Assignment 4-RADIOSS Material Laws Challenge

OBJECTIVE

• TO COMPARE THE 7 DIFFERENT CASES GIVEN FOR THE NUMBER OF CYCLES, ENERGY ERROR, MASS ERROR AND SIMULATION TIME TO UNDERSTAND THE PROPERTY DIFFERENCES.
• TO PLOT ENERGIES FOR ALL THE GIVEN CASES TO NOTICE DIFFERENCES.
• TO ARRIVE AT A CONCLUSION FOR SELECTING BETTER MATERIAL PROPERTIES FOR ON-FIELD SCENARIO.

PROCEDURE

• CASE 1

• HYPERMESH>FILE>IMPORT>SOLVER DECK>FILE 'select file'>IMPORT.
• MODEL>MATERIAL>NAME 'rename as specified'>OK.
• ANALYSIS>RADIOSS>SAVE AS 'select as needed'>RADIOSS.
• HYPERGRAPH>DATA FILE 'select as needed'>Y TYPE 'select as needed'>APPLY.

• CASE 2

• HYPERMESH>FILE>IMPORT>SOLVER DECK>FILE 'select file'>IMPORT.
• MODEL>FAILURES>Ifail_sh, Dadv, Ixfem 'edit as specified'>OK.
• MODEL>MATERIAL>NAME 'rename as specified'>OK.
• ANALYSIS>RADIOSS>SAVE AS 'select as needed'>RADIOSS.
• HYPERGRAPH>DATA FILE 'select as needed'>Y TYPE 'select as needed'>APPLY.

• CASE 3

• HYPERMESH>FILE>IMPORT>SOLVER DECK>FILE 'select file'>IMPORT.
• MODEL>FAILURES>'delete failure card'>OK.
• ANALYSIS>RADIOSS>SAVE AS 'select as needed'>RADIOSS.
• HYPERGRAPH>DATA FILE 'select as needed'>Y TYPE 'select as needed'>APPLY.

• CASE 4

• HYPERMESH>FILE>IMPORT>SOLVER DECK>FILE 'select file'>IMPORT.
• MODEL>MATERIALS>EPS_p_max 'edit as needed'>OK.
• ANALYSIS>RADIOSS>SAVE AS 'select as needed'>RADIOSS.
• HYPERGRAPH>DATA FILE 'select as needed'>Y TYPE 'select as needed'>APPLY.

• CASE 5

• HYPERMESH>FILE>IMPORT>SOLVER DECK>FILE 'select file'>IMPORT.
• MODEL>MATERIALS>CARD IMAGE>M1_ELAST>YES.
• MODEL>MATERIALS>Rho_Initial, E, Nu 'edit as specified'>OK.
• ANALYSIS>RADIOSS>SAVE AS 'select as needed'>RADIOSS.
• HYPERGRAPH>DATA FILE 'select as needed'>Y TYPE 'select as needed'>APPLY.

• CASE 6

• HYPERMESH>FILE>IMPORT>SOLVER DECK>FILE 'select file'>IMPORT.
• MODEL>MATERIALS>CREATE>'rename as needed'>CARD IMAGE>M36_PLAS_TAB>OK.
• MODEL>MATERIALS>'select new'>Rho_Initial, E, Nu, EPS_p_max, EPS_t, EPS_m 'edit as specified'>OK.
• MODEL>CURVES>CREATE>NEW>NAME 'edit as needed'>PROCEED>RETURN>'enter X and Y values'>UPDATE>CLOSE.
• MODEL>MATERIALS>'select new'>N_funct '1'>fct_ID>CURVE 'select as needed'>OK.
• MODEL>FAILURES>Mat_Id>'select as needed'>OK.
• ANALYSIS>RADIOSS>SAVE AS 'select as needed'>RADIOSS.
• HYPERGRAPH>DATA FILE 'select as needed'>Y TYPE 'select as needed'>APPLY.

• CASE 7

• HYPERMESH>FILE>IMPORT>SOLVER DECK>FILE 'select file'>IMPORT.
• MODEL>MATERIALS>'check all recommended properties'>OK.
• ANALYSIS>RADIOSS>SAVE AS 'select as needed'>RADIOSS.
• HYPERGRAPH>DATA FILE 'select as needed'>Y TYPE 'select as needed'>APPLY.

• THE FIRST GIVEN FILE, 'FAILURE_JOHNSON_0000.rad' WAS USED FROM CASESE 1 TO 5 AFTER MAKING POSSIBLE CHANGES.
• THE CASE 1 FILE WAS USED IN CASE 6 AS PER THE QUESTION.
• THE FILE 'LAW27_0000.rad' WAS USED 7 ONLY.

• VON MISSES BY SIMPLE AVERAGING WAS DONE @HYPERVIEW.
• HYPERVIEW>FILE>LOAD>RESULTS>'select as needed'>APPLY.
• CONTOUR>RESULT TYPE>VON MISES>AVERAGING METHOD>SIMPLE.

