Solution of the optimization problem for the purpose of designing a lattice polymer composite structure with the outer skin

Abstract

   In recent years, the urgency of the problem of launch vehicles load-bearing elements optimal design has continued to grow. One of the widespread structural designs is an anisogrid lattice structure made of polymer composite materials. Such structures are mass-produced and used as load-bearing bodies of space vehicles or fuselage compartments of atmospheric aircraft of advanced structural design. Until now, the weight and parameters of the skins used in products of rocket and space equipment have not been considered when solving optimal design problems, and the design problem has been reduced to optimizing lattice structures without skin. At the same time, the very use of skins for both atmospheric aircraft and load-bearing elements for space applications is a fairly common practice. However, not considering the availability of skin when designing a lattice load-bearing shell can lead to a significant increase in the mass of the structure with skin when applicable. The paper presents a method for the optimal design of lattice structures without ring ribs, but with the metal skin available, which can significantly reduce the weight of such structures, increasing the mass efficiency of products made of polymer composite materials used in aircraft. A confirmation of the results obtained with the help of an analytical solution and the results of a numerical experiment, obtained by modeling using the finite element method, is given. It is expected that the use of the proposed approach by considering the contribution of the skin response can lead to mass saving of the shell anisogrid structure up to 30 % compared with the methods of optimal design of lattice anisogrid structures currently used without considering the availability of skin in the design of the product.