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

AIM: To Mesh the given crash tube model with 6mm size and run the crash tube model by using differnt types of contact interfaces.

OBJECTIVE:

• Run the crash tube model with and without changing the parameters.
• Remove the notches from the crash tube model,Remove the boundary conditions from rigid body node and then run the simulation.
• Create notches in the middle and in the opposing faces of the crash tube model and then run the simulation.
• Perform geometry clean up on the bumper assembly and mesh the bumper assembly with 6mm size.

THEORY AND EXPLANATION:

HYPERCRASH:

Hypercrash is a specialized preprocessor for radioss.It always exsist as a part of Hyperworks.Hypercrash is mainly used for crash applications.

Hypercrash supports solvers like Radioss and LS DYNA.The units used in industries are kn,mm,ms,kg.

In hypercrash we have use only 0000.rad files.Cause hypercrash dosen't have its own file extension.

Hypercrash only detects the starter files,Cause these are the files only imported into hypercrash.

We can export bill of materials of all the models or you can also export as radioss file.We can export the model from hypercrash,But it will save the file as FIRST_RUN_0000.rad.It will create a backup file like FIRST_RUN_0000.rad.bak and store the previous file in this .bak file.

It will also create M000 file.Whenever we export a file from hypercrash,M000 file will be created.The M000 file will only our file structure details and weld data,Whenever we create weld,we will be having weld data.

If we delete M000 file and import only FIRST_RUN_0000.rad file,We won't be able to see the connection folder in the tree browser.

But all these connections will be listed as Type 2 Contact Interface.It will be listed in the contact interfaces folder in tree browser.

In hypercrash engine cards will be represented as control cards.ANIM DT files will be stored in A01 files.Data history files will go in T01 files.
Rigid Wall Forces,Contact Forces,All Energies ,all those things will go in T01 Files.

1) Interface Penalty Method
2) TYPE7,Variable Stiffness,Node to Surface Contact.
3) TYPE11,Variable Stiffness,Edge to Edge Contact.
4) TYPE24,Linear Stiffness,Node to Surface and Surface to Surface Contact.
5) TYPE19,Combination of TYPE7 and TYPE11.

Interface Penalty Method :

The penalty method treats the behavior between slave nodes and master segments as springs that generate resistive forces as a function of penetration.

• Here the interfaces are goverened by the penalty method.
• When the parts come into contact,The slave node tries to penetrate the mid surface.
• The solver introduces the 1D spring element once the slave node penetrates the gap.
• The spring stiffness is automatically computed according to the material and property of both master segment and slave node.
• If penetration is zero,the time step will be maximum.As the penetratiom goes on increasing,the time step goes on decreasing.
• Time Step Stiffness.

Interface Type 7 : Nodes to Surface Contact

• It is a general purpose interface and can simulate all types of impact between a set of nodes and a master surface.
• Non oriented and slave nodes can belong to the master surface,Hence auto impact possible.
• 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.

Inacti :

Inacti is nothing but Initial Penetration.
We will be giving this parameter to get rid off penetration in the model.

Initial Penetration :

Initial penetration result if a slave node is closer to the master segment than the calculated gap.
Initial repulsion forces give an error in the energy balance due to the interfaces work.
There are options in the solver to remove initial penetrations.
Inacti = 3 may create initial energy if the node belongs to a spring element.
Inacti = 6 is recommended instead of Inacti =5, in order to avoid high frequency effects into the interface.

Initial Intersections :

Intersections result if slave nodes are past the master segment (shells or solids).
This condition can cause locking situations leading to computation failure.
If slave nodes lie on the master segment an ERROR will occur because of the Type 7 contact stiffness definition.

Interface Type 11 (Edge to Edge Contact) :

• Type 11 is similar to the Type 7 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 association with interface TYPE7, interface TYPE11 solves the locking cases.
• Defined by identifying master and slave lines (edges)
• Impacts occur between a master and a slave line. A slave line can impact on one or more master lines. A line can belong to the master and the slave side.
• This allows self-impact.
• Works similar to Type 7 in terms of Penalty formulation, Gap definition and search method.
• Uses complicated mathematical algorithms; therefore, it is strongly advised to use it only when necessary. A huge interface TYPE11 can slow down the computation.

