Translational Acceleration Loads

To apply the acceleration loads, the program assumes that the restrained joints do not move. The applied force at a joint 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 at a joint times the 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 inertia is NOT needed for rotational acceleration. A unit rotation is applied about the given axis at the global origin. In time-history cases, you can specify a coordinate system and an angle (about Z), and the rotational acceleration will be applied from the vertical Z-axis. Rotational acceleration is then applied at the origin of that coordinate system, about the corresponding axis in that system at that origin..

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, At any point in the structure, the rotational acceleration is equal to that at the origin, and negative moments will be generated for rotational inertia, if any. At any point in the structure, the translational acceleration is given by the cross product of the position vector from the (relative to origin of rotation) and the acceleration vector. The negative Resultant force is then the negative of the product of this translational acceleration times value and the translational mass will be the force. The . For example, RY acceleration generates would generate MY, FX, and FZ .This is basic mechanics, the conjugate to summing moments at a point from moments and forces distributed throughout the structurevalues.