Week-6 Calculate the Stretch Ratio by comparing the ELFORM (-2,-1,1,2) with Ogden_Material Model.
AIM: The main aim of this week challenge is to perform tensile test on a cube.Run the simulation on four different element formulation and compare their engineering stress and stretch ratio.
PROCEDURE:
STEP 1: Open the LS-DYNA pre post and import the basic file containing the material property.
STEP 2: Create a solid cube.Go to mesh --> shapeM
STEP 3: To create a section card for the part, Open the keyword manager and check the all button.Under the SECTION keyword select the SOLID card for the parts.Now give the properties of shell as desired.
STEP 4: Now go to PART keyword and assign the part with the desired material and section cards.
STEP 5: Go to create entity and under boundary select SPC.Now select one side of the cube and constrain it along x-direction.
STEP 6: Then middle vertical nodes are selected and constrained at Zaxis and horizontal nodes are selected and constrained at y axis so that cube compress evenly in all direction because it a rubber material.
STEP 7:Now define a curve in order to give the displacement boundary condition.
STEP 8:Open the keyword manager and check the all button.Under the DEFINE keyword select the CURVE.
STEP 9: Open the keyword manager and check the all button.Under the BOUNDARY keyword select the PRESCRIBED_MOTION_SET.
STEP 10:Open the keyword manager and check the all button.Under the CONTROL keyword and select TERMINATION.Now give the total time of the simulation.
STEP 10:Open the keyword manager and check the all button.Under the CONTROL keyword and select TERMINATION.Now give the total time of the simulation.
STEP 11: Now run the simulation with different element formulation for (-2,-1,1,2) and get the result for all the element formulation.
Calculation of Engineering Stress, Strain and Stretch Ratio: -
The Output Stress and Strain Obtained From The Post-processing are Noted as True Stress and Strain values,
We know that,
| TIME | TRUE STRAIN | ENGG STRAIN | STRETCH RATIO |
| 0.00E+00 | 0.00E+00 | 0 | 0 |
| 1.29E-01 | 1.12E-01 | 0.118802 | 1.118802 |
| 2.29E-01 | 2.87E-01 | 0.332543 | 1.332543 |
| 3.29E-01 | 5.01E-01 | 0.649999 | 1.649999 |
| 4.29E-01 | 7.39E-01 | 1.093714 | 2.093714 |
| 5.29E-01 | 9.95E-01 | 1.705632 | 2.705632 |
| 6.29E-01 | 1.27E+00 | 2.547608 | 3.547608 |
| 7.29E-01 | 1.55E+00 | 3.714881 | 4.714881 |
| 8.29E-01 | 1.85E+00 | 5.335655 | 6.335655 |
| 9.29E-01 | 2.15E+00 | 7.608975 | 8.608975 |
| 1.00E+00 | 2.38E+00 | 9.757838 | 10.75784 |