Interface Type 19 (Combination of Type 7+11) :

• Combination of two symmetric TYPE7 interfaces and one TYPE11 interface
• Common input based on the same slave/master surfaces.
• Useful for complex contact problems such airbag unfolding
• Computationally expensive so only problematic segments should be defined
• Edges to edge contact flag edge.

PROCEDURE:

1) Mesh the Bumper assembly with 6mm size.

2) First import the bumper assembly into the GUI which is shown in below .

3) Then view the component by topo mode which is shown in below.

4) Now do a geometric cleanup on the model,There are some surfaces which are overlapping and the surfaces which are not equivalenced.

5) To fix the surfaces which are overlapping and the surfaces which are not equivalenced which is shown in above Figures 12 and 13.

6) To equivalence the surfaces,Go to Geometry >> Edge Edit >> Select the Lines Moved Edge and Retained Edge >> Replace.

7) We can also fix this by extending the lines over the surface using Extend Tool from Surface Edit Panel.

8) Now select the moved edge and retained edge to equivalence the surfaces.

9) Now intersect the surfaces which are overlapping.

10) To intersect the surfaces,Go to Geometry >> Surface Edit >>Trim With Surf/Plane >> Self Intersecting Surfaces >> Select the Two Surfaces >> Trim.

11) Select the Surfaces and Trim the Surfaces.

Import the Starter File into the Solver Deck Radioss :

While opening hypermesh software,A user profile window will pop up,Switch to the radioss user profile as shown in below Figure 26 and start importing the model into the solver deck.

Now after switch the user profile to radioss,import the model (starter file) into the radioss solver deck.

To import the model,Go to Standard Panel >> Import >> Import Solver Deck.

Case-1 Run the Crash Tube Model as it is default :

Here we have to create TH for the for all the parts.

Before running the simulation.We have to create TH for the interfaces.It should be followed for all the cases.

To create TH,Go to Solver Browser >> Right Click on TH >> Create >> Inter,

After creating TH,The contact interfaces should be assigned to that.

Now run the simulation,To run simulation,Go to Analysis Panel as shown.

Go to Analysis Panel >> Radioss >> Select the Input File >> Save it in Different Folder and Rename it as Case-1 >> Run.

Check the Include Connectors,If there are any connectors in the model,The connectors will also be taken into account.

Type -NT 4 in options tab,This will make the simulation faster.

Where NT indicates No of threads 4 indicates assigning the task to 4 cores in the system

Here save the input file in a different folder, and rename it as case-1 which is shown.

Now run the solver by hitting on radioss.

After completing the simulation,the radioss will pop up a solver window stating Radioss Job Completed which indicates the simulation has been completed,Which is shown.

After running the simulation,The animation files will be generated where we specified a location to store the files.

Now go and open the 00001.out file with notepad.

The obtained values for Energy Error,Mass Error,Internal Energy Error,Kinetic Energy Error and Contact Energy Error has been shown.

1) Review the Simulation using HyperView :

Hyperview allows for loading and viewing result files obtained from several sources.

Based on the solver type of the files and the results you would like to visualize and analyze,there are differnt ways to load the input deck and their corresponding results into hyperview.

First to begin the postprocessing in the Hypermesh,Split the Screen as shown.

Import the animation file .h3d into the hyperview.

And then activate the Client HyperView.

To access the load model panel

Select Load Model Button from the HyperView Panel and open .h3d file

After loading the model into hyperview,It will be represented.

After importing the .h3d file into the GUI,Enable the contour.

The contour tool create contour plots of a model graphically visualize the analysis results.

To enable contour,Go to Results ToolBar >> Contour

Now switch to the Von Misses Stress in result type and select the component,select the averaging method as simple and then click apply.

After applying ,Run the Simulation,The Simulation animation.

2) Plot the graphs using -Hypergraph 2D:

Now plot the graphs using Hypergraph 2D,We are plotting the graphs to see what is happening in the rail component.

Hypergraph 2D is a powerful data analysis and plotting tool with interfaces to many popular file formats.

It is sophisicated math engine capable of processing even the most complex mathematical expressions.

Hypergraph 2D combines these features with high quality presentation output and customization capabilities to create a complete data analysis system for any organization.

