Copy command

@COPY_COMMAND {
@COPY_COMMAND_NAME {CopyCommandName} {
@BASE_FRAME {BaseFrameName}
@COPY_FRAME {CopyFrameName}
@BASE_EXTENSION {BaseExtension}
@COPY_EXTENSION {CopyExtension}
@PHASE {φ}
@COMMENTS {CommentText}
}
}

Notes

  1. A many practical situations, multibody systems present an number of identical elements that appear at different locations, but whose physical properties are identical. Consider, for instance, a helicopter rotor consisting of four identical blades placed at 90 degree angles: when the blades are defined in a local coordinate system, they become indistinguishable. The copy command allows the automatic copying of structural elements that are identical when referred to local coordinate systems.
  2. The copy command CopyCommandName copies specific elements defined in the fixed frame BaseFrameName to elements with identical physical properties but defined in the fixed frame CopyFrameName. The elements to be copied are identified by their name which contains the extension BaseExtension. In the name of the duplicated element, the extension BaseExtension will be replaced by CopyExtension.
  3. For instance, if the copy command specifies
    @BASE_FRAME {frameHub1}
    @COPY_FRAME {frameHub2}
    @BASE_EXTENSION {Q1Q}
    @COPY_EXTENSION {Q2Q}
    a beam element called bladeQ1Q would be copied into a new beam element called bladeQ2Q. When referred to the fixed frames frameHub1 and frameHub2, respectively, beam elements bladeQ1Q and bladeQ2Q will be identical. It is important to note that many of the components used to define bladeQ1Q must also be copied. For instance, the name of the curve defining the geometry of bladeQ1Q should end with the extension Q1Q, say curveQ1Q, so it can be copied into a curve curveQ2Q used for the definition of bladeQ2Q. Note that geometric components affected by the frame change should be copied, whereas physical property components, such as the beam properties, are identical for both elements and should not be copied.
  4. When copying geometric entities, i.e. curves, fixed frame, points, surfaces, or triads, such entities must be defined with respect to a fixed frame. This fixed frame should be the fixed frame BaseFrameName of the copy command, or a fixed frame recursively defined with respect to the fixed frame BaseFrameName.
  5. When copying elements, it is common to encounter time functions. For instance, when copying a prescribed displacement element, the associated time functions must be copied as well. The copy command will copy the time function associated with the prescribed displacement element. If the time function is harmonic, the phasing angle φ will be added to the phase of each harmonic, unless the period of this harmonic Ti = 0.0.
  6. It is possible to attach comments to the definition of the object; these comments have no effect on its definition.

Example 1

The following geometric entities will be copied; note that both are defined in a fixed frame. The fixed frame frameBladeQ1Q is defined recursively. Fixed frames frameBladeQ1Q and frameBladeQ2Q have identical relative origin and orientations, but with respect to frames frameHub1 and frameHub2, respectively. Points pointTQ1Q and pointTQ2Q have the same relative coordinates, but with respect to fixed frames frameBladeQ1Q and frameBladeQ2Q, respectively.

@COPY_COMMAND {
@COPY_COMMAND_NAME {copy2} {
@BASE_FRAME {frameHub1}
@COPY_FRAME {frameHub2}
@BASE_EXTENSION {Q1Q}
@COPY_EXTENSION {Q2Q}
}
}
@FIXED_FRAME_DEFINITION {
@FIXED_FRAME_NAME {frameBladeQ1Q} {
@ORIGIN { 0.0, 0.0, 2.174}
@ORIENTATION_E2 { 0.0, 1.0, 0.0}
@ORIENTATION_E3 { -0.122, 0.0, 0.993}
@IS_DEFINED_IN_FRAME {frameHub1}
}
}
@POINT_DEFINITION {
@POINT_NAME {pointTQ1Q} {
@COORDINATES { 13.06, 0.0, 0.0}
@IS_DEFINED_IN_FRAME {frameBladeQ1Q}
}
}