STIMULATION OF ROOF CRASH ANALYSIS OF NEON BIW

STIMULATION OF ROOF CRASH ANALYSIS OF NEON BIW

OBEJECTIVE:

To stimulate roof crash analysis of Neon BIW assigning the required parameters and derive various output as shown in the question.

Import

• Car
  • Impactor

Transforms

• This will require (in order)
  • A 180° rotation about the global z-axis
  • A 5° rotation about the axis through axis AB
  • A 25° rotation about the axis through axis AC
  • A translation to put point A at global ( -3500.00, 584.822, 1343.06)

Interfaces

• Create a Type 7 contact interface between the impactor and the car
  • choose an appropriate stiffness definition
  • choose an appropriate minimum gap
  • change the coefficient of friction to 0.2
  • choose the appropriate friction penalty formulation
  • Save the data from the interface to the time history file.

Boundary condition

keep the suspension shock tower nodes locked in Z.

Impactor Boundary Conditions

• The impactor assembly contains a spring attached for stability. Create a BCS
  collector to fix the free end of the spring.
  • Create a moving SKEW to define the direction normal to the impactor’s
  face.
  • Create a BCS collector to guide the master node of the impactor rigid body
  so that it is free to translate normal to the face of the impactor, but is fixed
  in all other DOFs.

Imposed Displacement

• Impose the velocity of the impactor starting from 0 mm/s at t = 0. The
  displacement of the impactor should be 200 mm @ 200 ms.
  • Avoid abrupt changes in the acceleration of the impactor.

Control Cards

• /ANALY card
  • /DEF_SHELL card,
  • /DEF_SOLID card, and
  • /IOFLAG card
  • /SPMD card
  • /TITLE card

Engine File

• Use a constant nodal time step
  • Print time history every 0.0001 seconds
  • Solve for 200 ms
  • Create an animation file every 0.005 seconds

Include selected output in animation files:

• Elemental Energy
  • Elemental equivalent plastic strain
  • Elemental hourglass energy
  • Elemental von Mises stress
  • Nodal added mass
  • Turn on parallel arithmetic

Solution and Results Post Processing

• Run the model
  • Plot force vs. displacement. Check that the FMVSS 216 target load of
  47,000 N (= 3 * GVW) has been met.
  • Plot the energy vs. time curves

PROCEDURE:

• First, we have to import both car and the impactor into the radioss solver environment.

• Then translate the impactor according to the coordinates as shown in the question by tool – translate and tool – rotate option and select the required node to translate to required position of the impactor.
• Then we have to create type 7 contact interface with friction coefficient 0.2 by right click in solver – create – inter.
• First contact interface is self interface both slave and master node are car body.
• Second contact interface is impactor slave node will be the car body nodes and the master elements will be the impactor elements.

• Then we have to create the BCS to keep the suspension shock tower nodes locked in Z by 2D – rigid – circulated node – create and check only dof3 and dof6 to lock in Z direction.

• Create two skew on the node of the impactor in which the Z direction is pointed towards the roof of the car.
• Then we have to create BCS for impactor by right click solver – create – boundary condition – BCS.
• First BCS select the master node of the impactor and uncheck translation vz so it will locked in other directions.
• Second BCS select the free end of the spring of the impactor and check translation and rotational axis so it will lock in all directions.

• To Impose the velocity of the impactor starting from 0 mm/s at t = 0. The
  displacement of the impactor should be 200 mm @ 200 ms, create the function curve with required parameters 0,0 and 200,200.

• The to create the boundary condition right click solver – boundary condition – IMPDISP select the master on the impactor and assign the function curve, skew we created to it and give the direction as Z.

RESULTS POST PROCESSING:

VON MISES STRESS:

The max von mises stress is 2.126e-01 N/mm2.

DISPLACEMENT:

The max displacement is 3.054e+02mm.

PLASTIC STRAIN:

The max plastic strain is 1.281e-02.

NODAL MASS:

The max nodal mass is 9.315e-01kg.

ELEMENTAL ENERGY:

The max elemental energy is 4.432e+02N

CONCLUSION AND RESULTS:

Time - 10051.34 s

Energy error - -9.0%

Mass error - 0.4618E-01

Force vs displacement

Force vs displacement for impactor and car.

Force vs displacement foe car

FMVSS 216 target load

GVM for the car is 174.8 kg hence the target load is 3*174.8*9.81 = 5144.4N hence FMVSS target is not met because the model is reduced stimulation in case if it is a whole car is 1200 kg target load will be 3*1200*9.81 = 35316N hence the value is acceptable for FMVSS 216 target load.

Internal energy - 36.51J

Kinetic energy -119.2J

Contact energy -13.66J

Hourglass energy - 0.016J

Total energy - 145.26J

https://drive.google.com/file/d/1P6iP1OJad_vM_QvUapQoIrBh9I4y1F5m/view?usp=sharing