Model reduction of a multibody system including a very flexible beam element

An optimum method to reduce the system size of a multibody system including a very flexible beam element is presented. In this paper, the absolute nodal coordinate formulation (ANCF) is used to describe the motion of the flexible beam in this system. Based on continuum mechanics approach, the bending stiffness matrix of the system is assumed to be a constant matrix when the axial strain is small. Thus, free-interface method, in which modal coordinate vector is free from the boundary region, is used to reduce the degrees of freedom of a flexible beam with sliding joints. Finally, two numerical examples are presented to verify the efficiency and accuracy of this method. The results show that the present method can reduce the computing time with precision. Meanwhile, a deformation energy criterion of mode truncation is established.