Mechanical properties of composite anisogrid shell structures

Paper number

IAC-08.C2.4.4

Author

Mr. Felice De Nicola, CIRA Italian Aerospace Research Centre, Italy

Coauthor

Mr. Giovanni Totaro, CIRA Italian Aerospace Research Centre, Italy

Year

2008

Abstract

The paper is concerned with composite anisogrid shell structures made of a regular lattice of intersecting hoop and helical ribs through the filament winding technology. These structures exhibit excellent structural efficiency, if properly designed and manufactured, whereas the strength requirement is the driving factor for design. This is especially true in case of primary structures for spacecraft applications which are designed to sustain high axial compressive loads: interstages, and cone adapters for space launchers are the most typical examples.
Minimum mass analytical solutions have been already proven to be accurate enough within the frame of preliminary design to readily address the initial structural configuration. These closed forms are also useful to understand the role of the different parameters involved into design. Among these parameters a fundamental effect is obviously played by the mechanical properties of the ribs, namely: the modulus of elasticity of hoop and helical ribs, the compressive strength of helical ribs. These mechanical properties, which in principle can be rather different for hoop and helical ribs using two kinds of fibers, are strongly dependent on the specific manufacturing process. In particular, the typology of the adopted raw composite material (prepreg or dry fiber) is one of the critical factors.
Aim of this work is to give an experimental contribution via the realization of filament wound medium scale demonstrators in order to gain understanding of the effects of the manufacturing process on the final performance of composite anisogrid structures. More specifically, the effects of soft tooling preparation, of the resin mass fraction and of the winding tension have been evaluated and are critically discussed.

Abstract document

IAC-08.C2.4.4.pdf

Manuscript document

IAC-08.C2.4.4.pdf (🔒 authorized access only).

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