Assignment 5

Objective

The aim of the project is to create a 2D mesh for the bumper assembly and run the analysis of a crash tube by varying the kinematics conditions & create the notches in the model & compare the results.

Task

• Create a 2D mesh for the bumper assembly of mesh size 6mm.
• Run the crash tube model as it is.
• Change the Inacti=6 and run.
• Create the type 11 contact and run.
• Remove both notches and remove boundary conditions on a rigid body node then run.
• Create a new notch in the middle, select the whole section and run.
• Create a new notch with nodes only from opposing 2 faces and run.

Case Setup

1. Create a 2D mesh for the bumper assembly of mesh size 6mm.

• Import the bumper assembly model by clicking on file --> open --> model.

Bumper crash model

• Perform meshing of the model with an element size of 6mm.

Bumper Assembly mesh

Crash Impact Application

Type 7 - A general-purpose interface & can simulate all types of impact between a set of nodes and a master node.

Type 11 - Simulation of impact between edge to edge contact application.

Type 24 - Simulation of impact between the surface to surface contact application.

Import Interface parameters

Igap - Determines how the size of the gap is calculated.

Gapmin - Minimum gap for the activation of the interface.

Inacti - Check for the penetration of the elements.

Istf - Affects how the stiffness of the interface is calculated.

Iform - Friction formulation.

Stmin - Minimum stiffness to use for the interface.

Idel - It element deletion if it fails.

2. Run the crash tube model as it is

• Import the crash_tube_0000.rad file using file --> import --> solver deck.

• Create TH part by clicking on output block --> create, choose components & select all the components & name it has TH part.

• Export the radioss model as crash tube baseline & import into the model into the hyper crash & check for the errors.

• Click on Radioss --> analysis & provide a path for the file to be saved.

3. Change the Inacti=6 and run.

• Import the crash_tube_0000.rad file using file --> import --> solver deck.
• Create TH part by clicking on output block --> create, choose components & select all the components & name it has TH part.
• Export the radioss model as crash tube baseline & import into the model into the hyper crash & check for the errors. The Inacti value is set to 6 this is used to reduced & scaled the gap. The file is exported & saved as Crash_tube_0001.rad.

• Click on Radioss --> analysis & provide a path for the file to be saved.

4. Create the type 11 contact and run.

• Import the crash_tube_0000.rad file using file --> import --> solver deck.
• Create TH part by clicking on output block --> create, choose components & select all the components & name it has TH part.
• Export the radioss model as crash tube baseline & import into the model into the hyper crash & check for the errors. The interface type of 11 is set & parameters of type 11 are set. The file is exported & saved as Crash_tube_0002.rad.

• Click on Radioss --> analysis & provide a path for the file to be saved.

5. Remove both notches and remove boundary conditions on a rigid body node then run.

• Import the crash_tube_0000.rad file using file --> import --> solver deck.

• Create TH part by clicking on output block --> create, choose components & select all the components & name it has TH part.
• Export the radioss model as crash tube baseline & import into the model into the hyper crash & check for the errors. The file is exported & saved as Crash_tube_0003.rad.
• Click on Radioss --> analysis & provide a path for the file to be saved.

6. Create a new notch in the middle, select the whole section, and run.

• Import the crash_tube_0000.rad file using file --> import --> solver deck.

• Create TH part by clicking on output block --> create, choose components & select all the components & name it has TH part.
• Export the radioss model as crash tube baseline & import into the model into the hyper crash & check for the errors. The file is exported & saved as Crash_tube_0004.rad.
• Click on Radioss --> analysis & provide a path for the file to be saved.

7. Create a new notch with nodes only from opposing 2 faces and run.

• Import the crash_tube_0000.rad file using file --> import --> solver deck.

• Create TH part by clicking on output block --> create, choose components & select all the components & name it has TH part.
• Export the radioss model as crash tube baseline & import into the model into the hyper crash & check for the errors. The file is exported & saved as Crash_tube_0005.rad.
• Click on Radioss --> analysis & provide a path for the file to be saved.

Results

Case 2:

Contact forces contour

Specific energy contour

Contact energy plot

Energy plot

Normal force plot

Pshell_1

Pshell_2

Pshell_2mm

Pshell2_2mm

Case 3:

Contact forces contour

Specific energy contour

Contact energy plot

Energy plot

Normal force plot

Pshell_1

Pshell_2

Pshell_2mm

Pshell2_2mm

Case 4:

Contact forces contour

Specific energy contour

Contact energy plot

Energy plot

Normal force plot

Pshell_1

Pshell_2

Pshell_2mm

Pshell2_2mm

Case 5:

Contact forces contour

Specific energy contour

Contact energy plot

Energy plot

Normal force plot

Pshell_1

Pshell_2

Pshell_2mm

Pshell2_2mm

Case 6:

Contact forces contour

Specific energy contour

Contact energy plot

Energy plot

Normal force plot

Pshell_1

Pshell_2

Pshell_2mm

Pshell2_2mm

Case 7:

Contact forces contour

Specific energy contour

Contact energy plot

Energy plot

Normal force plot

Pshell_1

Pshell_2

Pshell_2mm

Pshell2_2mm

Interference

Case	Energy error (%)	Mass error (%)	Rigid Wall Forces	Specific Energy	Contact Forces	Plastic Strain
Model as it is	-0.1 to -4.3	0	1.28E+03	1.38E+05	93.3	1.395
Changing inacti = 6	-0.1 to -4.6	0	1.28E+03	1.39E+05	93.3	1.395
Create type 11	-0.1 to -4.6	0	1.30E+03	1.30E+05	85.07	1.609
Remove notches & B.C	-0.1 to -3.8	0	1.28E+03	1.31E+05	69.97	1.588
Notch at middle	-0.1 to -5.1	0	5.12E+03	1.61E+05	89.25	1.564
Notch at opposite faces	-0.1 to -0.6	0	1.36E+03	1.76E+05	87.25	1.203

The Notches help in increasing the energy of the model & also the contact forces of the model when both boundary condition & notches have been removed is the least.