GENERATE AN INSTABILITY CURVE BASED ON YIELD CURVE BASED ON SWIFT. THANKS TO PAUL DU BOIS FOR HIS GUIDANCE.¶
Generates a forming-limit instability curve from an effective stress vs. effective strain (Swift hardening) yield curve using one of four Swift-based instability criteria. Use this worker to derive triaxiality-vs.-failure-strain loci for GISSMO or FLD calibration workflows.
When to use¶
Classification: process.
Tagged: FLD, GISSMO, forming_limit, instability, mat_failure, paul_du_bois, swift, triaxiality.
Inputs¶
| Label | ID | Type | Default | Required | Description |
|---|---|---|---|---|---|
| Effective Stress Vs Effective Strain Curve | effective_stressvs_effective_strain_curve | vector | — | Effective stress vs. effective strain yield curve (dimensionless strain, stress in model units, e.g. MPa) used as the Swift hardening input; leave unconnected only if the curve is supplied via another upstream worker. | |
| Instability Type | type | scalar | swift_at | Swift instability criterion to apply: ‘swift_at’ (Considère / diffuse necking at), ‘swift_beps’ (biaxial equivalent plastic strain), ‘swift_beps1’ (alternate biaxial EPS formulation), or ‘swift_eps2_eps1’ (minor vs. major strain locus); default is ‘swift_at’. | |
| Start Search | start_search | scalar | -1 | Minimum triaxiality value for the sweep search domain (dimensionless); default –1.0 covers full compression-to-shear range. | |
| End Search | end_search | scalar | 1 | Maximum triaxiality value for the sweep search domain (dimensionless); default 1.0 covers up to equi-biaxial tension. | |
| Search Increment | search_increment | scalar | 0.001 | Triaxiality step size used during the sweep (dimensionless); default 0.001 gives high-resolution output — increase (e.g. 0.01) to reduce compute time for quick estimates. | |
| Reverse Points | reversepoints | scalar | yes | Whether to reverse the point order of the output curve (‘yes’ / ‘no’); default ‘yes’ orients the curve from high to low triaxiality as expected by most downstream LS-DYNA GISSMO inputs. |
Outputs¶
| Label | ID | Type | Description |
|---|---|---|---|
| curve_yield_stress_instability_output_1 | curve_yield_stress_instability_output_1 | vector | Computed Swift instability curve — triaxiality (x-axis, dimensionless) vs. equivalent plastic strain at instability (y-axis, dimensionless) — ready for direct use as a failure/instability locus in GISSMO or FLD definitions. |
Disciplines¶
- data.curve.transform
- engineering.material.calibration
- engineering.material.characterization
- engineering.material.failure
Runnable example¶
A runnable example is registered for this worker. Open the example workflow on the d3VIEW canvas: /api/workflow/example?id=curve_yield_stress_instability
Auto-generated from transformation schema. Worker id: curve_yield_stress_instability. Schema hash: c4b6e374a5b3. Hand-curated docs in workerexamples/ override this page when present.