COMPUTE THE NECKING STRAIN FROM AN ENG STRESS-STRAIN CURVE¶
Computes the necking (onset-of-instability) strain from an engineering stress-strain curve by converting to true stress-strain, then finding the intersection of the true-stress curve with its derivative. Use this worker during material characterization to extract the necking strain that separates uniform elongation from localised deformation.
When to use¶
Classification: process.
Tagged: engineering_stress_strain, intersection, material_characterization, necking, necking_strain, offset_method, true_stress_strain, uniform_elongation.
Inputs¶
| Label | ID | Type | Default | Required | Description |
|---|---|---|---|---|---|
| Eng Stress Strain Curve | engstressstraincurve | vector | — | Engineering stress-strain curve (stress vs. strain) supplied as an XY vector; this is the primary input from which necking strain is derived. | |
| Elastic Modulus | elastic_modulus | scalar | 0.0 | Young’s modulus (same stress units as the input curve, e.g. MPa or GPa); used to construct the offset yield line — set to 0.0 to let the worker estimate it from the initial slope. | |
| Yield Type | yield_type | scalar | offset | Method used to locate the yield point: ‘offset’ (0.2 % proof stress line), ‘strain’ (fixed strain value), ‘stress’ (fixed stress value), or ‘linearity’ (end of linear region); default is ‘offset’. | |
| Yield Offset Or Strain | yield_offsetor_strain | scalar | 0.002 | Numeric value that accompanies yield_type — the offset strain (e.g. 0.002 for 0.2 %) or the absolute strain/stress threshold; not used when yield_type is ‘linearity’; default is 0.002. | |
| Intersection Point Type | intersection_point_type | scalar | auto | Selects which intersection of the true-stress curve with its derivative to use as the necking point: ‘auto’ (first intersection), ‘xfirst’, ‘xlast’, ‘xavg’, or ‘xmode’; default is ‘auto’. | |
| Return Type | return_type | scalar | true | Value type to return |
Outputs¶
| Label | ID | Type | Description |
|---|---|---|---|
| curve_eng_get_necking_strain_output_1 | curve_eng_get_necking_strain_output_1 | vector | Single-point XY vector representing the necking strain (x) and the corresponding true stress at the onset of necking (y), extracted from the input engineering stress-strain curve. |
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=curve_eng_get_necking_strain
Auto-generated from transformation schema. Worker id: curve_eng_get_necking_strain. Schema hash: 5d0a43a2a812. Hand-curated docs in workerexamples/ override this page when present.