thermal_eigenstrain and an eigenstrain_source for linear_elasticity by petlenz · Pull Request #135 · NumSim-Stack/numsim-materials

petlenz · 2026-10-16T23:04:44Z

Closes #114. Part of the uvwmaterial port (#94); stacked on #134.

materials/thermal_eigenstrain.h (thermal_eigenstrain): ε_th = α (T − T_ref) I with the temperature from an external_scalar_source (history state, default name temperature). Output eigenstrain. This is the pattern for every eigenstrain (the chemical shrinkage of #115 follows it): a producer of eigenstrain, and elastic materials subtracting it.

linear_elasticity: optional eigenstrain_source (default none); with it σ = C : (ε − ε_eig), the tangent unchanged. Replaces eigenstrain_temperature_material_base, eigenstrain_material_base, thermo_mechanical_elastic and the thermo-mechanical bases of uvwmaterial as a graph wiring instead of an inheritance tree.

Tests (test_thermal_eigenstrain, 4): free expansion is stress free; constrained heating gives −3Kα ΔT on the diagonal; superposition with a mechanical strain, and no temperature change gives plain elasticity; creation from JSON.

No report yet: the report runner has no temperature path (listed in #126); the unit tests carry the closed forms.

762/762 tests pass (GCC 14, reports on).

JSON input

New material types: thermal_eigenstrain. A json_model document that loads (the FromJson test of the PR):

{"materials": [
  {"type": "external_strain_source", "name": "strain"},
  {"type": "external_scalar_source", "name": "temperature"},
  {"type": "constant_scalar", "name": "alpha", "value": 1e-5},
  {"type": "thermal_eigenstrain", "name": "thermal", "alpha_source": "alpha::value", "temperature_source": "temperature", "reference_temperature": 20.0},
  {"type": "linear_elasticity", "name": "elastic", "strain_producer_name": "strain", "eigenstrain_source": "thermal", "K": 100.0, "G": 40.0}
]}

alpha_source as material::property (a cure-dependent producer for the chemo variants); temperature_source a history source publishing state (default name temperature); output eigenstrain, consumed by linear_elasticity.eigenstrain_source (this PR) and hencky_elasticity.eigenstrain_source (#141).

petlenz · 2026-10-17T09:41:57Z

Review findings (design, tmech expressions instead of component loops, modern C++, comments, tests, correctness). Severity: must = wrong result, hang, build break or unreachable feature; should = design, duplication, accuracy; nit = style.

thermal_eigenstrain — ready with nits

[should] add_input_history for temperature although only new_value() is read → plain add_input accepts both plain and history sources (a constant_scalar cannot be wired today).
[nit] temperature_source vs temperature_name (kamal_sourour_rate: nth-order plus autocatalytic cure kinetics #136) naming; α scalar only — say "isotropic"; unnecessary temporary in linear_elasticity.h:66.

petlenz · 2026-10-17T17:24:11Z

Producer/consumer pass: the expansion coefficient is a consumed property, alpha_source ("alpha::value" of a constant_scalar, or a cure-dependent producer for the chemo variants); the alpha parameter is gone.

load_driver runs one material point under mixed strain/stress control (uniaxial stress solves the five lateral strains with the material tangent) and records the Newton residuals; material_report runs the load cases of a case.json and writes CSV; reports/make_report.py turns them into figures and the results section of docs/materials/<material>/README.md.

The correction solves (P:C:P + Isym - P + Iskw) : d_eps = -P:(sigma - sigma*) with tmech::invf instead of a hand-written 6x6 elimination; Iskw makes the operator regular on the full 9x9 space. Strain, stress and tangent are tensors, converted to and from the evaluator buffers with tensor_conversion.

A report document holds the model graph, the material point, recorded columns wired to any graph property ("material::property[i,j]"), the load cases, the figures and the checks. Includes merge shared cases and figures; "$name" strings take parameters. material_report writes resolved.json, graph.json (materials, parameters, produced and consumed properties) and CSV per case; make_report.py evaluates the checks against closed forms, draws the figures and writes the results with the wiring diagram. Every report is a ctest (checks only).

