Requests
Requests contain standard displacement, velocity, acceleration, or force information that can help you investigate the results of simulations. You can also define other quantities (such as pressure, work, energy, momentum, and more) that you want output during a simulation.
Adams stores the requests in request files (.req) and/or results files (.res).
Setting Request Activity
By default, requests for each element type are active. You can, however, deactivate requests for a certain element type. Activity changes can be saved to the subsystem file(s).
To set request activity:
1. From the Standard Interface's Tools menu, select Requests, then Request Activity.
3. Select OK.
Storing Request Activity
To store the
Requests activity for a non-standard object (for example, bushing, spring, damper and so on), you can take advantage of group activity using parameter variables, which are stored in
subsystem files.
To store request activity in Template Builder:
1. Create a parameter variable to store the activity of the request as a 1 for active, 0 for inactive.
For example, pvs_request_activity.
2. Create a group with command language:
Tools -> Command Navigator, group -> create. See
Group Create.
3. Add your requests to the group.
4. For the expr_active parameter of the group (1 = active, 0 = inactive), create a function that uses the parameter variable in step 1.
The commands might look as follows:
group create &
group_name = ._my_template.my_request_activity
objects_in_group = ._my_template.request0, &
._my_template.request1, &
._my_template.request2, &
._my_template.request3, &
expr_active = (pvs_request_activity)
For more examples, investigate templates in the shared database that have the group kinematic_mode_active, which is used for the Kinematic Mode option.
Request 907
Request 907 (req907) outputs displacement, velocity, accelerations, and body side-slip angle depending on the value of par(2) in the parameter list. Req907 is compatible with both dynamic and steady-state type analyses.
Input:
REQ/id, FUNCTION = USER(routing_code,type,imarker,jmarker,rmarker,scale, int_branch, zerolim)
Routine= abgVDM::req907
where:
Description |
|---|
routing_code | = | Used only when routine= is not specified to dispatch to the proper routine |
type | = | request type ■0 = returns displacement outputs ■1 = returns velocity outputs ■2 = returns acceleration outputs ■3 = returns side_slip_angle |
imarker | = | ID of I marker |
jmarker | = | ID of J marker |
rmarker | = | ID of reference marker |
scale | = | To set the scaling factor for translational velocities (and is not used for other output types).
If set to zero, translational velocity outputs are converted to MPH, for other values they are converted to KPH. |
int_branch | = | Used only for the lateral acceleration reported during "straight" and "skidpad" analysis |
zerolim | = | Result values smaller than zerolim (default is 1e-7) are returned as zero |
Request File Output
Column Number Output for request type = 0: (Angles in radians, longitudinal/lateral/vertical components are in the reference frame of jmarker)
1. Chassis Displacements- longitudinal
2. Chassis Displacements- lateral
3. Chassis Displacements- vertical
4. Chassis Displacements- roll
5. Chassis Displacements- pitch
6. Chassis Displacements- yaw
Column Number Output for request type = 1: (Translational velocity in KPH (or MPH), Angular velocity in radians/s, all components are in the reference frame of the rmarker)
1. Chassis Velocities - longitudinal
2. Chassis Velocities - lateral
3. Chassis Velocities - vertical
4. Chassis Velocities - roll
5. Chassis Velocities - pitch
6. Chassis Velocities - yaw
Column Number Output for request type = 2: (Translational acceleration in G's, Rotational acceleration in radians/s/2, all components are in the reference frame of the rmarker)
1. Chassis Accelerations- longitudinal
2. Chassis Accelerations- lateral
3. Chassis Accelerations- vertical
4. Chassis Accelerations - roll
5. Chassis Accelerations - pitch
6. Chassis Accelerations - yaw
Column Number Output for request type = 3: (Angle in radians)
1. Vehicle Statistics- side_slip_angle
2. (not used)
3. (not used)
4. (not used)
5. not used)
6. (not used)
Notes on Input and Output
1. Note that chassis displacements are provided in the reference frame of the j marker (ground), while velocities and accelerations are provided in the reference frame of the reference marker (typically on the body.)
2. During dynamics and non steady-state statics ("none", "settle"...) req907 calls sysfnc and sysary directly, but during steady-state static analyses ("straight" and "skidpad"), also leverages
req1090 and direct access to the consub performing the analysis to get values consistent with the steady-state conditions imposed for those solutions. Specifically, during "straight" and "skidpad" solutions:
♦for displacements: "longitudinal", "lateral", "vertical" and "yaw" are obtained directly from SYSARY and SYSFNC, but roll" and "pitch") are obtained from req1090;
♦for velocities: "longitudinal", "lateral" and "yaw" are obtained from req1090 and all other components are always zero;
♦for accelerations: "longitudinal" is obtained directly from the consub performing the analysis, "lateral" is obtained from req1090 and all other components are always zero;
♦for body sideslip: side_slip_angle" is obtained from req1090 and the other components are always zero.