Dimensionless numerical analysis method for flexible body with large deformation, displacement and time-varying length

Abstract

A tethered system, which is a multibody system in which multiple rigid bodies are connected via a flexible tether, is currently used for space and deep-sea exploration. In order to perform accurate work with such tethered systems, the ability to comprehend tether dynamics behavior with large deformation/displacement and time-varying length is crucial. Numerical analyses are beneficial in that it is difficult to carry out experiments in such environment. In this paper, an efficient numerical approach is proposed for a flexible body motion with time-varying length using a dimensionless equation of motion. Generally Absolute Nodal Coordinate Formulation (ANCF), which is a nonlinear finite element method is effective for dynamic simulation of a flexible body motion. VFE-ANCF, which applies variable-domain finite element (VFE) as a method of expressing time-varying length to ANCF, was proposed to represent the motion of a flexible body with large deformation, displacement and time-varying length. However, conventional approach using VFE-ANCF has a problem that the accuracy changes depending on the length change. So in this paper, to avoid this problem, dimensionless variables are introduced using representative value that changes with time-varying length. In addition, the usefulness of this method is shown by comparing the numerical results using this method and the conventional method.

Keywords

• multibody dynamics
• flexible body
• time-varying length
• non-dimensionized-modeling