Structural integrity is a major factor in aircraft design and construction. No production airplane leaves the ground before undergoing extensive analysis of how it will fly, the stresses it will tolerate and its maximum safe capability. Every airplane is subject to structural stress. Stress acts on an airplane whether on the ground or in flight. Stress is defined as a load applied to a unit area of material.
Stress produces a deflection or deformation in the material called strain.
Stress is always accompanied by strain. Current production general aviation aircraft are constructed of various materials, the primary being aluminum alloys. Rivets, bolts, screws and special bonding adhesives are used to hold the sheet metal in place. Regardless of the method of attachment of the material, every part of the fuselage must carry a load, or resist a stress placed on it. Design of interior supporting and forming pieces, and the outside metal skin all have a role to play in assuring an overall safe structure capable of withstanding expected loads and stresses.