Here switch to the Hypergraph 2D to plot the graphs.

To switch,Go to Client Selector >> Choose the Hypergraph 2D

The first graph is plotted for the Rigid Wall Forces.

To plot the graph,Go to Hypergraph 2D >> Data File >>Crash_TubeT01 >> Apply.

Here the graph has been plotted for the Rigid Wall Forces as shown in below Figure 54.

There are various parameters in Rigid Wall like Normal Force,Tangent Force,FX-X Total Force,FY-Y Total Force,FZ-Z Total Force,Total Resultant Force.

We are selecting only Total Resultant Force,Because we don't know the exact axis of the component placed,So that's why we are selecting Total Resultant

Force and then plotting the graph.

While plotting the graph,Units profile window will pop up,There select solver units and then plot the graph,Because the graphs will be plotted according to the solver units.

Now plot the graph for the rigid wall forces which is shown

Rigid Wall Forces:

Here the rigid wall forces starts from origin,Cause initially there is no contact between the crash tube and rigid wall.

And it goes on increasing,cause the elements are getting deformed and the rigid wall forces suddenly reaches peak,cause the entire crash tube collides with the rigid wall.

And again its decreasing,cause after the collision,the entire component will be at rest,So its decreasing.

Contact Forces:

Here the contact forces are in origin,cause initially there is no contact and impact.
And it goes on increasing slightly,cause the deformation is happening and suddenly it reaches peak,cause the entire crash tube collides to the rigid wall.
And it decreases,cause after collision,the crash tube will be at rest.

Kinetic Energy:

Here kinetic energy is increasing in the beginning itself,Why because the initial velocity is given for the component.

And it goes on decreasing,cause the deformation is happening to the crash tube,so the kinetic energy is decreasing.

Internal Energy :

The formula for Internal Energy is I.E = Q W.
Here the heat is neglected,Cause there is no heat transfer,We will be having only workdone.
W=FxD
F=ma

Here the internal energy is in Zero,Because there is no deformation initially,So the internal energy is in Zero and starts from Zero and goes on increasing.

The internal energy increases because the deformation is happening,there is a displacement,So the internal energy increases,when the displacement or deformation occurs.

Contact Energy:

Here the contact energy starts from origin,Cause the crash tube component is in intial condition.

Intially there is no contact between the crash tube component and rigid wall.

There is also no deformation intially,But when the component goes and hits on the rigid wall,The contact energy starts increasing.
When the deformation or displacement happens to the component,the contact energy increases,cause the crash tube comes into the contact to the rigid wall.So the contact energy goes on increasing.

Total Energy :

Total Energy is sum of Kinetic Energy+Contact Energy+Hourglass Energy + Internal Energy.

Here total energy starts from higher value,In starting itself its increasing,Why because the total energy is sum of Kinetic Energy+Contact
Energy+Hourglass Energy + Internal Energy.

All energies are in initial condition except kinetic energy,So kinetic energy is only there
Total Energy=Kinetic Energy+0+0+0.

Kinetic enrgy is directly proprtional to the total energy.

So the total energy is increasing in the beginning.
And its slightly decreasing,Due to -3.8% of energy error,the total energy is decreasing.

Hourglass Energy:

Here the hourglass energy is constant,Because the recommended parameter Ishell=24 has been assigned to the property card,So the hourglass energy is constant

All Energies:

Case-2 Change the Inacti=6 and run :

Here change the parameter value as Incti=6,Keep the remaining parameters as it is default.

When we change the Inacti Parameter=6,It will remove the penetration,the penetration won't happen between the slave and master node.

It will reduce the gap and adjust the gap.Like the gap will be reduced and scaled.The Iancti value is changed which is shown in below

Simillalrly,Now run the simulation using radioss,After running the simulation,The animation and TH files will be obtained in a required location,which is shown

Now go and open the 00001.out file with notepad.

The obtained values for Energy Error,Mass Error,Internal Energy Error,Kinetic Energy Error and Contact Energy Error has been shown

1) Review the Simulation using -HyperView.

After completion of running the simulation,Switch to the hyperview.

Open the appropriate .h3d file to review the simulation.