C++: load_control (stress/strain projectors), load_path (steps as a view), report_json (parsing into value types), case_runner (material_point and run_case over a step_sink concept), csv_sink, graph_description; the tool is now an entry point. load_driver keeps no per-step state: a step_result carries its start state, so tangent_error works for any earlier step. Produced properties are listed by name (the registry orders by address). Python: dataclasses for runs, cases and check results; expressions, checks, panel renderers (registry by kind) and Markdown sections as separate functions; unit tests in reports/test_make_report.py (ctest report_script).

core/eshelby.h: sphere in closed form from the projectors; elliptic and circular cylinders along any axis or direction (Mura 11.21); ellipsoids with any semi-axes from Mura's I-integrals through Carlson's R_D, the degenerate pairs (spheroid, sphere) from the sum rules, an infinite axis dispatching to the cylinder. Tests against the closed forms, the limits, uvwmaterial's spheroid formula and the identity S_iikk = (1 + nu)/(1 - nu).

…ses, projectors of the controls, load path accessors

…n tensor, float-safe rotation_to The elliptic integrals come from Boost.Math where they are first used (the Eshelby tensors). rotation() builds [axis]_x as -(epsilon . axis); rotation_to() uses 8 eps of the scalar type instead of 1e-14, which did not compile for float and would have been c > 1 there. [[nodiscard]] on the pure helpers.

…per shape eshelby_sphere, eshelby_cylinder, eshelby_spheroid and eshelby_ellipsoid consume nu_source / nu_property and publish the output "tensor"; the engine orders and re-evaluates them with nu. Two scalar producers feed them: poisson_ratio_from_moduli (K_source, G_source -> value) and isotropic_moduli (tangent_source -> K, G, poisson_ratio through isotropize, rejecting an anisotropic tangent). Composites hold a node through eshelby_tensor_interface (tensor() at the wired nu, tensor(nu) for the self-consistent iterate). core/eshelby.h keeps the closed forms: the integrals come from Boost.Math (ellint_rd), the tensors are assembled on the eigenprojectors, equal axes are detected at sqrt(eps).

core/isotropize.h: K = Pvol::C / Dim, G = Pdev::C / (2 (Dim(Dim+1)/2 - 1)), and the isotropic part built from them. core/lebedev.h with generated tables (tools/extract_lebedev.py from uvwmaterial's rule, precisions 3 to 23, up to 194 points): spherical means and integrals of tensor-valued functions of the direction. eshelby::depolarisation for ellipsoids via Carlson's R_J, the elliptic cylinder in closed form, and the cylinder along a direction.

Phases are materials providing a tangent, with volume fractions; outputs the effective tangent, the stress and the strain concentration tensors (sum c_i A_i = Isym). Report with the closed forms of the three kernels and their ordering. Report generator: derived values resolve in dependency order, independent of the key order.

…ent producer over phases The composite consumes the phases' produced tangents, fractions and Eshelby tensors and produces the effective tangent and the concentrations; the stress is a linear_stress on the tangent. It reaches into no other node: no material_ref, no eshelby(nu), no isotropisation of the matrix. Self-consistent is a graph cycle closed by one local edge: isotropic_moduli on the composite tangent produces nu of the effective medium, the Eshelby nodes read it with nu_edge = local (from nu_initial on the first pass), and one update() is one relaxed Picard step with "residual" as its error. The matrix is a phase with its own Eshelby node, so its shape is no longer a hard-coded sphere. material_point_evaluator closes the fixed point per host call (residual_property, residual_tolerance, max_passes; the report point names them). isotropic_moduli with a non-positive tolerance projects without the isotropy check, which the effective medium needs.

…ution Spheroidal fibres in an isotropic matrix with the second-order orientation tensor: Mori-Tanaka with the orientation-averaged dilute concentration, or the averaged unidirectional stiffness. Eshelby tensors per direction are cached for the matrix Poisson ratio. Report with aligned, injection-moulded and random states against the unidirectional composite and isotropy.

core/orientation.h: fit_acg solves a_i = R_D(b_j, b_k, b_i) / 3 with det b = 1 by Newton in the principal frame of the orientation tensor (any A, not only diagonal), the aligned case as a single direction, planar cases by an eigenvalue floor; nodes maps the Lebedev rule through B^-1/2; average integrates a function of the direction.

