Assignment 4-RADIOSS Material Laws Challenge
Aim - To run the given starter file for the given condition of material properties in radioss and post process for the results.
Objectives- Below shown the following cases can be run the files by using the Johnson cook material 0000.rd file and Law27. The specific materal properties can be run and simulate the results can obtained.
case1 Run the model as it is.Name it law2_epsmax_failuer.
case2 In/FAIL/JOHNSON,change ifail_SH=1,Dadv=1 and lxfem=1. Run the model as law2_epsmax_crack.
case3 Delete/FAIL/JOHNSON card,Run the model as Law2_epsmax_nofail.
case4 Delete the valueof EPS_p_max and run the model with name Law2.
case5 Convert this material model to Law1 elastic with same density,E,nu and run. Check the results.
Case6 Convert the card to a Law36 elasto-plastic based on the details in the next slide.
Case7 Open the Law27_0000.rad. Change the shell properties as the recommended shell properties.
notice the material card. Johnson cook parameters but different values for EPS based failure. Run the model in the name of Law27.
Key words - Eps_p_max, johnson cook, Strain energy, plastic brittle.
Introduction
In below shown the some material properties contineously using while doing the material slection.
In the form of material card
Law1-Elastic
Law2- Johnson cook
Law27- Elastic plastc brittle
Law36- Elastic plastic tabulated
Law42- Visco Hyperelastic
Law70- Foam
In the form of material properties
- Isontropic elasticity
- Isontropic elasto-plastic
- composits and anisotropic
- Viscous
- Hydrodynamics
- Explosives
Law 1 Elastic
- Isontropic means that a material will have the same properties in all directions.
- Under isontropic elasticity, Radioss provides 2 types of elasticity
- Linear Elasticity- Law1 elastic
- Hyperelastic - LAW 69 Tabulated hyperelastic
- The Radioss elasticity law follows the hooks law of eleacticity so, there is linear relationship between the stress and strain.
- Its available for beam, Truss, shell and solid elements.
- This material is exclusively for the elastic materilas.
- Material stiffness is determined by the modulus of elasticity . poissons ratio and shear modulus are calculated.
- G=E/2(1+`nu`)
Law2 Johnson-cook material(PLAST_JOHNS)
- 1) Its also called as plast_john material model.
- 2) This model is calculate the stress using plastic strain this stain rate and temp change.
- 3) So,in case doing multiple analysis case with higher deformation to induce the plastic strain then those things are ideal material model.
- 4) This model expressed material stress as a function of strain, strain rate and temperature.
- 5) A build-in-failuer criterion based on the maximum plastic strain is available.
Law 36 Elasic plastic
- This law models an isotropic elasto- plastic material using user defined functios for the work hardening portion of the stress - strain curve for the different strain rates.
- Isontropic elasto plastic material.
- user defined function for the work for the hardening portion of the stress strain curve. it is also available for the brick and shell materials.
- Elastic portion of material stress strain curve as been defined by youngs modulus and poissons ratio.
- Material plasticity curves can be given for up an arbitary number of strain rate.
- Linear interpolation of strain stress curve.
- For given strain rates
- For given plastic strain
Law27 (PLAST BRIT)Elasto plastic material with brittle failuer
- This law is combines an isotropic elasto-plastic johnson cook material model with an orthotropic brittle failuer model. Material damage is accounted for prior to failuer.
- Failuer and damage occure only in tension. This law is applicable only for shells.
- Yield surface defination same as johnson cook
- Damage and rupture defined with 4 parameter for each principle direction.
As similarly there are given below
Law 42 - Hyperelastic behavior
- This is mainly the hyper elastic behavior(non linear elastic)
- This law is generally used to model polymers and elastomers
Law70 - Tabulated foam
- This law is of Visco elastic behavior in the materials.
- Stress and strain relationship defined by functions according to strain rate.
- Unloading behavior defined by curves and hystreresis parameters.
Procedure
To knowing these all the laws to perform the different material properties with the post processing the results.
