Assignment 3
Objective :
To get an introduction of Radios.
To learn performing simulation by making desirable changes in Engine file and Property card.
To understand various energy interactions and load results.
Default Run:
In Engine file total time of simulation written = 60 ms which then changed to 55ms.
After importing the starter file in card files initial time changed from 0ms to 25ms.
By keeping the default property settings, Ran the Radios tab, and went for the results.
Engine Output file generated showed -10.3% (- ve) energy error & 0.1659e-03 mass error Thus proceeded for further results.
In Hypergraph 2D T01 file selected, generated time graph for Internal energy, Kinetic energy, hourglass energy, Contact energy, and total energy.
Also by sharing window Load results generated such as Displacement, Von Misses, and Hourglass energy by selecting an animation h3d file.
Modified Run:
Property Card updated to :
Ishell = 24QEPH, Ish3n = 2, N = 5, iPlast = 1, iThick = 1, iSmstrn = 1.
By making changes in property files again hypergraph files generated as above by following the same procedure.
Results:
Shell Element: 24 QEPH.
As it follows Reduced Integration type thus Overall cycle time reduced from 40ms to 23ms.
As QEPH uses the Stiffness method, thus Hourglass energy reduced from -10.3% to -0.1%.
The mass error which indicates mass reduction due to elemental deformation remained the same in both cases: 0.1659e-03.
As Stiffness was very low thus KE dropped severely and Internal energy increased.
In Both cases, displacement found to have occurred at the same node.
Hourglass Energy:
Sometimes Zero energy deformation element gets generated which are been deformed terribly but there is no stress associated with it is seen which leads to faulty and inaccurate results. In order to make repairment, the same element an artificial mode of energy involves preventing undesired elemental shape formation. This Energy is known as ‘Hourglass Energy’.
In order to stop forming this Hourglassing, Two material strengthening methods are:
1)Perturbation (Viscous Method) 2) Stiffness Method
In perturbation, method damping is given to the respective node which is being used by Q4 Ishell element wherein Stiffness method stiffness is provided to whole surface elements which are being used by QEPH shell elements.
In the second case, the energy required is quite less.