CONVERT TRUE TO EFFECTIVE STRESS VS STRAIN CURVES BY REMOVING ELASTIC STRAINS¶
Converts true stress–strain curves to effective (plastic) stress–strain curves by subtracting the elastic strain component. Supports multiple yield-point detection methods, post-necking treatments, and optional curve digitization and smoothing. Use this worker to prepare material hardening curves for LS-DYNA MAT_24 or similar plasticity card inputs.
When to use¶
Classification: process.
Tagged: MAT_24, effective_stress_strain, elastic_modulus, hardening_curve, material_processing, necking, plastic_strain, true_stress_strain.
Inputs¶
| Label | ID | Type | Default | Required | Description |
|---|---|---|---|---|---|
| True Stress Strain Curves | truestressstraincurves | vector | — | ✓ | One or more true stress vs. true strain curves (unitless strain, stress in GPa or MPa consistent with elastic_modulus); each curve is supplied as an XY vector pair. |
| Elastic Modulus | elastic_modulus | scalar | 210 | ✓ | Young’s modulus of the material in GPa (default 210 GPa for steel); used to compute and subtract the elastic strain component from each curve. |
| Yield Type | yield_type | scalar | offset | Method used to locate the yield point: ‘offset’ (default, 0.2% offset rule), ‘effective’ (stress at zero plastic strain), ‘strain’ (fixed strain threshold), ‘stress’ (fixed stress threshold), ‘linearity’ (end-of-linear-range), or ‘initial_peak_percentage’ (fraction of peak-initial-stress strain). | |
| Yield Strain Or Offset or R2 Limit | yield_strainor_offset | scalar | 0.002 | Numerical parameter paired with yield_type — for ‘offset’ this is the offset strain (default 0.002 for steel; use higher values such as 0.02 for polymers); for ‘strain’/’stress’ modes it is the fixed threshold value; for ‘linearity’ mode it is the R² limit. | |
| Post Necking Treatment | necking_treatment | string | none | Strategy for handling post-necking data: ‘none’ keeps the curve as-is, ‘truncate’ removes data beyond the necking point, or an extrapolation/extension method; leave as ‘none’ when diffuse-necking strain is not a concern. | |
| Slope For Extrapolation | slopefor_extrapolation | scalar | 0 | Slope for extrapolation | |
| Last Strain | last_strain | scalar | 1 | Last strain value for output curve | |
| Digitize | digitize | scalar | 100 | Number of points in the output curve. If negative, the effective curve is digitized only when the number of points is less than the abs(digitize) value. | |
| Saturation Strain | saturation_strain | scalar | 0 | ||
| Saturation Percentage | saturation_percentage | scalar | 0 | ||
| Intersection Point Type | intersection_point_type | scalar | auto | ||
| Digitize Option | digitize_option | scalar | yes | Option to digitize curve to required number of points provided in Digitize input | |
| Necking Strain | necking_strain | scalar | 0 | Necking strain | |
| Poisson’s Ratio | poissons_ratio | scalar | 0 | Poission’s ratio | |
| Loading Type | loading_type | scalar | tension | Tension-Compression-Shear flag to compute strains | |
| Enforce Y Monotonicity | enforce_y_monotonicity | select | no | If the input True-stress vs strain has non-monotonic y-values, this option allows to remove them before converting it to effective stress vs strain | |
| Remove Intersections | remove_intersections | scalar | no | Remove intersections before and after converting to effective stress | |
| Number Of Extrapolation Segments | num_extra_seg | scalar | 1 | The default is 1 which is one-segment resulting in linear extrapolation | |
| Slope Scale Factor During Extrapolation | slope_sf | scalar | 1.2 | When post-necking treatment type = extrapolation_regression, each segment slope is multipled by this number | |
| Extrapolation Slope | extra_slope_type | scalar | respective | When extrapolating curves using linear extrapolation, this slope type can determine which slope to use | |
| Smooth Curve After Conversion | smooth_curve | float | no | The final hardening curve is smoothed using the selected method to achieve smooth derivative | |
| How To Treat User-defined Yield | user_defined_yield_treatment | scalar | offset | When user defined yield is provided, this option allows us to either offset or find a smooth fit to satisy the user-defined yield | |
| Linearly extrapolate when no necking is found | linearly_extrapolate_when_no_necking_is_found | scalar | no | When necking (localization) is not found, this option allows to linearly extrapolate and overrides the extrapolation type chosen above |
Outputs¶
| Label | ID | Type | Description |
|---|---|---|---|
| curves_truetoeffectivestress_output_1 | curves_truetoeffectivestress_output_1 | vector | Effective (plastic) stress vs. effective plastic strain curves corresponding to each input true stress–strain curve, with elastic strains removed, yield-point correction applied, and post-necking treatment enforced; suitable for direct use as LS-DYNA MAT_24 hardening 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=curves_truetoeffectivestress
Auto-generated from transformation schema. Worker id: curves_truetoeffectivestress. Schema hash: bf26a596c34c. Hand-curated docs in workerexamples/ override this page when present.