ANALYSIS METHOD OF RIGID BODY MOTION AND ELASTIC DEFORMATION

摘要

PROBLEM TO BE SOLVED: To enable rigid body displacement and elastic deformation to be separated and analyzed even in the case of an object in which an elastic mode is expressed by unknown finite elements because of an ever-changing stiffness matrix.SOLUTION: A coordinate system using an initial center-of-gravity position and an initial inertia main axis of an object in a global coordinate system as an origin and an axis vector, respectively, is set as a local coordinate system, and a displacement of each joint of the object in the global coordinate system is set as a reference displacement of this joint. Then, setting of a new local coordinate system with a center-of-gravity position and an inertia main axis of the object after rigid body motion and elastic deformation in the local coordinate system as an origin and an axis vector, respectively, calculation of displacement due to elastic deformation of each joint, and updating for making the new local coordinate system to be a local coordinate system and making the displacement due to elastic deformation of each joint to be a reference displacement of each joint are performed until deviation of the local coordinate system between before and after the updating becomes equal to or less than a default value. The rigid body motion of the object is obtained from a coordinate value of the origin and a rotation matrix of the axis vector of the local coordinate system in the global coordinate system at that time, and the elastic deformation of the object is obtained from the deference displacement of each joint at that time.