Tanker Hull Finite Element Capability

For a variety of reasons, CTX needs to implement a tanker hull finite element capability. There are two requirements here.
  1. A design tool to the specs of the Downratchet Paper. This is a full hull model. The girth-wise mesh size is every stiffener. The longitudinal mesh size is every frame except where the frame spacing is more than three or four meters, it should be every half frame, but in way of the stringers it should be every quarter frame. (One can reasonably argue it should be every quarter frame everywhere in the cargo tank length to keep the element aspect ratio nearly square.) For its ULCC newbuilding program in 2000, Hellespont belatedly developed a model that almost met this spec. It had about 300,000 nodes and took about two hours to solve a load case on a PC costing less than $2,500. Such a model is not only now computationally feasible; it is dirt cheap.
  2. An on-board loading/salvage instrument. One obvious application of finite element is in combination with CTX_MATE to avoid the potentially, severely misleading problems of using beam theory in damage situations. The concept of using finite element to compute stresses in routine loading sitations may not yet be quite computationally feasible. But it certainly will be within five years. One short-run possibility here is a coarser FE Model, with a mesh similar to the Safehull system, that is about 4 m by 4m. Such a model with some 30,000 nodes could easily be used in routine loading situations right now.
The issue the CTX will have to explore is whether or not it is worth maintaining both a fine mesh and a coarse mesh model.

The first step will be to locate an Open Source finite element program which CTX can use/build on.

Email about this project should be sent to hull@c4tx.org.