# Nacelle frame

## Geometry

### Scaling scheme

Scheme for scaling of this part only.

Options:

Parent (default):

The scaling factor is set equal to the scaling factor for the parent part.

Override:

A scale factor (set by you) for this part only (i.e. the scale factor set for the parent part is overridden).

### Scaling factor

The geometry of this part will be scaled by this factor.

• Default value: 1
• Unit:
• Range: 0.001 — 1000

### Stiffness and mass scheme

The nacelle frame consists of a limited number of members (beams). The layout is not assumed to be the actual layout/design of the nacelle frame, but to give a realistic behaviour of the nacelle frame with respect to the global behaviour of the wind turbine. Thus, the deflections and stresses of the nacelle frame typically not found in the actual nacelle.

The structural system of a nacelle is typically more complicated than whatcan be achieved using FEM elements. Thus, the model of the nacelle frame used in Ashes should not be used for detailed design of the nacelle frame itself.

Options:

Infinite (default):

The members of the nacelle frame is very stiff (close to infinite) with very low mass (close to zero).

Steel:

Stiffness and mass of steel is used.

### Mass

The mass of the nacelle frame and the mass of the nacelle not modelled in another part. Currently includes the mass of the generator and gear box. The main shaft can be modelled with appropriate mass or massless (in which case the mass of the main shaft should also be included here). In a finite element analysis this mass is modeled as a point mass in the center of mass of the nacelle.

• Default value: 240000
• Unit: $\text{kg}$
• Range: 0 — 1e+09

### CM horizontal offset

The horizontal distance from the tower top to the center of mass (CM) towards the hub. Positve value means towards the rotor, negative value means away from the rotor. Thus, the distance is along the horizontal projection of the main shaft.

• Default value: -1.9
• Unit: $\text{m}$
• Range: -100 — 100

### CM vertical offset

The vertical distance from the tower top to the center of mass (CM). Must be positive which means above the tower top.

• Default value: 1.75
• Unit: $\text{m}$
• Range: 0 — 100

### CM lateral offset

The lateral, horzontal distance from the initial main shaft axis to the center of mass (CM). Positive means to the right of the main shaft when looking along the main shaft towards the hub.

• Default value: 0
• Unit: $\text{m}$
• Range: -100 — 100