Fundamental frequency of IsoTruss tubular composite structures

Abstract

To reveal free vibration modes and fundamental frequency of one-dimensional periodic IsoTruss tubular composite structures (ITTCSs), finite element modeling method and dynamic equivalent models were developed. ITTCS has two typical vibration modes: (a) shell-like modes and (b) beam-like modes. Short ITTCS and large inclinations of helical members easily induce shell-like vibration modes, while long ITTCS and small inclinations easily induce beam-like vibration modes. For shell-like vibration, the fundamental frequency is decided by the inclination, while the length has little influence. For beam-like vibration, the fundamental frequency depends on the column length and the inclination has slight influence. Dynamic continuum beam-like model and shell-like model were developed to predict the fundamental frequency of the IsoTruss structure. The predictions are consistent with the numerical simulations, and these models can be applied in engineering to instruct the dynamic design of the IsoTruss structure.