.. _auto_curves_compute_uniaxial_strain_rate:

*COMPUTE THE STRAIN-RATE FROM EFFECTIVE PLASTIC STRAIN VS TIME CURVES*
======================================================================

Computes the strain rate from effective plastic strain vs. time curves (or related time-history quantities such as displacement or velocity). Accepts multiple input curves and supports a variety of rate-calculation strategies including total average, regional averages, and value-at-threshold methods.

When to use
-----------

Classification: **process**.

Tagged: ``curve_derivative``, ``material_testing``, ``plastic_strain``, ``rate_calculation``, ``strain_rate``, ``time_history``, ``uniaxial``.

Inputs
------

.. list-table::
   :header-rows: 1
   :widths: 20 20 20 20 20 20

   * - Label
     - ID
     - Type
     - Default
     - Required
     - Description
   * - Time History Curves
     - time_history
     - vector
     - —
     - ✓
     - One or more time-history curves (e.g. effective plastic strain vs. time, displacement vs. time, or velocity vs. time) from which the strain rate will be derived; supply as a vector or collection of vectors.
   * - Timehistory Input Type
     - input_type
     - list
     - any
     - ✓
     - Declares the physical meaning of the supplied curves — choose 'any' for a generic quantity whose rate is needed, 'velocity' or 'displacement' for kinematics, or 'rate' if the curves already represent a rate quantity; defaults to 'any'.
   * - Rate Calculation Type
     - rate_type
     - scalar
     - total
     - ✓
     - Selects the rate-calculation strategy: 'total' averages over the full duration, 'start'/'end' evaluate at curve endpoints, 'failure_time' and 'start_to_failure_time_average' use a specific x-value threshold, 'failure_value' locates a target y-value, and '3r*'/'5r*' options average over equal sub-regions of the curve; defaults to 'total'.
   * - Value based on Strain-rate type specified above
     - rate_type_value
     - scalar
     - —
     - 
     - Threshold value used by rate-calculation methods that require a reference point — e.g. the specific x-value (time) for 'failure_time' or the y-value for 'failure_value'; leave blank when using 'total', 'start', 'end', or regional strategies.
   * - Reference Length
     - ref_length
     - scalar
     - 27.5
     - 
     - If the input type is velocity or displacement, the reference length is used to compute the rate
   * - Time Scale-factor
     - time_sf
     - scalar
     - 1.0
     - 
     - Scale factor applied to the time axis before rate computation, enabling unit conversion (e.g. ms → s: set to 0.001); defaults to 1.0 (no scaling).

Outputs
-------

.. list-table::
   :header-rows: 1
   :widths: 20 20 20 20

   * - Label
     - ID
     - Type
     - Description
   * - Strain-Rates
     - strain_rate
     - keyvalue
     - Key-value map of computed strain-rate scalars (units: 1/time unit of the input curves after time_sf is applied), one entry per input curve, keyed by curve identifier.

Disciplines
-----------

- data.curve.transform
- data.signal_processing
- engineering.material.characterization
- engineering.material.specimen

Runnable example
----------------

A runnable example is registered for this worker. Open the example workflow on the d3VIEW canvas: `/api/workflow/example?id=curves_compute_uniaxial_strain_rate <https://www.d3view.com/api/workflow/example?id=curves_compute_uniaxial_strain_rate>`_

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