Challenge

Study of Interfaces and Effect of Notch in Buckling on a Crush Tube

AAshwin K15 Mar 2021

OBJECTIVE

Crush Tube Analysis

PROCEDURE

a) Initial Setup:

i) Select Radioss from the user interface menu.

ii) First, we need to import the model into Hypermesh.

iii) To do so, click on Import -> Import Solver Deck -> Choose the starter file -> Import.

iv) After importing the following model is obtained:

b) Meshing:

i) The model is meshed using automesh option and appropriate connections were given.

ii) The model is shown below:

c) Case 1:

i) Run the simulation of the model without making any changes.

ii) To do the analysis, click on Analysis -> Radioss -> Select the file location and name -> Check 'include connectors' box -> Options = '-nt 4' -> Radioss.

[Note: When '-nt 4' is given in the options bar, the simulation will utilize 4 cores of the CPU thereby decreasing simulation time]

iii) To view the simulation, switch the menu to HyperView.

iv) Choose the required '.h3d' file from the simulation folder.

v) To plot the graphs we have to switch to HyperGraph 2D.

vi) Select the required T01 file from the simulation folder.

vii) To monitor the von mises stress in the simulation, click on Contour -> Result type=Von Mises(s) -> Averaging Method= Simple -> Apply.

viii) The following output is obtained:

d) Case 2:

i) Change Inacti=6 and run the model.

ii) Follow the aforementioned procedure to run the simulation and plot the graphs.

iii) The following output is obtained:

d) Case 3:

i) Create type 11 contact and run the model.

ii) To do so, click on Model -> Groups -> Create -> Card Image -> Type=11 -> Select the recommended properties.

iii) Follow the aforementioned procedure to run the simulation and plot the graphs.

iv) The following output is obtained:

e) Case 4:

i) Remove both the notches and the boundary condition on the rigid body node.

ii) The notch can be removed by using the Align node tool.

iii) To do so, click on Geom -> Node edit -> Align node -> Select the reference nodes -> Select the nodes to be aligned.

[Note: Shortcut for Node Edit tool is F7]

iv) Remove the boundary condition on the master node.

v) Follow the aforementioned procedure to run the simulation and plot the graphs.

vi) The following output is obtained:

f) Case 5:

i) Create a new notch in the middle using the translate tool.

ii) To do so, click on Tools -> Translate -> Select the elements -> Select N1,N2 -> Magnitude=10.

[Note: Shortcut for Translate tool is Shift + F4]

ii) Follow the aforementioned procedure to run the simulation and plot the graphs.

iii) The following output is obtained:

g) Case 6:

i) Create a notch on opposite faces only using the translate tool.

ii) To do so, click on Tools -> Translate -> Select the elements -> Select N1,N2 -> Magnitude=10.

[Note: Shortcut for Translate tool is Shift + F4]

ii) Follow the aforementioned procedure to run the simulation and plot the graphs.

iii) The following output is obtained:

RESULTS

a) Case 1:

Sl. No	Name	Image	Observations
1.	Von Mises Stress		The simulation represents the von mises stress present in the model. The Maximum Von Mises Stress obtained is 6.9E-01 KN/`mm^2`.
2.	Internal Energy		The internal energy here represents the strain energy generated when the tube is deforming. Maximum Internal energy is *42273.2 kg`mm^2`/`ms^2`**
3.	Kinetic Energy		Maximum Kinetic energy is 44400.8 *kg`mm^2`/`ms^2`**
4.	Contact Energy		Contact Energy is 2029.5 *kg`mm^2`/`ms^2`**
5.	Hourglass Energy		Hourglass Energy is zero.
6.	Rigid Wall		The graph represents the forces endured by the rigid wall.
7.	Total Energy		The graph represents the total energy in the system. The maximum value is 44400.8 *kg`mm^2`/`ms^2`**
8.	All Graphs		The graph represents all the energies in the system.
9.	Energy and Mass error		Energy error is -4.6%. Mass added is zero. Both the values are within an acceptable range.
10.	Run Time		Total run time= 410.48s(6:50 mins) Total number of cycles= 83496

b) Case 2:

Sl. No	Name	Image	Observations
1.	Von Mises Stress		The simulation represents the von mises stress present in the model. The Maximum Von Mises Stress obtained is 6.9E-01 KN/`mm^2`. Inacti=6 will deal with any initial penetrations.
2.	Internal Energy		The internal energy here represents the strain energy generated when the tube is deforming. Maximum Internal energy is *42273.2 kg`mm^2`/`ms^2`**
3.	Kinetic Energy		Maximum Kinetic energy is 44400.8 *kg`mm^2`/`ms^2`**
4.	Contact Energy		Contact Energy is 2029.5 *kg`mm^2`/`ms^2`**
5.	Hourglass Energy		Hourglass Energy is zero.
6.	Rigid Wall		The graph represents the forces endured by the rigid wall.
7.	Total Energy		The graph represents the total energy in the system. The maximum value is 44400.8 *kg`mm^2`/`ms^2`**
8.	All Graphs		The graph represents all the energies in the system.
9.	Energy and Mass error		Energy error is -4.6%. Mass added is zero. Both the values are within an acceptable range.
10.	Run Time		Total run time= 404.11s(6:44 mins) Total number of cycles= 83496

c) Case 3:

