Abstracts of Journal Articles - Accepted for Publication


Non-conservative Stability Analysis of Columns with Various Loads and Boundary Conditions using Fully Intrinsic Equations

Authors
SA Fazelzadeh, M Tashakorian, E Ghavanloo (Shiraz University, Iran), MI Friswell & MR Amoozgar (Swansea University)
Journal
AIAA Journal
accepted for publication
Abstract
In this paper, the stability analysis of the elastic columns subjected to seven different types of the non-conservative force is investigated on the basis of fully intrinsic beam equations. The generalized differential quadrature method is used for the discretization of the first-order intrinsic equations and corresponding boundary conditions. Altogether, four important boundary conditions, including simply supported, clamped-simply supported, clamped-free and clamped-clamped conditions, are considered. Furthermore, the effect of the combined action of an end- concentrated force and a distributed tangential follower force is investigated. To confirm the validity of the proposed intrinsic formulations, the present results are compared with those obtained from classical formulations. Our results reveal that the fully intrinsic formulation is a suitable framework to model non-conservative problems.

Composite Rotor Blade Twist Modification in Flight by Using a Moving Mass and Stiffness Tailoring

Authors
MR Amoozgar, AD Shaw, J Zhang & MI Friswell (Swansea University)
Journal
AIAA Journal
accepted for publication
Abstract
In this paper, a new concept for morphing composite blades is proposed, and how this concept changes the twist distribution of the blade is explained. A change in the blade twist is obtained by adding a mass to the blade which produces an extra centrifugal force. This centrifugal force then may produce a moment that can change the blade twist via the extension-twist or bend-twist coupling of the composite lamination. These types of couplings are present in anti-symmetrically and symmetrically laminated beams, respectively. The dynamics of the rotating composite blade is modeled by using the geometrically exact fully intrinsic beam equations. The concentrated mass is considered as a non-structural concentrated mass which has offsets with respect to the beam reference line. The nonlinear partial differential equations are discretized by using a time-space scheme, and the converged results are compared with those reported in the literature and very good agreement is observed. It is found that for an antisymmetric lamination, the spanwise location of the concentrated mass affects the twist while in the symmetric case the chordwise position of the concentrated mass is the source of twist change. It is also found that introducing the concentrated mass to a real blade can change the twist dramatically.