INCAS BULLETIN, Volume 9, Issue 4/ 2017, pp. 3 – 10 (P) ISSN 2066-8201, (E) ISSN 2247-4528
Integral Method for Static, Dynamic, Stability and
Aeroelastic Analysis of Beam-like Structure Configurations
Viorel ANGHEL*
*Corresponding author
“POLITEHNICA” University of Bucharest, Strength of Materials Department,
Splaiul Independenţei 313, 060042, Bucharest, Romania,
vanghel10@gmail.com
DOI: 10.13111/2066-8201.2017.9.4.1
Received: 23 October 2017/ Accepted: 31 October 2017/ Published: December 2017
Copyright©2017. Published by INCAS. This is an “open access” article under the CC BY-NC-ND
license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Abstract: This work presents a synthesis of the use of an integral approximate method based on
structural influence functions (Green’s functions) concerning the behavior of beam-like structures.
This integral method is used in the areas of static, dynamic, aeroelasticity and stability analysis. The
method starts from the differential equations governing the bending or/and torsional behavior of a
beam. These equations are put in integral form by using appropriate Green’s functions, according to
the boundary conditions. Choosing a number of n collocation points on the beam axis, each integral
are then computed by a summation using weighting numbers. This approach is suitable for
conventional Euler-Bernoulli beams and also for the thin-walled open or closed cross-section beams
which can have bending-torsion coupling. Generally, for a static analysis this approach leads to a
linear system of equations (the case of the lift aeroelastic distribution analysis) or to an eigenvalues
and eigenvectors problem in the case of dynamic, stability or divergence analysis.
Key Words: Integral Method, Green Functions, Collocation, Static, Dynamic, Stability, Aeroelasticity
1. INTRODUCTION
The use of the structural influence functions (Green’s functions) in the structural and
aeroelastic analysis are presented in [1]. In Romania this approach is widely used by
Professor A. Petre in his works on aeroelasticity in fixed wing aircraft [2, 3]. In the case of
the rotating beams and blades the method using Green’ s functions was presented for simple
configurations in order to obtain the natural frequencies for the bending and bending-torsion
vibration analysis [4, 5]. The coupled bending vibration analysis in the case of pretwisted
blades was presented in [6]. Then, a general case of the coupled bending-bending-torsion
vibration analysis of straight beams and blades was described in [7]. The papers [8, 9]
concern the dynamic analysis of rotating beams with tip mass. Other works related to the
dynamic analysis of rotating beams and blades are [10, 11]. The method of Green’s functions
was then applied for composite beams both for dynamic analysis [12] and static analysis
[13]. Other applications are then presented in [14, 15]. In [15] a short application concerning
the buckling analysis of a straight uniform beam was also performed. Aspects concerning the
aeroelastic analysis of wings are presented in work [16]. New developments of the methods
based on Green’s functions in dynamic analysis of beams and blades are recently reported in
[17, 18].