# Pfc Contact Models > Child skill of pfc-workflow for PFC 6.0 contact model selection, CMAT setup, contact properties, bonding methods, and contact-law audits. - Skill: `jiangnan030-del/pfc-contact-models` (Agent Skill, multi-file: 12 files) - Install (CLI): `npx skillmds@latest add jiangnan030-del/pfc-contact-models` - Raw SKILL.md: https://api.skillmd.com/api/skills/jiangnan030-del/pfc-contact-models/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: AI & ML - Author: jiangnan030-del (https://skillmd.com/u/jiangnan030-del) - Updated: 2026-09-21 - Page: https://skillmd.com/skills/jiangnan030-del/pfc-contact-models --- # PFC Contact Models Use this skill to choose, explain, adapt, or audit PFC contact-model setups. The skill is self-contained: PFC 6.0 linear and linear-parallel-bond examples are stored under `scripts/canonical/`, and documentation notes checked through `pfc-mcp` are stored under `references/contact-model-doc-notes.md`. ## Parent Skill Relationship `pfc-contact-models` is a child skill of `pfc-workflow`. It does not own the full PFC lifecycle. Use it for contact-law selection, CMAT/property setup, bond activation, stiffness/strength property audits, and contact-model migration notes. Return to `pfc-workflow` for full case planning, solve orchestration, post-processing routing, verification, and delivery. Parent/child split: - Parent `pfc-workflow`: owns complete PFC project lifecycle and decides when contact-model support is needed. - Child `pfc-contact-models`: owns contact laws, CMAT, contact properties, contact methods, bond setup, and contact-law validation checks. - Sibling child `pfc-fish`: owns detailed FISH helper/callback implementation. - Sibling child `pfc-servo-calibration`: owns servo control and manual macro-calibration sequencing. - Sibling child `pfc-standard-tests`: owns standard laboratory-test templates. - Sibling child `pfc-dynamics`: owns dynamic/seismic loading assumptions. - Sibling child `pfc-fluid-coupling`: owns PFC CFD/seepage/buoyancy workflows. - Sibling child `pfc-flac-coupling`: owns PFC-FLAC/FLAC3D coupling. - Sibling child `pfc-postprocessing`: owns standard figures and field exports after solve. - Sibling child `pfc-ae-energy`: owns AE, energy, and source-mechanism outputs after solve. ## When To Use Use through `pfc-workflow` when a task needs contact-law reasoning: - choose between `linear`, `linearpbond`, `linearcbond`, `hertz`, `flatjoint`, `smoothjoint`, `softbond`, `rrlinear`, or plugin contact laws - set CMAT defaults before contact creation - assign or modify properties on existing contacts - activate bonds or set deformability through contact methods - explain property inheritance from ball/wall/clump surfaces - audit legacy contact-property blocks for PFC 6.0 compatibility - connect micro-properties to macro-test calibration requirements ## Required Inputs Ask for these if missing: - PFC version and dimensionality. - Material behavior: unbonded granular, cemented/rock-like, nonlinear elastic, jointed, rolling-resistance, or plugin-defined. - Contact types involved: ball-ball, ball-facet, pebble-pebble, rblock, fracture, or mixed. - Target macro behavior: stiffness, friction angle, tensile strength, cohesion, peak/residual behavior, dilation, or damage pattern. - Whether contacts already exist or CMAT will be set before `model clean`. - Calibration/validation test: UCS, Brazilian, biaxial, triaxial, direct shear, contact-level two-ball test, or custom. ## Documentation-Backed Rules The following PFC 6.0 documentation points were checked through `pfc-mcp` and are expanded in `references/contact-model-doc-notes.md`: - `contact cmat default` defines default Contact Model Assignment Table behavior for future contacts. - `contact model` changes existing contacts and replaces prior contact-model state. - `contact property` changes properties on existing contacts that recognize the property. - `contact method` executes model-specific operations such as `bond`, `deformability`, or `pb_deformability`. - `contact cmat apply` applies CMAT to existing contacts and reassigns contact models. - `contact list` is used to verify contact model, force, energy, and contact state. - `ball property` and `wall property` assign surface properties used by contact models; they are distinct from attributes. - `model clean` creates contacts and initializes contact state after pieces/geometry are created. ## Canonical Template Map | Topic | Folder | Files | Purpose | | --- | --- | --- | --- | | Linear model PFC 6.0 | `scripts/canonical/linear-model-pfc6/` | `1faxiang.dat`, `2qiexiang.dat` | Two-ball normal/shear loading demonstration for the linear contact model. | | Linear parallel bond PFC 6.0 | `scripts/canonical/linearpbond-model-pfc6/` | `1faxiang.dat`, `2qiexiang.dat`, `3qiexiang_2.dat` | Two-ball normal/shear and bond stress/strength demonstrations for `linearpbond`. | ## Contact-Model Checklist Use this checklist before writing or changing contact logic: 1. Select the contact law according to material behavior, not just available properties. 2. Define CMAT rules before creating/cleaning contacts whenever possible. 3. Run `model clean` after piece creation and before assuming contacts exist. 4. Use `contact method bond` only after compatible contacts exist. 5. Use `contact property` only when intentionally changing existing contacts. 6. Document whether properties are contact-level, ball/wall surface-level, inherited, or method-derived. 7. Add histories or contact listings that verify force, displacement, bond stress, failure, or energy response. 8. Route macro calibration back through `pfc-workflow` and, when needed, `pfc-servo-calibration` or `pfc-standard-tests`. ## Working Rules - Prefer PFC 6.0-safe syntax unless the user explicitly targets another version. - Treat files in `scripts/canonical/` as reference templates, not final calibrated models. - Do not publish generated `.sav`, project metadata, videos, PDFs, archives, or large output dumps as authoritative assets. - Do not claim macro mechanical behavior from micro-properties without calibration or validation. - If the task becomes a full calibration or validation study, hand control back to `pfc-workflow`. ## Output Contract A complete child-skill handoff back to `pfc-workflow` should include: - Selected contact law and why it fits. - Required files or snippets from `scripts/canonical//`. - CMAT/property/method command order. - Existing-contact vs future-contact assumptions. - Required histories/list checks for validation. - Macro-calibration caveats and target tests. - A clear note that full case execution, post-processing routing, V&V, and delivery continue in `pfc-workflow`. ## Local Contents - `references/overview.md`: detailed self-contained contact-model boundaries and source map. - `references/contact-model-doc-notes.md`: PFC 6.0 command/reference notes checked through `pfc-mcp`. - `examples/README.md`: how to validate bundled contact-model demonstrations. - `scripts/canonical/`: PFC contact-model source snippets. - `scripts/canonical/manifest.json`: file inventory with sizes and SHA-256 hashes. - `scripts/README.md`: helper-script policy and future maintenance guidance.