Final report for WP4.3: Enhancement of design methods ... - Upwind

Figure 4.5: Output positions in the tripod.
At each of the output positions, forces and moments are investigated in terms of member loads, whereas
the outputs at nodes where more than two members intersect are the member loads of legs and braces
acting upon the joints. Loads at positions P07 and P08 are expressed in global coordinates, all other outputs
are given in local coordinates defined as follows: the local x-axis is aligned with the member axis; the
local z-axis is perpendicular to a plane formed by the global x-axis and the local x-axis; and the y-axis
forms a right handed coordinate system. In case of a local x-axis and the global x-axis being parallel, the
local y-axis is parallel to the global y-axis. For all outputs in local axes, the x-axis points away from the
closest joint. This leads to sensors named such as P03Mx describing the member moment around the
local x-axis (the torsional moment) at position P3 (in the downwind leg with negative global y-coordinates
as shown in Figure 2).
Table 4.2 shows the absolute extreme values of the tower top deflection in the global coordinate system
for all the load cases simulated. Values for the beam model and the super-element model are given together
with the differences between both, with the differences related to the super-element results. The
values for UX-MIN and RY-MIN are close to zero and not shown.
Table 4.2: Extreme values of tower top axial deflections and rotations for the beam- and the super-element model.
Value Beam Super Diff [%]
UX-MAX 0.503 0.56 10.2
UY-MIN -0.262 -0.323 18.9
UY-MAX 0.121 0.166 27.1
UZ-MIN -0.015 -0.022 31.8
UZ-MAX -0.011 -0.02 45
RX-MIN -0.094 -0.129 27.1
RX-MAX 0.256 0.298 14.1
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