Assignment 5-RADIOSS Interfaces & Study of Effect of Notches Challenge

OBJECTIVE: 

1. Create the mesh for the bumper assembly with element size = 6mm.

 2. Plot RWALL forces , Contact Forces ,Energies and observe the differences for the following cases :

 Case 1 : Run the crash tube model as it is

 Case 2 : Change the Inacti=6 and run.

 Case 3 : Create the type 11 contact and run.

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

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

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

 

Case Setup & execution:

Case 1 : 

The given radioss file is imported in to the hypermesh and the file is run in the RADIOSS Solver  with the defualt card images for the materials, element shell formulation and contact interfaces with the  default values. Following are the images for  the material card, Element card & Contact interfaces. The value for the Inacti = 0 i.e,Default value .

  FIG 1 MATERIAL CARD INPUT_CASE 1         

FIG 2 ELEMENT SHELL FORMULATION_CASE1

FIG 3 CARD INTERFACE INPUTS_CASE1

Case 2 : 

    The value for Inacti i.e, the action to take if the intial penetration exists is cahnged to " 6 : Gap is variable with time and intial penetration is computed" and the file  is run in the RADIOSS Solver.

  FIG 4 INTERFACE INPUTS_INACTI VALUE=6_CASE2

Case 3 :       

     The Contact interfce type11card is created in the solver tree and the Master and the Slave components are identified and incorporated in the card image.  The following values are incorporated in the interface card :

1. Igap = 3 (gap variation according to the characterisitics of the main and the slave lines and also the gap taken into account size of the mesh                        element)

2. Gap min = 0.5 (specifying minimum thickness of the model.)

3. Inacti = 6  (Remove the Intial  peneteration wherever possilble and elsewhere reduce it to 30% of the defined gap value and adjust the gap.)

4. Istf = 4  (set stiffness of the interface based on the softer of the master and the slave.)

5. St min = 1000 N/mm (specify minimum thickness to avoid too soft contact.)

6. Idel = 2 (Remove slave node from contact because of element deletion.)

7 . Iform =2 (Sliding forces are computed  using the stiffness of the Interface resulting in bigger time step.)

 

FIG 5 CREATING THE TYPE 11 CONTACT INTERFACE

 FIG 6 TYPE 11 CONTACT INTERFACE CARD

Case 4 :

     The Notches on the either sides are removed and they are replaced with flat faced elements..

FIG 7 NOTCHES TO BE REMOVED

FIG 8 BOTH NOTCHES REMOVED

The Boundary condition for the Rigid body is removed and the model is run using the radioss solver.

FIG 9 REMOVING THE RIGID BODY BOUNDARY CONDITION

Case 5 :

   The notch is created in the middle by translating the nodes and the model is run in the radioss solver.

FIG 10 CREATING A NEW NOTCH IN THE MIDDLE

Case 6 :

  In addition to the existing notch in the middle, new notches on the opposing faces are created and the moedl is run in the Radioss Solver.

FIG 11 CREATING ADDITIONAL NOTCHES ON OPPOSING FACES

 RESULTS :

1. RIGID WALL FORCES COMPARISON

FIG 12 RIGID WALL FORCES COMPARISON

Observation:

1 . The rigid wall forces are maximum for the case 3 in which the contact interface type 11 has been deveoped.i,e Maximum value = 980 N

2.  The rigid wall forces decrease in case 5 where in the notch has been shifted to the middle .

2. INTERNAL ENERGIES COMPARISON

FIG 13 INTERNAL ENERGY COMPARISON

Observation:

1. The internal energy stays almost the same in all the cases. 

2.The internal energy increases exponentially upto a certain point and then becomes constant till the end.

3. The maximum value of the internal energy being 4260 N-mm.

3. CONTACT ENERGIES COMPARISON

FIG 14 CONTACT ENERGY COMPARISON

Observation:

1. The contact energy increases to a maximum value and then drops off to a lower level.

2. The contact energy is very high in case 1 & 2 at the end of the simulation where only Type 7 interface has been used.

3. For the case 3 where the type7 and type 11 contact interfaces have been used , the contact energy is reduced to a maximum value of

     1160N-mm.

4. The contact energy decreases at the end of the simulation in case 4 where  the notches have been removed.

4. TH/PART COMPARISON

 FIG 15 TH FORCE COMPARISON

Observation:

 1. The maximum value of the TH/Part is more in case3 wherein the type 11 interface have been created in addition to the Type 7 interface.

 2. The Maximum value is the least in case 5 where in the notch have been created in the middle.

 3. There is reduction in the maximum value of the TH/Part in case 4 where the notches have been removed.

 4. The maximum value increases again in case6 where two more notches on the opposing faces were introduced.

CONCLUSION :

1. THE GIVEN BUMPER SYSTEM WITH THE REQUIRED SIZE WAS MESHED SUCCESSFULLY.

2. THE SIMULATION WAS RUN SUCCESSFULLY FOR ALL THE CASES AND RESULTS WERE PLOTTED FOR THE SAME.