Physical and Mechanical Study of the Behavior of Hybrid Structures

Abstract

The aim of the study is to comparatively evaluate the strength and mass characteristics of the all-metal and metal–composite versions of the helicopter fuselage design. The main emphasis is laid on the possibility of modernizing existing structures by partially replacing metal elements with polymer composite materials (PCMs). The research methodology includes the development of a standard fuselage design, the construction of finite-element models, and strength calculations. The study is based on a comparison of two configurations: an all-metal structure made of D16 alloy and a hybrid design with selective use of composite materials. For the analysis, the maneuverable calculation cases “pull-up” and “side-slip” are used. The main results show that replacing some of the metal elements with composite materials makes it possible

• to maintain the required static safety factor (η ≥ 1.01);

• to achieve a 24% reduction in the weight of replaceable components (from 48.2 to 36.7 kg);

• to ensure an overall weight saving of the fuselage structure of approximately 12%.

The study identifies optimal areas for PCM application: fuselage center skin, tail boom, engine and gearbox cowlings, fairings, and cabin floor panels. The findings of the study confirm the effectiveness of the combined approach to helicopter fuselage design. The obtained results demonstrate that partial replacement of metal elements with composite ones allows for a significant reduction in the weight of the structure while maintaining the required strength characteristics. The developed methodology can be used in the modernization of the existing helicopter fleet and in designing new aircrafts. The practical significance of the work lies in the possibility of using the obtained results to improve helicopter technology in order to enhance its flight performance.