Finite Beam Elements for Variable Stiffness Structures

T. Macquart, A. Pirrera, P. M. Weaver
2018 AIAA Journal  
General rights This document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: I. Introduction Current aircraft wings and wind turbine blades are lighter, slender and more flexible than their predecessors. Due to the increasing slenderness and compliance, wings and blades can no longer be assumed to be torsionally rigid, as small torsional deflections can significantly influence their
more » ... astic responses. Capturing the flexibility of modern aerospace structures with numerical models is, consequently, crucial to further improving their aeroelastic efficiency [1,2]. However, highly refined, and thus computationally expensive models are generally required to obtain accurate results [3, 4] , leading to long run-times, which contrasts with the rapid structural performance evaluation needed for optimisation. Considering the increased reliance on numerical simulations and the critical choices that must be made during early design stages, this paper focuses on the development of a rapid, yet accurate, finite element (FE) beam model for the preliminary design of slender structures. FE analysis employing beam elements is a common design tool for slender structures [5] . The need for beam models able to capture structural couplings resulting from non-conventional, non-uniform cross-sections, and geometric non-linearities has been a significant driver towards the development of refined beam theories [6] [7] [8] [9] . In contrast to these refined theories, aimed at capturing high-order deformations, we focus on the improvement of beam elements derived by axiomatic formulations [10]; The issue of spurious nodal strains observed at the interface between elements [11] being central to this work. Although a converged strain state can be reached with mesh refinement, the incurred rise in computational cost conflicts with the need for cheap structural calculations. The goal of this work is to enhance beam elements to reach converged
doi:10.2514/1.j056898 fatcat:tyyrvzgrmngahpc3ojhkwaotsy