COMPARING THE BASE SETUP SIMULATION RESULTS AND DIFFERENT KINEMATIC CONDITION RESULTS
Objective:
- To be able to the mesh for bumper assembly with mesh size 6mm.
- To be able to create interfaces for given model, assign the parameters for interfaces which are applicable for crash structure applications, Comparing the base setup simulation results and different kinematic condition simulation results from the following cases:
- Run the given crash tube model as it is.
- Change the Inacti=6 and run.
- Create type 11 contact and run.
- Remove the both notches and remove boundary condition on rigid body node then run.
- Create a new notch in the middle, select whole section and run.
- Create a new notch with nodes only from opposing 2 faces and run.
Case set up and Execution with images:
A.Create mesh for bumper assembly with mesh size 6mm
Import the given bumper system into the hyper mesh.
Mech creation is done by cleaning the geometry (Removing the excess lines), changing the geo to 2D in menu page, open the automesh option in the panel area or F12 in the functional keys then select the surfs of the component, give element size 6mm, mesh type quads and click mesh icon to create mesh on the component.
Creating 1D connectors for assemble the crash box upper, crash box lower with bumper beam to make bumper system. Connectors are generated by changing the 2D to 1D in menupage, open connectors option in panel area, select the seam connector to join the components by selecting the line location with component elements (by appropriate spacing and tolerance with plot type) then hit create for generating 1D elements in it.
B.Comparing the simulation results with different interface types
Interfaces are defined to model how parts interact when they come into contact with each other.
- Run the given crash tube model as it is.
Sol: Import the given crash tube and create TH/PART for all parts.
Run the simulation without changing the interface parameters in type 7.
After running the simulation with type 7 interface with Inacti 0 review the starter output file failure crash_tube _0001.out file with a text editor and check the total number of cycles, energy error and mass error at the end of computation.
Inacti 0 indicates the no action in initial penetration.
The energy error -3.8% and mass addition 0.00 are acceptable results for plotting the graphs.
Counter plot of contact forces
Plotting the Graphs
The output key parameters from case 1:
|
Sl.no |
Key Parameters |
Result |
|
1 |
Maximum Normal Resultant Force |
1340.658 KN |
|
2 |
Maximum Internal Energy |
42269.742188 J |
|
3 |
Maximum Contact Energy |
2031.595703 J |
|
4 |
Maximum Kinetic Energy |
44400.78125 J |
|
5 |
Number of cycles |
83691 Cycles |
|
6 |
Simulation time |
1148.53 sec |
|
7 |
Elapse time |
84.54 sec |
|
8 |
Energy error |
-3.80% |
|
9 |
Mass addition |
0.00% |
2.Change the Inacti=6 and run.
Sol: Change inacti=6 value in the type 7 (Nodes to surface contact) interface.
After running the simulation with type 7 interface with Inacti 6 review the starter output file failure crash_tube _0001.out file with a text editor and check the total number of cycles, energy error and mass error at the end of computation.
Inacti 6 indicates the gap is reduced and scaled for good accuracy to obtain initial penetration.
The energy error -3.8% and mass addition 0.00 are acceptable results for plotting the graphs.
Counter plot of contact forces
Plotting the graphs
The output key parameters from case 2:
|
Sl.no |
Key Parameters |
Result |
|
1 |
Maximum Normal Resultant Force |
1340.658 KN |
|
2 |
Maximum Internal Energy |
42269.742188 J |
|
3 |
Maximum Contact Energy |
2031.595703 J |
|
4 |
Maximum Kinetic Energy |
44400.78125 J |
|
5 |
Number of cycles |
83691 Cycles |
|
6 |
Simulation time |
1273.65 sec |
|
7 |
Elapse time |
202.99 sec |
|
8 |
Energy error |
-3.80% |
|
9 |
Mass addition |
0.00% |
3.Create type 11 contact and run.
Sol: Create the type 11 interface, change the interface parameters which are recommendations for crash applications and create TH/PART for it.
