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

ASSIGNMENT 5 – RADIOSS (INTERFACES & STUDY OF EFFECT OF NOTCHES )

Objective :

To study the interfaces and effect of different notches on the model s

To mesh bumper model with mesh size of 6mm

Run the simulation for 6 different cases as mentioned below.

• Run the model as it is
• Change Inacti= 6 and run
• Create type 11 contact and run
• Remove both notches and remove boundary condition
• Create notch in the middle and run the simulation
• Create notch with nodes only from opposing faces

To plot the graphs with RWALL forces ,contact forces ,internal energy (post –processing )& compare results .

Study the effects of notches

To study different cases with their effect

PROCEDURE

Meshing of bumper model

To start with we have to import model in hypermesh environment , which can be done by IMPORT SOLVER DECK >> IMPORT MODEL >> BROWSE- BUMPER_SYSTEM.HM FILE >>IMPORT

Once model is been imported in hyper mesh , we have to pin point the short comings in the model for which we have change the GEOMETRY COLOUR MODE to BY TOPO which highlights single cone and double / triple cone in the model

These single cones and triple cones with free nodes has to be removed where it is necessary .

In above image free nodes are visible to remove them go to TEMP NODES >> SELECT ALL NODES >> DELETE

To better understand the geometry and where clean up is necessary hide one of two components

We selected one of two component to work as shown in below picture where middle surface in not properly intersected with upper and lower surfaces

To deal with this we have used extend method

To extend go to SURFACE EDIT PANEL >> CHANGE (MAX EXTENSION BOX )TO ( EDGE OVER EDGE ) >> SELECT LINES TO EXTEND >> SURFACE TO EXTEND >> AND TARGET SURFACE once this is done it will appear as below .

Moving to second component we can clean up this by using projection method or in some case it can be done by extend and intersection method

After this do auto clean-up and mesh the models with target element length of 6 mm

Hence meshing of the bumper model is done

MODEL 2

CASE1 : Run the model as it is.

Go o FILE >> IMPORT >> SOLVER DECK >> CRUSH_TUBE_0000.RAD >> IMPORT

On importing model ,it is visible in wire frame mode which we can change to shaded element mode for better understanding of model

Once model is imported we have to observe the properties of model

The model has 1 material property and 2 property ID and both property cards are set to recommended property values

Material EPS_p_max values is zero

Now go to ANALYSIS>>RADIOSS >>INPUT FILE >> INCLUDE CONNECTOR>> OPTIONS=-NT 4 >> RADIOSS.

This will run the radioss simulation

Open.out engine file from saved folder and check final values of energy error ,mass error ,simulation time and total no. of cycles.

Now open .h3d file in hyperview

In hyper view go to CONTOUR >> RESULT TYPE >> VON MISSES >>AVERAGING METHOD >> SIMPLE >> APPLY

In thos simulation ewe can see that the tube starts to bend at the upper notch where in intial plastic strain occurs and eventually the tube starts to bend at the lower notch .we can also observe that the tube fails between the notch region and then the region above the notch is crushed .

The maximum von misses stress and maximum plastic strain is formed at the corner section of tube

Open hypergraph 2D and load .TO1 file

Go to GLOBAL VARIABLE >> INTERNAL ENERGY , KINETIC ENERGY and TOTAL ENERGY >>MAG >> apply . this will plot the energy graph ,animation of this graph is shown above in forth window

The kinetic energy having higher value at the start of the simulation eventually starts to reduce with time as it gets converted into internal energy . as this tube is being crushed. Thus ,total energy remains constant with respect to time

But we can see a slight drop in energy at time equals to 25ms . this is because the tube is totally crushed and the energy is lost to friction between elements

This can be observered by contact enregy graph

The contact energy increases initially at a slow pace and rapidliy between 20 to 26 ms , because after 20 ms the tube deformation is is completed and the force is crushing the surfaces of the tube in the formation of folded layers . here the corner surfaces come in close contact with each other , resulting in the spring formation to repell the surfaces from intersecting each other

Now plote the rigid wall forceses graph

A pattern is observed in the resultant normal force , where a small amount of force increases at a regular interval of time this increase in force is when the corner edge fold the tube and slave nodes try to penetrate into master surface , the spring stiffness increases the force to oppose the slave node after 20 ms we see greater rise in force value as tube is crushed and more number of nodes come to closer. Then force is reduces and reaches to zero value.

Case 2 : change the Inacti= 6 and run.

