COMPUTE THE VDI TIME-HISTORY FROM ACCELERATION¶
Computes the Vehicle Pulse Index (VPI) time-history from a vehicle acceleration signal using a lumped spring-mass model parameterised by slack, stiffness, and mass. Use this worker to evaluate VPI as a crash pulse quality / occupant-loading metric derived directly from measured or simulated vehicle acceleration.
When to use¶
Classification: process.
Tagged: acceleration, crash_pulse, occupant_loading, spring_mass, time_history, vehicle_pulse_index, vpi.
Inputs¶
| Label | ID | Type | Default | Required | Description |
|---|---|---|---|---|---|
| Vehicle Acceleration | vehicle_acceleration | vector | — | Vehicle acceleration time-history curve (time vs. acceleration, typically in g or m/s²) used as the excitation signal for the VPI lumped-model integration. | |
| Slack | slack | scalar | 1 | Free-play / slack distance (length units consistent with stiffness) in the lumped spring-mass model before contact force is engaged; defaults to 1. | |
| Stiffness | stiffness | scalar | 1 | Spring stiffness of the lumped occupant-restraint model (force/length units); controls the rate at which load builds after slack is consumed; defaults to 1. | |
| Mass | mass | scalar | 1 | Lumped occupant mass (kg or consistent mass unit) used to scale the inertial response in the VPI model; defaults to 1. |
Outputs¶
| Label | ID | Type | Description |
|---|---|---|---|
| curve_vpi_acceleration_output_1 | curve_vpi_acceleration_output_1 | scalar | Computed VPI scalar or time-history value derived from integrating the spring-mass model against the input vehicle acceleration; represents the Vehicle Pulse Index metric for crash pulse assessment. |
Disciplines¶
- data.curve.transform
- engineering.crash.dynamics
- engineering.crash.occupant_safety
Runnable example¶
A runnable example is registered for this worker. Open the example workflow on the d3VIEW canvas: /api/workflow/example?id=curve_vpi_acceleration
Auto-generated from transformation schema. Worker id: curve_vpi_acceleration. Schema hash: 475367e4db32. Hand-curated docs in workerexamples/ override this page when present.