.. _auto_curve_enforce_derivative_monotonicity:

*TREAT YPE*
===========

Enforces derivative monotonicity on a stress-strain (or similar) curve by treating the Young's modulus / plastic-entry region (YPE), ensuring the slope does not decrease non-physically before the specified strain limit. Use this worker to clean up noisy or non-monotonic hardening curves prior to material calibration or LS-DYNA MAT_24 ingestion.

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

Classification: **process**.

Tagged: ``YPE``, ``curve``, ``derivative``, ``hardening``, ``mat_24``, ``monotonicity``, ``smoothing``, ``stress_strain``.

Inputs
------

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

   * - Label
     - ID
     - Type
     - Default
     - Required
     - Description
   * - Curve
     - curve
     - vector
     - —
     - 
     - Input stress-strain (or generic X-Y) curve as a two-column vector; this is the curve whose derivative will be checked and corrected for monotonicity.
   * - Xlimit
     - xlimit
     - float
     - 0.05
     - 
     - Upper X-axis limit (e.g. strain) up to which the derivative-monotonicity correction is applied; defaults to 0.05 (5 % strain) — increase for materials with a wide elastic-to-plastic transition.
   * - Scalefactor
     - scalefactor
     - float
     - 1
     - 
     - Multiplicative scale factor applied to the curve Y-values before processing; defaults to 1.0 (no scaling) — change only when unit conversion is needed in the same step.

Outputs
-------

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

   * - Label
     - ID
     - Type
     - Description
   * - curve_enforce_derivative_monotonicity_output_1
     - curve_enforce_derivative_monotonicity_output_1
     - vector
     - Corrected curve with a monotonically non-decreasing derivative up to xlimit, returned as a two-column vector in the same X-Y format as the input.

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

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

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

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

.. raw:: html

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   Auto-generated from <code>transformation</code> schema. Worker id: <code>curve_enforce_derivative_monotonicity</code>. Schema hash: <code>2e987c252ddb</code>. Hand-curated docs in <code>workerexamples/</code> override this page when present.
   </p>