To study the different type of Interface/contact Modeling   on a box beam crashing to a rigid wall

To study the different type of Interface/contact Modeling on a box beam crashing to a rigid wall

Objectives: To analyze and compare different cases with various contact type and different parameters as well as notch positions and compare the results for the same boundary conditions

• Procedure:

The following are the 6 cases that we have to simulate,

1. Case1: Run the crash tube model as it is.
2. Case2: Change the Inacti=6 and run.
3. Cases3: Create the type 11 contact and run.
4. Case4: Remove both notches and remove boundary condition on rigid body node then run.
5. Case5: Create a new notch in the middle ,select the whole section and run.
6. Case6 : Create a new notch with nodes only from opposing 2 faces and run.

• To create the mesh for Bumper
• Import bumper_assembly.hm to hypermesh under radios profile
• Select the mesh size as 6 mm in mesh paramenters and press f12 to do the meshing
• Now we have to create connections between the crash box and rear bumper. So go to connector – seam and provided the necessary value, there are different types of connections are available , apart from this we have chosen seam wield which is used to connect the two different materials
• Shift +F3 is used to equivalent the nodes and connect them . Nodes are also connected using F3
• Save the model
• file- https://1drv.ms/u/s!AlDYq9nTGAGChl7xj8a5HKzh02fv?e=kz1Cp7

Interfaces/ contact Modeling

• In this model we are focusing on the interfaces
• Interfaces- Interfaces are defined to model how parts interact when they come into contact with each other
• VARIATIONS OF INTERFACES
• A wide Range of interfaces Type are Available In radios
• Out of the many interfaces types listed,the most used ones for impact simulations are
• Interface Type 7: Nodes to Surface Contact
  • Automatic node to surface contact interface using penalty method with variable stiffness
  • A gap is defined around the master segment and the slave nodes
  • The contact gap can be constant or variable
  • Resistive forces are applied to keep slave nodes out of the contact gap
  • Interface time step is computed to insure stability

CASE1: Run the crash tube model as it is.

1. Importing the model , Open hyperworks and select import solver deck and import the model
2. In order to create the THPART we have to click on the output block and create the TH/PART, in entity id instead of nodes keep component and select all four component and click on ok. Then the TH part is created
3. Run the model as it is without changing ant values in the interfaces card
5. We have to run the simulations, go the hypermesh panel in the analysis menu and load the starter input file from the target folder and hit radios tab, so that required file can be saved in the respected folder it will generate animations file in .h3d and time history in runmane_T01.
6. After running the file open the output file and check the energy error and mass error
8. Play the animation file as we seen in the graphical area the model simulate
10. VONMESIS
12. Now let us generate the necessary plots. Open a new page and switch to hypergraph 2D . load the time history file from the target folder
13. To plot the graph go to global variable and generate the plot for internal Energy, kinetic energy, hourglass energy ,contract energy and total energy

Case-2: Change the Inacti=6 and run.

1. In this case also same type 7 contact is used only changes here is in interface card (actions to take if initial penetrations exist) is changed to 6.
3. So select interface type-7 and change the inactive as 6
4. Import the crushtube_0000.rad in hypercash go to interfaces card change to inacti-6
6. Export the file to case2 folder
8. Go back to Hyermesh and import the exported. Rad file
9. We have to run the simulations, go the hypermesh panel in the analysis menu and load the starter input file from the target folder and hit radios tab, so that required file can be saved in the respected folder it will generate animations file in .h3d and time history in runmane_T01.
10. After running the file open the output file and check the energy error and mass error
12. Play the animation file as we seen in the graphical area the model simulate
15. Now let us generate the necessary plots. Open a new page and switch to hypergraph 2D . load the time history file from the target folder
16. To plot the graph go to global variable and generate the plot for internal Energy, kinetic energy, hourglass energy ,contract energy and total energy

Case-3: Create the type 11 contact and run.

Interface Type 11: Edge to Edge Contact

This interface simulates impact between edge to Edge or lines. A line can be a beam or truss element or a shell edge or spring elements.

In the case of edges crossing, Type 11 interface can be added to capture the physics correctly

• Type 11 is defined by identifying master and slave lines (edges)
• Type 11 works similar to Type 7 in terms of:
• Penalty formulation
• Gap definition
• Search method

1. For creating type 11 contact we can use hypercrash
2. Go to load case create new interface select type 11, Assign the recommended value to the type 11 contact
4. slave node are selected
6. After adding recommended Value we have to open the model in hypermesh by using input solver deck, and we have to simulate by using radios
8. We have to run the simulations, go the hypermesh panel in the analysis menu and load the starter input file from the target folder and hit radios tab, so that required file can be saved in the respected folder it will generate animations file in .h3d and time history in runmane_T01.
9. After running the file open the output file and check the energy error and mass error
11. Play the animation file as we seen in the graphical area the model simulate
14. Now let us generate the necessary plots. Open a new page and switch to hypergraph 2D . load the time history file from the target folder
15. To plot the graph go to global variable and generate the plot for internal Energy, kinetic energy, hourglass energy ,contract energy and total energy

Case-4: Remove both notches and remove boundary condition on rigid body node then run.

