Challenge

Assignment 4

1. Total number of cycles, Energy error, mass error and simulation time.

For case1:

For case2:

For case3:

For case4:

For case5:

For case6:

For case7:

2. Notice the animation of all 5 and describe the animations in brief on the basis of whether the elements are being deleted or cracked.

case1

case2

case3

case4

case5

case6

case7

EXPLANATION FOR CASE1:

In case1 we should run the model as default from this we can observe the elements getting deleted as shown in the above animation.
Here we used the jhonson cook law2 elasto_plastic material thats why graph showing the both elastic and plastic region.
And aslo we should observe the internal energy is fluctuating in the plastic region that is because of the elements are the moving out of the original position then that elements have some internal energy.
Then the kinetic energy is also fluctuating because when the ball hits the surface of the plate then the elements in the plate udergoing some motion which have the small kinetic energy.

EXPLANATION FOR CASE2:

In case2 we are running the model by adding the values of the Ifail_sh=1,Dadv=1 and Ixtem=1 for the failure card.
If you observe the simulation when we add the Ixfem we can see that elements are getting craked as shown in the animation.
Ixfem is repersented the cark over the elements and it will give more realastic behaviour to the simulation.
When comming to the graph there both elastic and plastic region is shown in the above graph and having some fluctuating in kinetic and interal energy of elements when they deform.
If your material model should be very accurate and then the way Ixfem treatment goes it dicipates little more energy and because of that ,for smaller propagation or for local deformations Ixfem could be the good method.
Ixfem is only used for shell elements only.

EXPLANATION FOR CASE3:

In case3 we are running the model by deleting the failure card, As we observe in the animation the elements getting deleted directly as shown in the above image.
As we comapre the case1 and case3 there is very small very in the stress .
But when we are not given the failure card there is directly deformation occurs.
When comming to the graph there both elastic and plastic region is shown in the above graph and having some fluctuating in kinetic and interal energy of elements when they deform.
As shown in the above graph the kinetic energy started at zero and at the time of ball hits the surface of the palte the deformation in occurs on the elements then they will obsorb some kinetic energy that fluctuating is shown in the above graph.

EXPLANATION FOR CASE4:

In case3 here we are deleting the Eps_max value, Eps_max value is the maximum plastic strain for element deletion for any loading (tensile , shear or compression).
Here we are not given the Eps_max value so that the animation showing that there is direct deletion of elements without cracks.
As we observe the graph it showing only the elastic region there is a no plastic region that means it breaking happens after the elastic region.

EXPLANATION FOR CASE5:

In case5 we are converting the material model to law1 elastic with the same density,young's modulus and poission ratio.
As we observe the animation there is no element deletion because it is the an law1 elastic material.
As we abserve the graph it represents a linear relationship between stress and strain as shown in above graph.
And there there is no fluctuation of kinetic and internal energy because there is no element deletion here it is purely elastic material.
In this case Deformation is occurs with in the elastic limit .

EXPLANATION FOR CASE6:

In the case6 we are running the model by the changing shell properties I_shell=24,I_smstr=2,I_sh3n=2,N=5,I_thick=1,I_plas=1.
Here we are using the law27 that means elasto-plastic materials with the brittle failure .
This law only applicable for shell elements.
Here we can observe the animation there is huge deformation taking place in between elements as shown in the above animation.
As shown in the above graph the kinetic energy started at zero and at the time of ball hits the surface of the palte the huge deformation in occurs on the elements then they will obsorb some kinetic energy that fluctuating is shown in the above graph.

EXPLANATION FOR CASE7:

In case7 we are using the law36 (elastic plastic piecewise linear material).This law models an isotropic elasto-plastic material using user-defined functions for the workhardening portion of the stress-strain curve (for example, plastic strain vs. stress) for different strain rates.
Here we are feeding the stress strain curve to the model to interpolates the both curves For a given strain rate and For a given plastic strain.
In order to avoid poor curve extrapolation during the strain calculation, a dummy curvedefined for a high strain rate value can be added in the model—typically the highest strain rate curve is repeated.
The curves have to be defined such as they don’t intersect themselves in the strain range being used.Otherwise the calculation may fail.
Here we can observe the animation sudden deformation taking place in between elements as shown in the above animation.
Here the kinetic energy and internal energy are fluctuating more compare to the previous cases as shown in the above graph.

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