How to Solve 8 Tough Ocean Engineering Problems with Dynamic Analysis

Many engineers think of dynamic analysis as being required for analyzing risers and moorings in the offshore industry. But dynamic analysis is used in many other marine sectors for alternative applications.

ProteusDS is DSA’s dynamic analysis software. It is used by ocean engineers and industry professionals to conduct a dynamic analysis of systems that are exposed to extreme wind, current and waves. There are many applications for the software outside of offshore oil & gas – so let’s explore just how diverse the software is…

Aquaculture

These systems include traditional fish farms in both circular and square cage designs along with shellfish aquaculture farms. These systems often contain nets which are connected to moored rigid or semi-rigid structures, such as buoys and floating collars.

As the aquaculture industry continues to grow, the number of traditional sheltered sites is declining, and thus an increasing number of installations are operating in regions that are exposed to high energy ocean swell, current, and wind conditions. The need to understand how to design aquaculture installations is necessary.

To support accurate aquaculture analysis, we have recently added wake-shielding and self-shielding models to ProteusDS, which is essential to avoid any overly conservative estimation in the loads on fish farms for installations.

Debris Impact & Cable Contact

ProteusDS has been recently enhanced to model contact between bodies. This technology could be used to predict the effects of ice or a log impacting a floating platform. Alternatively, lines running through a sheave or a chute can be modeled. This capability is under active development, and users interested in testing it should contact us.

Cable Ferry

ProteusDS is used by naval architecture firms to predict the motion of vessels and marine platforms. Used in conjunction with BEM software like DSA’s ShipMo3D, ProteusDS is used to perform seakeeping and manoeuvring studies. These studies can include moorings, towlines and cables.

ProteusDS was recently used to conduct an in-depth analysis of a cable ferry running between Vancouver Island and Denman Island in Western Canada. The ferry was modeled using a 6 DOF rigid body. The model developed captured key sources of loading, including wave diffraction and wind loading on the superstructure. The ferry travelled across the channel using a simulated traction winch that acted on the drive cable.  The cables were modeled using the finite element cable model that also interacts with the bathymetry of the channel. The ultimate and fatigue loads in the cables were assessed using the model.

Image of a Cable Ferry simulation in ProteusDS

 

 Commercial Fisheries 

The ability to model winches, lines, vessels and nets allow for modeling many types of fishing operations. Through numerical modeling of commercial fishing operations, ProteusDS has been used to cut client’s’ costs by limiting snarls and providing feedback on optimal tow arrangements and winch selections. DSA has also generated informative 3D visualizations of the behaviour of fishing gear in the water and supervised flume tank testing of fishing gear.

Elastic Moorings

Elastic moorings are often used in situations where elongation or compliance is needed, but where a chain mooring is not practical or may harm the environment, or where space is limited. The Seaflex elastic mooring technology relies on a viscoelastic rubber hawser with specially formulated characteristics that is used to manage loads.

The load response of Seaflex depends on the time history of loading.This complex hysteretic phenomenon, while well understood from a conceptual standpoint, can be difficult to represent numerically. Seaflex and DSA worked together to solve this problem and accurately model the response of Seaflex mooring technology using nonlinear axial rigidity parameters. This nonlinear axial rigidity modeling capability is also useful for synthetic rope with nonlinear elongation characteristics – such as Nylon.

Image of an elastic mooring in ProteusDS


Towed Arrays & Towfish

ProteusDS can also be used to simulate towed systems such as towfish or towed arrays. For towfish, the foil model is used to model control surfaces. The control surfaces can be actively controlled to maintain depth or altitude. The tow cable and vessel dynamics can be incorporated to perform layback analysis.

Similarly, the high fidelity cubic finite-element cable model can be used to analyze the loading and profiles of high speed towed arrays for seismic or defence applications.

Launch & Recovery 

Safely deploying and recovering equipment (spools, jumpers, AUVs, ROVs, small craft) from vessels in various sea conditions is a potentially high risk operation. Predicting the limits of safe launch and recovery operations in terms of human factors, loading and motions can enable operators to make good decisions in the field and prevent errors.

ProteusDS contains a mechanism modeling and control infrastructure that model A-frames, cranes, and other handling equipment. Offloading, lowering, and many other operations can be simulated. An important benefit of this type of analysis is that visualization of these simulations helps managers, analysts, and others better communicate with each other about how complicated operations will take place.

Image of a launch and recovery simulation in ProteusDS of a recovery boat from a frigate

Tidal Device Installation

In many ocean sectors, sea trials or operator experience largely guide routine marine operations. However, in tidal energy, the strong directional currents and narrow deployment windows make it difficult to perform sea trials safely and cost-effectively, and there is often less operator experience. ProteusDS has the ability to perform fully coupled analysis of floating service vessels installing structures such as tidal turbines, floating platforms, or laying cable.

Modeling the waves and currents in tidal passages is important for these assessments.  ProteusDS contains a spatially and time-varying current modeling capability that enables accurate representation of large-scale eddies and turbulence which will impact towing operations.

Image in engineering mode of the Cape Sharp Tidal platform with tug configuration in ProteusDS dynamic analysis software.

 

 

Designing for the ocean environment is a constant challenge. Dynamic analysis with ProteusDS allows for rapid innovation and optimization while reducing risk.

To learn more about DSA’s services, or licensing the ProteusDS software please feel free to: