.. _auto_curves_truetoengstress:

*TRUE TO ENG*
=============

Converts one or more true stress–strain curves to engineering (nominal) stress–strain curves using the inverse of the standard logarithmic relations, with optional Poisson's-ratio correction and tension/compression mode selection. An optional post-necking failure model can be appended uniformly to every input curve, truncating at the peak and adding a concave-down power-decay segment that terminates at a user-specified engineering failure point.

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

Classification: **process**.

Tagged: ``compression``, ``curve-conversion``, ``failure-model``, ``material-testing``, ``poissons-ratio``, ``post-necking``, ``stress-strain``, ``tension``.

Inputs
------

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

   * - Label
     - ID
     - Type
     - Default
     - Required
     - Description
   * - True Stress Vs Strain Curve
     - truestressstraincurves
     - vector
     - —
     - 
     - One or more true stress vs. true strain curves (dimensionless strain, stress in consistent pressure units) to be converted to engineering stress–strain; accepts multiple curves in a single batch.
   * - Poisson's Ratio
     - poissons_ratio
     - scalar
     - 0.0
     - 
     - Poisson's ratio of the material (dimensionless scalar, e.g. 0.3 for steel); default 0.0 applies no lateral-strain correction — set to the material value when width/thickness contraction matters.
   * - Tension/Compression Flag
     - tension_compression_flag
     - text
     - tension
     - 
     - Specifies whether the input curves represent tensile ('tension') or compressive ('compression') data, controlling the sign convention used in the conversion; default is 'tension'.
   * - Model Post-Necking Failure
     - model_failure
     - select
     - no
     - 
     - When set to 'Yes', appends a post-necking failure extension to every converted curve, truncating at the curve's own peak and adding a concave-down power-decay segment down to (Failure Strain, Failure Stress); default 'No' leaves curves as-is.
   * - Failure Strain (eng)
     - failure_strain
     - scalar
     - 0
     - 
     - Engineering strain at fracture/failure (dimensionless); must exceed each curve's necking (peak) strain — used only when Model Post-Necking Failure is 'Yes'; default 0.0.
   * - Failure Stress (eng)
     - failure_stress
     - scalar
     - 0
     - 
     - Engineering stress at fracture/failure (same pressure units as input curves); defines the terminal stress of the power-decay segment — used only when Model Post-Necking Failure is 'Yes'; default 0.0.
   * - Post-Necking Exponent (n)
     - post_necking_exponent
     - scalar
     - 2
     - 
     - Power n in sigma(t) = sigma_u - (sigma_u - sigma_f) * t^n. n = 2 (default) matches typical ductile metals.

Outputs
-------

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

   * - Label
     - ID
     - Type
     - Description
   * - curve_truetoengstress_output_1
     - curve_truetoengstress_output_1
     - vector
     - Converted engineering stress vs. engineering strain curve(s) — one output curve per input true stress–strain curve, with the optional post-necking failure extension appended if requested.

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

- data.curve.transform
- 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=curves_truetoengstress <https://www.d3view.com/api/workflow/example?id=curves_truetoengstress>`_

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   Auto-generated from <code>transformation</code> schema. Worker id: <code>curves_truetoengstress</code>. Schema hash: <code>7c8fa3af9cd9</code>. Hand-curated docs in <code>workerexamples/</code> override this page when present.
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