Simulating deep-sea, heavy-lift cables

Autonomous guided undersea cables

A recent project of note involved heavy-lifting undersea cables. As George says, "We really don’t have any specialty as FEA consultants, except how to figure out how to model complex systems."

That was especially true in this complex project involving the dynamic movement of undersea tensioned cables. As the cables pump or tow objects, they whip back and forth due to both sea currents and lift operations. With an estimated cost per cable in the millions of dollars, it was crucial to find a model solution.

Our work demonstrates a numerically elegant manner to simulate the FSI forces acting on large diameter high-modulus polyethylene rope (Spectra) during a deep-sea heavy lift operation.

Advanced LS-DYNA Analysis to Simulate Fluid Drag, Vortex Shedding on Undersea Cables


New LS-DYNA case study focuses on O-Ring Analysis

Dr. Laird recently finished a new LS-DYNA case study focusing on O-Ring Analysis. As he states in the intro, the analysis of O-rings has historically been difficult since the modeling process involves large displacement, and large nonlinear strains couple to multi-body contact between the O-ring, its gland cavity and the mating part.

In our prior engineering services work, we would have to run the model in explicit mode and just live with the long run times even through the model was axisymmetric. In the last couple of years, the implicit capabilities of LS-DYNA have significantly grown and we can now run such models much faster and with no inertia effects.

O-Ring Analysis Using Advanced Elastomeric Material Laws with LS-DYNA


Basics of Composite Analysis for Engineers

At our Seattle FEMAP Symposium, George Laird from Predictive Engineering presented a brief on "Basics of Composite Analysis for Engineers."

It focuses on the underlying basis of how composites function, and shows how this ties to simple and verifiable simulation models that can be easily validated for common engineering applications. The idea is to provide a roadmap on how one can idealized a structure into a composite model and have confidence that the final FEA results will validate. We view this as a multi-step process, that with a little bit of thinking will save a lot of hard work. Starting with some basics we’ll carry an example analysis forward toward final validation.

As George puts in the intro: “Once you remove a bit of the fear, uncertainty and doubt about composite simulation, building accurate first order FEM’s is pretty basic.”

We're included a link to George's presentation, as well as video of a related simulation showing decompression of composite container.

DOWNLOAD PDF: "Basics of Composite Analysis for Engineers"


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Siemens PLM Software
Livermore Software Technology Corporation
Applied CAx
Sherpa Design