alivirgo COMSOL Multiphysics Finite Element Simulation AI Skill Guide (Claude)
Overview & Engine Architecture
COMSOL Multiphysics 6.2 is a finite element analysis (FEA) simulation platform engineered for coupled partial differential equation (PDE) solving across structural mechanics, fluid dynamics (CFD), electromagnetics (RF/Wave Optics/AC-DC), acoustics, and heat transfer. The core engine is powered by MUMPS/PARDISO direct linear solvers, GMRES/BiCGStab iterative solvers with Algebraic Multigrid (AMG) preconditioning, a Java API (ModelUtil), the MPh Python automation bridge, and distributed MPI cluster batch execution (comsol batch). Claude operates as a Principal Multiphysics Simulation Architect and Computational Physicist, specializing in nonlinear solver convergence remediation, MPh Python batch scripting, boundary layer mesh generation, and bidirectional LiveLink automation.
CODESYS & COMSOL Solver Architecture & API Stack
┌─────────────────────────────────────────────────────────────┐
│ COMSOL Multiphysics Stack │
│ │
│ Engineering & Model Builder Layer │
│ ├── Model Tree (Geometry, Physics Interfaces, Multiphysics)│
│ ├── Application Builder (Custom Simulation Apps & WebApps) │
│ └── LiveLink Bridges (MATLAB, SolidWorks, AutoCAD, Revit) │
│ │
│ Numerical Discretization & Solver Core │
│ ├── Finite Element Engine (Lagrange, Serendipity, Nedelec) │
│ ├── Direct Solvers (PARDISO, MUMPS, SPOOLES) │
│ └── Iterative Solvers (GMRES, FGMRES, AMG Preconditioners) │
│ │
│ Automation & Headless Execution Subsystem │
│ ├── COMSOL MPHServer (Java IPC Daemon: Default Port 2036) │
│ ├── `MPh` Python Automation Library (`import mph`) │
│ └── MPI Cluster Batch Engine (`comsol batch -inputfile...`)│
└─────────────────────────────────────────────────────────────┘
Operational Capabilities & Agent Directives
- MPh Python Automated Simulation Pipelines: Author Python scripts utilizing the
MPhlibrary to connect tomphserver, parameterize geometric/physics properties, execute parametric sweeps, and export numerical datasets. - Nonlinear Solver Convergence Triage: Remediate divergence errors by switching from Fully Coupled to Segregated solvers, implementing Newton-Raphson damping ($0.5-0.75$), and designing Auxiliary parameter continuation sweeps.
- Geometry Defeaturing & Boundary Layer Meshing: Eliminate CAD sliver faces and short edges using Virtual Operations (
Form Composite Faces) and inject structured prism boundary layers for fluid wall shear and thermal gradients. - HPC Batch Cluster Scripting: Construct Slurm/PBS batch submission scripts executing distributed simulations across multi-node compute clusters via
comsol batch.
Production Python Automation: COMSOL Headless Simulation & Parameter Sweep (MPh)
Save this script as run_thermal_simulation.py (requires pip install mph and a running comsol mphserver -port 2036):
"""
COMSOL Multiphysics Python Automation Client (MPh)
Connects to COMSOL MPHServer, modifies heat flux parameters, solves study, and extracts peak temperatures.
"""
import sys
import mph
import pandas as pd
COMSOL_PORT = 2036
MODEL_PATH = "C:/SimulationModels/HeatSink_Thermal_Stress.mph"
def run_parametric_study():
print(f"--- [INITIALIZING COMSOL MULTIPHYSICS AUTOMATION PIPELINE] ---")
# 1. Connect to Standalone COMSOL Server
print(f"Connecting to COMSOL MPHServer on port {COMSOL_PORT}...")
client = mph.start(port=COMSOL_PORT)
print("✅ Connected to COMSOL Backend Server!")
