COMPUTE THE VDI TIME-HISTORY FROM DISPLACEMENT¶
Computes the Vehicle Pulse Index (VPI) time-history from a vehicle displacement curve using a lumped mass-spring model with configurable slack, stiffness, and mass parameters. Use this worker to derive the VPI signal as part of crash pulse characterisation or occupant-environment interaction analysis.
When to use¶
Classification: process.
Tagged: crash_pulse, displacement, lumped_mass_spring, time_history, vehicle_pulse_index, vpi.
Inputs¶
| Label | ID | Type | Default | Required | Description |
|---|---|---|---|---|---|
| Vehicle Displacement | vehicle_displacement | vector | — | Vehicle displacement time-history curve (time vs. displacement, typically in ms and mm from a crash simulation or physical test); the first channel of this vector is used as the input signal. | |
| Slack | slack | scalar | 1 | Free-play / slack distance in the lumped model (same length units as the displacement curve, e.g. mm); leave at default of 1 if no slack is present. | |
| Stiffness | stiffness | scalar | 1 | Spring stiffness of the lumped mass-spring model (force/length units consistent with mass and displacement, e.g. N/mm); leave at default of 1 for a unit-stiffness baseline. | |
| Mass | mass | scalar | 1 | Lumped mass value used in the VPI computation (kg or consistent mass unit); leave at default of 1 for a normalised, unit-mass result. |
Outputs¶
| Label | ID | Type | Description |
|---|---|---|---|
| curve_vpi_displacement_output_1 | curve_vpi_displacement_output_1 | scalar | Computed VPI time-history scalar output derived from the vehicle displacement curve using the specified slack, stiffness, and mass parameters; represents the Vehicle Pulse Index signal over time. |
Disciplines¶
- data.curve.transform
- data.signal_processing
- engineering.crash.dynamics
Runnable example¶
A runnable example is registered for this worker. Open the example workflow on the d3VIEW canvas: /api/workflow/example?id=curve_vpi_displacement
Auto-generated from transformation schema. Worker id: curve_vpi_displacement. Schema hash: 951a7e8e48ae. Hand-curated docs in workerexamples/ override this page when present.