.. _auto_keyvalue_to_ersatz_eng:

*ERSATZ ENGINEERING STRESS-STRAIN CURVE FROM A KEYVALUE*
========================================================

Takes the keyvalue emitted by curve_engstress_stats and reconstructs a full engineering stress-strain curve using hybrid energy-matched defaults (Voce pre-neck + power_concave_down post-neck), faithfully reproducing the plateau-then-cliff post-neck profile typical of ductile metals. No separate anchor or shape wiring is needed — all six anchor points and optional shape/energy keys are read directly from the keyvalue. Wire curve_engstress_stats → keyvalue_to_ersatz_eng for a one-step measured-to-reconstructed curve workflow.

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

Classification: **process**.

Tagged: ``curve_engstress_stats``, ``curve_reconstruction``, ``ductile_metal``, ``energy_match``, ``engineering_stress_strain``, ``ersatz``, ``keyvalue``, ``power_concave_down``.

Inputs
------

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

   * - Label
     - ID
     - Type
     - Default
     - Required
     - Description
   * - Engstress Stats
     - engstress_stats
     - keyvalue
     - —
     - 
     - Keyvalue output of the curve_engstress_stats worker; must carry the six anchor fields (yield_strain, yield_stress, eng_ultimate_strain, ultimate_stress, failure_strain, failure_stress) and, for energy-matching, energy_yield_to_ultimate and energy_ultimate_to_failure; optional shape-override keys (post_shape, post_power, damage_max, plateau_fraction, pre_ult_shape, pre_ult_power, voce_k, match_energy, target_energy, target_energy_uf, material_name) override the hybrid defaults when present; leave unconnected only if the downstream step does not require a reconstructed curve.

Outputs
-------

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

   * - Label
     - ID
     - Type
     - Description
   * - keyvalue_to_ersatz_eng_output_1
     - keyvalue_to_ersatz_eng_output_1
     - vector
     - Reconstructed engineering stress-strain curve as a two-column vector (strain, stress in model units), built from the keyvalue anchor points with Voce pre-neck and energy-matched power_concave_down post-neck segments; suitable for direct use as a MAT_24-style load curve or further curve processing.

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

- ai_ml.surrogate
- 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_ersatz_eng <https://www.d3view.com/api/workflow/example?id=curve_ersatz_eng>`_

.. raw:: html

   <hr style="margin-top:2em">
   <p style="font-size:11px;color:#888">
   Auto-generated from <code>transformation</code> schema. Worker id: <code>keyvalue_to_ersatz_eng</code>. Schema hash: <code>339ef2166e92</code>. Hand-curated docs in <code>workerexamples/</code> override this page when present.
   </p>