Histories

Load case US_NCAP
 

Define x-acceleration of nodes:

1. Select the Histories tab.
2. From the possible history types select: NODOUT.
3. For Component select from the list Acceleration.
4. For Direction select X Component.
5. For Node ID enter 3740178.
   (The acceleration of the left seat is measured by node 3740178.
   To see the position of the node click on the ID-number.)
6. For Filtering choose SAE Filter.
7. Enter 60.0 for Frequency.
8. For Case switch to US_NCAP.
9. For History Name enter accel_left_seat.
10. Push the Add button.

For the rest of the Acceleration-Histories ( e.g. accel_right_seat,  accel_engine_top, accel_engine_bottom,  accel_B_pillar_r, accel_B_pillar_l ) repeat the steps 2 to 10, updating only the Node IDs and Names.

Define intrusion:

1. From the possible history types select: NODOUT.
2. For Component select from the list Deformation.
3. For Direction select X Component.
4. For Coordinate System select Local.
5. For Identifier Type switch to ID.
6. For Local x-axis from enter 2362340 to 2352390, 3rd node ID 2214602.
7. For Measured Node ID enter 2057404.
   (To see the position of the node click on the ID-number.)
8. For Reference Node ID enter 2362340.
9. For Filtering choose None.
10. For Case switch to US_NCAP.
11. For History Name enter intrusion_rail_l.
12. Push the Add button.

For the rest of the Intrusion-Histories ( e.g. intrusion_rail_r,  intrusion_break_pedal, intrusion_gas_pedal, intrusion_steering, intrusion_firewall_left, intrusion_firewall_right) repeat the steps 1 to 12, updating only the Measured Node IDs and Names.

 Define an Expression:

Now we would like to calculate the average accelaration of a seat. Therefore we use the predefined histories accel_left_seat and accel_right_seat.

1. From the possible history types select: Expression.
2. In the input field for an algebraic expression enter (accel_left_seat+accel_right_seat)/2.
3. For Case switch to US_NCAP.
4. For History Name enter accel_seat_average.
5. Push the Add button.

 Define the same histories for the load case IIHS, that you defined for the load case US_NCAP.

Load case Torsion
 

Define Displacement:

1. From the possible history types select: RBDOUT.
2. For Rigid Body ID enter 2000804.
3. For Component select from the list Displacement.
4. For Direction select Z Component.
5. For Case switch to Torsion.
6. For History Name enter z_displ_2000804.
7. Push the Add button.

Repeat steps 1 to 7 to define other displacements ( e.g. z_displ_2000805, y_displ_2000804, y_displ_2000805), updating the IDs, Directions and Names.

Define X-Moment:

1. From the possible history types select: SECFORC.
2. For Section ID enter 1.
3. For Component select from the list X moment.
4. For Filtering choose None.
5. For Case switch to Torsion.
6. For History Name enter x_monent.
7. Push the Add button.

 Define the torsion angle:

We need to define two expressions before calculating torsion angle. The first one is the difference between the displacements in z direction we defined above (z_diff = z_displ_2000804 - z_displ_2000805). And the second one ist the difference between the coordinates of the displacements in y direction ( y_coord_diff = y_displ_2000804 - y_displ_2000805+1122.4566) The value 1122.4566 is the initial distance between the y coordinates.

Now we can define the torsion angle:

1. From the possible history types select: Expression.
2. In the input field for an algebraic expression enter atan(z_diff/y_coord_diff).
3. For Case switch to Torsion.
4. For History Name enter torsion_angle.
5. Push the Add button.