Cured Shape of Cross-Ply Composite Thin Shells

Abstract

For a composite laminated plate, it has been found that classical laminate theory (CLT) can not always predict the final cured shape correctly and geometric nonlinearity must be considered. For composite laminated shells, experiments show that the cured shape depends on stacking sequence, radius, thickness, and size. This paper investigates the cured shape of several cross-ply composite shells. The cured shape of a cross-ply shell is generally cylindrical. A model is established to predict the cured shape. The model is based on the Rayleigh-Ritz energy method and considers geometric nonlinearity. Modeling and experiment show that, for certain stacking sequences, the generator of the cured shape may be orthogonal to the original generator, while other stacking sequences can lead to deeper or shallower cured shapes. The predictions of the model are very close to the results of FEM analysis and experiment. This model can be used as a guide in the manufacture of unsymmetric cross-ply laminates.

Finite Element Analysis of Multi-stable Structures

“…It is potentially suitable for a wide variety of systems, such as morphing aircraft (Yokozeki et al, 2006;Diaconu et al, 2008;Schultz, 2008), deployable structures (Lei & Yao, 2010) and mechanical switches. The studies of multi-stable structures reported in open literatures are dominated by the bi-stable unsymmetric composite laminates (Jun & Hong, 1992 Hyer, 1998;Maenghyo et al,1998;Hufenbach et al, 2002Hufenbach et al, , 2006Ren, & Parvizi-Majidi, 2003Gigliotti et al, 2004;Dai et al 2007;Etches etal., 2009). A typical bi-stable composite laminate is shown as in Fig.1, which means that applying an external force the room temperature cylindrical shape can be snapped into another cylinder with curvature of equal magnitude and opposite sign.…”

Effect of initial tool-plate curvature on snap-through load of unsymmetric laminated cross-ply bistable composites

“…Bistable composites have two stable shape (cylindrical shapes [1][2][3][4][5][6][7] or saddle shapes [8]) as a result of the coupling effect between their residual stress and geometric nonlinearity. These composites can be snapped through (i.e.…”

Generalized curvature tailoring of bistable CFRP laminates by curing on a cylindrical tool-plate with misalignment

“…Originally, Hyer [1,3] proposed the model for cross-ply laminate which is based on the polynomial displacement field and von-Karman non-linearity. This analytical modeling technique proposed by Hyer has been extended to various bistable panel problems, such as approximation of bifurcation temperature/side length [4][5][6], deformation behavior of angle-ply laminate [6,7], slippage effect between laminate and tool plate [8,9], identification of snap-though force [10,11], and initial curvature effect [12][13][14].…”

“…The effect of initial curvature on bistable structures has been discussed by Ren et al [12], Pirrera et al [13], and Ryu et al [14]. Ryu et al [14] shows that the final curvature of a bistable CFRP cross-ply laminate can be easily predicted because the final curvature of the laminate with initial curvature can be expressed as the sum of the tool-plate curvature and final curvature of the laminate without initial curvature.…”

“…Ryu et al [14] shows that the final curvature of a bistable CFRP cross-ply laminate can be easily predicted because the final curvature of the laminate with initial curvature can be expressed as the sum of the tool-plate curvature and final curvature of the laminate without initial curvature. However, initial curvature was limited to tailoring the curvature of only one state of the two equilibrium states [12][13][14]. Therefore, the curvature of the other state mode cannot be tailored in the bistable CFRP cross-ply laminates as shown in Fig.…”