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

AIM

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

OBJECTIVE

To calculate stretch ratio & compare respective for element formulation

PROCEDURE

* Create a block of 10mmx10mmx10mm dimension with 10 elements for each direction and use the material card attached (Ogden_Material.k).

* Creating a set of nodes for applying boundary conditions.

* Introducing Prescribed motion set and Boundary SPC set assigning the corresponding node set

* Define Load curve and assign it in Prescribed motion set.

* Creating solid section with element formulation 1.

Strain vs Time curve of specified element.

Stress vs Time curve of specified element.

Stress vs Strain curve of specified element.

Calculation

• Enginnering stress= Applied load /Original C/S area
• Stretch ratio=1+Enginnering strain
• True Stress= Enginnering stress*(1+Engineering strain)
• True Strain=ln(1+Engineering strain)

* Stretch ratio l is defined as the ratio between the final length L and the initial length L0 of a component i.e. it is equal to (1 + engineering strain)

* Based on the formulas the engineering stress and engineering strain values are calculated inorder to plot Nominal stress vs Stretch ratio as shown below.

Element Formulation_1

CASE 2

Element Formulation_2

CASE 3

Element Formulation_-1

CASE 4

Element Formulation_-2

* As we can see we have applied uniaxial tension on the cube and the stretch ratio is increasing exponentialy with respect to the
normal stress.

CONCLUSION

* Hereby we have done a simulation on the Ogden material cube with uniaxial tensile load and find out the engineering stress and
strain and stretch ratio and plotted the graph of Normal stress vs stretch ratio.