A forum to discuss structures and properties of materials
Dear Friends.
I want to simulte the mechanic behavior of of Fiber Reinforced Composites and Textile Reinforced Composites.
Could you give me some advice on which software is suitable?
Thank you in advance
Eric qiu
Does any one knows a good reference about lath martensite?
Why we see the retained austenite? why doesn't it transformto martensite? What's its effect on the phase transformation? Does the plasticity change the morphology of the transfromation? How about the speed of the transfromation? When should we expect to see the lath martensite? What's the effect of the diagonal terms in the transformation matrix? What's the effect of the shear components? Is there any difference between 2d and 3d simulations, and which one is more realistic?
Recent experiment have shown the size effect of the materials, when the characteristic length associated with non-uiform plastic deformation is on the scale of micros.The classic plasticity theories can't explain such phenomenon as their constitutive models posses no intrinsic length scale. The new models which contain strain gradient plasticity now are used to explain the experiment.
What can we do in this discovery and creation?
By Xudong Wang, Jinhui Song, Jin Liu, Zhong Lin Wang*
Graphene is the world's thinnest material.
The one-atom-thick carbon layers have shown remarkable strength and stiffness.
The so-called "graphene-based sheets" can be mixed into polymers, glasses and ceramics, to produce novel composite materials with useful thermal, electrical and mechanical properties.
Determination of Strain Gradient Elasticity Constants for Various Metals, Semiconductors, Silica, Polymers and the (Ir) relevance for Nanotechnologies
Strain gradient elasticity is widely used as a suitable alternative to size-independent classical continuum elasticity to, at least partially, capture elastic size-effects at the nanoscale. In this work, borrowing methods from statistical mechanics, we present mathematical derivations that relate the strain-gradient material constants to atomic displacement correlations in a molecular dynamics computational ensemble. Using the developed relations and numerical atomistic calculations, the dynamic strain gradient constants have been explicitly determined for some representative semiconductor, metallic, amorphous and polymeric materials. This method has the distinct advantage that amorphous materials can be tackled in a straightforward manner. For crystalline materials we also employ and compare results from both empirical and ab-initio based lattice dynamics. Apart from carrying out a systematic tabulation of the relevant material parameters for various materials, we also discuss certain subtleties of strain gradient elasticity, including: the paradox associated with the sign of the strain-gradient constants, physical reasons for low or high characteristic lengths scales associated with the strain-gradient constants, and finally the relevance (or the lack thereof) of strain-gradient elasticity for nanotechnologies.
Using classical molecular dynamics and empirical potentials, we show that the axial deformation of single-walled carbon nanotubes is coupled to their torsion. The axial-strain-induced torsion is limited to chiral nanotubes—graphite sheets rolled around an axis that breaks its symmetry. Small strain behavior is consistent with chirality and curvature-induced elastic anisotropy (CCIEA)—carbon nanotube rotation is equal and opposite in tension and compression, and decreases with curvature and chirality. The largestrain compressive response is remarkably different.
Dear Fellow Mechanicians,
My group is looking into some aspects of fracture in "functionally graded materials". I was curious to know if there are groups (on imechanica) interested or actively pursuing research on functionally graded materials or nanocomposites.
kubair [at] aero.iisc.ernet.in
