Session: VIB-14-01: Vibration of Continuous Systems

Paper Number: 97713

97713 - A New Dynamic Model of Tensegrity Structures for Vibration Analysis 

Tensegrity structures have experienced continued R&D interests in the past several decades. Dynamic model of a tensegrity structure can be represented by a system of ordinary differential equations, which is a significant advantage over other flexible structures modeled by partial differential equations. While in operation, a tensegrity structure must (i) be self-stressed to gain desired stiffness and natural frequencies, and meanwhile (ii) achieve a desired shape under excitations. However, these two objectives are difficult to achieve due to a missing link that clearly reveals a relationship between dynamic excitations and responses of the structure.

A common issue in traditional dynamic modeling methods of tensegrity structure is the over simplification of bars and cables, which are the two main types of members of the structure. In these methods, internal displacements of the members were not taken into consideration in the dynamic model so developed. Bar members were modeled either as rigid bodies with no internal displacement at all or as elastic rod elements with uniform displacement distribution along its longitudinal direction. Similar issue was also seen in cable member modeling, where cable members were modeled either as massless springs or nonlinear elastic rods, that only sustain tension forces, with uniformly distributed longitudinal displacement. These oversimplified models for bar and cable members of a tensegrity structure will inevitably prevent the dynamic model from revealing accurate dynamic responses, especially those in higher frequency domain.

To resolve this, a new dynamic model of tensegrity structures for vibration analysis is proposed. This method is based on spatial discretization method that treats displacement of continuous members, bars and cables, of a tensegrity structure as a summation of boundary-induced terms and internal terms. A nonlinear dynamic model of a tensegrity structure is derived from Lagrange equation, as a system of ordinary differential equations. This dynamic model can be linearized at an equilibrium configuration for vibration analysis. More degrees of freedom of the dynamic model is added by the introduced internal displacements of bar and cable members. This will grant the proposed dynamic model an ability to achieve accurate dynamic responses of tensegrity structures, especially for vibration analysis in higher frequency domain.

Presenting Author: Sichen Yuan Lawrence Technological University

Presenting Author Biography: Dr. Sichen Yuan is an Assistant Professor in A. Leon Linton Department of Mechanical, Robotics and Industrial Engineering at Lawrence Technological University. He received his Ph.D. and Master's degree in mechanical engineering at University of Southern California in 2019 and 2014, respectively. He received his Bachelor's degree in mechanical engineering at Shanghai Jiao Tong University in 2012. His research interests include computational solid mechanics, dynamics and control, vibrations of deployable structures, robotics and deep learning.

Authors:

Sichen Yuan Lawrence Technological University
Weidong Zhu University of Maryland, Baltimore County