Improving the mass efficiency of a composite launch vehicle head fairing with a sandwich structure

Andrii Kondratiev

doi:10.15587/1729-4061.2019.184551

Abstract

Analysis of practical experience in the construction and operation of the main fairings of launch vehicles has revealed the currently widely used sandwich structures with composite load-bearing sheathing combined with a cellular filler. The considered structures are characterized by a rather large number of parameters whose variation significantly changes the mass of an article.An approach to optimizing such structures as the main fairing of a launch vehicle in terms of mass has been further developed. The approach includes the essentially improved components of fragments of known analogs, previously developed by a team of authors, as well as the new fragments, which were not taken into consideration before. In contrast to known works, the approach has made it possible to solve the complex multi-parametric task on the optimal design of the considered class of equipment, almost without loss of accuracy. To this end, the optimization process was divided into several stages based on the reasonable levels of parameters’ significance that are included in the objective function ‒ a minimal mass. An analysis of effectiveness of the reinforcement structure for bearing sheaths has been performed, as well as the preliminary optimization of a cellular filler’s properties, which significantly simplified the selection of their optimal parameters. It has been shown that at a minimum gain in mass due to the optimal reinforcement scheme, which is approximately 5 % compared to a quasi-homogeneous sheath, there is an actual risk of a two-fold increase in the mass of a sheath when choosing a substantially non-optimal structure of the sheath.The result of this study is the established rational parameters for a scheme of reinforcement of bearing sheaths and a cellular filler, as well as their geometric parameters, which ensured a reduction in the mass of the main fairing in comparison with the basic variant, by 51 % or 118.2 kg. The results obtained allow further development and improvement, with almost no changes in its concept and structure in the direction of integration of auxiliary structural elements of the head fairing into optimization

Highlights

In today’s growing competition in the global space services market, the main trend in the development of rocket and space industry is to reduce the high cost of delivering a payload into orbit
Modern rocket and space equipment have a series of features that distinguish it as a separate class of equipment, which necessitates the development of specific methods for optimal design [14]
Ensuring a minimum of the mass of a head fairing is predetermined: – first of all, by the thickness of bearing sheaths; – in the second place, by the separation of carrying layers, that is the height of a cellular filler; – in the third place, by the configuration of the cell associated with the physical and mechanical characteristics of a cellular filler

Summary

Introduction

In today’s growing competition in the global space services market, the main trend in the development of rocket and space industry is to reduce the high cost of delivering a payload into orbit. A sandwich structural-strength scheme makes it possible to implement some of the highest indicators of specific strength and rigidity at a minimum mass, which is the determining criterion for the efficiency of units related to the considered class of equipment [9, 10] The feasibility of these capabilities depends on the effectiveness of structural-technological decisions made as a result of optimization during the product design process. There have been no procedures for the optimal design of sandwich composite structures that would integrate such varying parameters as the thicknesses of bearing sheaths, cellular filler, and frame belts, as well as the geometric parameters of cells [3] Under these conditions, of special relevance are the issues related to scientific substantiation of implementing the potential to improve the mass efficiency of the considered sandwich structural-strength scheme at a regulated carrying capacity of the head fairing

Literature review and problem statement

Statement of the problem and initial data

The aim and objectives of the study

Study materials and methods

Findings

Conclusions