The .h3d file is loaded and it is shown in below Figure 65.

Here the stess generated for this case is 0.73 Mpa.The behaviour is same similar to the previous case 1.

2) Plot the graphs using-Hypergraph 2D.

Now switch to the Hypergraph 2D and plot the graphs.

The rigid wall forces graph is plotted which is shown in below

Rigid Wall Forces:

The obtained graph for rigid wall forces is shown in above Figure 66.Here The rigid wall forces is similar to the previous case 1.

Contact Forces:

The obtained graph for contact forces is shown in below Figure 67.Here the contact forces are also some what similar to the previous case 1.

Kinetic Energy:

The obtained graph for kinetic energy is shown in below Figure 68.Here aslo kinetic energy is similar to the previous case 1.

Contact Energy:

The obtained graph for contact energy is shown in below Figure 69.Here aslo contact energy is similar to the previous case 1.

Internal Energy:

The obtained graph for internal energy is shown in below Figure 70.Here aslo internal energy is similar to the previous case 1.

Total Energy:

The obtained graph for total energy is shown in below Figure 71.Here aslo total energy is similar to the previous case 1.

Hourglass Energy:

Here the hourglass energy is constant,Because the recommended parameter Ishell=24 has been assigned to the property card,So the hourglass energy is constant.

All Energies:

Case-3 Create the type 11 contact and run:

Now for this case,we have to create new contact called Type 11 [Edge to Edge Contact].Some parameters should be given which is shown in below.

Here i'm giving type 7 parameters to the type 11,Cause the type 11 is similar to the type 7 contact.

Now define the slave and master for the type 11 contact which is shown in below.Select all the elements.

Now request for the TH.TH is requested for type 11 contact.While defining TH all the interfaces should be selected which is shown in below

To create TH,Go to Solver Browser >> Right Click on TH >> Create >> Inter,Which is shown.

After creating TH,The contact interfaces should be assigned to that,Which is shown in below

1) Review the Simulation using -HyperView.

Now run the simulation,After running the simulation,Switch to the Hyperview and load the .H3D file to view the results of simulation which is shown in below

Now go and open the 00001.out file with notepad.

The obtained values for Energy Error,Mass Error,Internal Energy Error,Kinetic Energy Error and Contact Energy Error has been shown

2) Plot the graphs using -Hypergraph 2D.

Here the Kinetic,Internal,Contact,Internal and Hourglass Energy is similar to the previous case.

The graphs plotted for Kinetic,Internal,Contact,Internal and Hourglass Energy is shown

Rigid Wall Forces:

The graph obtained for the rigid wall forces is shown in below Figure 81.

Here the rigid wall forces are increased when compared to the previous case.It is increased between the range of (1400-1600).

They are increased cause the type 11 contact is also defined with the type 7 contact,so they are increased.

Self Contact Forces:

The graph obtained for the contact forces is shown in below Figure 82.

Here the contact forces starts from origin and suddenly reaches peak,Cause the all the elements come into the contact,In that time the contact forces reaches peak and decreases cause the crash tube will be in rest after collision.

Type 11 Contact Forces:

The graph obtained for the Type 11 Contact Forces is shown in below.

Here the Type 11 Contact Forces are starting from origin and increasing due to the elements come into the contact and its suddenly reaches at peak due to there will be no edge to edge penetration,all the elements come into the contact,So its suddenly reaches the peak.

And its decreasing after the collison,Cause the crash tube will be at rest.

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

Here in this case,We have to remove the notches and boundary conditions as per the question.

To remove the notches,use align node tool and align them properly to remove the notches.

To Align,Go to Geometry >> Node Edit >> Node 1,2,3 >> Align Node.

The notches have been removed for this case,which is shown in below

Then Remove the Boundary Condition which is shown in below.

1) Review the Simulation using -HyperView.

Now run the simulation,After running the simulation,Switch to the Hyperview and load the .H3D file to view the results of simulation which is shown in below.

Here the buckling is happening at the contact due to the removal of notches.

In previous cases buckling was happening,where the notches were.

Now go and open the 00001.out file with notepad.

The obtained values for Energy Error,Mass Error,Internal Energy Error,Kinetic Energy Error and Contact Energy Error has been shown

2) Plot the graphs using -Hypergraph 2D.