… in the fibre frame Both phases come in as produced properties (tangent, fraction, the fibre's Eshelby tensor along x1); the composite consumes them, forms the dilute concentration once in the fibre frame, rotates onto the quadrature directions with otimesu(R, R) fixed per direction, and produces the tangent and the two concentrations. The stress is a linear_stress on the tangent. No material_ref.

…history sigma_{n+1} = sigma_n + C : (eps_{n+1} - eps_n) with the tangent read from another material, for path-dependent tangents. Report: equals the total form on every path, a closed path returns to zero, exact for any step. Drivers: the convergence test also scales with |C| |d eps| (|A| |dF|), so a hypoelastic stress crossing zero under stress control converges.

eps_th = alpha (T - T_ref) I from a scalar temperature source; linear elasticity subtracts an optional eigenstrain: sigma = C : (eps - eps_eig).

Main has the reviewed split of this branch (#199-#203), so main's version is taken everywhere; the branch no longer differs from main.

…ls-and-constants # Conflicts: # tests/CMakeLists.txt

…eshelby-tensors # Conflicts: # tests/CMakeLists.txt

…v-depolarisation # Conflicts: # tests/CMakeLists.txt

…/rule-of-mixture # Conflicts: # tests/CMakeLists.txt

# Conflicts: # include/numsim-materials/report/report_json.h # tests/CMakeLists.txt

residual_source, residual_tolerance and max_passes are driver parameters (material_point's defaults) and keys of the report's "point"; the mean-field tangent report uses them for the self-consistent fixed point.

…averaging # Conflicts: # tests/CMakeLists.txt

…-composite # Conflicts: # tests/CMakeLists.txt

…-elasticity # Conflicts: # include/numsim-materials/umat/deformation_gradient_driver.h # include/numsim-materials/umat/material_point_driver.h # tests/CMakeLists.txt

…genstrain # Conflicts: # tests/CMakeLists.txt

This was referenced Oct 16, 2026

kamal_sourour_rate: nth-order plus autocatalytic cure kinetics #136

Merged

Port uvwmaterial to numsim-materials #94

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petlenz force-pushed the feature/incremental-elasticity branch from 6579831 to 69465a8 Compare October 16, 2026 23:43

petlenz force-pushed the feature/thermal-eigenstrain branch from 81327cc to 891c53f Compare October 16, 2026 23:43

petlenz force-pushed the feature/incremental-elasticity branch from 69465a8 to 865a597 Compare October 17, 2026 14:21

petlenz force-pushed the feature/thermal-eigenstrain branch 2 times, most recently from b3e882d to 41afa98 Compare October 17, 2026 14:31

petlenz force-pushed the feature/incremental-elasticity branch 2 times, most recently from ab93cbb to 0f0130a Compare October 17, 2026 15:48

petlenz force-pushed the feature/thermal-eigenstrain branch from 41afa98 to c667526 Compare October 17, 2026 15:48

petlenz force-pushed the feature/incremental-elasticity branch from 0f0130a to b110fb5 Compare October 17, 2026 16:48

petlenz force-pushed the feature/thermal-eigenstrain branch from c667526 to 829454b Compare October 17, 2026 16:57

petlenz force-pushed the feature/incremental-elasticity branch from b110fb5 to 5e03c07 Compare October 17, 2026 21:26

petlenz force-pushed the feature/thermal-eigenstrain branch from 829454b to 0c29804 Compare October 17, 2026 21:26

petlenz force-pushed the feature/incremental-elasticity branch from 5e03c07 to 40a9c01 Compare October 17, 2026 22:46

petlenz force-pushed the feature/thermal-eigenstrain branch from 0c29804 to ba5606b Compare October 17, 2026 22:46

petlenz force-pushed the feature/incremental-elasticity branch from 40a9c01 to 78698ad Compare October 18, 2026 12:13

petlenz force-pushed the feature/thermal-eigenstrain branch from ba5606b to ca687fc Compare October 18, 2026 12:23

