Challenge

Assignment 3-2D Element Formulation Challenge

PPardeep Singh10 Feb 2022

ASSIGNMENT NO 3

Recommended properties:

Parameters		Comment
I_shell=24		QEPH 4 nodes shells are best combination of cost and accuracy.
I_smstr=2		Full geometric nonlinearities (default)with possible small strain formulation activation in RADIOSS Engine.
I_sh3n=2		Standard 3 noded shell (C0)with modification for large rotation(default)
N=5		Number of integration points set to 5 for accuracy bending.
I_thick=1		Thickness change is taken into account for accuracy.
I_plas=1		Iterative plasticity for good accuracy.

Questions:

Comparison of 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. 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. At the end of the simulation, do the energy error and mass error checks and determine whether results would be 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. Follow steps 5 and 6.

8. Create a brief report comparing all the results from steps 5 and 6 for both simulations.

9. Comment whether there is any change in the results and why there is any change in the result.

ANSWER:

1.OPEN HYPERWORKS AND CHANGE THE PROCESSOR TO RADIOOS AND SELECT THE FILE AND IMPORT THE MODEL.

2. GO TO CARDS AND CLICK ON ENGINE_RUN AND CHANGE THE TIME TO 55ms

3. GO TO ANALYSIS TOOL AND SELECT THE RADIOOS AND RUN THE SIMULATION AND SAVE IT IN THE LOACTION.

1. AS ASKED IN THE QUESTION NEED TO SET FREQUENCY FOR ANIMATION STEPS BETWEEN 25 TO 60. FOR THE SAKE OF SIMPLICITY I HAVE SET THE ANIMATION SET TO 55 WE KNOW THE FORMULA:

T=TOTAL RUN TIME/NO. OF ANIMATION STEP REQUIRED = 55/55=1.0

AND RUN THE SIMULATION.

RUN THE ANIMATION WITHOUT CHANGING THE ELEMENT SIZE AND PROPERTIES.

GO TO HYPERVIEW AND OPEN THE .h3d FILE AND PLAY THE SIMULATION. AFTER THAT OPEN THE .OUT FILE AND GIVE THE ENERGY ERROR AND MASS ERROR:

CYCLE TIME TIME-STEP ELEMENT ERROR I-ENERGY K-ENERGY T K-ENERGY R EXT-WORK MAS.ERR
0 0.000 0.2642E-02 NODE 81500 0.0% 0.000 0.6131E+08 0.000 0.000 0.1659E-03
ANIMATION FILE: FIRST_RUNA001 WRITTEN
10 0.2640E-01 0.2639E-02 NODE 81500 0.0% 0.3512E+05 0.6128E+08 201.1 -145.6 0.1659E-03
20 0.5279E-01 0.2639E-02 NODE 81500 -0.0% 0.7053E+05 0.6124E+08 361.3 -145.6 0.1659E-03
30 0.7919E-01 0.2639E-02 NODE 81500 -0.0% 0.1057E+06 0.6121E+08 318.8 -145.6 0.1659E-03
40 0.1056 0.2639E-02 NODE 81500 -0.0% 0.1409E+06 0.6117E+08 285.1 -145.6 0.1659E-03
50 0.1320 0.2639E-02 NODE 81500 -0.0% 0.1761E+06 0.6114E+08 214.7 -145.6 0.1659E-03
60 0.1584 0.2639E-02 NODE 81500 -0.0% 0.2107E+06 0.6110E+08 284.8 -145.6 0.1659E-03
70 0.1848 0.2639E-02 NODE 81500 -0.0% 0.2450E+06 0.6107E+08 438.5 -145.6 0.1659E-03
80 0.2112 0.2639E-02 NODE 81500 -0.0% 0.2820E+06 0.6103E+08 575.4 -145.6 0.1659E-03
90 0.2376 0.2639E-02 NODE 81500 -0.0% 0.3207E+06 0.6099E+08 751.6 -145.6 0.1659E-03
100 0.2639 0.2639E-02 NODE 81500 -0.0% 0.3589E+06 0.6095E+08 910.0 -145.6 0.1659E-03
110 0.2903 0.2639E-02 NODE 81500 -0.0% 0.3967E+06 0.6092E+08 1112. -145.6 0.1659E-03
120 0.3167 0.2639E-02 NODE 81500 -0.0% 0.4340E+06 0.6088E+08 1250. -145.6 0.1659E-03
130 0.3431 0.2639E-02 NODE 81500 -0.0% 0.4708E+06 0.6084E+08 1463. -145.6 0.1659E-03
140 0.3695 0.2638E-02 NODE 81500 -0.0% 0.5070E+06 0.6081E+08 1768. -145.6 0.1659E-03

GO TO HYPERGRAPH AND CREATE THE GRAPH FOR THE FOLLOWING

rigid wall forces, internal energy, hourglass energy, contact energy, total energy

OPEN THE FILE FIRST_RUNT01 IN THE HYPERGRAPH AND SELECT THE GLOBAL VARIABLE AND SELECT THE ENERGY WE NEED AND SELECT MASS AND APPLY.

Change all the shell elements properties to recommended properties, save this as separate, rad files and run the simulation.

Recommended properties:

Parameters		Comment
I_shell=24		QEPH 4 nodes shells are best combination of cost and accuracy.
I_smstr=2		Full geometric nonlinearities (default)with possible small strain formulation activation in RADIOSS Engine.
I_sh3n=2		Standard 3 noded shell (C0)with modification for large rotation(default)
N=5		Number of integration points set to 5 for accuracy bending.
I_thick=1		Thickness change is taken into account for accuracy.
I_plas=1		Iterative plasticity for good accuracy.

GO TO ANALYSIS AND SAVE THE FILE AND RUN THE RADIOOS.

FOLLOW THE 5 AND 6 STEP TO PLOT THE GRAPH.

WE CAN SEE THE GRAPHS FOR THE DIFFERENCES

LEFT WINDOW IS CREATED WITHOUT CHANGE AND RIGHT WINDOW IS WITH THE RECOMMENDED PROPERTIES.

FIRST FIVE LINES SHOWS THE GRAPH WITH THE RECOMMENDED CHANGES AND LAST FIVE SHOWS THE IDEAL TYPE OF ELEMENT WITHOUT ANY CHANGE.

FROM THIS WE CAN SEE THE DIFFERENCE BETWEEN THE HOURGLASS ENERGY AFTER CHANGES THE VALUE OF PROPERTIES THE DECREASE IN THE ENERGY WE CAN SEE. SAME THING CAN BE SEEN THE DIFFERENCE IN ALL ENERGIES.

1. KINETIC ENERGY