases with increase in temperature

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Dear Colleges i want to know why natural frequency of FGM plate reduces with increase of temperature 

Asymmetric stress strain response

Hello,

I need advice about how to model the asymmetric plastic response of POM in Abaqus?

The yield point in tension is 70mpa and 120mpa in compression. Also the elastic behaviour of the POM is very nonlinear and visco.

Please advice how to model these behaviors in Abaqus.

 

Best regards 

Ali

Moving load on roller coaster track

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Hi friends

I have model roller coaster track in Adams software and i have obtained force-time history but i do not now how to apply this history in abaqus.

  Any help will be greatly appreciated.

Insert cohesive element between every two elements

Hello everyone

I am wondering how to insert the cohesive element between every two solid elements in Abaqus, such that each element can separate with others? Is there a tool can do this and generate Abaqus input file?

Thanks

Mirkhalaf's picture

Post yield response of amorphous polymers under different stress states

In this contribution, an elasto-viscoplastic constitutive model based on the single mode EGP (Eindhoven Glassy Polymer) model is proposed to describe the deformation behaviour of solid polymers subjected to finite deformations under different stress states. The material properties of the original model are determined and calibrated from a uniaxial compression-loading test. Then, several numerical examples under different stress states are presented to illustrate the limitations.

Arash_Yavari's picture

The Anelastic Ericksen's Problem: Universal Eigenstrains and Deformations in Compressible Isotropic Elastic Solids

The elastic Ericksen's problem consists of finding deformations in isotropic hyperelastic solids that can be maintained for arbitrary strain-energy density functions.  In the compressible case, Ericksen showed that only homogeneous deformations are possible. Here, we solve the anelastic version of the same problem, that is we determine both the deformations and the eigenstrains such that a solution to the anelastic problem exists for arbitrary strain-energy density functions. Anelasticity is described by finite eigenstrains.

Jinxiong Zhou's picture

Predicting origami-inspired programmable self-folding of hydrogel trilayers

Imitating origami principles in active or programmable materials opens the door for development
of origami-inspired self-folding structures for not only aesthetic but also functional purposes. A
variety of programmable materials enabled self-folding structures have been demonstrated across
various fields and scales. These folding structures have finite thickness and the mechanical
properties of the active materials dictate the folding process. Yet formalizing the use of origami

mohsenzaeem's picture

Formation path of delta hydrides in zirconium by multiphase field modeling

A multiphase field model is developed to study the effects of metastable ζ and γ hydrides on the nucleation and growth of the stable δ hydrides in α zirconium matrix.  Acta Materialia 123 (2017) 235-244 

Wenbin Yu's picture

A Better Alternative to RVE Analysis

RVE analysis is popular for computational homogenization. It can be used independently for virtual testing or as a module for multiscale modeling. Its popularity is mainly due to the maturity and acceptance of commercial finite element software. RVE analysis usually requires a 3D domain to obtain 3D properties and local fields. If a 2D RVE is used, only 2D properties and local fields are obtained. To obtain the complete set of properties, multiple analysis is needed. For example, to obtain the complete stiffness matrix, six 3D RVE analyses are needed.

Mohr Coulomb plasticity model

Hello everyone,

 

I am trying to implement a Mohr Coulomb plasticity model(no hardening at the moment) for the plane strain case. However, the results are not making so much sense.

I was wondering if any of you have tried to code this material model successfully before, or if you could provide me with some algorithm or reference which you know works properly.

 

Thank you.

Setareh

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