Case1 Run the model as it is.Name it law2_epsmax_failuer.
Open the hypermesh and select the profile as radioss
Import the starter file from the solver deck as shown in below and import in to GUI.
Import the model from the solver deck as the jhohnson _0000.rad. click on import.
The johnson material has been seems to be below shown
Also need to be visible the regid wall in the GUI.
The below shown the object and regid in to the GUI.
As per the case 1 the material has been shown. Keep the material card as it is.
Run the given model as it is and name it as Law2_epmax_failuer.
After running the case1 file the analysis has been saved. After opening 0001.out file.
splitting the screen in to required no as shown in below.
Run the animation file in the hyperview.
The h3d file has been import and apply .
The animation file has been run in the contour, result type is to be in von mises and apply.
The animation image has been shown in the below. By visualizing the animation image the elements get deleting before its reaches the max. limit.
Plot the graph for all energies by using the hypergraph
Import the TO1 file by selecting the global variables with different type of enrgies and apply.
Below shown the global variable energies has been ploted.
All energies can be discuss seperatly. below shown the internal energy graph.
To verify the max note in graph will be taken by selecting the single curve math.
As we concluded the internal energy has been start form the origine, there is not having any changes in the material as initially.
After by time interval regid body hit the object(plate) and the graph is goes on increasing. It has been the constant as for some time interval.
For kinetic energy was initially low for the base plate. It shows some variations in the graph due to sound waves. Once hitting the regid body in to the deformable object
due to kinetic energy it has been increases as shown in below and max point has been reaches.
The contact energy has been shown the constant in graph because of the there is two different types of materials of regid body and base plate.
Due to standerd parameters assigned so, the hourglass effect has beeen constant its shown in figure.
Total energy has been taking into count of all resultant energies and it has been start from the where the error energy will occure. The energy error will be in the range of -15% to 5% is acceptable. Perticularly for this case the energy error has been shown as 0.8% so, its acceptable.
The rigid body force can also plot the graph as regid wall, total resultant forces and apply.
The below shown the total resultant force for regid body has been staring from the origin and before hitting the regid body to deformable base plate the
resultant force will increases some time interval after hitting the base plate the force will be reduced. Its shown in graph.
The given results got from the simulation.
Cycle time - 49379
Energy error - 0.8%
Mass error - 0%
Elapsed time = 248.20 s
Case2 In/FAIL/JOHNSON,change ifail_SH=1,Dadv=1 and lxfem=1. Run the model as law2_epsmax_crack.
For the case2 assign the value for the given material parameters
Ifail_sh(Initiate the crack when it reaches ultimate stress.)=1,
Dadv(Shell is deleted or cracked, if there is one layer in the failure zone)=1,
lxfem (Crack the elements and delete the elements. (Ixfem is only applicable for shell elements))=1
For given parameters has been assigning failuer johnson material model.
Run the given model as it is and name it as Law2_epmax_crack.
Open the 0001.out file. It shows the all results of all energies.
The h3d file has been import and apply
Below shown figure von mises animation image for deformable base plate. Base plate will resist due to strain energy in some time interval and after the elements gets the deleted.
Import the T01 file and to plot the graphs and apply.
The global variables of the all energies are plotted in single graph.
Now study for the individual for the all energy graph.
In internal energy it has been start from the origine and gradually increases w.r. t time period. The deformation in the deformable base plate is
initially there is no variation. After some time interval the deformation will occure in the base plate.
The K.E of the deformable base plate is constant but some variation will occure because of the speed of sound after hitting the regid object to the base plate the
K.E will increases untill the base plate will get cracked.
The contact energy will be constant over the simulation because of the 2 different surface of material gets contact so, the contact energy will be constant.
Due to hourglass parameters assigned in the model so there is constant over the simulation process.
Total energy has been taking into count of all resultant energies and it has been start from the where the error energy will occure. The energy error will be in the range of -15% to 5% is acceptable. Perticularly for this case the energy error has been shown as 4.1% so, its acceptable.
For the regid body force will be selected and apply for the total resultant force.
