Assignment 4-RADIOSS Material Laws Challenge

Assignment 4-RADIOSS Material Laws Challenge

Objectives: - Run the given model with different material parameters and compare all the cases.

Materials: -

The overview of the materials in the RADIOSS library can be classified as shown below:

We will have a look at the following material laws:

• Law 1 – Elastic
• Law 2 – Johnson-Cook
• Law 27 – Elastic-Plastic Brittle
• Law 36 – Elastic-Plastic Tabulated
• Law 42 – Ogden (Visco Hyperelastic)
• Law 70 – Foam

The materials may be categorized as

• Isotropic Elasticity
• Isotropic Elasto-Plastic
• Composite and Anisotropic
• Viscous
• Hydrodynamic
• Explosives

1. Law 1 - Elastic: -

This keyword /MAT/ELAST defines an isotropic, linear elastic material using Hooke’s law. This law represents a linear relationship between stress and strain. It is available for truss, beam (type 3 only), shell, and solid elements. Useful for elements attached to rigid bodies. This material law is used to model purely elastic materials. The material stiffness is determined by only two values: Young’s modulus (E), and Poisson’s ratio (n). The shear modulus (G) can be computed using E and n, as shown below:

2. Law 2 - Johnson-Cook:-

In isotropic elasto-plastic, there are many models which are based on von mises hardening without damages, von mises hardening with ductile damage, and von mises with the visco-plastic flow. The Johnson-cook [/JOHNS] & Tabulated piecewise linear [/PLAS_TAB] are majorly used.

3. LAW27 - Elastic-Plastic Brittle

This law combines an isotropic elasto-plastic Johnson-Cook material model with an orthotropic brittle failure model. Material damage is accounted for prior to failure. Failure and damage occur only in tension. This law is applicable only for shells.

4. LAW36 - Elastic-Plastic Tabulated

This law models an isotropic elasto-plastic material using user-defined functions for the work-hardening portion of the stress-strain curve (for example, stress versus plastic strain) for different strain rates.

5.Law 42 -Ogden (Visco Hyperelastic)

This keyword defines a hyperelastic, viscous, and incompressible material specified using the Ogden, Mooney-Rivlin material models.

This law is generally used to model incompressible rubbers, polymers, foams, and elastomers. This material can be used with shell and solid elements.

6. LAW70 -Foam

This law describes the visco-elastic foam tabulated material. This material law can be used only with solid elements.

Law Name	Group	Type	Model Description	Application	Viscosity	Orthotrop	Embedded Thermal Option**	Strain Rate	Formulation
/MAT/LAW1 (ELAST)*	Other materials	Elastic	Isotropic, linear elastic material using Hooke's law	Metals and elastic materials for small deformation only	No	No	No	No	Lagrange
/MAT/LAW2 (PLAS_JOHNS)*	Elasto-plastic materials	Metal	Isotropic elasto-plastic material using the Johnson-Cook material model	Metals, elasto-plastic materials, mild steels, strain-rate dependent, temperature-dependent, isotropic and kinematic hardening, duroplaste, low alloy steel, ST52, and DP600	No	No	Yes	Yes	Lagrange
/MAT/LAW27 (PLAS_BRIT)*	Elasto-plastic materials	Brittle Metal and Glass	Aluminum, glass, etc.	Hard steel, Dual-phase steel, DP800, DP1000, casting, aluminum,	No	No	No	Yes	Lagrange
/MAT/LAW36 (PLAS_TAB)*	Elasto-plastic materials	Metal	Tabulated piecewise linear	Elasto-plastic material	No	No	No	Yes	Lagrange
/MAT/LAW42 (OGDEN)*	Hyper and visco-elastic materials	Rubber	Hyper visco-elastic	Incompressible rubber materials	Yes	No	No	No	Lagrange
/MAT/LAW70 (FOAM_TAB)*	Hyper and visco-elastic materials	Foam	Tabulated law, hyper visco-elastic	Compressible foams, PU, EPP, and PVC	Yes	No	No	Yes	Lagrange

Procedure: -

1. Import the given file FAILURE_JOHNSON_0000.

Given Model: -

Now, perform the simulation with different material parameters.

CASE 1: -

In case 1, we perform the simulation with the default parameter.

After importing the model open the properties & material and check the parameter once.

Now, analyze the model using radioss. For that go to analysis and select Radioss.

Wait until the job is complete.

Here, the total number of cycles is 49380 and it takes 147.33 s to complete.

Here, we get the energy error of 0.8% and kinetic energy of 67.81.

Now, the simulation procedure is completed. Open the model in contour mode and select Von Mises. For that changing view of Hypermesh to HyperView.

Select the Law2_epsmax_failure_h3d file and then press apply.

After that open the contour mode and select von mises in the result and apply.

After that, view the model in HyperGraph.