petlenz force-pushed the feature/incremental-elasticity branch from 78698ad to 3a67d63 Compare October 18, 2026 13:38

petlenz force-pushed the feature/thermal-eigenstrain branch from ca687fc to c32b2f9 Compare October 18, 2026 13:38

petlenz force-pushed the feature/incremental-elasticity branch from 3a67d63 to 81931b5 Compare October 18, 2026 20:03

petlenz force-pushed the feature/thermal-eigenstrain branch from c32b2f9 to b075d06 Compare October 18, 2026 20:03

petlenz force-pushed the feature/incremental-elasticity branch from 81931b5 to 9bb4ac2 Compare October 18, 2026 20:22

petlenz force-pushed the feature/thermal-eigenstrain branch from b075d06 to 031b4e7 Compare October 18, 2026 20:22

petlenz added 4 commits October 19, 2026 05:49

petlenz added 13 commits October 19, 2026 05:49

noexcept on the helpers that cannot throw: identities, projectors, ba…

4549791

…ses, projectors of the controls, load path accessors

short_fibre_composite report: the aligned check as a ratio against zero

369385f

thermal_eigenstrain and an eigenstrain_source for linear_elasticity

25909f3

eps_th = alpha (T - T_ref) I from a scalar temperature source; linear elasticity subtracts an optional eigenstrain: sigma = C : (eps - eps_eig).

petlenz force-pushed the feature/incremental-elasticity branch from 9bb4ac2 to 108389e Compare October 19, 2026 04:06

petlenz force-pushed the feature/thermal-eigenstrain branch from 031b4e7 to 25909f3 Compare October 19, 2026 04:06

petlenz added 3 commits October 23, 2026 22:05

Merge main into feature/material-reports

ea56e0d

Merge main into feature/material-reports

ea3a120

Main has the reviewed split of this branch (#199-#203), so main's version is taken everywhere; the branch no longer differs from main.

Merge branch 'feature/material-reports' into feature/elliptic-integra…

fe57dcf

…ls-and-constants # Conflicts: # tests/CMakeLists.txt

petlenz changed the base branch from feature/incremental-elasticity to main October 24, 2026 21:16

petlenz added 9 commits October 24, 2026 23:22

Merge branch 'feature/elliptic-integrals-and-constants' into feature/…

b3414d0

…eshelby-tensors # Conflicts: # tests/CMakeLists.txt

Merge branch 'feature/eshelby-tensors' into feature/isotropize-lebede…

ed3f23e

…v-depolarisation # Conflicts: # tests/CMakeLists.txt

Merge branch 'feature/isotropize-lebedev-depolarisation' into feature…

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…/rule-of-mixture # Conflicts: # tests/CMakeLists.txt

Merge branch 'feature/rule-of-mixture' into feature/mean-field-composite

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# Conflicts: # include/numsim-materials/report/report_json.h # tests/CMakeLists.txt

Drivers pass the residual settings through to the material point (#210)

b2ed115

residual_source, residual_tolerance and max_passes are driver parameters (material_point's defaults) and keys of the report's "point"; the mean-field tangent report uses them for the self-consistent fixed point.

Merge branch 'feature/mean-field-composite' into feature/orientation-…

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…averaging # Conflicts: # tests/CMakeLists.txt

Merge branch 'feature/orientation-averaging' into feature/short-fibre…

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…-composite # Conflicts: # tests/CMakeLists.txt

Merge branch 'feature/short-fibre-composite' into feature/incremental…

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…-elasticity # Conflicts: # include/numsim-materials/umat/deformation_gradient_driver.h # include/numsim-materials/umat/material_point_driver.h # tests/CMakeLists.txt

Merge branch 'feature/incremental-elasticity' into feature/thermal-ei…

427897e

…genstrain # Conflicts: # tests/CMakeLists.txt

petlenz marked this pull request as ready for review October 27, 2026 17:50

petlenz merged commit 6a4e9fa into main Oct 27, 2026
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thermal_eigenstrain and an eigenstrain_source for linear_elasticity - #135

thermal_eigenstrain and an eigenstrain_source for linear_elasticity#135
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