/SENSOR

Format

Beside sensor type=TIME, additional cards are required if the following sensor types are used.

Definitions

Sensor Type

Type

Description

TYPE0, TIME

Start time

TYPE1, ACCE

Accelerometer

TYPE2, DIST

Nodal distance

TYPE3, SENS

Activation with sens_ID₁

Deactivation with sens_ID₂

TYPE4, AND

ON when sensors sens_ID₁ AND sens_ID₁ are ON

TYPE5, OR

ON when sensors sens_ID₁ OR sens_ID₂ are ON

TYPE6, INTER

Activation/Deactivation of sensor by interface contact

TYPE7, RWALL

Activation/Deactivation of sensor by contact with rigid wall

TYPE8, NOT

ON when sens_ID₁ is OFF

TYPE10, GAUGE

Pressure gauge

TYPE11, RBODY

Activation of sensor by Rigid Body force criteria

TYPE12, SECT

Activation of sensor by Section force criteria

TYPE13, WORK

Activation of sensor by Work criteria

TYPE14, ENERGY

Activation of sensor by part or subset internal or kinetic energy criteria

TYPE15, DIST_SURF

Shortest distance from a reference node to a plane or a surface

TYPE16, HIC

Head Injury Criteria (HIC)

USER1, USER2, USER3

User's sensor

Comments

1. The sensor types AND, OR, NOT, INTER, RWALL, RBODY and SECT work with all options using sensors.
2. USER1, USER2 and USER3 are sensors that you may create.

   The input format must be defined by a user supplied program. Refer to the Radioss User Subroutines Manual for more information about programming user sensors.

3. Sensors can be used to activate airbags, imposed forces, pressures, and fixed velocities.
4. Sensors can be used to activate or deactivate these elements: brick, quad, shell, truss, beam, spring or 3N Shell with /ACTIV.
5. For Sensor type TIME, the sensor is activated after the time delay T_delay. T_delay is not applicable with the force based sensors type RWALL, INTER, RBODY, WORK or SECT.
6. For Sensor type ACCE:
   • Sensor is activated (at T_sensor) if one of the accelerometers gives an acceleration greater than Γ_min during a time greater than T_min:

     T_sensor = T_delay + T_min

     with, T_min (time when the criteria is reached).

   • Dir defines the acceleration direction:

     X

     X direction

     Y

     Y direction

     Z

     Z direction

     XY

     XY plane $\left(\sqrt{{\gamma }_x^2+{\gamma }_y^2}\right)$

     YZ

     YZ plane $\left(\sqrt{{\gamma }_y^2+{\gamma }_z^2}\right)$

     ZX

     ZX plane $\left(\sqrt{{\gamma }_z^2+{\gamma }_x^2}\right)$

     XYZ

     total acceleration $\left(\sqrt{{\gamma }_x^2+{\gamma }_y^2+}{\gamma }_z^2\right)$

7. For Sensor type DIST:
   • Nodal distance node_ID node_ID₂ is defined as: D_min < | node_ID node_ID₂ | < D_max.

   • If D_max is reached in traction (| node_ID node_ID₂ | > D_max) or D_min is reached in compression (| node_ID node_ID₂ | < D_min) at time T_sensor, the sensor is then activated at time T_sensor:

     T_sensor = T_delay + T_R

8. For Sensor type GAUGE:
   • Sensor is activated (at T_start) if one of the gauges gives a presure greater than P_min during a time greater than T_min.

     T_sensor = T_delay + T_start

   • T_start is the time when pressure criteria is reached.
9. For Sensor types SENS, AND, OR:
   • The sensor is activated after activation of sensor sens_ID₁.
   • Minimum activation duration is given by T_delay.
   • After T_delay, sensor is deactivated if sens_ID₂ is activated.
   • If sens_ID₂=0, the sensor is deactivated after T_delay.
10. For Sensor type SENS:

    
    
    Figure 1.

11. For Sensor type AND:
    The sensor is activated one cycle after activation at the same time as sensor sens_ID₁ and sens_ID₂.

    
    
    Figure 2.

12. For Sensor type OR:
    The sensor is activated one cycle after the activation of sensor sens_ID₁ or after the activation of sens_ID₂.

    
    
    Figure 3.

13. For Sensor type NOT:
    The sensor is activated one cycle after deactivation of sens_ID₁.

    
    
    Figure 4.

