Assignment 3

ASSIGNMENT 3

OBJECTIVES:

To Compare the results with base simulation and improved shell element properties

1.Using the crash beam file from the previous assignment, change the run time to 55 ms.

2. 2. Change the number of animation steps during simulation to a minimum of 25 and maximum of 60.
3. Run the base simulation without any modification to element properties.
4. 4. At the end of the simulation, do the energy error and mass error checks and determine whether results would be acceptable.
5. 5. If acceptable, Plot rigid wall forces, internal energy, hourglass energy, contact energy, total energy of the simulations.
6. 6. Change all the shell elements properties to recommended properties, save this as separate, rad files and run the simulation.
7. 7. Follow steps 5 and 6.
8. 8. Create a brief report comparing all the results from steps 5 and 6 for both simulations.
9. 9. Comment whether there is any change in the results and why there is any change in the result.

PROCEDURE:

Case1:

• Import the file into the radioss user profile.
• Change the card ENG_ANMI_DT Tstart value into 25.
• Change the card ENG_RUN Tstop value into 55.
• Then go to analysis – radios – select the path of the file – check – include connectors – type -nt 4 in option – then click radioss to run the stimulation.
• Check the errors in the engine 001.rad file.
• The change the environment into hyperview – locate the path of h3d file – then click apply.
• Then go to contour – select the resultant – select the component – click apply to see the result.
• The change the environment into hypograph2d – locate the path of T01 file- then select global variable – energy to display – MAG – the click apply.

Case1:

• Import the file into the radioss user profile.
• Change the card ENG_ANMI_DT Tstart value into 25.
• Change the card ENG_RUN Tstop value into 55.
• Change the property

Parameters		Comment
Ishell =24		QEPH 4 nodes shells are best combination of cost and accuracy.
Ismstr=2		Full geometric nonlinearities (default)with possible small strain formulation activation in RADIOSS Engine.
Ish3n=2		Standard 3 noded shell (C0)with modification for large rotation(default)
N=5		Number of integration points set to 5 for accuracy bending.
Ithick=1		Thickness change is taken into account for accuracy.
Iplas=1		Iterative plasticity for good accuracy.

• Then go to analysis – radios – select the path of the file – check – include connectors – type -nt 4 in option – then click radioss to run the stimulation.
• Check the errors in the engine 001.rad file.
• The change the environment into hyperview – locate the path of h3d file – then click apply.
• Then go to contour – select the resultant – select the component – click apply to see the result.
• The change the environment into hypograph2d – locate the path of T01 file- then select global variable – energy to display – MAG – the click apply.

DEFAULT PROPERTY CARD CHANGED

DEFAULT POPERTY CARD CHANGED

DEFAULT PROPERTY CARD CHANGED

DEFAULT PROPERTY CARD CHANGED

DEFAULT PROPERTY CARD CHANGED

DEFAULT PROPERTY CARD CHANGED

DEFAULT PROPERTY CARD CHANGED

RESULT AND CONCLUSION:

• I_shell =0 is a default option. I_shell =24 QEPH is used for 4 node elem with integration point on the surface and physical hourglass stabilization it is the best option in case of cost ant accuracy.
• I_smstr=0 small strain, usually for problem with small deformation I_smstr=2 larger strain with full geometric non-linear, this is used for problems for large displacement and strain, strain compute based on element shape and size.
• I_sh3n=0 default 2. I_sh3n=2 standard triangle with modification of large rotation, one integration point on the surface and no hourglass dehormation.
• N=5 it shows the number of integration point, normally it kept as 5.
• I_thick=2 default thickness kept constant. I_thick=1 thickness change taken into account, for better results strongly recommend in spring, plastics with different thickness.
• I_plas=1 iteration projection with three newton iterations, it will update strain through the thickness and compute the new thickness of the shell element.

Hourglass:

Hourglass modes are non-physical mode of deformation that occur under integrated elements are produce no stress i.e. hourglass is zero energy modes where the stress won’t occur and affect the result.

Methods to reduce hourglass:

• Perturbation (q4 element)
• Physical stabilization (QEPH element)

https://drive.google.com/file/d/1f-YgPeig_c302NMbKeJbqUoLllEdEDJ9/view?usp=sharing