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Bin Liu's picture

The widely used tensile stiffness ratio is not a correct measure of anisotropy degree

In our recent paper, some interesting conclusions are found when we attempt to establish a standardized compliance matrices for general anisotropic materials. The abstract is as follows.

UMAT for isotropic hardening

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Hello,

I'm new here and I'm not sure if this a right place to ask a question or not.

I'm trying to practice writing UMAT code and I just finished the (Coding for isotropic Mises plasticity) from the the attached document. I'm trying to check validity of this code with simple model: what kind of this simple model? how can I do that? 

 

Please help me with this problem

Regards,

Qusay

Chiqun Zhang's picture

On the relevance of generalized disclinations in defect mechanics

Chiqun Zhang            Amit Acharya

The utility of the notion of generalized disclinations in materials science is discussed within the physical context of modeling interfacial and bulk line defects like defected grain and phase boundaries, dislocations and disclinations. The Burgers vector of a disclination dipole in linear elasticity is derived, clearly demonstrating the equivalence of its stress field to that of an edge dislocation. We also prove that the inverse deformation/displacement jump of a defect line is independent of the cut-surface when its g.disclination strength vanishes. An explicit formula for the displacement jump of a single localized composite defect line in terms of given g.disclination and dislocation strengths is deduced based on the Weingarten theorem for g.disclination theory at finite deformation. The Burgers vector of a g.disclination dipole at finite deformation is also derived.

Arash_Yavari's picture

On the Stress Field of a Nonlinear Elastic Solid Torus with a Toroidal Inclusion

In this paper we analyze the stress field of a solid torus made of an incompressible isotropic solid with a toroidal inclusion that is concentric with the solid torus and has a uniform distribution of pure dilatational finite eigenstrains. We use a perturbation analysis and calculate the residual stresses to the first order in the thinness ratio (the ratio of the radius of the generating circle and the overall radius of the solid torus). In particular, we show that the stress field inside the inclusion is not uniform.

International Conference ECCOMAS SMART 2017, Madrid, Spain, on smart materials

Within the frame of the 8th ECCOMAS Thematic Conference on Smart Structures and Materials (SMART 2017), to be held in Madrid, Spain, on June 5-8, 2017, we are organizing minisymposium MS13 titled “Smart materials capable of recoverable inelastic strain”. 

Relevant contributions are solicited specifically in the following technical areas:

mesarovic's picture

Special Issue: Granular materials; Journal: Materials

Journal: Materials  (flyer attached)

Impact Factor 2.728

Special Issue: Granular materials   Special Issue Editor: Sinisa Mesarovic       Deadline: 15 April 2017

D. Schulte's picture

Wissenschaftlicher MA - Numerische Mechanik (FEM) -

Am Institut für Kontinuumsmechanik der Leibniz Universität Hannover ist eine Stelle als

"Wissenschaftliche Mitarbeiterin / Wissenschaftlicher Mitarbeiter" - EntgGr. 13 TV-L, 100 % - zum nächstmöglichen Zeitpunkt zu besetzen.
Die Stelle ist auf 4 Jahre befristet.

Zhengjin WANG 王正锦's picture

Extrusion, slide, and rupture of an elastomeric seal

Elastomeric seals are essential to two great technological advances in oilfields:  horizontal drilling and hydraulic fracturing.  This paper describes a method to study elastomeric seals by using the pressure-extrusion curve (i.e., the relation between the drop of pressure across a seal and the volume of extrusion of the elastomer).  Emphasis is placed on a common mode of failure found in oilfields:  leak caused by a crack across the length of a long seal.  We obtain an analytical solution of large elastic deformation, which is analogous to the Poiseuille flow of viscous liquids.

A slip wave solution in anti-plane elasticity

Abstract:

It is shown that a slip wave solution exists for anti-plane sliding of an elastic layer on an elastic half-space. It is a companion solution to the well-known Love wave solution.

https://dx.doi.org/10.1093/gji/ggw464

bardia's picture

PhD/masters position in Mechanical Department at University of Hawaii at Manoa

A PhD/masters position is available in AMMI Lab at University of Hawaii at Manoa in the field of surgical robotics. Interested and outstanding candidates should visit my website at http://uhatmanoa.wixsite.com/ammi. Information about general admission process could be found on http://uhatmanoa.wixsite.com/ammi/prospective-students.

Emilio Martínez Pañeda's picture

Damage modeling in Small Punch Test specimens

I hope some of you may find this work interesting:

Damage modeling in Small Punch Test specimens

E. Martínez-Pañeda, I.I. Cuesta, I. Peñuelas, A. Díaz, J.M. Alegre

Theoretical and Applied Fracture Mechanics, 86A, pp. 51-60

http://www.sciencedirect.com/science/article/pii/S0167844216301616

A pre-print is available at www.empaneda.com

zichen's picture

How the embryonic chick brain twists

During early development, the tubular embryonic chick brain undergoes a combination of progressive ventral bending and rightward torsion, one of the earliest organ-level left–right asymmetry events in development. Existing evidence suggests that bending is caused by differential growth, but the mechanism for the predominantly rightward torsion of the embryonic brain tube remains poorly understood.

mesarovic's picture

Special Issue: Plasticity of Crystals and Interfaces; Journal: Crystals

Journal: Crystals

Special Issue: Plasticity of Crystals and Interfaces

Special Issue Editor: Sinisa Dj. Mesarovic

Deadline for submission of papers: 30 April 2017

 

ahmed.hussein's picture

The strength and dislocation microstructure evolution in superalloy microcrystals

In this work, the evolution of the dislocations microstructure in single crystal two-phase superalloy microcrystals under monotonic loading has been studied using the three-dimensional discrete dislocation dynamics (DDD) method. The DDD framework has been extended to properly handle the collective behavior of dislocations and their interactions with large collections of arbitrary shaped precipitates. Few constraints are imposed on the initial distribution of the dislocations or the precipitates, and the extended DDD framework can support experimentally-obtained precipitate geometries.

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 

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