This page is dedicated to those of you (like myself) that need some explanations of basic aeroelasticity terms. This is intended to be a work in progress for this class, not an exhaustive compilation.

span: length from the tip of one wing to the tip of the other

semi-span: length of one wing from the body of the aircraft to its tip

chord: distance from the leading edge of the airfoil to the trailing edge

aspect ratio: ratio of span to chord length

aerodynamic center: for a particular cross section, this is the point at which a single lift force could replace the distributed lift forces caused by the pressure difference between the top and bottom of the airfoil

elastic axis: line of shear centers

• It becomes the axis of twist when a twisting moment is applied
• This is why A Modern Course in Aeroelasticity (Dowell, E.H., ed.; 1995) notes that it is also the point of spring attachment for the various models examined in the book.
• The elastic axis is the point about which the airfoil rotates.

shear center: point where an applied force causes only bending deflection, not torsional deflection

• This location may or may not be on the member itself, depending on geometry.
• For further review, consult an undergraduate text on mechanics of materials

• For a brief on-line review of shear centers and other mechanics of materials subjects, click HERE for Mississippi State University's Tutorial Page of Aerospace Structures (TuPAS), developed by Masoud Rais-Rohani and Kristin A. Young