Important interface parameters:
|
Igap |
Determines how the size of the gap is calculated |
|
Gapmin |
Minimum gap for activation of interface |
|
Inacti |
Action to take if initial penetrations exist |
|
Istf |
Affects how the stiffness of the interface is calculated |
|
Iform |
Friction formulation |
|
Stmin |
Minimum stiffness to use in the interface |
|
Idel |
What to do with slave nodes and master segments if element fails (deleted) that they are attached to |
Creating type 11 interface with crash application parameters to crash tube
After running the simulation with type 11 interface review the starter output file failure crash_tube _0001.out file with a text editor and check the total number of cycles, energy error and mass error at the end of computation.
The energy error -3.8% and mass addition 0.00 are acceptable results for plotting the graphs.
Counter plot of contact forces
Plotting the graphs
The output key parameters from case 3:
|
Sl.no |
Key Parameters |
Result |
|
1 |
Maximum Normal Resultant Force |
1340.558 KN |
|
2 |
Maximum Internal Energy |
42268.62500 J |
|
3 |
Maximum Contact Energy |
2032.4368 J |
|
4 |
Maximum Kinetic Energy |
44400.78125 J |
|
5 |
Number of cycles |
83909 Cycles |
|
6 |
Simulation time |
1388.24 sec |
|
7 |
Elapse time |
81.44 sec |
|
8 |
Energy error |
-3.80% |
|
9 |
Mass addition |
0.00% |
Comparison of case 1, case 2 and case 3:
|
Case 1 (Interface Type 7 with Inacti 0) |
Case 2 (Interface Type 7 with Inacti 6) |
Case 3 (Interface type 7 & 11 with crash application parameters) |
|
Energy error (-3.8%) and Mass addition (0) are acceptable |
Energy error (-3.8%) and Mass addition (0) are acceptable |
Energy error (-3.8%) and Mass addition (0) are acceptable |
|
Contact energy is lower then case 3 |
Contact energy is lower then case 3 |
Contact energy is higher then case 1 & 2 |
|
Internal energy is higher then case 3 |
Internal energy is higher then case 3 |
Internal energy is lower then case 1 & 2 |
|
Normal resultant force is equal to case 2 & 3 |
Normal resultant force is equal to case 1 & 3 |
Normal resultant force is equal to case 1 & 2 |
|
Simulation time is 1148.53 sec |
Simulation time is 1273.65 sec |
Simulation time is 1388.24 sec |
|
Elapse time is 84.54 sec |
Elapse time is 84.54 sec |
Elapse time is 84.54 sec |
Comparing the simulation results with different kinematic condition results:
4.Remove the both notches and remove boundary condition on rigid body node then run.
Sol: As per this case we need to remove the notches by align elements to surface and remove all boundary conditions.
After running the simulation review the starter output file failure crash_tube _0001.out file with a text editor and check the total number of cycles, energy error and mass error at the end of computation.
The energy error -3.0% and mass addition 0.00 are acceptable results for plotting the graphs.
Counter plot of contact forces
Plotting the graphs
The output key parameters from case 4:
|
Sl.no |
Key Parameters |
Result |
|
1 |
Maximum Normal Resultant Force |
1198.705 KN |
|
2 |
Maximum Internal Energy |
42601.32 J |
|
3 |
Maximum Contact Energy |
1555.319946 J |
|
4 |
Maximum Kinetic Energy |
44400.69 J |
|
5 |
Number of cycles |
78018 Cycles |
|
6 |
Simulation time |
976.21 sec |
|
7 |
Elapse time |
205.85 sec |
|
8 |
Energy error |
-3.0% |
|
9 |
Mass addition |
0.00% |
5.Create a new notch in the middle, select whole section and run.
Sol: Creating the notch at middle of crash tube.
After running the simulation review the starter output file failure crash_tube _0001.out file with a text editor and check the total number of cycles, energy error and mass error at the end of computation.
The energy error -3.3% and mass addition 0.00 are acceptable results for plotting the graphs.
Counter plot of contact forces
Plotting the graphs
The output key parameters from case 5:
|
Sl.no |
Key Parameters |
Result |
|
1 |
Maximum Normal Resultant Force |
1105.84 KN |
|
2 |
Maximum Internal Energy |
42553.769 J |
|
3 |
Maximum Contact Energy |
1685.275 J |
|
4 |
Maximum Kinetic Energy |
44401.125 J |
|
5 |
Number of cycles |
81788 Cycles |
|
6 |
Simulation time |
1036.36 sec |
|
7 |
Elapse time |
210.09 sec |
|
8 |
Energy error |
-3.3% |
|
9 |
Mass addition |
0.00% |
6.Create a new notch with nodes only from opposing 2 faces and run.
