TABLE OF CONTENTS With the present chapter we begin the purely aeronautical section of the book, where we consider structures peculiar to the field of aeronautical engineering. These structures are typified by arrangements of thin, load-bearing skins, frames and stiffeners, fabricated from lightweight, high strength materials of which aluminium alloys are the most widely used examples.
As a preliminary to the analysis of the basic aircraft structural forms presented in subsequent chapters we shall discuss the materials used in aircraft construction.
Several factors influence the selection of the structural material for an aircraft, but amongst these strength allied to lightness is probably the most important. Other properties having varying, though sometimes critical significance are stiffness, toughness, resistance to corrosion, fatigue and the effects of environmental heating, ease of fabrication, availability and consistency of supply and, not least important, cost.
The main groups of materials used in aircraft construction have been wood, steel, aluminium alloys with, more recently, titanium alloys, and fibre-reinforced composites. In the field of engine design, titanium alloys are used in the early stages of a compressor while nickel-based alloys or steels are used for the hotter later stages. As we are concerned primarily with the materials involved in the construction of the airframe, discussion of materials used in engine manufacture falls outside the scope of this book.
Pure aluminium is a relatively low strength extremely flexible metal with virtually no structural applications. However, when alloyed...