The total resultant forces has been start from the origine and due to K.E the total resultant forces are to be gets high and when it hit the base plate
it will the gets dicreasing as shown in below.
The given results got from the simulation
Cycle time - 49216
Energy error - -4.1%
Mass error - 0%
Elapsed time = 286.22 s
Case3 Delete/FAIL/JOHNSON card,Run the model as Law2_epsmax_nofail.
For the case2 assign the value for the given material parameters.
For this case delete the failuer johnson material model.
Run the given model as it is and name it as Law2_epmax_nofail.
Open the 0001.out file. It shows the all results of all energies.
The h3d file has been import and apply
Below shown figure von mises animation image the deformable base plate. base plate will resist in some time interval after the elements gets cracked fully due to failuer johnson material.
Import the T01file and to plot the graphs in hypergraph and apply.
The global variables of the all energies are plotted in single graph.
For this the internal energy has been initially no deformation occours in the deformable base plate so, its start from the origine.
The kinetic energy has been not apply on the base plate when the regid body comes in to hit with the base plate the shows the max
deflection over the base plate.
The contact energy will be constant over the simulation because of the 2 different surfaces of material gets cantacted so, the contact energy will be constant.
Due to hourglass parameters assigned in the model it self so there is constant over the simulation process.
Total energy has been taking into count of all resultant energies and it has been start from the where the error energy will occure. The energy error will be in the range of -15% to 5% is acceptable. Perticularly for this case the energy error has been shown as 0.8% so, its acceptable.
For the regid body force will be selected and apply for the total resultant force and apply.
For the regid wall forces has been initially incraesing and after some time regid body hit to the deformable base plate with the decreases and its shown in below.
The given results got from the simulation
Cycle time - 49216
Energy error - 0.8%
Mass error - 0%
Elapsed time = 231.94 s
case4 Delete the valueof EPS_p_max and run the model with name Law2.
For the case2 assign the value for the given material parameters
For this case delete EPS_p_max the failuer johnson material model.
Run the given model as it is and name it as Law2_epmax_nofail.
Open the 0001.out file. It shows the all results of all energies.
Below shown figure von mises animation image the deformable base plate. By deleting the Eps_max of plastic strain can avoid without any element deleting the the material gets resist deformation of base plate..
Import the T01 file and plot the graphs for all energies and apply.
The global variables of all energies are plotted in below shown in single graph.
For this the internal energy has been initially no defoemation in the deformable base plate so, its start from the origine.
The kinetic energy has been not apply on the base plate initially. when the regid body hit with the base plate the shows the max
deflection over the surface.
The contact energy will be constant over the simulation because of the 2 different surface of material gets cantacted so, the contact energy will be constant.
Due to hourglass parameters assigned in the model so there is constant over the simulation process.
Total energy has been taking into count of all resultant energies and it has been start from the where the error energy will occure. The energy error will be in the range of -15% to 5% is acceptable. Perticularly for this case the energy error has been shown as 1.1% so, its acceptable.
For the regid body force will be selected and apply for the total resultant force and apply.
The regidwall of total resultant forces has been start from the origine with K.E. When regid body hit with base plate gradually changing the resultant force
The given results got from this simulation
Cycle time - 49303
Energy error - 1.1%
Mass error - 0%
Elapsed time = 295.72 s
Case 5 Convert this material model to Law1 elastic with same density,E,nu and run. Check the results.
Open the hypermesh and select the profile as radioss.
Import the starter file from the solver deck as shown in below and import in to the GUI.
Import the model from the solver deck as the jhohnson _0000.rad. click on import.
The johnson material has been seems to be below shown
Also need to be visible the regid wall in the GUI.
The below shown the object and regid in to the GUI.
As per the case 5 the material has been shown. Select the material card as M1_ELAST.
other parameters keep as it is.
Run the given model as it is and give the name it as Law1.
After running the case1 file the analysis has been saved. After opening 0001.out file.
Import the h3d file in to the and apply on screen.
