1. Local element axis definition

Additional to Arbitrary system AR.

This data group may be used to specify a reference vector that is used to determine the initial orientation of the local y- and z-axes of beam elements.

If a local element axis is not specified for an element, the local element coordinate system is given by the default procedure described in see Element coordinate system.

This data group must be given for all elements with the net loads (hydrodynamic load type HNET) as the reference vector and the element’s x-axis define the net plane.

1.1. Data group identifier, one input line

LOCAl ELEMent AXIS

1.2. Number of input lines for special axis definition, one input line

NAXDEF

  • NAXDEF: integer: Number of input lines for special axis definition

1.3. Specification of reference vector for definition of the local axes in the initial configuration, NAXDEF input lines

LINE-ID ISEG IEL RNX RNY RNZ

  • LINE-ID: character(8): Line identifier.

  • ISEG: character/integer: Local segment number within line LINE-ID

    • = 0 or ALL means all segments in specified line

  • IEL: character/integer: Local element number within segment ISEG

    • = 0 or ALL means all elements in specified segment ISEG

  • RNX: real: X-component of the reference vector

  • RNY: real: Y-component of the reference vector

  • RNZ: real: Z-component of the reference vector

The reference vector is to be given in global system.

The element’s local x-axis goes from end 1 to end 2 of the element.

The element’s local z-axis is given by the cross product between the element’s local x-axis and the reference vector.

The element’s local y-axis is given by the cross product of the local z-axis and the local x-axis.

The reference vector must not be parallel with the element’s initial x-axis.

For beam elements, the element axes are found at the stress-free configuration and will subsequently follow the element.