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mohsenzaeem's picture

Generalized stacking fault energies, ductilities, and twinnabilities of CoCrFeNi-based face-centered cubic high entropy alloys

Effects of Cu, Mn, Al, Ti, Mo on generalized stacking fault energies, Rice-criterion ductilities, and twinabilities of CoCrFeNi-based face-centered cubic high entropy alloys were investigated using density functional theory calculations. The calculated barrier energies and twinnabilities revealed that the addition of Ti or Mo increased the tendency of dislocation glide and deformation twinning, while addition of Mn, Cu and relatively high amount of Al facilitated dislocation gliding and martensitic transformation. Low amount of Al resulted in only dislocation gliding.

Mike Ciavarella's picture

Some Closed-Form Results for Adhesive Rough Contacts Near Complete Contact on Loading and Unloading in the Johnson, Kendall, and Roberts Regime

Michele Ciavarella  Yang Xu Robert L. Jackson

Some Closed-Form Results for Adhesive Rough Contacts Near Complete Contact on Loading and Unloading in the Johnson, Kendall, and Roberts Regime

Journal of Tribology Copyright VC 2018 by ASME JANUARY 2018, Vol. 140 / 011402-1

 

Recently, generalizing the solution of the adhesiveless random rough contact proposed

by Xu, Jackson, and Marghitu (XJM model), the first author has obtained a model for

adhesive contact near full contact, under the Johnson, Kendall, and Roberts (JKR)

Dependence of Equilibrium Griffith Surface Energy on Crack Speed in Phase-Field Models for Fracture Coupled to Elastodynamics

Phase-field models for crack propagation enable the simulation of complex crack patterns without complex and expensive tracking and remeshing as cracks grow. In the setting without inertia, the crack evolution is obtained from a variational energetic starting point, and leads to an equation for the order parameter coupled to elastostatics. Careful mathematical analysis has shown that this is consistent with the Griffith model for fracture. Recent efforts to include inertia in this formulation have replaced elastostatics by elastodynamics.

Ruobing Bai's picture

Fatigue fracture of tough hydrogels

Dear colleagues,

Attached please find our new paper "Fatigue fracture of tough hydrogels" published on Extreme Mechanics Letters.

 

Fatigue fracture of tough hydrogels

Ruobing Bai, Quansan Yang, Jingda Tang, Xavier P. Morelle, Joost Vlassak, Zhigang Suo

ntuecd's picture

Model two heat source for arc welding simulation using ls-dyna??

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Hallo,

 

i am trying to compute the temperature distribution in arc welding simulation by using two heat source simultaneously (first one on the top of the plate and second one on the bottom of the plate). For this simulation i am using the software LS-DYNA. But, unfortunately my simulation terminate with following error which i am unable to understand:

 

*** Error 60110 (IMP+110)
terminating : MF2 Factorization error 14
E r r o r t e r m i n a t i o n

 

ntuecd's picture

Temperature field simulation by using LS-DYNA??

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Hallo welding simulation experts,

 

i am trying to simulate the temperature field in a single pass weld by using the commercial software LS-DYNA. I had simulated the welding torch by using beam element concept and it works perfect.

 

Zhaohe Dai's picture

Measuring Interlayer Shear Stress in Bilayer Graphene

Monolayer two-dimensional (2D) crystals exhibit a host of intriguing properties, but the most exciting applications may come from stacking them into multilayer structures. Interlayer and interfacial shear interactions could play a crucial role in the performance and reliability of these applications, but little is known about the key parameters controlling shear deformation across the layers and interfaces between 2D materials. Herein, we report the first measurement of the interlayer shear stress of bilayer graphene based on pressurized microscale bubble loading devices.

mohsenzaeem's picture

Effects of specimen size and yttria concentration on mechanical properties of single crystalline yttria-stabilized tetragonal zirconia nanopillars

The nanoscale plastic deformation of yttria-stabilized tetragonal zirconia (YSTZ) is highly dependent on the crystallographic orientations, i.e., dislocation is induced when the loading direction is 45° tilted to {111} and {101} slip planes, while tetragonal to monoclinic phase transformation dominates the plastic deformation when loading direction is perpendicular to the slip planes.

boechler's picture

Geometrically nonlinear microstructured materials for mechanical wave tailoring

Geometrically nonlinear microstructured materials for mechanical wave tailoring

Nicholas Boechler, Department of Mechanical Engineering, University of Washington 

LS DYNA-Structural Mechanics

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I am trying to simulate a seismic earthquake analysis in order to study collapse pattern on LS DYNA.

