Frame element twist
The Frame element twist (noted Twist (structural) in the Beam element sensor) is an output of frame elements in Ashes. It defines how much an element has rotated around its axial direction compared to its inital position. This output is relevant for any frame element, as opposed to Pitch, which is only relevant for blades, Blade shape twist which is only relevant for Blade aerodynamical station and Blade structure twist which is only relevant for blade structural elements.
For a pitch regulated WT, the Twist (structural) of a frame element of a blade will include the change of pitch relative to the initial pitch.
For example, consider the following model:
If a force is applied onto the node on the right side of the model (indicated by the red vector in the figure below), this will produce a moment on the vertical elements that will make them rotate along their axes. The Twist (structural) output of the Beam element sensor will tell you how much the element has rotated with respect to its initial position.