Inelastic analysis of prismatic and nonprismatic aluminum members

Abstract Today, many structures are subjected to stresses beyond the elastic limit of the material, creating a loading condition of great significance to the design engineer. This is particularly important for aircraft and aerospace structures and for any structure subject to earthquake and blast loads. Since both prismatic and nonprismatic members may be used in these structures, the analysis can be very complicated, especially when the moment of inertia Ix and the modulus of elasticity Ex vary along the length of the member. The method of equivalent systems development by Fertis [Dynamics and Vibration of Structures. John Wiley (1973); revised Edn., Krieger (1984)], Fertis and Keene [J. Struct. Engng116(2) (1990)] and Fertis and Taneja [J. Struct. Engng. 117(2) (1991)] provides an accurate and simplified method of analysis for the solution of such problems in ferrous alloys. This paper deals with the utilization of equivalent systems of constant stiffness E1I1 where both Ex and Ix of the original member are permitted to vary in any arbitrary manner, in order to determine the rotations and deflections of prismatic and nonprismatic aluminum alloy members. In the analysis, the material of the member is permitted to be stressed well beyond its elastic limit, and all the way to failure.