Drafting / 3D Modeling
Rhino is a 3D modeling program based on NURBS geometry entities. It was originally intended for visualizations and more artistic modeling, but has blossomed into a fully functional 3D modeling program for technical purposes. It includes numerous plugins to extend its capabilities. Some of the most impressive features for the marine community:
- NURBS can easily handle the complex curvature of ships hulls.
- Includes extension to export 3D model into GHS model for hydrostatics.
- Includes artistic rendering capability. Excellent for conveying visualization to clients.
AutoCAD is the de facto standard for drafting in the maritime community. Simply put, expect to work with AutoCAD if you will work with engineering drawings. AutoCAD features multiple versions of the software for various price points and capabilities. Spend some time carefully investigating your exact needs. Some of the most impressive features include:
- Standardization of printing and drafting settings across a company
- Blocks for time saving.
- 3D / 2D editing.
- What can I say. AutoCAD fairly well defined all the modern concepts of computer aided drafting.
Microstation is another drafting program. They are a major competitor to AutoCAD, offering most of the same capabilities in a different package. I have no personal experience with Microstation and can’t offer many details. I do know that although it is similar capabilities as AutoCAD, but works in a completely different process. Expect extensive retraining if you are switching from AutoCAD.
- Delftship has seen years of further development, has less bugs and is a much more mature program.
- Freeship has the ability to export to IGES files which can be imported by other drafting programs. Delft specifically removed this capability from the free version.
Lofting / CAM
Dozens of shipyard use ship constructor. It allows you to go from contract level drawings to a detailed 3D model with subassemblies defined and will automatically generate detailed construction drawings. ShipConstructor is an AutoCAD based software product line created for design, engineering and construction in the shipbuilding industry. ShipConstructor’s AutoCAD foundation provides a user environment that is a globally recognized CAD/CAM standard. This results in an existing labor pool of expertise, a common DWG format for sharing information with other applications, and a portfolio of complementary Autodesk products.
- How deep and at what attitude will it float?
- How much load will it carry?
- When will it capsize?
- Will it survive if damaged?
Delftship provides extensive capabilities for hydrostatics and stability analysis. The nice part is that each of these stability capabilities comes from a series of individual program extensions. Only pay for the features you need.
- Damage stability (deterministics)
- Inclined hydrostatics
- Bending moment and shear forces
- Critical points
- Intact stability (load cases)
- Dredger extension
- Cross curves
- Max. allowable VCG calculations
- Marpol Oil Outflow MEPC.141(54)
- Tank modeling
- Probabilistic damage stability
Hydromax is part of the MaxSurf design suite. It includes all the features of a robust stability / hydrostatics program. All functions within Stability are performed using a graphical multi-
Hydrostatics / Stability
FEA / Structural Analysis
ANSYS is a massive modeling and simulation company. And they began with FEA. ANSYS Mechanical is a powerhouse of FEA, capable of handling almost any type of program or model size you can throw at it. This is reflected in the license cost. One opinion from my own personal experience: As a company, ANSYS expanded through buying other software companies. Each of their software modules was an independent company at one time. This means that their various simulation components don’t always integrate perfectly.
Algor is now owned by Autodesk. They offer the lighter version of FEA, at a lower price point.
NASTRAN is an FEA package with a long history. Originally built for NASA in the 1960’s, it has gone through a long legal history that resulted in different versions of NASTRAN owned by multiple companies. NASTRAN is just the core solver. On top of that, you also have to consider the front end GUI. It is a well known, well developed FEA code with a host of capabilities to match almost any need. I suggest you start by reading the development history of NASTRAN and then begin investigating each of the four current sources.
OpenFOAM is open source software for CFD analysis. It includes a range of solvers to achieve all the major tasks necessary for marine CFD analysis. It is not quite as robust as commercial packages, but free is a good price.
StarCCM+ is published by CD-adapco/Siemens and is a powerhouse CFD package. Includes capabilities for almost any type of CFD analysis. Most important, it includes several features like VOF and waves, which are necessary for marine simulation.
