```html Seastead Wave‑Structure Simulation – Software Recommendations

Simulation Software for a Small Ocean‑Going Platform

The design you described (40 ft × 16 ft living area, four 45° inclined “legs”/floats, cables, thrusters, ~36 000 lb displacement) can be modelled with a combination of CAD, hydro‑dynamic and structural analysis tools. Below is a curated list of programs that can handle each aspect, together with a suggested workflow.

1. 3‑D CAD & Geometry Creation

SolidWorks – Industry‑standard CAD. Good for exporting parasolid or STEP files to analysis packages.
Autodesk Fusion 360 – Cloud‑based, free for hobbyists, easy to share models.
Rhino + Grasshopper – Very flexible for parametric geometry (e.g., generating the 45° legs and cable routes).
Blender – Free, can export STL/OBJ for CFD/meshing.

2. Hydro‑dynamic & Wave‑Load Simulation

Software	Primary Capability	Typical Use for Your Platform	Licence
ANSYS AQWA	Linear & non‑linear wave loading, RAO (Response Amplitude Operator) analysis, mooring analysis	Compute wave forces on the floating legs, generate motion RAOs, check mooring line tensions	Commercial (free student version available)
OrcaFlex	Comprehensive mooring & marine system modelling, time‑domain dynamics	Model the 2‑cable-per‑leg network, redundancy cable, and simulate dynamic tension under waves	Commercial (trial version)
MOSES	General‑purpose marine hydro‑structure analysis, fatigue	Good for complex 3‑D float geometry and internal pressure effects	Commercial
WAMIT	Potential‑flow wave interaction (panel method)	Accurate wave‑run‑up & added mass for the 4‑leg configuration	Commercial (academic licence)
OpenFOAM (waves2Foam)	CFD – Navier‑Stokes, wave generation, fluid‑structure interaction	Detailed vortex shedding, thruster‑induced flow, complex free‑surface physics	Open‑source
DualSPHysics	SPH (Smoothed Particle Hydrodynamics) for free surface	Excellent for breaking wave impact on the legs & cables	Open‑source

3. Structural & Stress Analysis

ANSYS Mechanical – Finite‑element analysis (FEA) for the duplex stainless steel shells, internal pressure (10 psi), and cable‑anchor points.
ABAQUS (Dassault Systèmes) – Advanced non‑linear FEA, good for thick‑walled cylinders under external pressure.
SolidWorks Simulation – Integrated with CAD, quick linear analysis for the ¼ in wall & ½ in dished ends.

4. Thruster / Propulsion Modelling

ANSYS Fluent / CFX – CFD of the 2.5 m propellers, thrust‑force curves, interaction with hull.
OpenFOAM (propeller‑foam) – Open‑source propeller simulation.
Marine Propeller Toolkit (MATLAB) – Quick thrust‑power estimation based on geometry and operating point.

5. Recommended Workflow

Create CAD model (SolidWorks/Fusion 360) of the living platform, legs, and cable attachment points. Export as STEP or Parasolid.
Import geometry into hydro‑dynamic tool (e.g., OrcaFlex or AQWA). Define water depth, wave spectrum (JONSWAP), and the 45° leg angle. Add mass, buoyancy (half‑submerged length), and internal pressure (as a uniform internal load).
Add mooring system: model each leg‑to‑corner cable (two per leg) and the redundant rectangle cable. OrcaFlex can automatically compute line tensions.
Run wave‑load & motion analysis to obtain RAOs, peak motions, and cable tensions. Verify that tensions stay below the allowable load for the stainless‑steel cables (typically 15‑20 % of break strength).
Export leg & platform geometry into FEA (ANSYS Mechanical). Apply the pressure loads (external wave pressure from AQWA + internal 10 psi). Use linear or non‑linear material model for duplex stainless (typical yield ~50 ksi).
Thruster modelling: obtain thrust curves for the 2.5 m low‑speed mixers (manufacturer data or CFD). Import thrust vectors into the motion model to evaluate maneuvering performance (0.5‑1 mph). Adjust propeller RPM to verify that the platform can overcome the estimated drag (≈ 0.5 – 1 kN at 1 mph).
Coupled analysis (optional): Use OrcaFlex‑Mechanical link or ANSYS‑AQWA‑Mechanical co‑simulation to capture the full interaction of wave loads, cable dynamics, and structural stresses.

6. Quick Start – Free Tools

OpenFOAM + waves2Foam – download the official release and follow the waves2Foam tutorial to set up a simple wave tank. Import your CAD as an STL for the floating bodies.
DualSPHysics – grab the Windows/Linux binaries from the project page. Use the “floating body” example to see how to attach a rigid body (your leg) to the SPH fluid.
OrcaFlex Student Version – request a free licence (limited to 10 m depth). It includes a simple “floating platform” tutorial that you can adapt to your geometry.

Tip: When you export your CAD, keep the geometry clean (remove small fillets, simplify the cable anchor points). Most hydro‑dynamic packages require a “watertight” mesh for accurate pressure integration.

7. Summary

You don’t need a single “all‑in‑one” program; a typical pipeline is:

CAD → define the 40 ft × 16 ft house, legs, cable points.
Hydro‑dynamics (OrcaFlex/AQWA) → wave loads, motion, cable tensions.
Structural FEA (ANSYS Mechanical) → verify ¼‑in/½‑in duplex steel can handle the pressure and external loads.
Propulsion CFD / Thrust‑model → confirm the 2.5 m mixers can move the platform at the desired speed.

All of the above packages can import/export standard CAD formats (STEP, IGES, STL) and can be coupled via neutral files or API scripts, letting you build a “digital twin” of your seastead for both design‑iteration and eventual regulatory submittal.

Feel free to copy the HTML above into your site, modify the styling, or add a contact form if you need further assistance. Good luck with the project!

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