Local buckling of wide-flange thin-walled anisotropic composite beams

Abstract

The present contribution deals with the onset of local buckling of compressively loaded thin-walled beams with open I, C, Z, T and L-cross-sections made of laminated composite materials. The method employs a discrete plate analysis approach in the course of which each structural subelement of interest-which presently is the flange-of the thin-walled cross-section is considered as a separate composite plate with elastic rotational restraints at those edges where an adjacent substructural element is located. While in many investigations the lamination schemes of webs and flanges are considered to be purely orthotropic, in the present paper the laminate layups are allowed to be of an arbitrary non-orthotropic nature, which also allows for the analysis of laminates with inherent bending-torsion coupling. The analysis of the buckling loads of the flanges of thinwalled composite beams is performed using the Ritz-method for which some especially adjusted displacement shape functions are employed. For the case of pure orthotropy, a novel closed-form solution is described. The accuracy of the employed approaches is established by comparison with accompanying finite element simulations of thin-walled composite beams. It is revealed that the presented methodology is highly efficient in terms of computational effort and yet performs with satisfying accuracy, which makes it very attractive for actual practical applications whenever the local stability behaviour of wide-flange thin-walled composite beams is to be considered.Keywords Buckling · Composites · Laminates · Thin-walled anisotropic beams · Flanges 1 Introduction Motivation and scope of the present workIn the framework of e.g., aerospace engineering, thin-walled beams are important structural elements wherein the structural subelements which form the cross-section-i.e., the webs and flanges-in many application cases are made of laminated composite materials. Common examples for open cross-sections (meaning crosssections which exhibit free edges) are I, C, Z, T and L-profiles as depicted in Fig. 1. Naturally, one of the main factors driving the design and analysis process of such thin-walled beam structures is the stability behaviour. If the length of a beam is sufficiently high, it can be assumed that rather global buckling modes in the form of Euler buckling or torsional-flexural buckling occur. However, depending on the geometry and the applied loadings, beams with thin-walled cross-sections very often also suffer from local buckling problems such as the buckling of the flanges for which adequate means of analysis have to be found. One very common concept is the so-called discrete plate analysis. In the course of this methodology, the structural subelement of interest is cut from the cross-section. At the resultant edges, rotational restraints are considered which are characterized C. Mittelstedt (B)

Review on Local Buckling of Hollow Box FRP Profiles in Civil Structural Applications

“… The percentage share of each cross-sectional shape in civil structural applications along with the studies (experimental and numerical) characterising its local buckling behaviour (I-shape: [ 17 , 52 , 53 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 ], Box-shape: [ 17 , 29 , 53 , 54 , 55 , 56 , 58 , 63 , 72 , 75 , 76 , 82 , 85 , …”

“… The number of publications on the manufacturing design parameters of local buckling for different FRP composite geometries (Wall slenderness: Open-section [ 17 , 66 , 67 , 72 , 75 , 76 , 77 , 81 , 83 , 84 , 87 , 90 , 108 , 109 , 111 ], Plate [ 133 , 137 , 143 , 144 , 145 , 146 , 152 , 153 , 169 ], and Box [ 54 , 76 , 94 ], Cross-sectional aspect ratio: Open-section [ 63 , 64 , 65 , 68 , 69 , 74 , 86 , 111 ] and Box [ 63 , 106 , 108 ], Corner geometry: Open-section [ 61 , 89 ], Fibre angle: Open-section [ 53 , 58 , 74 , 78 , 80 , 87 , 97 , 113 , 114 ], Plate [ 131 , …”

Local buckling of laminated composite beams based on different plate theories

“…[4], [5]), FSDT (cf. [3]) and TSDT for I-beams as they would be typically applied in a civil engineering application.…”

Computation of Buckling Strength of Reinforced Concrete Columns by the Transfer-Matrix Method

“…Following the pioneer work by Euler, numerous steps have been made to solve that problem (Buket and Aysun , 2010;Hamid and Mohammad ,2010;Germain, 2006 ;Dinis and Frangopol, 2003) . Those work have contributed to the development of various approaches (Kazem and Gowhari , 2008;Mittelstedt, 2007;Kwak and Kim,2004; Kim and Yang, 1995). The most general are those which can be found in finite elements software which take into account material non linearity's and geometrical imperfections.…”