Sl. No	Name	Image	Observations
1.	Von Mises Stress		The simulation represents the von mises stress present in the model. The Maximum Von Mises Stress obtained is 6.9E-01KN/`mm^2`. Type 11 contact is an edge to edge contact that will overcome the limitations of type 7 contact of reduced time step.
2.	Internal Energy		The internal energy here represents the strain energy generated when the tube is deforming. Maximum Internal energy is *43006.7 kg`mm^2`/`ms^2`**
3.	Kinetic Energy		Maximum Kinetic energy is 44400.8 *kg`mm^2`/`ms^2`**
4.	Contact Energy		Contact Energy is 1187.06 *kg`mm^2`/`ms^2**
5.	Hourglass Energy		Hourglass Energy is zero.
6.	Rigid Wall		The graph represents the forces endured by the rigid wall. The maximum value is 1588.71N.
7.	Total Energy		The graph represents the total energy in the system. The maximum value is 44400.8 *kg`mm^2`/`ms^2`**
8.	All Graphs		The graph represents all the energies in the system.
9.	Energy and Mass error		Energy error is -2.7%. Mass added is zero. Both the values are within an acceptable range.
10.	Run Time		Total run time= 1035.81s (17:15mins) Total number of cycles= 127876

d) Case 4:

Sl. No	Name	Image	Observations
1.	Von Mises Stress		The simulation represents the von mises stress present in the model. The Maximum Von Mises Stress obtained is 6.5E-01KN/`mm^2` In this case, the buckling happens at the the interface due to the absence of notches. In the previous cases, buckling happens at the notch
2.	Internal Energy		The internal energy here represents the strain energy generated when the plate is deforming. Maximum Internal energy is *42594 kg`mm^2`/`ms^2`**
3.	Kinetic Energy		Maximum Kinetic energy is 44400.7 *kg`mm^2`/`ms^2`**
4.	Contact Energy		Contact Energy is 1561.45 *kg`mm^2`/`ms^2`**
5.	Hourglass Energy		Hourglass Energy is zero.
6.	Rigid Wall		The graph represents the forces endured by the rigid wall. The maximum value is 1199N.
7.	Total Energy		The graph represents the total energy in the system. The maximum value is 44400.7 *kg`mm^2`/`ms^2`**
8.	All Graphs		The graph represents all the energies in the system.
9.	Energy and Mass error		Energy error is -3.7%. Mass added is zero. Both the values are within an acceptable range.
10.	Run Time		Total run time= 394.18s(06:34 mins) Total number of cycles= 78409

e) Case 5:

Sl. No	Name	Image	Observations
1.	Von Mises Stress		The simulation represents the von mises stress present in the model. The Maximum Von Mises Stress obtained is 6.8E-01KN/`mm^2`
2.	Internal Energy		The internal energy here represents the strain energy generated when the beam is deforming. Maximum Internal energy is *42371.9 kg`mm^2`/`ms^2`**
3.	Kinetic Energy		Maximum Kinetic energy is 44401 *kg`mm^2`/`ms^2`**
4.	Contact Energy		Contact Energy is 1689.22 *kg`mm^2`/`ms^2`.**
5.	Hourglass Energy		Hourglass Energy is zero.
6.	Rigid Wall		The graph represents the forces endured by the rigid wall. The maximum value is 1279.6N.
7.	Total Energy		The graph represents the total energy in the system. The maximum value is 44401 *kg`mm^2`/`ms^2`**
8.	All Graphs		The graph represents all the energies in the system.
9.	Energy and Mass error		Energy error is -3.9%. Mass added is zero. Both the values are within an acceptable range.
10.	Run Time		Total run time= 480s(8:00 mins) Total number of cycles= 92607

f) Case 6:

Sl. No	Name	Image	Observations
1.	Von Mises Stress		The simulation represents the von mises stress present in the model. The Maximum Von Mises Stress obtained is 6.7E-01KN/`mm^2`
2.	Internal Energy		The internal energy here represents the strain energy generated when the plate is deforming. Maximum Internal energy is *42381.5 kg`mm^2`/`ms^2`**
3.	Kinetic Energy		Maximum Kinetic energy is 44400.9 *kg`mm^2`/`ms^2`**
4.	Contact Energy		Contact Energy is 1676.82 *kg`mm^2`/`ms^2`**
5.	Hourglass Energy		Hourglass Energy is zero.
6.	Rigid Wall		The graph represents the forces endured by the rigid wall. The maximum value is 1361.32N
7.	Total Energy		The graph represents the total energy in the system. The maximum value is 44400.9 *kg`mm^2`/`ms^2`**
8.	All Graphs		The graph represents all the energies in the system.
9.	Energy and Mass error		Energy error is -3.8%. Mass added is zero. Both the values are within an acceptable range.
10.	Run Time		Total run time= 503.25s(8:23mins) Total number of cycles= 102326