Geometrical and finite-element modeling of lattice conical shell with geodesic path of spiral ribs

Cylindrical and conical lattice shells are used in the space industry as the parts of stages of launch vehicles, load-bearing spacecraft constructions and payload adapters serving for connection with spacecraft launch vehicles. Conical shells, currently used in JSC “Information satellite systems” named after academician M. F. Reshetnev”, are designed and manufactured by an automatic winding with paths of the spiral ribs oriented along the geodesic lines. Such lines are the straight lines on the involute of surface of the cone. This article discusses distinguishing features of geometrical and finite-element modeling of lattice conic shells with geodesic path of spiral ribs, which are used by payload adapters for spacecraft launchers. The algorithm of calculation of coordinates of points of an elementary segment of a lattice conic shell is described. The elementary segment represents a set of the pieces connected among each other. The task about creation of geometrical model of an elementary segment is reduced to determination of coordinates of points of the beginning and end of each piece of a segment in the set system of coordinates depending on the key design parameters of a lattice conical shell. The algorithm of calculation of these coordinates is received as a result of the analysis of the involute of surface of a lattice conical shell. Realization of this algorithm in the built-in programming language of any CAE-system allows building in the automatic mode geometrical model of an elementary segment of a lattice conical shell for her subsequent splitting into finite elements. The offered algorithm will allow considerably simplifying and accelerating the process of the analysis of the lattice conical shell by means of software.