SCREENSHOTS

• CASE 1 (HYPERMESH) @Sample 1 (HYPERGRAPH) @Sample 2
• CASE 2 (HYPERMESH) @Sample 3 (HYPERGRAPH) @Sample 4
• CASE 3 (HYPERMESH) @Sample 5 (HYPERGRAPH) @Sample 6
• CASE 4 (HYPERMESH) @Sample 7 (HYPERGRAPH) @Sample 8
• CASE 5 (HYPERMESH) @Sample 9 (HYPERGRAPH) @Sample 10
• CASE 6 (HYPERMESH) @Sample 11, 12 (HYPERGRAPH) @Sample 13
• CASE 7 (HYPERMESH) @Sample 14 (HYPERGRAPH) @Sample 15
• VON MISSES COMPARISON BY SIMPLE AVERAGING @Sample 16, 17, 18, 19, 20, 21 AND 22.
• COMPARISON IMAGE (h3d) @Sample 23
• GIF ATTACHED @C1, C2, C3, C4, C5, C6, C7 AND COMPARISON ALL CASES GRAPHICS.

RESULTS

• COMPARISON ON THE TOTAL NUMBER OF CYCLES, ENERGY ERROR, MASS ERROR AND SIMULATION TIME.

No.	Failure Card.	Material Card	E% error	M% error	Simulation Time	Total No. of cycles
Case 1	FAILURE_JOHNSON_0000	M2_PLAS_JOHNS_ZERIL	0.8%	0.000	64.42	49384
Case 2	Law2_epsmax_failure_0000	M2_PLAS_JOHNS_ZERIL	3.7%	0.000	107.85	49407
Case 3	Law2_epsmax_crack_0000	M2_PLAS_JOHNS_ZERIL	0.8%	0.000	65.04	49405
Case 4	Law2_epsmax_nofail_0000	M2_PLAS_JOHNS_ZERIL	3.0%	0.000	63.71	48737
Case 5	Law2_epsmax_nofail_0000 (LAW 1)	M2_ELAS	0.3%	0.000	61.32	47969
Case 6	Law2_epsmax_failure_0000 (LAW 36)	M27_PLAS_BRIT	0.8%	0.000	64.64	49384
Case 7	Law27_0000 (LAW 27)	M36_PLAS_TAB	-4.4%	0.000	54.53	41855

• ANIMATION COMPARISON.

1. (C1) Failure of the elements happen when 1 Integration Point reaches the EPS_max. The shell elements is deleted once the value reaches the maximum plastic strain defined in the model. Initially the crack formation is even and then we can see the elements being deleted.
2. (C2) Elements are getting cracked at the initial stage itself. The cracking happens due to @Ixfem=1. An increase in internal energy is noted greater than previous case, this is due to energy being stored as internal energy.
3. (C3) Here there is no failure model included, shell elements are deleted once it reaches the maximum plastic strain defined in the model. Initially the crack formation is even and then we can see the elements being deleted.
4. (C4) Here the elements are being stretched like an elastic material; this is because the strain enters the plastic stage but as there is no EPS_max set, the radioss will consider as the material not to fail under plastic strain.
5. (C5) Here the plate componenet is defined as an elastic material, hence the component will show elastic property but not the plastic one. So no crack is initiated and the maximum stress is developed at the contact surcaces only. Internal energy is increased close to 800000.
6. (C6) Here we use Law36 material with CASE 1 FILE. Here we observe that the material fail at maximum stress value and some elements are deleted once thay reach the value EPS_f. This type of failure is a real life failure as similar to defining true stress-strain curve. Energy seem less than 30000.
7. (C7) Here we use Law27 material card with the LAW27_0000.rad FILE. Here the failure happens only in tension. Brittle failure observed and along with element deletion. Here the less variation in kinetic energy is observed as the material fails like brittle failure.

• ENERGY DIFFERENCES

1. (C1) VS (C2) SMALL ENERGY CHANGE IS NOTED AND THE CHANGE IS DUE TO CRACK INITIATION AND PROPOGATION.
2. (C3) VS (C4) INTERNAL ENERGY INCREASES AS LINEAR BUT DIFFERENT IN THE OTHER CASE.
3. (C5) MATERIAL SEEMS ABSORBING LOT OF ENERGY, ELASTIC BEHAVIOUR. INTERNAL ENERGY BEHAVIOUR IS EXPONENTIAL.
4. (C6) INTERNAL ENERGY AND TOTAL ENERGY INCREASES SIMILARLY UPTO CERTAIN POINT. KINETIC ENERGY VALUE FLUCTUATION WAS NOTED.
5. (C7) DUE TO PLASTIC-ELASTO MATERIAL, STRESS VALUE IS MUCH HEIGHER. IK AND KE @ALMOST SAME.

• HENCE WE COULD CONCLUDE THAT FROM ALL THESE CASES, LAW36 IS THE PREFERED ONE FOR BECAUSE THE FAILURE CAN BE EASILY MANAGED AND CAN BE USED FOR ALL TYPES OF ELEMENTS. THUS LAW36 IS THE RECOMMENDED MATERIAL CARD FOR ON-FIELD SCENARIO.