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

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

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


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