14. For Sensor type INTER:
    A Sensor is activated when contact on interface is detected, and following force criteria is satisfied:

    • $F_{cont}<F_{\min }$ or $F_{cont}>F_{\max }$ during T_min
    Dir defines Force direction:

    FN

    Normal Force

    TF

    Tangent Force

    Sensor is deactivated if the contact is lost

    If there is no impact during a time equal to T_delay (Line 3), the sensor is deactivated.

    A sensor is used for one interface or sub-interface. You can use several type INTER sensors.

    
    
    Figure 5.

15. For Sensor type RWALL:

    The sensor is activated one cycle after impact on the rigid wall.

    A sensor is used for one rigid wall. You can use several type RWALL sensors.

    
    
    Figure 6.

    Sensor is activated when contact on the rigid wall is detected, and the following force criteria is satisfied:

    • $F_{RWALL}<F_{\min }$ or $F_{RWALL}>F_{\max }$ during T_min
    Dir defines Force direction:

    FN

    Normal Force

    FT

    Tangent Force

    X

    Force in X direction

    Y

    Force in Y direction

    Z

    Force in Z direction

    Sensor is deactivated if the contact is lost

16. For Sensor type RBODY:
    Sensor is activated when the force in the rigid body satisfies the criteria:

    • $F_{RBODY}<F_{\min }$ or $F_{RBODY}>F_{\max }$ during T_min
    Dir defines Force or Moment output to monitor:

    TF

    Total Force

    TM

    Total Moment

17. For Sensor type SECT:
    Sensor is activated when section force satisfies the criteria:

    • $F_{sect}<F_{\min }$ or $F_{sect}>F_{\max }$ during T_min
    Dir defines Force direction:

    TF

    Total Force

    TM

    Total Moment

    FN

    Normal Force

    FT

    Tangent Force

    FX

    Force in X direction

    FY

    Force in Y direction

    FZ

    Force in Z direction

    MX

    Moment in X direction

    MY

    Moment in Y direction

    MZ

    Moment in Z direction

18. For sensor type WORK:

    Sensor is activated when work satisfies the criteria:

    $Work>Wmax$ during T_min(1)

    $$Work=\left|{\displaystyle {\int }_{x}F\left(\sec t\_ID\right)}dx\right|+\left|{\displaystyle {\int }_{x}F\left(rbody\_ID\right)}dx\right|+\left|{\displaystyle {\int }_{x}F\left(int\_ID\right)}dx\right|+\left|{\displaystyle {\int }_{x}F\left(rwall\_ID\right)}dx\right|$$
    Where,

    x

    Distance between node_ID₁ and node_ID₂

    F(sect_ID)

    Force in the selected section force

    F(rbody_ID)

    Force in the selected rigid body

    F(int_ID)

    Force in the selected contact interface

    F(rwall_ID)

    Force in the selected rigid wall

    If sect_ID is 0, $F\left(\sec t\_ID\right)=0$

    If rbody_ID is 0, $F\left(rbody\_ID\right)=0$

    If int_ID is 0, $F\left(int\_ID\right)=0$

    If rwall_ID is 0, $F\left(rwall\_ID\right)=0$

    Work of all forces is calculated in the direction N1-N2, it is always positive.

    If node_ID₂ is not defined (0), the distance x becomes the displacement of the node_ID₁

19. For sensor type ENERGY.
    The sensor is activated when the internal or kinetic energies satisfies the criteria for the defined part or subset:

    • Internal energy < IE_min or Internal energy > IE_max
    • Kinetic energy < KE_min or Kinetic energy > KE_max
20. For Sensor type DIST_SURF, the sensor is activated when distance $D<D_{\min }$ or $D>D_{\max }$ during T_min value.
21. For Sensor type HIC, criteria is computed with:(2)
    $$HI{C}_{Period}=\max \left\{(t_2-t_1){\left[\frac{1}{t_2-t_1}{\displaystyle {\int }_{t_1}^{t_2}a(t).dt}\right]}^{\frac{5}{2}}\right\}$$

    With $(t_2-t_1)<Period$ and $a(t)=\frac{acceleration(t)}{gravity}$ .

    The sensor is activated when $HI{C}_{Period}>value$ after T_min value.

22. To obtain a class 1000 SAE filtering, the recommended value for F_cut is 1650 Hz (1.65 ms-1). Application of the filter helps to prevent wrong activation of the force-based sensor, due to a local force peak. Another method to avoid this is to use a small value for T_min.
23. Values for force and moment component limits in the force-based sensors (types RWALL, SECT) can be positive and negative. Normal, tangent, total force and moment values are always positive.