theperfectfasad.blogg.se - Orcaflex 2rd limiting stress

In the case of nonlinear bend stiffness, you must also specify whether the hysteretic bending model should be used. For homogeneous pipes the plasticity wizard may be useful to help set up the table. The bend moment must be zero at zero curvature. OrcaFlex uses linear interpolation within this table, and linear extrapolation for curvature values beyond those given. Nonlinear bend stiffnessįor nonlinear behaviour, use variable data to specify a table of bend moment magnitude against curvature magnitude. The bend stiffness represents the bend moment required to bend the line to a curvature of 1 radian per unit length. This slope is the equivalent $EI$ value for the line, where $E$ is Young's modulus and $I$ the second moment of area of the cross section. Linear bend stiffnessįor normal simple linear behaviour, specify the bend stiffness to be the constant slope of the bend moment-curvature relationship. See calculating bend moments for further details of the bending model used. You can specify the bend stiffness to be linear, elastic nonlinear, hysteretic nonlinear or externally calculated, as follows. The $x$ and $y$ values will often be the same, and this can be indicated by setting the $y$-value to '~', meaning "same as $x$-value". The bend stiffness is the slope of the bend moment-curvature curve. Note however that the axial and torsional stiffnesses are still assumed to be linear.

A variable data item defines a nonlinear stress-strain relation which results in a bending stiffness with nonlinear elastic behaviour.

A constant value results in linear material properties.

This determines the axial, bending and torsional stiffnesses – these stiffness data items are reported on the data form (in the all view mode), although they cannot be edited. For homogeneous pipes only, a value may be given for the Young's modulus of the material.