Assignment 3-2D Element Formulation Challenge
Report on Assignment 3-2D Element Formulation Challenge
1.Using the crash beam file from the previous assignment, change the run time to 55 ms.
2. Change the number of animation steps during simulation to a minimum of 25 and maximum of 60.
Here i had taken animation step=55, Tfreq=(simulation time)/(animation step)=55/55=1
3. Run the base simulation without any modification to element properties.
Done
4. At the end of the simulation, do the energy error and mass error checks and determine whether results would be acceptable.
There is no error found in energy error and mass error, here ERR(energy error)=10.3% and mass error i.e dm/m*100=1.659*10^-4*100=1.659*10^-4% (it is tollerance zone ), hence it is acceptable
5. If acceptable, Plot rigid wall forces, internal energy, hourglass energy, contact energy, total energy of the simulations.
6. Change all the shell elements properties to recommended properties, save this as separate, rad files and run the simulation.
7.After Changing all the shell elements properties to recommended properties, Plot rigid wall forces, internal energy, hourglass energy, contact energy, total energy of the simulations.
8. Comment whether there is any change in the results and why there is any change in the result.
Yes , by changing all the shell elements properties to recommended properties Hourglass energy is totally decrease because shell formulation like we use
- I shell-24 i.e QEPH , it is an improved under-integrated 4 noded element with 1 integration point on the surface, it stabilized the physical hourglass and in this case hourglass is reduce to zero
- Hourglass modes are non-physical modes of deformation that occur in underintegrated element and produce no stress
- I stmr-2 i.e large strain with full geometrical nonlinearities , it means it is suitable for the problem with large displacements and strains
but rest of the parameter like Plot rigid wall forces, internal energy, contact energy, total energy have not much significant changes