I have build the keyword from scratch.Although, I am new to LS Dyna, I have never performed such a simulation, I have build a test model consisting of 2 columns joined by a beam resting on a finite element representing soil.

Call for White Papers - Adaptive Biomimetic Aircraft Structures

Research opportunity in Adaptive Biomimetic Aircraft Structures, Solicitation Number: W911W6-17-R-0018 @ www.fbo.gov Response Date: Jul 14, 2017 2:00 pm Eastern

kourousis's picture

SLM Ti-6Al-4V Plastic Anisotropy

Cyclic Plasticity and Microstructure of As-built SLM Ti-6Al-4V: The Effect of Build Orientation

D. Agius, K.I. Kourousis, C. Wallbrink, T. Song

Materials Science & Engineering: A (2017) -- Free access to the full article available at: https://authors.elsevier.com/a/1VHXL_Ky~FZJ6H

marco.paggi's picture

Reaction diffusion problems in mechanics

For those interested in this topic, we are organizing a minisymposium at the European Solid Mechanics Conference (sponsored by EUROMECH) in Bologna, in 2018, see session 9.2:

http://www.esmc2018.org/drupal8/node/9

Some examples are:

Reaction diffusion and Brinkman flow to model chemical reactions and the motion of a contaminated viscous fluid:

Sundaraelangovan selvam's picture

What is the physical meaning of Green-Lagrangian strain and Eulerian-Almansi strain measures?

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Hello, researchers. I have difficulty in understanding the physical meaning of Green-Lagrangian strain (E) and Eulerian-Almansi strain (A) measures. Mathematically speaking, I can derive the equations of these strains in different ways. But physically speaking, it's a bit harder to understand how these strains (E and A) can be pictured and how to give a proper physical definition for them. In a simple case, considering a uni-axial bar (Please refer the attached file), Engineering strain can be understood easily, but in E and A equations, from where do the squares of the lengths originate?

marco.paggi's picture

Latest progresses on the phase field model for brittle fracture

Dear Fracture mechanician,

In my group we published 2 articles with novelties on the phase field model for brittle fracture:

 

Emilio Martínez Pañeda's picture

A cohesive zone framework for environmentally assisted fatigue (code included)

I hope some of you find this work interesting, the code with the cohesive zone model for fatigue can be downloaded as a user element (UEL) subroutine for Abaqus from empaneda.com/codes

A cohesive zone framework for environmentally assisted fatigue

Susana del Busto, Covadonga Betegón, Emilio Martínez Pañeda

Engineering Fracture Mechanics (2017)

http://www.sciencedirect.com/science/article/pii/S001379441730098X

Rui Xiao's picture

Recent Work "Modeling the Energy Storage and Structural Evolution during Finite Viscoplastic Deformation of Glassy Polymers"

The enthalpic response of amorphous polymers depends strongly on their thermal and deformation history. Annealing just below the glass transition temperature (Tg) causes a large endothermic overshoot of the isobaric heat capacity at Tg as measured by differential scanning calorimetry, while plastic deformation (cold work) can erase this overshoot and create an exothermic undershoot. This indicates that a strong coupling exists between the polymer structure, thermal response and mechanical deformation.

Teng Li's picture

CiteScore 2016 indicates soaring impact of Extreme Mechanics Letters

CiteScore is an impact factor based on a 3-year citation window, calculated using data from the Scopus database. CiteScore is free to use, comprehensive and transparent.

Frank Richter's picture

Bone remodeling: Komarova model

Dear Community,

I make a code public for bone remodeling, using the Komarova model. It was developed by me alone. I provide the code as is, without warranty.

The agreement between my data and the ones from a reference are very good for fixed loading, but deviate for a more intricate loading. Lacking access to Abaqus with a Fortran compiler, I am at present unable to pinpoint the cause for the discrepancy between my data and data from the reference. The code can serve as a starting point and I give directions how to identify the cause for that discrepancy.

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