.. _auto_curves_failurepoint_min_derivative:

*COMPUTE THE POINT AT WHICH THE Y-VALUE DROPS TO ZERO OR STARTS TO DECLINE AT THE END OF THE CURVE. USEFUL FOR MATERIAL FAILURE ETC*
====================================================================================================================================

Identifies the failure point on one or more curves by locating the position of the steepest negative slope (minimum derivative) near the end of the curve, optionally verifying that the Y-value subsequently stays below a specified ratio of the maximum. Useful for extracting material failure strains, ultimate loads, or any critical drop-off point from stress-strain or force-displacement curves.

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

Classification: **process**.

Tagged: ``curve_analysis``, ``drop_detection``, ``failure_point``, ``material_failure``, ``min_derivative``, ``negative_slope``, ``stress_strain``.

Inputs
------

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

   * - Label
     - ID
     - Type
     - Default
     - Required
     - Description
   * - Curves From Which The Failure Point Is To Be Extracted
     - curvesfromwhichthefailurepointistobeextracted
     - vector
     - —
     - 
     - One or more input curves (e.g., force-displacement or stress-strain) from which the failure point is to be detected; accepts d3VIEW curve vectors.
   * - Ratio
     - ratio
     - scalar
     - —
     - 
     - Dimensionless scalar threshold (0–1): the algorithm searches for the steepest negative slope in the region where the Y-value falls below this fraction of the curve's maximum Y; defaults to checking the full tail if left blank.
   * - Ensure Sustainability
     - ensuresustainability
     - string
     - no
     - 
     - Set to 'yes' to require that the Y-value remains below the ratio threshold after the detected minimum-derivative point, confirming a sustained drop; set to 'no' (default) to return the steepest-slope point unconditionally.
   * - Return Type
     - return_type
     - string
     - count
     - 
     - Controls what value is returned at the failure point: 'xval' returns the X-axis coordinate (e.g., strain or displacement), 'yval' returns the Y-axis coordinate (e.g., stress or force); leave at default 'count' to return the point index.
   * - Return previous point to min derivative
     - returnpreviouspointtominderivative
     - string
     - no
     - 
     - Set to 'yes' to return the data point immediately before the minimum-derivative location (i.e., the last stable point prior to failure onset); set to 'no' (default) to return the value at the minimum-derivative point itself.

Outputs
-------

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

   * - Label
     - ID
     - Type
     - Description
   * - curves_failurepoint_min_derivative_output_1
     - curves_failurepoint_min_derivative_output_1
     - dataset
     - Dataset containing the extracted failure-point value (X coordinate, Y coordinate, or point index depending on 'return_type') for each input curve, one row per curve.

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

- data.curve.transform
- engineering.material.characterization
- engineering.material.failure

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

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

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   Auto-generated from <code>transformation</code> schema. Worker id: <code>curves_failurepoint_min_derivative</code>. Schema hash: <code>9d055b1fedb4</code>. Hand-curated docs in <code>workerexamples/</code> override this page when present.
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