Go to FILE > IMPORT > SOLVER DECK > CRUSH TUBE_0000.RAD > IMPORT

Go to INTER > TYPE7 > INACTI = 6

Now go to ANALYSIS > RADIOSS > INPUT FILE > INCLUDE CONNECTOR > OPTIONS = -nt 4 > RADIOSS

This will run the radios simulation

Open.out engine file from save folder and check final value of energy error ,mass error ,simulation time and total no. cycles.

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Open . h3d file in Hyperview window .

In Hyperview go to CONTOUR > RESULTS TYPE = VON MISES > AVERAGING METHOD = SIMPLE > APPLY

This simulation is same as Case 1 simulation . there is is no geometric change in the model and also maximum stresses and the strain values

The only change in this case is that Inacti=6 is set ,which reduces the gap and uses scaling

Inacti 6 removes the initial penetration and moves nodes 30% of initial gap to avoid contact stability issue .as this is performed before simulation . we observe no difference in the simulation as in case 1 .

Open Hypergraph 2D and load TO1 file

Go to GLOBAL VARIABLE >> INTERNAL ENERGY , KINETIC ENERGY and TOTAL ENERGY >>MAG >> apply . this will plot the energy graph .

The energy graph is same as case 1

Now plot contact energy

The contact energy increases when the friction contact is defined . at 20 ms the contact energy increases due to the friction formulation defined .

Now plot total resultant force

The force graph is similar to earlier case . the resultant normal force and total resultant force is similar as the variation in resultant tangent force is negligible

Case 3 : create type 11 contact and run .

Now we have to create a new contact as type 11 which can be done doing right click on GROUPS in model browser

New window will pop up .in it go to create once it is crated double click on it where it ask for CARD IMAGE in here we have to select type 11 contact

In type 11 input all the recommended properties as shown in the picture below

Now go to ANALYSIS > RADIOSS > INPUT FILE > INCLUDE CONNECTOR > OPTIONS = -nt 4 > RADIOSS

This will run the radios simulation

Open.out engine file from save folder and check final value of energy error ,mass error ,simulation time and total no. cycles.

Open . h3d file in Hyperview window .

In Hyperview go to CONTOUR > RESULTS TYPE = VON MISES > AVERAGING METHOD = SIMPLE > APPLY

In this case type 11 interfaces is used which removes the edge to edge intersection .in the model as there are few edge the result doesn’t vary with respect to earlier results

Open Hypergraph 2D and load TO1 file

Go to GLOBAL VARIABLE >> INTERNAL ENERGY , KINETIC ENERGY and TOTAL ENERGY >>MAG >> apply . this will plot the energy graph

The graphs are similar as discussed earlier

There is more energy error than type 7 interfaces

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

Go to FILE > IMPORT > SOLVER DECK > CRUSH TUBE_0000.RAD > IMPORT

For this case we have to remove notches and delete the boundary condition

Press F7 to go to the node edit panel .align the nodes with the align option in the node edit panel

To delete boundary conditions we first have to activate SOLVER DECK from VIEW available in the menu bar as shown in below

Once solver deck is been activated go to BCS available in it , you can either delete it or remove its all constrains

Now go to ANALYSIS > RADIOSS > INPUT FILE > INCLUDE CONNECTOR > OPTIONS = -nt 4 > RADIOSS

This will run the radios simulation

Open.out engine file from save folder and check final value of energy error ,mass error ,simulation time and total no. cycles.

Open . h3d file in Hyperview window .

In Hyperview go to CONTOUR > RESULTS TYPE = VON MISES > AVERAGING METHOD = SIMPLE > APPLY

In this case the notches are removed and hence we have uniform section . the tube starts deforming at bottom region and the same layered pattern is followed for deformation . the maximum von misses stress is less than the earlier cases

Open Hypergraph 2D and load TO1 file

Go to GLOBAL VARIABLE >> INTERNAL ENERGY , KINETIC ENERGY and TOTAL ENERGY >>MAG >> apply . this will plot the energy graph simiarly plot contact energy and total resultant

Due to notch is removed the drop in the kinetic energy at the end is not seen . hence total energy remains almost constant

The contact energy is lower than 1600 kgmm2/ms2 , where previously the contact energy increased above 2000 kgmm2/ms2. This reductions is due to less friction between the elements as notch is removed

The total normal and total resultant force is observed to be less then the previous cases . the max forces value is 1200 KN where the previous cases recorded up to 1350 N

This drop is due to removal of boundary condition .

