Flexcom > Theory > Model Building > Geometry > Lines > Modelling Repeating Sub-Sections

Overview

While the Lines modelling feature is far more powerful than the traditional approach of working directly with nodes, elements and cables, using the *LINES keyword alone does not result in optimum user experience. Specifically, each sub-section within a line (i) has to be defined explicitly, and (ii) requires a unique name.

Where a model contains a large number of similar sections, another complementary feature is provided which allows repeated sections to be modelled quickly and easily. A group of sub-sections may be defined under a *LINE SECTION GROUPS keyword, which may then be subsequently referenced under the normal *LINES keyword as required.

When the repeat section group option is invoked, Flexcom automatically populates each line section with as many of the sub-section groups as will fit between the specified start and end distance for that line section. If the repeated group length doesn’t divide into the distance evenly, a notification message is issued to that effect, and the last section group truncated appropriately.

Consider for example the sample floating hose model which is shipped with Flexcom. It contains 52 identical sections of buoyed hose, separated by standard/unbuoyed hose sections in between. This geometry would require over 250 lines of keyword data to construct using *LINES alone. However, using *LINES SECTION GROUPS in conjunction with *LINES results in an over 80% reduction in volume of required keyword data.

Relevant Keywords

•*LINES is used to define a line (and sections within that line), by specifying relevant set names, lengths, start and end locations, and mesh generation settings.

•*LINE SECTION GROUPS is used to define groups of line sections which may be reused and repeated along line sections.

If you would like to see an example of how these keywords are used in practice, refer to E03 - Floating Hose.