Week - 4 - Crash Box Simulation

AIM:-To perform the stimulation of the crash box by varying the thickness of 1.5mm and 1.2mm.

PROCEDURE:-

1. Import the model into ls perpost.
2. Apply the material property for the parts given.
3. Apply the Section property to the parts in the model.
4. Then after we need to give boundary conditions to the model.
5. Then we need to give the runtime and time step to the model.
6. We need to request the output results from the solver.
7. Analyze the result from the solver.

IMPORTING THE MODLE

• To import the model we need to open ls prepost and select file.
• Click on import select ls-Dyna binary polt and select the file location and press enter.

MATERIAL PROPERTY ASSIGNMENT

• For assigning the material property we need to go to keyword manager and select all.
• And then we need to go to MAT and select concerning material.
• Assigning the linear elastic material to the phone and rigid material to the ground
• And we are considering the material property of steel

• As we are concentrate on the results of the crash box so no need to give an eq 2 and add an hourglass keyword to control the hourglass energy.
• But we must give a fully integrated formulation that decreases the hourglass and increases the accuracy of the solution or hourglass key can control.

• we need to assign an hourglass to the part by giving HGID.

BOUNDARY CONDITIONS:-

• First, we need to create a rigid wall.
• To create the rigid wall we need to go to entity creation and select rigid wall
• select planar and select on create then click on the node and by translate move the wall.

• After that, we need to give the velocity of 13.6 mm/ms
• To give velocity we need to select the initial and select velocity and select the nodes and apply.
• Before that, we need to go to constrained and select nodal rigid body and select the nodes.

• Then after we need to mass to the CNRB to give mass we need to go to element and give the mass.

• After that, we need to give contact between them.
• In this, we can have automatic single surface contact in this we need to specify on the slave part crash box
• After that click on apply.

• After that, we need to request the output for the results.
• To request the outputs we need to go to the database and select the ASCII option.
• And enable them to get the output results.
• DT is time to print the results out.

• ELOUT:-database for element results for SSD (stress and strain
  components).

  D3PLOT:-Database for the entire model.

  GLSTAT:- file is the sum of internal energy of discrete elements.

  MATSUM:- Energy values part by part.

SPCFRC:-Single point force constrained

• After that, we need to give the runtime.

OUTPUT:-

CRASH BOX 1.2MM

• The maximum von mises stress attained by the body is 343.9Mpa
• The yield strength of the material is 210MPa so that the component has undergone the plastic state.
• The material has undergone failure as per the theory of failure and we are observing the plastic behavior.
• So that the body will not come to its initial state.

• As we can see that the component has contact with the rigid wall at 1.2 ms at that state the k.E decreasing and I.E is increasing
• The total Energy attained in this component is 107000 N-mm.

• From this graph, we can understand that the contact between the rigid wall and component happened at 1.2mm
• From that force is started increases it reached 82000N which is happened at 3.8mms at where the total force is been distributed

• If you see in the graph the after 1.2ms the highest acceleration is been is 2500 mm/ms^2 where it is been deceleration.

CRASH BOX WITH CRUSHING

• The maximum von mises stress attained by the body is 468.6Mpa
• The yield strength of the material is 210MPa so that the component has undergone the plastic state.
• The material has undergone failure as per the theory of failure and we are observing the plastic behavior.
• So that the body will not come to its initial state.

• As we can see that the component has contact with the rigid wall at 1.2 ms at that state the k.E decreasing and I.E is increasing
• The total Energy attained in this component is 9.63e+6 N-mm.

• From this graph, we can understand that the contact between the rigid wall and component happened at 1.2mm
• From that force is started increases it reached 28000N which is happened at 1.3mms at where the total force is been distributed
• As the mass is added to the component it will capable to resist the force up to a certain limit.

• If you see in the graph the after 2ms the highest acceleration is been is 225 mm/ms^2 where it is been deceleration.

CRASH BOX 1.5MM

• The maximum von mises stress attained by the body is 325.7Mpa
• The yield strength of the material is 210MPa so that the component has undergone the plastic state.
• The material has undergone failure as per the theory of failure and we are observing the plastic behavior.
• So that the body will not come to its initial state.
• As the thickness of the component increases so that the stress developed is reduced it able to resist high forces.

• As we can see that the component has contact with the rigid wall at 1.2 ms at that state the k.E decreasing and I.E is increasing
• The total Energy attained in this component is 1.35e+06 N-mm.

• From this graph, we can understand that the contact between the rigid wall and component happened at 1.2mm
• From that force is started increases it reached 0.11e+06 N which is happened at 6.7mms at where the total force is been distributed

• As we can see that the acceleration is high at 2.3ms is 1.75E+3 mm/ms^2

CRASH BOX WITH LOAD

• The maximum von mises stress attained by the body is 379.6Mpa
• The yield strength of the material is 210MPa so that the component has undergone the plastic state.
• The material has undergone failure as per the theory of failure and we are observing the plastic behavior.
• So that the body will not come to its initial state.
• As the thickness of the component increases so that the stress developed is reduced it able to resist high forces.

• As we can see that the component has contact with the rigid wall at 1.2 ms at that state the k.E decreasing and I.E is increasing.
• The total Energy attained in this component is 9.8e+06 N-mm.

• As we can see that the acceleration is high at 2.3ms is 150 mm/ms^2

• From this graph, we can understand that the contact between the rigid wall and component happened at 1.2mm.
• From that force is started increases it reached 0.375e+06 N which is happened at 1.2ms at where the total force is been distributed.

PROPERTY	THICKNESS	STRESS	TOTAL ENERGY	STRAIN	SEC FORCE
No crushing	1.2mm	350.602	107646	0.00757315	82298
No crushing	1.5mm	343.64	134435	0.00712224	112040
With crushing	1.2mm	4994.01	9.61E+06	0.441188	281530
With crushing	1.5mm	3589.92	9.66E+06	0.428595	374360

CONCLUSION:-

• As we can see that as thickness is increased then the internal energy is increasing and there is a decrease in the stress
• And the force for the component has high sec force than the 1.2mm thick component there will be less chance for developing the strain.
• For the crushing component due to high mass, the stress is developed high
• We understood how to perform analysis and get output result from the solver