# 2. Load Model
print(f"Loading Model: {MODEL_PATH}...")
model = client.load(MODEL_PATH)
# 3. Update Model Parameters
heat_flux_values = [500.0, 1000.0, 1500.0, 2000.0] # W/m^2
results_data = []
print("\n--- [EXECUTING PARAMETRIC STUDY SWEEP] ---")
for flux in heat_flux_values:
print(f"Applying Heat Flux: {flux} W/m^2...")
model.parameter("q_in", f"{flux}[W/m^2]")
# 4. Solve Study (std1)
print(" • Solving Finite Element Study (std1)...")
model.solve("std1")
# 5. Evaluate Maximum Temperature in Domain
max_temp_degC = model.evaluate("maxop1(T)") - 273.15
max_von_mises = model.evaluate("maxop1(solid.mises)") / 1e6 # Convert Pa to MPa
print(f" ✅ Max Temp: {max_temp_degC:.2f} °C | Max Von Mises: {max_von_mises:.2f} MPa")
results_data.append({
"Heat_Flux_W_m2": flux,
"Max_Temperature_C": max_temp_degC,
"Max_Von_Mises_MPa": max_von_mises
})
# 6. Export Results to CSV
df = pd.DataFrame(results_data)
df.to_csv("Thermal_Parametric_Results.csv", index=False)
print(f"\n✅ Results exported to: Thermal_Parametric_Results.csv")
# Clean disconnect
client.clear()
print("COMSOL session closed.")
if __name__ == "__main__":
run_parametric_study()
Technical Troubleshooting Matrix
| Issue & Failure Signature | Root Cause Analysis | Diagnostic & Resolution Pathway |
|---|---|---|
| "Failed to find consistent initial values" | Incompatible initial conditions in coupled Navier-Stokes / Heat Transfer equations. | 1. In Study Step $\rightarrow$ Solver Configurations, switch to Segregated Solver.2. Add an Auxiliary Sweep starting with low fluid velocity to ramp initial conditions smoothly.3. Set Newton-Raphson Method to Constant (Damped) with factor $0.5$. |
| "Face has short edges / sliver surface" (Mesh Failure) | Imported STEP/IGES CAD model contains sub-millimeter geometry defects. | Under Geometry $\rightarrow$ Virtual Operations, add Form Composite Faces and Collapse Short Edges to defeat micro-features. |
| Out of Memory during 3D Solid Mechanics Solution | Direct solver (PARDISO/MUMPS) exceeded available RAM during matrix factorization. | In Solver Configuration $\rightarrow$ Stationary Solver, change Direct Solver to an Iterative Solver (GMRES) with Geometric Multigrid (GMG) preconditioning. |
MPh Throws Server Connection Refused |
COMSOL MPHServer is not running or listening on a different TCP port. | Start the server in terminal: comsol mphserver -port 2036 -login auto. |
Command Line Syntax & Batch Processing
# 1. Start COMSOL Headless MPHServer Daemon
comsol mphserver -port 2036 -login auto
# 2. Run Headless Batch Simulation on 16 CPU Cores
comsol batch -np 16 -inputfile "C:\Models\HeatSink.mph" -outputfile "C:\Results\HeatSink_Solved.mph" -study std1
# 3. Distributed MPI Cluster Batch Solve on Slurm
mpirun -np 64 comsol batch -inputfile "Turbine.mph" -outputfile "Turbine_Out.mph" -distributed
Essential File Locations
- COMSOL Preferences:
%USERPROFILE%\.comsol\v62\comsol.prefs - Recovery Directory:
%USERPROFILE%\.comsol\v62\recoverydir\ - COMSOL Executable:
C:\Program Files\COMSOL\COMSOL62\Multiphysics\bin\win64\comsol.exe
Agent Operational Directive
MANDATORY: When solving highly nonlinear coupled multiphysics models (e.g. Joule heating with temperature-dependent conductivity), always configure a Segregated Solver with damped Newton iterations before resorting to direct solvers.