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Hidroxid's picture

Assigning crystal plasticity material constants for one crystal with more than one element (default of Dr Huangs model)

Hi!

 

I am just a beginner in Abaqus UMAT and I have started working with Dr Huang's crystal plasticity UMAT in Abaqus.

When I am assigning one material constants for one element crystal it works but when I try to assign it to more than one element for one crystal (for example group of elements with same grain orientation) it give me error code 144.

Can anybody explain me the reason?

 

 

Thanks in advance,

Kind regards,

Omid

 

CTE: coefficient of thermal expansion - Secant Method - Ansys

Choose a channel featured in the header of iMechanica: 

Hello,

 

I have to perform a thermo-mechanical simulation in Ansys WB and I have to provide the cte of a material.

I have few experience with thermo-mechanical simulation.

I have got a document with the material properties of this material; there I have the Tg (glass transition temperature)

and two coefficients: cte1 (below Tg) and cte2 (above Tg).

 

-->  How should I calculate the CTE for a temperature range (e.g. -50 < Tg < 300) ?   <---

 

sandeep@iit_guwahati's picture

A new time integration scheme for dynamic problems

(Master's thesis attached)An extension to an implicit time integration scheme of Silva and Bezerra has been proposed . It is proposed to combine the Newmark scheme with the three point backward Euler scheme to have more user controlled numerical properties like high frequency dissipation. Also, the stability, accuracy, and dissipation of the proposed scheme have been studied. This is achieved by studying the spectral radius, period elongation, and amplitude decay.

bitamendi's picture

Looking for a VUMAT programmer to share publication with

Dear researchers,

 

I’m Joseba Mendiguren, researcher at the Advanced Manufacturing Group of Mondragon Unibertsitatea. I’m currently working on advanced yielding/hardening models for metals.
I’m in the middle of a paper writing work but I cannot find time to sit down and program the VMAT that I need to run some simulations for the paper. I’m looking for a VUMAT programmer researcher willing to work on the topic and share the publication authorship on return.

Gyanender Singh's picture

Clarification on creep

Hello,

My work is related to creep in ceramics. Often I find the relation between the creep strain rate and stress as:

creep_strain_rate = constant x stress x other_factors                  (1)

 

"stress" is a general term here. Sometimes this relation (1) is applied along the principal stress direction; stress then refers to principal stress. In other cases stress is used to represent the effective stress which is expressed as following (not sure if this is complete/correct definition):

 

Giorgio Carta's picture

Dynamic response and localisation in strongly damaged waveguides

In this paper, we investigate the formation of band-gaps and localisation phenomena in an elastic strip nearly disintegrated by an array of transverse cracks. We analyse the eigenfrequencies of finite, strongly damaged, elongated solids with reference to the propagation bands of an infinite strip with a periodic damage. Subsequently, we determine analytically the band-gaps of the infinite strip by using a lower-dimensional model, represented by a periodically-damaged beam in which the small ligaments between cracks are modelled as ‘elastic junctions’.

Davide Bigoni's picture

Can an elastic rod attain self-encapsulation when loaded transversally at midspan?

Can an elastic rod attain self-encapsulation when loaded transversally at midspan?

The elastic rod assumes the form of a liquid drop at self-encapsulation!
Enjoy the dripping of an elastic rod at
http://www.ing.unitn.it/~bigoni/dripping.html

linst06's picture

3D Printing of Highly Stretchable and Tough Hydrogels into Complex, Cellularized Structures

Sungmin Hong, Dalton Sycks, Hon Fai Chan, Shaoting Lin, Gabriel P. Lopez, Farshid Guilak, Kam W. Leong, Xuanhe Zhao, Advanced Materials, 27, 4035-4040, 2015. 

 

Kumar Ankit's picture

Phase-field simulations of non-cooperative eutectoid transformation proceeding from polycrystalline austenite in Fe-C steels

Link to the article published in Acta Materialia: http://authors.elsevier.com/a/1RMRv_UwYsChmK (Free access for 50 days)

K. Ankit, R. Mukherjee, B. Nestler. Deviations from cooperative growth mode during eutectoid transformation: Mechanisms of polycrystalline eutectoid evolution in Fe–C steels. Acta Materialia 97 (2015) 316–324.

Wenbin Yu's picture

Micromechanics Simulation Challenge Level I Initial Results Available

The initial results of level I of micromechanics simulation challenge have been compiled into a report, which is available at https://cdmhub.org/resources/948.  Results for various composites including iber reinforced composites, particle reinforced composites, laminates, woven composites, short fiber composites from several readily available micromechanics simulation tools include MAC/GMC, MAC/HFGMC, FVDAM, MDS, DIGIMAT, SwiftComp are compiled.

