Blade Loads Outputs at Principal Elastic Axes System

• The positive z-axis follows the local deflected neutral axis at each blade station towards the blade tip.
• The positive y-axis is defined by the principal elastic axes orientation.
• The positive x-axis is orthogonal to the y and z and follows the right-hand rule.

Figure 1: Blade principal elastic axes coordinate system

Note that there is a subtle difference between the principal elastic axes coordinate system and the underlying blade local element axes coordinate system, whereas the latter is used to calculate the orientation of the principal elastic axes. The Principal elastic axes orientation is calculated by taking the average orientation of the two blade elements at the node where the elements join. This is illustrated in Figure 2. The two adjoining local element frames are shown in green and red. The principal elastic axes output frame is shown in blue.

Figure 2: Principal elastic axes and local element axes orientations

Last updated 13-12-2024