Week-6 Calculate the Stretch Ratio by comparing the ELFORM (-2,-1,1,2) with Ogden_Material Model.

AIM: To simulate tensile behavior for the model with of 10mmx10mmx10mm dimension with 10 elements for each direction and use the material card attached (Ogden_Material.k) and plot graphs.

PROCEDURE:

• Firsr we will open .k file in LS-DYNA.

• Now we have to apply card to the model so for that we have to create the box model.
• To create box model go to the MESH>SHAPEMESHER and then give the dimesion of the box.

• Now we hav to select section for it with different ELFORM= 1, 2, -1, -2.
• For that go to MODEL>KEYWRD>SECTION>SOLID

NOTE: We will use different types of ELFORM to check the variations in results.

• Now we will apply the material and section to the PART we created.
• For that go to MODEL>KEYWRD>PART

• Now for the boundary conditions to the box model.
• Here we constrained the one side of the box. And then give the prescribed motion to the opposite side.
• Because we have to simulate the tensile stress.

For this go to MODEL>CREENT>BOUNDARY>SPC

• First we will constrained all nodes in X direction.

• Now next we will constrained vertical in Z direction.

• Horizontal Constrained in Y direction

.

• Now the next is prescribed motion.
• So we will give the motion to the Opposite face of the
• The prescribed motion has to be defined to give a displacement by assigning a curve. The box is subjected to tension at X- direction and the plot figured up to stretch ratio 5 in all cases.
• We can to create a curve for this.
• For that go to MODEL>KEYWRD>DEFINE>CURVE

• Now we have applied BCS we have to apply control card for the simulation.
• For that go to the MODEL>CONTROL>IMPLICIT_AUTO
• It is used to defined the timstep for the IMPLICIT simulation.

• Now next MODEL>CONTROL>IMPLICIT_GENERAL
• This Control card activate the implicit function.

• Next is MODEL>CONTROL>IMPLICIT_SOLVER

• Now MODEL>CONTROL>IMPLICIT_SOLUTION

• Now next is for the OUTPUT that we required for that first MODEL>KEYWRD>DATABASE>EXTENT_BINARY

• MODEL>KEYWRD>DATABASE>BINARY_D3PLOT

• MODEL>KEYWRD>DATABASE>ASCII_option
• We will select GLSTAT, MATSUM, NODOUT for the output with DT=0.01

• For data termination go to the MODEL>KEYWRD>CONTROL>TERMINATION

• Now we will run the .k file.

D3PLOT:

ELFORM=1

• Now with the help of FringComp we will get the data of true stress and strain and with the help of that we will plot Engineering stress Vs Stretch Ratio
• The formulae given below:

Ɛ_true = ln ( 1 + Ɛ_eng)

Ɛ_eng = EXP Ɛ_true – 1

σ _true = σ_eng (1+ Ɛ_eng )

Ɛ_true = true strain

Ɛ_eng = Engineering Strain

σ _true = True stress

σ_eng = Engineering stress

ELFORM=2

ELFORM=-1

ELFORM=-2

• FE model of solid block was created with ogden material to simulate uniaxial tension test for different cases of ELFORM (1, -1, 2, -2).
• The Engineering stress/strain and stretch ratio was calculated to plot a graph of Engg. stress vs stretch ratio up to stretch ratio 4.
• The uniaxial tension test was solved using implicit solver since the analysis is similar to a quasi-static analysis on a hyperelastic non-linear material with slow steady loading conditions.