Meisam. Asgari's picture

The edge effect in open lipid bilayers

Highlights:

 A model for the free energy of the edge of an open lipid bilayer is derived.

The derivation is based on the interactions of the molecules comprising the edge.

The derived model can be employed to study pore growth in open lipid bilayers.

The model captures bending and torsional energies of the edge, in addition to the line tension.

The molecular origins of spontaneous curvatures and elastic moduli are investigated.

Applied Mechanics Division – Haythornthwaite Foundation Research Initiation Grants

With funding from the Haythornthwaite Foundation, the Executive Committee (EC) of the Applied Mechanics Division (AMD) of ASME is pleased to announce the establishment of the Haythornthwaite Research Initiation Grant Program, targeting university faculty engaged in research in theoretical and applied mechanics that are at the beginning of their academic careers. Applicants must hold a tenure-track appointment at the rank of Assistant Professor at a US university on October 1, 2015, and must not be more than 5 years beyond receipt of their doctoral degree at the time the award is made.

Regarding the ABAQUS Subroutine 'FRIC'

Dear all,

I have recently using the subroutine FRIC in ABAQUS, and I found that there is a variable 'PRESS' which is specified as 'contact pressure at end of increment' in the ABAQUS documentations. However, I have extracted this PRESS in a text file through applying the subroutine FRIC in a two-block compression model, and I found that the PRESS is different from the contact pressure (CPRESS) which can be obtained from the field output and it seems that there are two values in each simulation increment.

alicia's picture

Postdoc opening in design optimisation at the University of California, San Diego

The Multiscale and Multiphysics Design Optimization Group at the University of California, San Diego, is looking for a Postdoc. The research will develop numerical methods in coupled multiphysics and multiscale topology optimisation in aircraft in a modularized and parallel computing environment. It is expected that the applicants would have background in topology optimization or level set method, aeroelasticity, computer programming and computational mechanics.

*BEAM GENERAL SECTION

Choose a channel featured in the header of iMechanica: 

Hi 

Could you please tell me how to create a *Beam General Section(abaqus) for triangular element with all sieds are equal.

 

Ravi 

ASME Applied Mechanics Division Seeks Nominations for Awards

The Applied Mechanics Division, of the American Society of Mechanical Engineers, seeks nominations for the awards listed below. All the awards are international. Neither the nominee nor the nominator need be a member of the ASME. However nominators must not be active members of the respective award committees. Further descriptions of the awards are given at http://divisions.asme.org/amd/Honors_Awards.cfm. A PDF version of this announcement can be found as an attachment at the end of this blog entry.

Eran Bouchbinder's picture

Dynamic instabilities of frictional sliding at a bimaterial interface

Understanding the dynamic stability of bodies in frictional contact steadily sliding one over the other is of basic interest in various disciplines such as physics, solid mechanics, materials science and geophysics. Here we report on a two-dimensional linear stability analysis of a deformable solid of a finite height H, steadily sliding on top of a rigid solid within a generic rate-and-state friction type constitutive framework, fully accounting for elastodynamic effects.

Mario Juha's picture

Large-eddy simulation with near-wall modeling using weakly enforced no-slip boundary conditions

In the present paper, weakly enforced no-slip wall boundary conditions are revisited in the context of Large-Eddy Simulations (LES) with near-wall modeling. A new formulation is proposed in the framework of weakly enforced no-slip conditions that is better aligned with traditional near-wall modeling approaches than its predecessors.

shuyang's picture

Journal Club Theme of July 2015: Reconfigurable metamaterials -- putting the holes in the right place

Reconfigurable metamaterials -- putting the holes in the right place

 

Shu Yang1 and Jie Yin2

1Department of Materials Science and Engineering, University of Pennsylvania, E-mail: shuyang@seas.upenn.edu

Opening for new Ph.D. students in the Computational Mechanics group, The University of Iowa.

The Computational Mechanics group at The University of Iowa, led by Professor S. Rahman, is looking for new Ph.D. students, who are capable of and interested in performing high-quality research on engineering design. The research, supported by National Science Foundation and others, entails building a solid mathematical foundation, devising efficient numerical algorithms, and developing practical computational tools for stochastic design optimization. A substantial background in solid mechanics and structural optimization is a must; exposures to stochastics and probabilistic methods are highly desirable.

If you are interested in pursuing a Ph.D. degree at Iowa, please contact and send a resume to: Professor Sharif Rahman at sharif-rahman@uiowa.edu. Please note that we are interested in students who already have M.S. degrees in engineering or mathematics. The desired start date is Spring 2016 or sooner.

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