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AnimeshAnimesh 

How to measure strain rate in material studio to develop stress strain curve in different strain rate?????

we known that  strain rate  = velocity (dx/dt)  X original length (x)
During mechanical calculation, if you change velocity of atom after NVE run . Can we say different strain rate ???? 
Otherwise what are the procedure to run different strain rate in material studio???   
Jason DeJoannisJason DeJoannis
Hi Animesh,

No I would not recommend tampering with atom velocities to achieve a stress-strain simulation. 
Actually there is a script shipped with Materials Studio that already does this:

File | Import | Examples\Scripting\StressStrain.pl

It also comes with another file

Examples\Scripting\StressStrain User Menu.xml

which you can import into your User Menu, giving you the following dialog:
User-added image

The script applies a uniaxial stress and measures the strain response. The stress is incremented
systematically to produce a stress-strain curve.

Best,
Jason
AnimeshAnimesh
Jason SIr,
Thanks for reply. This is for stress strain curve. But i want to develop strain rate based stress strain curve. Strain rate will be changed . Please help in this matter.
---Animesh
Jason DeJoannisJason DeJoannis
Here's one that does that:
AnimeshAnimesh
Dear Jason Sir,
I want to develop similar stress strain diagram as attachment photo ( stress strain diagram in different strain rate).
 
Jason DeJoannisJason DeJoannis

Animesh,

The MakeStrainGetStressV1.pl script can be used. The strain rate is determined by the three input parameters:

  1. $compression
  2. $numberSteps
  3. $timeStep
For instance with the default settings, each strain value is subjected to 50,000 dynamics steps with a time step of 10 fs. This works out to a duration of 500 ps or 5e-10 seconds.

The default compression setting is 0.03. That means initially the system moves from a strain of 0 to a strain of 0.03. Dividing 0.03 by 5e-10 gives the initial strain rate 6.0e7 per second.

Best,
Jason
AnimeshAnimesh
Dear Jason Sir,
For tensile purpose can i give (-0.03)( negative sign). Can I get Full  stress strain diagram  ( elastic + plastic ) deformation???? i.e Yield stress,Ultimate stress and failure stress. I have to find out work hardening constant in plastic region. Work hardening exponent is very essential in impact analysis.
Jason DeJoannisJason DeJoannis
Yes you can use negative values to induce tension. What type of materials are you applying this to?
AnimeshAnimesh
I am using  thermoplastic  elastomer like SBS, PU which microstructure consists of soft and hard phase. All are diblock or triblock copolymer. Our intention is to develop three stress strain curve
1. In different temperature 
2. In dfferent strain rate
3. In different strain hardening