Add Rotating Frame and Gravity nodes to create the loads caused by gravity or accelerated frames. This gives load contributions from all nodes in the physics interface that have a density or mass, such as Linear Elastic Material, Rigid Domain, Added Mass, or Point Mass.

In the following, the mass density ρ should be considered as generalized. It can represent mass per unit volume, mass per unit area, mass per unit length, or even mass, depending on the dimensionality of the object giving the contribution.

The gravity acts in a fixed spatial direction eg. The intensity is

where g is the acceleration of gravity. The action of gravity can also be presented as a linearly accelerated frame of reference. Thus, it can be accounted for as a contribution into the effective acceleration via the frame acceleration term given by:

A centrifugal force acts radially outward from the axis of rotation defined by the axial direction vector eax. The rotation is represented by the angular velocity vector:

where Ω is the angular velocity. In vector form, the acceleration contribution and the loads are:

where rp is the rotation position vector that contains the coordinates with respect to any point on the axis of rotation. The point is given by its radius vector in the global coordinate system rbp.