research

In this manuscript (available at http://arxiv.org/abs/1004.1765), we present a systematically improvable, linear scaling formulation for the solution of the all-electron Coulomb problem in crystalline solids. In an infinite crystal, the electrostatic (Coulomb) potential is a sum of nuclear and electronic contributions, and each of these terms diverges and the sum is only conditionally convergent due to the long-range 1/r nature of the Coulomb interaction.

In the study of thermoelastic actuation of dielectric elastomer, we can write the Helmholtz free-energy as a function of stretch ratio, nominal electric displacement and temperature (T).

The entropy (S) is the negative partial differential coefficient of W with respect of temperature (T). And we can see the change of S is due to three components: deformation, heat conduction and polarization. In an isothermal state, the deformation part has been fully investigated by Arruda and Boyce in 1993, but the polarization-induced entropy (Sp) has not been clearly stated.

Hi All,

Most exisiting failure critera delevolped for fiber composite laminates and they are rough estimations for fabric composite. I want to know if there is a suitable failure criterion for fabric composites.

Thanks

Azadeh

Dear all,



I have modeled a cyclic ball indentation problem in
Abaqus. The sphere has been modeled as axisymmetric rigid surface while
the plate is axisymmetric deformable. The material data fed in for the
plate has been obtained from low cycle fatigue experiments and the
combined hardening model using half-cycle has beem employed.



Apart from this, the loading is displacement-controlled and sphere
is the master surface while the plate is slave surface. The other

Amit Acharya and Kaushik Dayal

 (To appear in Quarterly of Applied Mathematics)

This paper presents a generalization of traditional continuum approaches to liquid crystals and

liquid crystal elastomers to allow for dynamically evolving line defect distributions. In analogy with

recent mesoscale models of dislocations, we introduce fields that represent defects in orientational

and positional order through the incompatibility of the director and deformation ‘gradient’ fields.

Hi

I have a problem with the simulation of Mohr Coulomb problem. I want to set the properties of a sand. I use the experimental data from papers and i try to find the bearing capacity for a footing on sand. I set density ρ, E modulus of elasticity , ν Poissoin's ratio and for the Mohr Coulomb model i set φ shear strength, ψ dilatancy , c cohesion (a very small value=0.00001 ) for strain 0 . Does it need anything else? Does it need for hardening parameters any diagram for cohesion -plastic strain for the Mohr Coulomb model? 

Dear All,

             There is an excellent tool called Mendeley that can be freely downloaded from (www.mendeley.com). It helps you in organizing the literature collection and  in optimizing the literature review process.

Thanks and Regards,

Naga Sai Rohith

Hi everybody,

I am dealing with a beam with a hole containing a crack loaded at the mid-span. I am wondering if the stress intensity factors

(KI, KII) closed form solution have been expanded for this case or not? I would appreciate if anybody could hlep me about this

case.

Thank you,

Parisa

A review paper on stretchable electronics written by Professors John A. Rogers, Takao Someya, and Yonggang Huang was published in a recent issue of Science . This paper gives a nice summary on the recent advances in inorganic and organic stretchable electronics. Materials, structures and mechanics of these systems are discussed. Many attractive applications of stretchable electronics are introduced, such as stretchable silicon circuit, electronic eyeball camera, and flexible LED display.