ANSYS provides CFX and Fluent packages for CFD analysis. These are fully featured programs One opinion from my own personal experience: As a company, ANSYS expanded through buying other software companies. Each of their software modules was an independent company at one time. This means that their various simulation components don’t always integrate perfectly.
Fine marine is another set of CFD analysis. Fine Marine targets their CFD programs much more specifically. They are intended to work very well for specific applications like resistance analysis, with little need for advanced customization.
Hydrostatics / Stability
Resistance Estimate / CFD Light
MaxSurf is an integrated design suite. It includes capabilities for resistance estimates using parametric regressions and Mitchel’s integral methods. There are also powering prediction methods. It also includes a velocity prediction program for sailing yachts.
NavCAD is a resistance estimate/powering estimate program based on parametric regression. It offers a huge range of parametric regressions to fit almost any hull type. And it includes extensive modules to handle propellers, waterjets, and engine curve matching.
Michlet is a free program for resistance analysis based on Mitchel’s integral. It also includes an evolutionary optimization module to rapidly evolve the hull parameters.
Calculate pressure loss & flow rate in pipe systems. Models open/closed loops, components & pump curves. Includes Fluids & Pipes Database. Solve Pipe Networks
- Up to 1000 pipes
- Flow calculations
- Pipe pressure drops
- Re-circulating systems
- Pump curves & NPSHa
- Flow controls & demands
Maneuvering / DP Analysis
DynaSim© is a user-friendly ship dynamics simulator that incorporates Systems Identification Techniques to determine ship maneuvering characteristics. Once these parameters are known the simulator can accurately reproduce ship motion in the presence of waves, wind, currents, and obstacles or other ships. Multi-threading enables simultaneous simulation of multiple ships. The initial efforts to develop the technology were funded by Small Business Innovation Research (SBIR) awards from the National Science Foundation the Department of Defense (see the presentation on that site: Virtual Showcase) and The National Oceanic and Atmospheric Administration.
Orcaflex is best known for its versatility. Originally targeted at the offshore industry, Orcaflex was best explained as an FEA package specifically for 1D elements. This made it very good for modeling pipelines, catenary mooring lines, flexible risers, and other underwater line elements. Backed by strong user support, Orcaflex expanded its capabilities to include a wide array of modeling scenarios. Now, it can handle almost any type of seakeeping analysis. Most seakeeping programs started with attention on the diffraction analysis and developed the simulation capabilities as an after-thought. Orcaflex took the opposite approach. They focused on the simulation capability and excluded the diffraction analysis. Instead, the program included the ability to import data from nearly any other diffraction program. This paired very well with programs like WAMIT that only focused on the diffraction side. As of spring 2019, Orcaflex also included its own diffraction analysis capability.
AQWA is a 3D radiation-diffraction program published by ANSYS. It includes extensive capabilities for mooring analysis and is used widely in the offshore industry. As a company, ANSYS expanded through buying other software companies. Each of their software modules was an independent company at one time. This means that their various simulation components don’t always integrate perfectly.
MOSES is a 3D radiation-diffraction program published by Bentley. It includes extensive capabilities for mooring analysis and is used widely in the offshore industry.
WAMIT is a 3D radiation-diffraction program. It includes robust capabilities to handle multiple types of structures. However WAMIT only generates the hydrodynamic database. It does not include any capabilities to post process this data in frequency domain or time domain analysis.
MaxSurf motions includes seakeeping analysis capabilities from thin ship theory (Lewis sections) and 3D diffraction-radiation methods.
Nemoh is an Open source seakeeping code. Nemoh calculates first order wave loads on offshore structures (added mass, radiation damping, diffraction forces). It was developed by researchers at Ecole Centrale de Nantes for 30 years. It is still used in many of their research projects. Typical use is estimation of dynamic response of floating structures or performance assessment of wave energy converters.
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