Case 5 : create new notch in the middle and run the simulation

To create notch in the middle we have to use TRANSLATE option available in the TOOL

Now go to ANALYSIS > RADIOSS > INPUT FILE > INCLUDE CONNECTOR > OPTIONS = -nt 4 > RADIOSS

This will run the radios simulation

Open.out engine file from save folder and check final value of energy error ,mass error ,simulation time and total no. cycles.

Open . h3d file in Hyperview window .

In Hyperview go to CONTOUR > RESULTS TYPE = VON MISES > AVERAGING METHOD = SIMPLE > APPLY

Open Hypergraph 2D and load TO1 file

Go to GLOBAL VARIABLE >> INTERNAL ENERGY , KINETIC ENERGY and TOTAL ENERGY >>MAG >> apply . this will plot the energy graph simiarly plot contact energy and total resultant

In the graph we can observe slight reduction in the kinetic energy and slight increase in the internal energy at 11ms .

Where the deformation in the upper section starts . this is mainly due to notch created in the middle of the section of the tube .

Here we can see that contact energy slightly increases at the point of shift deformation. And also contact energy and the end is above 1500 kgmm2/m2

In the previous cases we observe slight increase in the forces where deformation shifted from notch section

Similarly ,a single (as we have only one notch )slight rise and fall in the forces is seen at 11 ms where the deformation is shifted to upper section of the tube.

Case 6 : create new notch with nodes only from opposing two faces and run

To create notch in the in opposing faces we have to use TRANSLATE option available in the TOOL

First open the model in hypermesh go to TOOLS> TRANSLATE > SELECT NODES to be translate enter appropriate distance and translate them as shown below

Now go to ANALYSIS > RADIOSS > INPUT FILE > INCLUDE CONNECTOR > OPTIONS = -nt 4 > RADIOSS

This will run the radios simulation

Open.out engine file from save folder and check final value of energy error ,mass error ,simulation time and total no. cycles.

Open . h3d file in Hyperview window .

In Hyperview go to CONTOUR > RESULTS TYPE = VON MISES > AVERAGING METHOD = SIMPLE > APPLY

In this case initial deformation is again at the notch section due to stress concentration but the faces having notch deforms inwards and the faces with no notch deforms outward .

Open Hypergraph 2D and load TO1 file

Go to GLOBAL VARIABLE >> INTERNAL ENERGY , KINETIC ENERGY and TOTAL ENERGY >>MAG >> apply . this will plot the energy graph simiarly plot contact energy and total resultant

As compared to previous cases the graph does not show slight deformation at 11 ms

The contact energy recorded is lower than previous cases the contact energy at the end is about 1500 kgmm2/ms2. the increase in the contact energy at the beginning is very less

The total resultant force shows ups and down also at the peak region. there is more there is more deviation in the resultant tangent forces

Observations :

Case	Total no. of cycle	Energy error	Mass error	Simulation time	Max von misses stress
1`	83527	-3.8%	0%	61.33	0.6949
2	83469	-3.8%	0%	60.30	0.6953
3	85294	-4.0%	0%	69.72	0.6441
4	77306	-3.0%	0%	54.35	0.6533
5	82015	-4.2%	0%	58.94	0.6280
6	79862	-2.9%	0%	57.00	0.6560

• In here type 7 contact interface are used for the first two cases and then type 11 contact interface is created .hence when the both of theses cases work together make simulation stable
• The deformation of the tube is observed in the layers, where slave nodes try to enter master gap , the penalty method create a spring and resistive force is applied
• The energy error is caused when stiffness value increases to a greater value , minimizing the time step and hence elements are deleted . the deletion of element releases the energy .
• In the second case we only observe the change in the simulation time , because Inacti 6 is set which performs initial penetration check before simulation
• In third case type 7 and type 11 works together increases simulation time . the energy error is also increased
• In fourth case we observe less no. of cycle and lower energy error as boundary conditions and notches were removed
• In fifth case we observe increase in energy error as notches is created at the middle of the section
• In sixth case we observe no. of cycles is to be greatest among all the cases .also there is reduction in energy error as opposite faces notches are created

Learning outcomes :

• To apply different interfaces to the component
• Study the result of interfaces type
• Understand parameter check before simulation
• Significance of inacti 6
• To plot energy and rigid wall forces

Conclusion :

Hence by performing this project we conclude that we have studied the type 7 and type 11 interfaces and also their working together, we studied the effect of notches base on their location and no. of notches , the parameter check before and during the simulation are also studied