Flexcom > Theory > Model Building > Geometric Properties

Flexcom provides different formats for specifying structure geometric properties, although ultimately the information is the same and is used in the same way by the program. These are termed Flexible Riser, Rigid Riser and Mooring Line formats.

•The Flexible Riser format is so called because it is the format commonly used when defining flexible risers. Specifically, the data to be specified in this case comprises bending stiffnesses about two axes, torsional stiffness, axial stiffness, mass per unit length etc.

•When you use the Rigid Riser format on the other hand, you input internal and external diameters, Young’s modulus, shear modulus, mass density etc. – data for the analysis of a rigid riser (whether a top tensioned riser or an SCR) would normally be available in this format.

•The Mooring Line format is similar to the Flexible Riser format, but fewer input terms are required. It is geared towards cables and wires which typically have very low resistance to bending and torsion, hence the governing inputs are axial stiffness and mass per unit length.

It is important to stress that there is of course no requirement that the structure you are analysing with Flexcom be a flexible riser, rigid riser or mooring line. These terms are used simply because the formats are traditionally used for these types of structure.

•Stress Properties details the use of property data in calculating cross-section stresses.

•Coatings describes the coatings facility and how coatings affect element properties.

•Poisson’s Ratio describes how Poisson’s ratio effects are modelled.

•Tangent and Secant Stiffness describes the traditional and alternative approaches for modelling non-linear materials.

•Non-linear Material Force Term explains the theory behind the right-hand side force term which accompanies stiffness terms for non-linear material elements.

•Compression and Buckling discusses the critical Euler load, the maximum compressive load which a beam can sustain without buckling laterally.