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Modeling/defining Loop of blocks of different load amplitude

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Dear all

In the experiment setup, the fatigue loading spectrum has a loop of 2 blocks of load amplitude. First load amplitude the higher applied for 2X time period followed by lower load amplitude for X time period then the loop repeated till failure.  the load sequence was High-Low and Low-High in this loop. X was in thousands so might be suggested as the cyclic response will be stabilized in the first 10 cycles, the first block will dominate the fatigue behaviour at least till fracture, or damage initiation.

sergkuznet's picture

Topology optimization of magnetic source distributions for diamagnetic and superconducting levitation

Topology optimization is used to obtain a magnetic source distribution providing levitation of a diamagnetic body or type I superconductor with maximized thrust force. We show that this technique identifies non-trivial source distributions and may be useful to design devices based on non-contact magnetic suspension and other magnetic devices, such as micro-magneto-mechanical devices, high field magnets etc.

Mike Ciavarella's picture


If you have seen the very nice PNAS paper which just appeared

Sahli, R., Pallares, G., Ducottet, C., Ben Ali, I.E., Al Akhrass, S., Guibert, M., Scheibert, J., 2018, Evolution of real contact area under shear, Proceedings of the National Academy of Sciences, 115(3), pp. 471-476.

Here we provide a simple explanation.


Series: Mechanical Engineering

DOI: 10.22190/FUME180108007C

Short Communication


UDC 539.6

Emilio Martínez Pañeda's picture

Non-local plasticity effects on notch fracture mechanics (code included)

I hope some of you find this work interesting, the code with the control algorithm (Segurado and Llorca, 2004) to avoid convergence problems in cohesive zone model analyses of crack propagation can be downloaded from (documentation and Abaqus input files are provided).

Non-local plasticity effects on notch fracture mechanics

Emilio Martínez-Pañeda, Susana del Busto, Covadonga Betegón 

Theoretical and Applied Fracture Mechanics (2017)

Mahdi Z.'s picture

Mechanics of an elastic solid reinforced with bidirectional fiber in finite plane elastostatics

A continuum-based model is presented for the mechanics of bidirectional composites subjected to finite plane deformations. This is framed in the development of a constitutive relation within which the constraint of material incompressibility is augmented. The elastic resistance of the fibers is accounted for directly via the computation of variational derivatives along the lengths of bidirectional fibers. The equilibrium equation and necessary boundary conditions are derived by virtue of the principles of virtual work statement.

Arash_Yavari's picture

Compatible-Strain Mixed Finite Element Methods for Incompressible Nonlinear Elasticity

We introduce a new family of mixed finite elements for incompressible nonlinear elasticity — compatible-strain mixed finite element methods (CSFEMs). Based on a Hu-Washizu-type functional, we write a four-field mixed formulation with the displacement, the displacement gradient, the first Piola-Kirchhoff stress, and a pressure-like field as the four independent unknowns. Using the Hilbert complexes of nonlinear elasticity, which describe the kinematics and the kinetics of motion, we identify the solution spaces of the independent unknown fields.

Wenbin Yu's picture

Some ideas for a possible new journal

Inspired by the discussion with Mike Ciavarella on, I am thinking about a journal with the following attributes:

Ajeet Kumar's picture

An asymptotic numerical method for continuation of spatial equilibria of special Cosserat rods

We present an efficient numerical scheme based on asymptotic numerical method for continuation of spatial equilibria of special Cosserat rods. Using quaternions to represent rotation, the equations of static equilibria of special Cosserat rods are posed as a system of thirteen first order ordinary differential equations having cubic nonlinearity. The derivatives in these equations are further discretized to yield a system of cubic polynomial equations.

Partial constraint singularities in elastic rods

We present a unified classical treatment of partially constrained elastic rods. Partial constraints often entail singularities in both shapes and reactions. Our approach encompasses both sleeve and adhesion problems, and provides simple and unambiguous derivations of counterintuitive results in the literature. Relationships between reaction forces and moments, geometry, and adhesion energies follow from the balance of energy during quasistatic motion. We also relate our approach to the configurational balance of material momentum and the concept of a driving traction.

