Stability of Skin Added Lattice Structure

Abstract

Composite lattice structure, consisting of helical and hoop ribs intersecting each other in a regular pattern, is considered to be a superior candidate as the lightweight aerospace structure such as payload attachment adapter and inter-stage structure of launch vehicles. The present study focuses on the buckling behaviors of lattice cylinders under compressive loading. The buckling modes of lattice structures are deeply affected by the local rotational deformation of the ribs. In order to prevent this local rotation effect, the addition of thin skin to the lattice cylinders is proposed. The buckling load of the skin-added lattice cylinders significantly increases. A parametric study is also carried out to obtain the optimal designs of skin thickness and cross-sectional dimensions of the ribs. It is shown that the addition of skin has different effects on the improvement of bucking loads depending on the rib dimensions. As a result of parametric study, the new lattice model which has no hoop ribs is proposed and the buckling behavior of the structure is investigated. The elimination of hoop ribs is also meaningful from the manufacturing point of view. It may leads to the drastic reduction of the fabrication cost.