Pfc Stress Wave Aelocation

PFC Stress Wave And AE Location

Use this skill to design, explain, or implement stress-wave propagation and acoustic-emission (AE) source localization workflows in PFC. It covers elastic wave propagation, numerical dispersion, source excitation, boundary reflection/absorption, P/S wavefront and radiation-pattern checks, and 2D velocity-free AE source location from sensor-cluster time delays.

Parent Skill Relationship

pfc-stress-wave-aelocation is a child skill of pfc-workflow. It owns the elastic-wave and source-location specialist portion, not the full model lifecycle.

Use these handoffs:

• Parent pfc-workflow: owns full planning, calibration, solve campaign control, V&V, and delivery.
• Sibling pfc-dynamics: owns general dynamic/seismic loading, damping/timestep audits, and inertial response assumptions.
• Sibling pfc-ae-energy: owns AE hit/event tables, energy figures, moment tensors, T-k/Hudson/source-mechanism plots.
• Sibling pfc-fish: owns waveform callbacks, absorbing-boundary FISH, histories, tables, and reusable helper refactoring.
• Sibling pfc-contact-models: owns bonded/flat-joint contact model setup and property audits.
• Sibling pfc-postprocessing: owns wavefield, waveform, error-map, and summary figures after export.
• Sibling pfc-gbm-brittle-rock or pfc-flat-joint-brittle-rock: owns brittle-rock GBM/FJM specimen construction if the wave source is embedded in those models.

When To Use

Use through pfc-workflow when the task asks to:

• simulate stress-wave, elastic-wave, seismic-wave, ultrasonic, or blasting-wave propagation in PFC
• compare P-wave/S-wave speed, wavefronts, attenuation, dispersion, or radiation patterns
• generate sine or Ricker wavelet sources in FISH
• design absorbing, free, or rigid boundaries for wave propagation
• localize AE sources from sensor arrays or arrival-time differences
• use Kundu velocity-free localization or arbitrary-triangle sensor clusters
• compute time delay by cross-correlation
• validate a flat-joint plate or brittle-rock model with pencil-lead-break style source localization

Required Inputs

Ask for these if missing:

• PFC version, dimensionality, and whether dynamic mode/license is available.
• Wave goal: 1D chain, 2D wavefront, source radiation pattern, boundary test, or AE location.
• Particle size / spacing and target maximum frequency for dispersion check.
• Contact model and elastic parameters for wave speed.
• Source type: sine, Ricker velocity, Ricker force, point force, wall motion, or bond-break source.
• Boundary type: rigid, free, absorbing, or long-enough domain.
• Sensor coordinates, sampling interval, and waveform export format for AE location.
• Error tolerance and source-location evaluation metric.

Operating Rules

1. Check dispersion before model construction: use wavelength-to-particle spacing ratio lambda / D >= 10 for accurate wave propagation.
2. Prefer Ricker wavelets over simple sine pulses when broadband high-frequency corners would cause strong numerical dispersion.
3. Turn off local damping for physical wave propagation unless the task explicitly studies attenuation.
4. Use small, fixed timesteps; do not use mass/density scaling for wave-speed studies.
5. Reset mechanical time before source excitation when the waveform depends on time.
6. Treat absorbing boundaries as part of the model, not an afterthought.
7. Use cross-correlation for cluster-internal time delays; avoid manual arrival picking when waveforms are similar.
8. For velocity-free localization, reject near-parallel cluster-pair rays and report geometry degeneracy.

Core Workflow

1. Classify the task: wave propagation, source excitation, boundary behavior, wavefield/radiation pattern, or AE location.
2. Run the dispersion pre-check: estimate wave speed, maximum frequency, wavelength, and lambda / D.
3. Build the model: 1D chain, 2D hexagonal lattice, plate specimen, or calibrated brittle-rock specimen.
4. Configure dynamic assumptions: damping, timestep, mechanical time reset, histories, and export interval.
5. Add the source: Ricker velocity/force or another documented waveform.
6. Add boundaries: rigid/free/absorbing and document expected reflection behavior.
7. Export waveforms at monitors/sensors.
8. For AE location, compute time delays by cross-correlation.
9. Convert each sensor cluster to an arrival direction; intersect cluster rays for source candidates.
10. Filter poor geometry, compute location error, and hand off figures/tables to pfc-postprocessing or AE interpretation to pfc-ae-energy.

Documentation-Backed Rules

PFC command families checked with pfc-mcp are summarized in references/pfc-doc-notes.md:

• model configure dynamic, model dynamic
• model mechanical timestep, model mechanical time-total
• model cycle, model solve
• ball attribute, wall attribute
• fish define, fish callback, fish history
• ball history, wall history, measure history
• model energy, history export, table export
• program call

Formula And Code Migration Rules

When the request asks about theory, formulas, exact algorithms, or code migration, load these first:

• references/wave-theory.md: 1D and 2D wave speed, dispersion, boundary reflection, and radiation formulas.
• references/source-excitation.md: Ricker/sine source rules and FISH source templates.
• references/ae-location.md: Kundu and arbitrary-triangle velocity-free localization formulas.
• references/cross-correlation.md: time-delay estimation and Python implementation notes.
• references/calibration-plate.md: plate calibration, sensor layouts, and expected location accuracy.
• scripts/canonical/: reusable source, absorbing-boundary, localization, cross-correlation figure, and plotting templates.

Output Contract

A complete handoff back to pfc-workflow should include:

• wave type and model type
• dispersion calculation and pass/fail status
• source waveform parameters and implementation route
• damping/timestep/dynamic-mode assumptions
• boundary condition and reflection/absorption expectation
• monitor/sensor layout
• exported waveform requirements
• localization method, time-delay algorithm, and geometry filters
• error metrics and recommended figures/tables

Local Contents

• references/wave-theory.md: wave equations, speeds, dispersion, boundaries, and radiation patterns.
• references/source-excitation.md: sine/Ricker sources and PFC implementation templates.
• references/ae-location.md: velocity-free source-location formulas.
• references/cross-correlation.md: signal processing and Python implementation details.
• references/calibration-plate.md: granite/flat-joint plate parameters and sensor layouts.
• references/pfc-doc-notes.md: PFC 6.0 documentation notes checked through pfc-mcp.
• examples/README.md: materialization and validation patterns.
• scripts/canonical/: PFC/FISH/Python templates.
• templates/: YAML parameter templates for sensors and wave settings.