Sol: Creating the notch with nodes on opposing 2 faces.
After running the simulation review the starter output file failure crash_tube _0001.out file with a text editor and check the total number of cycles, energy error and mass error at the end of computation.
The energy error -2.8% and mass addition 0.00 are acceptable results for plotting the graphs.
Counter plot of contact forces
Plotting the graphs
The output key parameters from case 6:
|
Sl.no |
Key Parameters |
Result |
|
1 |
Maximum Normal Resultant Force |
1316.727 KN |
|
2 |
Maximum Internal Energy |
42660.968 J |
|
3 |
Maximum Contact Energy |
1596.27 J |
|
4 |
Maximum Kinetic Energy |
44401.0039 J |
|
5 |
Number of cycles |
72071 Cycles |
|
6 |
Simulation time |
1036.28 sec |
|
7 |
Elapse time |
178.89 sec |
|
8 |
Energy error |
-2.8% |
|
9 |
Mass addition |
0.00% |
Comparison of case 4, case 5 and case 6:
|
Case 4 (Crash tube is notch free) |
Case 5 (Notch is created at middle of the crash tube) |
Case 6 (Notch is created with nodes on opposing 2 faces of the crash tube) |
|
Energy error (-3.0%) and Mass addition (0) are acceptable |
Energy error (-3.3%) and Mass addition (0) are acceptable |
Energy error (-2.8%) and Mass addition (0) are acceptable |
|
Contact energy is lower than case 5 and case 6 |
Contact energy is higher than case 4 and case 6 |
Contact energy is higher than case 4 and lower then case 5 |
|
Internal energy is lower than case 6 and higher then case 5 |
Internal energy is lower than case 4 and case 6 |
Internal energy is higher than case 4 and case 5 |
|
Normal resultant force is higher than case 5 and lower then case 6 |
Normal resultant force is lower than case 4 and case 6. |
Normal resultant force higher then case 4 and case 4 |
|
Simulation time is 976.21 sec |
Simulation time is 1036.36 sec |
Simulation time is 1036.28 sec |
|
Elapse time is 205.85 sec |
Elapse time is 210.09 sec |
Elapse time is 178.89 sec |
Comparison of TH/PART for all parts in crash tube:
Comparison through internal energy:
|
Sl.no |
Part name |
ID |
Maximum internal energy (J) |
|
1 |
PSHELL1 |
1 |
13686.00 |
|
2 |
PSHELL2 |
3 |
13629.70 |
|
3 |
pshell_2mm |
5 |
7462.85 |
|
4 |
pshell_2mm |
6 |
7491.16 |
Comparison through kinetic energy
|
Sl.no |
Part name |
ID |
Maximum kinetic energy (J) |
|
1 |
PSHELL1 |
1 |
61.07 |
|
2 |
PSHELL2 |
3 |
60.92 |
|
3 |
pshell_2mm |
5 |
49.29 |
|
4 |
pshell_2mm |
6 |
48.96 |
Based on the comparison of TH/PART for all parts the PSHELL1 has high capability of withstanding internal & kinetic energy as per above graphs.
Result:
Bumper system assembly is done successfully with 1D seam connectors.
Comparing the base setup simulation results by creating different types of interfaces and the different kinematic condition results by creating the notch at various places in crash tube are done successfully. A part from the internal energy withstanding capability the type 7 interface high internal energy compare to type 11 interface and the notch created with nodes only opposing two faces has high internal energy compare to creation of notch at middle of crash tube. By comparing the simulation results with notch, the parts which are notch free has high internal and kinetic energy withstanding capability.
Conclusion:
By this assignment I am able to learn about how to assemble the bumper system, compare the results with base setup simulation, different kinematic condition simulation, how to create TH/PART for all parts, how to assemble the bumper system with connectors, how to align the nodes and translate the elements to create notch on crash tube and also how to utilize the hyper crash for creating the different types of interfaces which are recommended for crash applications.
Google drive link:
https://drive.google.com/open?id=18tSfPURqGpzlUVJbgeR_zITu5gFz7F_2