Translational acceleration loads

CSI Software applies an acceleration load in reference to the fixity of restraints. At each joint, the force of an acceleration load is simply the negative of the product of assembled mass and input acceleration.

Rotational acceleration loads

Rotational acceleration is calculated independently from rotational inertia. This is done by applying, at the global origin, a unit rotation about the axis considered for rotational-acceleration computation.

While applying a rotational acceleration load during time-history analysis, users may specify a coordinate system and an angle from the vertical Z-axis. Rotational acceleration is then applied at the origin of that coordinate system, about the corresponding axis.

Rotational acceleration is constant through all points in a structure.

Rotational inertia may induce negative moment values.

Translational acceleration, at any point in a structure, is given by the cross product of the position vector (relative to the origin of rotation) and the acceleration vector. Resultant force is then the negative of the product of this translational acceleration value and the translational mass. For example, RY acceleration would generate MY, FX, and FZ values.