1. Here We have to remove all notches and boundary conditions
2. Notches are removed by using translate options or align options
4. Boundary conditions is removed by clicking on load collectors-rbody and off the translations and rotations
6. We have to run the simulations, go the hypermesh panel in the analysis menu and load the starter input file from the target folder and hit radios tab, so that required file can be saved in the respected folder it will generate animations file in .h3d and time history in runmane_T01.
7. After running the file open the output file and check the energy error and mass error
9. Play the animation file as we seen in the graphical area the model simulate
13. Now let us generate the necessary plots. Open a new page and switch to hypergraph 2D . load the time history file from the target folder
14. To plot the graph go to global variable and generate the plot for internal Energy, kinetic energy, hourglass energy ,contract energy and total energy

Case-5: Create a new notch in the middle ,select the whole section and run.

1. In this case we have to create a new notch at middle
2. Open Applications> Hyercrash , set KN mm ms KG unit system
3. Import the model in hypercrash
4. Create a notch in the middle using Mesh editing > move, under Defined Displacement select the odes, vector and distance
7. Export model to case5 folder
8. Import the model in hypermesh ,go to Analysis> Radioos
9. We have to run the simulations, go the hypermesh panel in the analysis menu and load the starter input file from the target folder and hit radios tab, so that required file can be saved in the respected folder it will generate animations file in .h3d and time history in runmane_T01.
10. After running the file open the output file and check the energy error and mass error
12. Play the animation file as we seen in the graphical area the model simulate
15. Now let us generate the necessary plots. Open a new page and switch to hypergraph 2D . load the time history file from the target folder
16. To plot the graph go to global variable and generate the plot for internal Energy, kinetic energy, hourglass energy ,contract energy and total energy

Case-6: Create a new notch with nodes only from opposing 2 faces and run.

1. In this case we have to create a notch with opposite side of box
2. Notches are created by using translate options or align options
4. We have to run the simulations, go the hypermesh panel in the analysis menu and load the starter input file from the target folder and hit radios tab, so that required file can be saved in the respected folder it will generate animations file in .h3d and time history in runmane_T01.
5. After running the file open the output file and check the energy error and mass error
7. Play the animation file as we seen in the graphical area the model simulate
10. Now let us generate the necessary plots. Open a new page and switch to hypergraph 2D . load the time history file from the target folder
11. To plot the graph go to global variable and generate the plot for internal Energy, kinetic energy, hourglass energy ,contract energy and total energy

Result study:

When there is no notch case4, the crushing happen uniform throughout the entire tube .

When notch were created in middle case5, the crushing happens in the notch once the tube hits wall and proceeds the uniform crushing pattern to reaming areas

When notch were present in only 2 opposite sides case6 the sides are subjected to deformations first when tubes hits rigids wall and then remaining area are affected.

Case N0	parameter	no. of cycles	Error (%)	Mass error (%)	Simulations time	VonMises Stress max
1	Run the crash tube model as it is.	83600	-3.8	0	156.20s	6.964E-01
2	Change the Inacti=6 and run.	83600	-3.8	0	196.60s	5.879E-01
3	Create the type 11 contact and run.	83500	-4.0	0	95.96s	5.763E-01
4	Remove both notches and remove boundary condition on rigid body node then run.	77800	-3.1	0	181.41s	7.449E-01
5	Create a new notch in the middle ,select the whole section and run.	92600	-3.3	0	87.77s	6.509E-01
6	Create a new notch with nodes only from opposing 2 faces and run.	82300	-2.9	0	191.49s	6.101E-01

In the above graph it clear shows that there is a mass error remain same for all the cases, as well as hour glass remain constant in all the cases and the minimum contact is zero

For case 6 we can clearly see an increase in the internal and kinetic energy, this is because the notches are not continuous in the model and are only on a small part of the faces of the model.

We can also observe that the contact energy has increased as compared to case 5 , While in the simulation it has also been observed that the internal energy and kinetic energy have increased as compared to the previous case

Conclusions:

1. The bumper Assembly is meshed with 6mm and connections are represented
2. In this assignment we have learent about two types of interfaces type7 and type 11
3. Six cases are simulated with edge to edge and node to surface type and reported
4. Energy graph and Rigidwall Force graphs are plotted for all cases and compared

link for file - https://1drv.ms/u/s!AlDYq9nTGAGChl9u2PbALpSJx3gd?e=sIQERo

link for bumper_system- https://1drv.ms/u/s!AlDYq9nTGAGChl7xj8a5HKzh02fv?e=ddQSWw