It is not shows the any changes in basically so, to make animation choose the contour and select the von mises for the compoenent.
While applying the animation file it was showing the proper resist over the deformable surface as compering with the all 4 cases.
Because of the material the using as the Law1 elastic property so, the base plate material gets resist up to maximum elesticity it can reach.
For this case it has been reches the max for von mesis also not showing any crack or deleting the elements over the image.
Also plot the graph for the different global variables.
Select all required global variables and apply. click on solver and ok.
The below shown the all required energies in one graph shown in below.
or this the internal energy has been initially no deformation in the deformable base plate so, its start from the origine.
The kinetic energy has been not apply on the base plate when the regid body comes to contact with the base plate the shows the max
deflection over the surface.
The contact energy will be constant over the simulation because of the 2 different surfaces of material gets cantacted so, the contact energy will be constant.
Due to hourglass parameters assigned in the model so there is constant over the simulation process.
Total energy has been taking into count of all resultant energies and it has been start from the where the error energy will occure. The energy error will be in the range of -15% to 5% is acceptable. Perticularly for this case the energy error has been shown as 1.3% so, its acceptable.
To know the regid wall forces in to graph and apply.
The total resultant forces are to be the initially with the K.E the graph is increasing for some time interval and when hit the base plate there is decreasing in the
total resultant forces as shown in below.
The given results got from the simulation
Cycle time - 47968
Energy error - 1.3%
Mass error - 0%
Elapsed time = 218.32 s
Case6 Convert the card to a Law36 elasto-plastic based on the details in the next slide.
Open the hypermesh and select the profile as radioss
Import the starter file from the solver deck as shown in below and import in to GUI.
Import the model from the solver deck as the jhohnson _0000.rad. click on import.
The johnson material has been seems to be below shown
Also need to be visible the regid wall in the GUI.
The below shown the object and regid in to the GUI.
As per the case 6 more challenging then all other cases. Select the material card as Elasto plastic
First select curve to ceate new curve by selecting curve and create.
As per the given parameters value for assigning, get the new graph can created as shown in below.
For materials and select the M36_PLAST_TAB.
Select the fct_ID has to be curve and select the plotted curve as shown in below.
Also assign the all parameter values as shown in below.
By doing all this parameter assigning and all select the analysis .
The select the save as and give the name for that Law36 and select the include connectors. select the option as -nt 4.
After open the 0001.out file. It shows the all results of all energies.
Import the h3d file and select that file and apply. The file has in the animation for the model.
The below shown the elements with surface will gets deleted and this is due to law36 elasto plastic property deleting while hitting the regid body in to it.
The global variables of all selected energies are plotted as shown in below.
The selected all energy has beeen plotted below.
As discuss the all selected energy graphs are one by one.
The initial energy of deformable base plate is selected parameter is Law36(ELASTO PLASTIC) so, up to elastic limit it should be resist and afterthat the base plate has been braeak.
The kinetic energy has been not in initial stage and after some time interval due to hitting the regid body shows the increase in the kinetic energy
and suddenly drop the energy due to plastic deformation in the plate.
The contact energy will be constant over the simulation because of the 2 different surface of material gets contacted so, the contact energy will be constant.
Due to hourglass parameters assigned in the model so there is constant over the simulation process.
Total energy has been taking into count of all resultant energies and it has been start from the where the error energy will occure. The energy error will be in the range of -15% to 5% is acceptable. Perticularly for this case the energy error has been shown as -1.8% so, its acceptable.
Now check for the regid wall force and the regid body for the resultant forces.
The initially the rigid wall force will be start from the origine and increases with the some instant. After some time the resultant force will be decreases.
The given results got from the simulation
Cycle time - 52174
Energy error - -1.8%
Mass error - 0%
Elapsed time = 267.27 s
Case7 Open the Law27_0000.rad. Change the shell properties as the recommended shell properties.
Open the hypermesh and select the profile as radioss.
Import the starter file from the solver deck as shown in below and import in to GUI.
Import the model from the solver deck as the jhohnson _0000.rad. click on import.