Plot the graph of internal energy, kinetic energy, and total energy.

Select the Law2_epsmax_failureT01 file and then create a new plot.

All the energies in one graph.

CASE 2: -

In case 2, we perform the simulation by changing some values in failure i.e.

Ifail_sh = 1, Dadv=1 & Ixfem = 1 XFEM formulation.

After that, do the same procedure to analyze the model.

Here, the total number of cycles is 49217 and it takes 144.70 s to complete.

Here, we get the energy error of 4.1% and kinetic energy of 141.9.

Now, view the model in HyperView. Do the same procedure as previously. Open the contour mode and select von mises in the result and apply.

After that, view the model in HyperGraph.

All the energies in one graph.

CASE 3: -

In case 3, we perform the simulation by deleting the failure card and checking the result.

Now, analyze the model using radioss. For that go to analysis and select Radioss.

Here, the total number of cycles is 49408 and it takes 144.09 s to complete.

Here, we get the energy error of 0.8% and kinetic energy of 87.08.

After that open the contour mode and select von mises in the result and apply.

After that, view the model in HyperGraph.

All the energies in one graph.

CASE 4: -

In case 4, we perform the simulation by putting 0 value in EPS_p_max.

After that, do the same procedure to analyze the model.

Here, the total number of cycles is 49304 and it takes 141.85 s to complete.

Here, we get the energy error of 1.1% and kinetic energy of 3.931.

Now, view the model in HyperView. Do the same procedure as previously. Open the contour mode and select von mises in the result and apply.

After that, view the model in HyperGraph.

All the energies in one graph.

CASE 5: -

In case 5, we perform the simulation by converting the material to Law 1 elastic i.e., M1_ELAST with the same density, E, nu.

After that, do the same procedure to analyze the model.

Here, the total number of cycles is 47969 and it takes 142.36 s to complete.

Here, we get the energy error of 1.3% and kinetic energy of 1677.

Now, view the model in HyperView. Do the same procedure as previously. Open the contour mode and select von mises in the result and apply.

After that, view the model in HyperGraph.

All the energies in one graph.

CASE 6: -

In Case 6, we perform the simulation with another .rad file i.e., Law27_0000.rad.

Import the file and open the properties and set recommended properties.

Now, analyze the model using radioss. For that go to analysis and select Radioss.

Here, the total number of cycles is 49508 and it takes 54.70 s to complete.

Here, we get the energy error of 0.8% and kinetic energy of 65.00.

Now, the simulation procedure is completed. Open the model in contour mode and select Von Mises. For that changing view of Hypermesh to HyperView.

After that open the contour mode and select von mises in the result and apply.

After that, view the model in HyperGraph.

All the energies in one graph.

CASE 7: -

In case 7, we perform the simulation by creating a new curve and the material card to Law36 i.e., M36_PLAS_TAB.

Now, go to the curve and create a new curve named CASE_7.

Put the X & Y values and then create a curve.

After that, change the card image to M36_PLAS_TAB & put the other value of density, E & nu. Also put N_function = 1 and assign the fuc_ID CASE_7.

Now, analyze the model using radioss. For that go to analysis and select Radioss.

Here, the total number of cycles is 40245 and it takes 100.07 s to complete.

Here, we get the energy error of 3.6% and kinetic energy of 3.822.

Now, the simulation procedure is completed. Open the model in contour mode and select Von Mises. For that changing view of Hypermesh to HyperView.

After that open the contour mode and select von mises in the result and apply.

After that, view the model in HyperGraph.

All the energies in one graph.

Comparison of all the 7 cases: -

Create the table, so the comparison will be easy.

Cases	No. of Cycle	Energy Error	Mass Error	Simulation Time	Result of Model
CASE 1 [Law2_epsmax_failure]	49380	0.8%	0	147.33	Deleted
CASE 2 [Law2_epsmax_crack]	49217	4.1%	0	144.70	Cracked
CASE 3 [Law2_epsmax_nofail]	49408	0.8%	0	144.09	Cracked
CASE 4 [Law2]	49304	1.1%	0	141.85	Cracked
CASE 5 [Law1]	47969	1.3%	0	142.36	No cracked or deleted
CASE 6 [Law27]	49508	0.8%	0	54.70	Deleted
CASE 7 [Law36]	40245	3.6%	0	100.07	No cracked or deleted

Learning Outcomes: -

1. Learn about different types of Laws used in the material.

2. Learn about different material parameters how they affect the simulation due to changing other's values.

3. Learn about how to plot the graph for different energies like internal energy, kinetic energy, and total energies.

Conclusions: -

In this challenge, we perform the simulations with different types of cases i.e., CASE 1 to CASE 7. And compare all the cases with No. of cycles, energy error, mass error, and simulation time. Also comment on the cases, which case is deleted or cracked in the result column.