Assignment 3-2D Element Formulation Challenge

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Conclusion: When Default values are changed to recommended values we notice the following changes:

• The Hourglass energy remains constant near to Zero throughout the simulation. The Total energy remains at a constant value which is ideally desired as per energy conservation principle, since there is miniscule change in hourglass energy.
• In second case i.e Stiffness method (QEPH) Ishell=24, hourglass energy deformation is controlled and thus there is very less need for hourglass energy. So, the accuracy of model is increased in second case. Thus, with activation of small strain formulation, Co-triangular formulation for 3 noded shell elements (little modification in case of large rotations) and QEPH 4 noded elements are best combination of accuracy and cost in case of critical analysis.
• The Hourglass energy is not counted in second case of energy balance, and we see a negative energy error of -0.1% at the end of simulation.(by using Ishell=24 (QEPH), as there is no Hourglass). Since it is negative, it means that some energy has been dissipated.