Rigid Wall Forces:

The obtained graph for the rigid wall forces is shown in below.

Here the rigid wall forces is reduced due to the removal of notches.

The maximum rigid wall forces value obtained in this case is 1213.89.It is low when compared to the previous cases.

Contact Forces:

The obtained graph for the contact forces is shown in below.

Here the contact forces increases faster due to the removal of notches.

Internal Energy:

The obtained graph for the Internal Energy is shown in below.

It is similar to the previous case.

Kinetic Energy:

The obtained graph for the Kinetic Energy is shown in below.

It is similar to the previous case.

Total Energy:

The obtained graph for the Total Energy is shown in below.

It is similar to the previous case.

All Energies:

The obtained graph for the All Energies is shown in below.

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

Here for this case,Create notches in the middle by using element offset.

To create notches in the middle,Go to 2D panel >> Element Offset >> Select Elements >> Distance=2 >> Offset+.

Here you have to give a distance,To give a distance,Measure the distance between the notches which is shown in below.

Here the distance is 4,You have to offset,So give the distance as 2 to create a notches in the middle which is shown in below

1) Review the Simulation using -HyperView.

Now run the simulation,After running the simulation,Switch to the Hyperview and load the .H3D file to view the results of simulation which is shown in below.

Here the buckling is happening,Where the notches exsist.

Now go and open the 00001.out file with notepad.

The obtained values for Energy Error,Mass Error,Internal Energy Error,Kinetic Energy Error and Contact Energy Error has been shown in below

2) Plot the graphs using -Hypergraph 2D.

Rigid Wall Forces:

The obtained graph for rigid wall forces is shown in below Figure 104.

Here the rigid wall froces are similar to the previous case,But the buckling is happeneing where the notches exsist in the crash tube.

Contact Forces:

The obtained graph for the contact forces is shown in below Figure 105.

Here the contact forces are also some what similar to the previous cases.

Internal Energy:

The obtained graph for the Internal Energy is shown in below.

It is similar to the previous case.

Kinetic Energy:

The obtained graph for the Kinetic Energy is shown in below Figure 107.

It is similar to the previous case.

Total Energy:

The obtained graph for the Total Energy is shown in below Figure 108.

It is similar to the previous case.

All Energies:

The obtained graph for the All Energies is shown in below

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

Here for this case create a notches in the two opposit faces and run the simulation.

The notches created in the two opposite faces is shown in below

1) Review the Simulation using -HyperView:

Now run the simulation,After running the simulation,Switch to the Hyperview and load the .H3D file to view the results of simulation which is shown in below.

Here also the buckling is happening,Where the notches exsist.

Now go and open the 00001.out file with notepad.

The obtained values for Energy Error,Mass Error,Internal Energy Error,Kinetic Energy Error and Contact Energy Error has been shown in below

2) Plot the graphs using -Hypergraph 2D.

Rigid Wall Forces :

The obtained graph for rigid wall forces is shown in below Figure 113.

Here the rigid wall forces are similar to the previous case,But the buckling is happeneing where the notches have been created in the crash tube.

Contact Forces:

The obtained graph for the contact forces is shown in below Figure 114.

Here the contact forces are also some what similar to the previous cases.

Internal Energy:

The obtained graph for the Internal Energy is shown in below.

It is similar to the previous case.

Kinetic Energy:

The obtained graph for the Kinetic Energy is shown in below.

It is similar to the previous case.

Total Energy:

The obtained graph for the Total Energy is shown in below.

It is similar to the previous case.

All Energies:

The obtained graph for the All Energies is shown in below

Comparison of all the Cases:

RESULT:

Hence the simulation for all the cases were carried out with different parameters.
Hence the simulation for all the cases were runned successfully.
Hence the simulation for all the cases were reviewed by hyperview.
Hence the graphs were plotted for all the cases successfully.
Hence meshed the bumper component with 6 mm size.
Atlast,Compared all the results for those cases.

Conclusion and Learning Outcome:

In this challenge,I came to know bout
The types of interfaces and their applications.
The effect of notches in the model.
The penetration causes.
The diferent parameters for the interfaces.
The elements deformation during the interface.