Assignment 4-RADIOSS Material Laws Challenge

                                           COMPARING DIFFERENCE MATERIAL LAWS IN RADIOSS 

OBJECTIVE:

In this assignment we have to compare 7 cases as discussed in last 3 slides, in atabulated format on the basis of :

1. total number of cycles. Energy error, mass error & simulation time . notice the animation in brief on the basis of whether the element are being deleted or created .

2. Plot engine and notice any difference.

3. Based on all results, which case would represent the on-field scenario.

4. Prepare a ppt/docx and list down case by result and your conclusion as to why the failure happened.

CASE 1 & CASE 2:

• In this comparison we have to compare two johnson cook material model failure card.
• Johnson cook material is used for isotropic elastic-plastic material. 
• In case 1 ifail_sh=0, Dadv=0, ixfem=0(default) while in case 2 ifail_sh=1, Dadv=1, ixfem=1.
• Dadv and ixfem is for crack, due to that in case 1 element will deleted without crank while in case 2 element will crack first then deleted.
• Due to crack in elements case 2 take more time than case 1.
• The stress generated in case 1 is less than case 2 because crack is generated in case 2.
• In case 1 the element are deleted first so the kinetic force have sudden hike but in case 2 it has more smother than case 1 becasuse of the crack will form first.
• 
• In both the cases the internal energy increases linearly and become sustain because initially both has elastic strain.
• Due to QEPH the hourglass energy is zero.

CASE 3 AND CASE 4

• In this comparision we have to deleted the Johnson failure card in case 2 and then delete the epsmax value in case4.
• Epsmax value is the maximum strain percentage value of the material.
• In case 3 epsmax value is given hence there is deletion of elements but in case 4 there is no epsmax value hence it has infinite deformation.
• Due to deletion of elements stress in case 3 is less than case4.
• In case 3 the kinetic energy is sudden hike due to element deletion while in case 4 initially a sudden hike is there but after it almost constant.
• 
• In both the case the internal energy is increases exponentially but in case 3 in become almost constant after the elements are get deleted.
• .
• Due to QEPH the hourglass energy is zero.

CASE5:

• In this case we have to change the material card into law1.
• The law1 is based on the parameters density, young’s modulus and poission ratio.
• Density = 0.0027
• E= 71000
• Poission ratio = 0.33. In law1 there is no deletion of elements the deformation will be until the failure plastic strain reaches the epsmax 16%.It is mainly used in large deformations.

CASE6:

• In this case we have to change the card to law 27.
• Law 27 is used for brittle failure where equivalent stress is lower than the plastic yield stress.
• Failure and damage occur only in tension.
• This law is applicable only in shell.
• Due to eps_f1=0.151 the material breaks like glass.
• Hourglass is zero because of QEPH.

CASE7:

• This model is an isotropic elastro-plastic material using user-defined for stress and strain curve.
• It is available for both shell and brick materials.

• The curve is defined by young’s modulus and poission ratio.
• We have to plot the engineering value of stress strain curve and assign them.

RESULT AND CONCLUSION:

In this assignment learnt about the different material laws in RADIOSS and how to assign them.