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@@ -49,6 +49,7 @@ pressure) is a degree of freedom of the existing DOF framework, not a separate s
 | M20 Damage, fracture, fatigue and adhesion | Continuum damage beyond Johnson–Cook (Lemaitre, ductile and shear criteria) for implicit and explicit; fracture mechanics (J-integral and stress intensity factors, crack-front meshes from the hex mesher; XFEM later); fatigue (S–N and ε–N with mean-stress corrections, rainflow counting, Paris crack growth); adhesion and debonding by cohesive zones (bilinear and exponential traction–separation, mixed mode with Benzeggagh–Kenane) as cohesive elements and cohesive contact; adhesive joints. Verified by DCB, ENF and MMB delamination tests and published fatigue data | planned |
 | M21 Biomechanics and biomaterials | Soft tissue: Holzapfel–Gasser–Ogden fibre-reinforced hyperelasticity with dispersion, Fung, transversely isotropic models; biphasic and poro-hyperelastic cartilage (M19); active muscle (Hill-type); hydrogel swelling. Bone: density-dependent moduli from CT data, strain-energy-density remodelling (Huiskes, Beaupré). Growth and remodelling by kinematic growth (F = Fe·Fg). Implants and biomaterials (titanium, PEEK, UHMWPE) from the M17 library. Verified against published experiments with their tolerances | planned |
 | M22 Design studies | Parameters of the SolidCraft design driven from FieldCraft: parametric sweeps, design of experiments, response surfaces and sensitivities; topology optimisation (SIMP with filters, manufacturing constraints); size and shape optimisation; submodelling (driven boundaries from a global model); uncertainty quantification | planned |
+| M23 Wave propagation and ultrasound | Elastic, acoustic and coupled waves from the explicit solver's 1D bar today to guided and ultrasonic waves: spectral elements (high-order Gauss–Lobatto–Legendre hexes with diagonal mass) on the hex meshes, and a mesh check in elements per wavelength with the dispersion error it implies; absorbing boundaries (convolutional PML, absorbing layers with increasing damping) and infinite media; tone-burst sources (Hann-windowed cycles), point, line and surface excitation, and piezoelectric transducers (M19); anisotropic media (composites, crystals) and viscoelastic, power-law-in-frequency attenuation; fluid–solid interfaces and fluid-loaded plates; ultrasound in water and tissue, nonlinear acoustics (Westervelt, KZK) for focused ultrasound. Guided waves: dispersion curves by semi-analytical finite elements (SAFE) for plates, pipes, rails and layered and anisotropic laminates — Lamb, Rayleigh, Love and SH modes — with phase and group velocities and mode shapes; mode-selective excitation. Output: A-scans and B-scans at sensors, wavefield snapshots, 2D FFT (frequency–wavenumber) for mode identification. GPU paths (M12's backend) for long runs. Verified by Lamb's problem (point load on a half-space), Rayleigh-wave speed, Rayleigh–Lamb dispersion, Love waves in a layer over a half-space, reflection and transmission at interfaces, and published guided-wave measurements | planned |
 | Continuous: verification and validation | Every capability checked against theory (closed forms), experiments (published measurements) and published benchmarks (NAFEMS, vendor benchmark and verification manuals such as Abaqus's), each case our own model in `tests/oracle/` with its cited reference and tolerance; `cargo xtask oracle` runs them and writes docs/oracle.md; once a case matches, our result is frozen as a fixture so fidelity cannot regress (docs/verification.md). Runner, fixtures and CI job: done; 26 theory cases (patch tests of every solid element, cantilevers, Lamé in 3D, plane strain and axisymmetric, Kirsch in 3D and plane stress, rotating disc and cylinder, beam frequencies, couplings, explicit waves, impact and J2 plasticity, CDT invariants), 9 published benchmarks (MacNeal–Harder solid tests, Scordelis–Lo with solids, NAFEMS LE1 in 3D and 2D, LE10, FV32) and 9 pending cases with citations (shells, thermal, static plasticity, Taylor bar, CFD); `mesh.block` mapped blocks and 2D patches build their meshes | started |
 | Continuous: performance | CPU first, deterministic: results never depend on the thread count (fixed partitions, sums in a fixed order; checked by hashing results on 1, 2 and 7 threads). Supernodal left-looking Cholesky (11–15× faster than the column solver on one thread), parallel element matrices, stresses and Lanczos products, explicit element updates and LBM cell blocks on rayon threads (done — `fieldcraft-parallel`, `threads` on the solve commands, `FIELDCRAFT_THREADS`); parallel forward/back substitution and explicit tet4 assembly; GPU paths later, within a stated tolerance of the CPU | started |
 | Continuous: desktop and agents | Desktop app (viewport, model tree, commands, control channel, the open design drawn, `ui.capture` of the whole window offscreen: done; toolbar of every capability from the catalogue, ready or coming soon with its milestone, icons drawn with VectorCraft, docs/features.md: done; the Craft-family shell — title bar, workspaces and ribbon drop-downs, browser, context panel, command search, journal timeline, light and dark themes — native file pickers with background opening, drag and drop and recent files, samples and one-click Solve: done; MCP server over stdio, headless or bridged to the app, with read and write roots, docs/mcp.md: done; caps labels in Inter SemiBold; the README's analysis video recorded through MCP by `tools/demo-video`: done; support, load and coupling symbols in the viewport, a camera parameter for screenshots, a ribbon that follows the command being run: in progress), browser build, command schema as the public API | started |
@@ -82,4 +83,5 @@ What exists and what is missing, by area; each gap is in a milestone above.
 | Failure | Johnson–Cook damage and element erosion (explicit) | Fracture mechanics, fatigue, cohesive zones, composite progressive damage (M18, M20) |
 | Biomechanics | — | Tissue models, cartilage, muscle, bone remodelling, growth (M21) |
 | Fluid dynamics | LBM D3Q19 TRT, walls, inlets/outlets, obstacle forces | Turbulence with wall models, thermal and conjugate heat transfer, non-Newtonian, porous media, multiphase, GPU (M12, M13) |
+| Wave propagation | One-dimensional elastic waves and impact in the explicit solver (bar cases in the oracle) | Spectral elements, absorbing boundaries, tone-burst and transducer sources, attenuation, Lamb/Rayleigh/Love guided waves and SAFE dispersion curves, ultrasound in fluids and tissue, nonlinear acoustics, A/B-scans and frequency–wavenumber analysis (M23) |
 | Design | — | Parametric studies on SolidCraft parameters, optimisation, submodelling (M22) |