The johnson material has been seems to be below shown
Also need to be visible the regid wall in the GUI.
The below shown the object and regid body in to the GUI.
As per the case 7 the material has been shown. Keep the material card as it is.
With these parameters run the for the simulation in radioss.Save the files in the name of LAW27.
After open the 0001.out file. It shows the all results of all energies.
Import the h3d file and select that file and apply. The file has in the animation for the model.
The animation image seen with the help of contur. In von mises version select and apply. By showing the animation image the huge elements with base plate some portion also will gets fractur in this case as shown in figure.
The graph for the simulation has beeen plotted in hypergraphs by selecting the global variables of energies.
The below shown the all required energies in one graph shown in below.
For the individual graph of internal energy has been shown in below. Initially there is no change in the deformation so,The graph starts from origine and goes on increasing in nature.
The Kinetic energy has been not there initially for the base plate after some time interval when hit the regid body to the base plate the graph will incrases at some point.
The contact energy will be constant over the simulation because of the 2 different surfaces of material gets cantacted so, the contact energy will be constant.
Due to hourglass parameters assigned in the model so there is constant over the simulation process.
Total energy has been taking into count of all resultant energies and it has been start from the where the error energy will occure. The energy error will be in the range of -15% to 5% is acceptable. Perticularly for this case the energy error has been shown as 0.8% so, its acceptable.
The regid wall force can be potted as the total resultant force and apply.
The total resultant forces has been start from the origine and due to K.E the total resultant forces are to be gets high and when it hit the base plate It will the graph with the resultant forces will decreasing as shown in below.
The given results got from the simulation.
Cycle time - 49506
Energy error - 0.8%
Mass error - 0%
Elapsed time = 300.26 s
Results
| sr no | Cases | Case-1 | Case-2 | Case-3 | Case-4 | Case-5 | Case-6 | Case-7 |
| 1 | Energy error | 0.8% | 4.1% | 0.8% | 1.1% | 1.3% | -1.8% | 0.8% |
| 2 | Mass error | 0% | 0% | 0% | 0% | 0% | 0% | 0% |
| 3 | Cycle time | 49379 | 49216 | 49407 | 49303 | 47968 | 52174 | 49506 |
| 4 | Elapsed time | 248.20 s | 286.22 s | 231.94 s | 295.72 s | 218.32 s | 267.27 s | 300.26 s |
| 5 | Condition of elements | Deleting | Cracked and Deleting | Deleting | Due to strain energy only Cracked | due to elastic prop, not crack and delete | Fracture | fractur and Deleting |
Comparisons with the cases
The Case1 and Case2 has the has the johnson cook material has been with help of the predefined property the case 1 can be run for that deleting of elements. In case 2 by deleting the johnson cook material and introduce the ifail_SH=1,Dadv=1 and lxfem=1 these standerd parameters will gives the resist to max cracking and element deletion.
For case3 and case4 the assigning the standerd parameter of Eps_p_max will gives the strain deformantion in the deformable plate the elements gets deleted. The case 4 the Eps_p_max will be make it 0 so run the model and the effect on the plate will seems to be only cracking is showing. Its due to the strain energy the Eps_p_max will be gets 0.
The variation in cases has been elastic with same density,E,nu gives the good elastic property for the base plate so, its good to have these kind of property without any cracking .
In case 6 there is the elasto-plastic material parameters are assigned and due to that the base plate gets fracture when hits the regid body.
The case 7 Law 27 id has been inserted and keep run the end of the result will be the base plate will get the fracture.
Conclusion
- By doing this cases the material property how it will behave while analyasis by changing the Law1, Law2, Law36 and Law27.
- The behavior of strain energy (Eps max) value for the different cases with the different conditions.
- To applying the elastic property for material to know the behavior of the regid body.
- To introducing the elasto plastic brittle properties the check the behavior in material for the given conditions.
- The damage and delete the as per the different cases can be obtained.
- The change in the energy error for different cases.
- Time taken for the different cases of different elapsed time and and cycle time.