Karol Frydrych's picture

4-noded to 10-noded tetrahedron

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Does anyone know, if there is a simple way to change the order of tetragonal mesh. I have a mesh given by list of nodes and a list of elements so I need to add additional nodes. The elements have straight edges, so there is no problem of curvature.

Kind regards,


mohamedlamine's picture

Concrete stress-strain curve

The concrete stress-strain curve corresponds to the compression case with negative values plotted on positive axis. If one needs to plot the tensile curve for this concrete material this will be almost similar with {0.1*compression} stresses with positive values. Furthermore if one needs to plot on the same axis the tensile steel and concrete stresses for a composite mixture he needs to consider this last case. Fortunately the tensile and compression steel stresses are quite similar with opposite values.

keyhani's picture

Experimental Study of Natural Convection from an Array of Square Fins

In this research, we experimentally investigate natural convection heat transfer of three finned-tube exchangers with an array of square fins and a fin spacing of 5, 9, and 14 mm. The exchangers are in a 5.8m x 4m x 3m control room where temperature and humidity are automatically controlled with heating, cooling, humidifying, and dehumidifying equipment. We changed the surface temperature of the center tube by varying the input power of the heating element from 8.4 to 56.7 Watts.

mohsenzaeem's picture

Understanding Homogeneous Nucleation in Solidification of Aluminum by Molecular Dynamics Simulations (OPEN ACCESS)

Homogeneous nucleation from aluminum (Al) melt was investigated by million-atom molecular dynamics (MD) simulations utilizing the second nearest neighbor modified embedded atom method (MEAM) potentials. The natural spontaneous homogenous nucleation from the Al melt was produced without any influence of pressure, free surface effects and impurities. Initially isothermal crystal nucleation from undercooled melt was studied at different constant temperatures, and later superheated Al melt was quenched with different cooling rates.

Amir Abdollahi's picture

Flexoelectricity in Bones: A nanophenomenon that triggers the bone-repair process

Bones generate electricity under pressure, and this electromechanical behavior is thought to be essential for bone's self-repair and remodeling properties. The origin of this response is attributed to the piezoelectricity of collagen, which is the main structural protein of bones. In theory, however, any material can also generate voltages in response to strain gradients, thanks to the property known as flexoelectricity.

ntuecd's picture

Welding simulation

The aim of this tutorial is to develop a step-by-step instructions for simulation of a welding process with the FEA-program LS-PrePost. The tutorial contain a simulation of a single-pass gas metal arc welding, but we can use the same method to simulate multi-pass welding.

Yizhe_Tang's picture

Inertia of Dislocation Motion and Negative Mechanical Response in Crystals

Dear Colleagues,

Please see attached a recent article published in Scientific Reports on the fundamental nature of dislocation motion in crystals. Leave your comments or whatever you think of it.




User defined contact output (at contact pairs)

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Hi all,

Jingjie Yeo's picture

High-Strength, Durable All-Silk Fibroin Hydrogels with Versatile Processability toward Multifunctional Applications Hydrogels are the focus of extensive research due to their potential use in fields including biomedical, pharmaceutical, biosensors, and cosmetics. However, the general weak mechanical properties of hydrogels limit their utility. Here, pristine silk fibroin (SF) hydrogels with excellent mechanical properties are generated via a binary-solvent-induced conformation transition (BSICT) strategy.

Sundaraelangovan selvam's picture

Validation of Numerical (INCS) method for Elastic wave case

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Dear mechanician,

Mike Ciavarella's picture

Nobel laureate Randy Schekman: How journals like Nature, Cell and Science are damaging science

An article on the Guardian here.  Critics will say Shelkman has founded his own open access journal, here, probably competing with Nature, Cell and Science, which explains a lot.



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