A shear beam finite element for the damping analysis of tubular laminated composite beams

Saravanos, Dimitris A.; Varelis, Dimitris; Plagianakos, Theofanis S.; Chrysochoidis, Nikolaos A.

doi:10.1016/j.jsv.2005.06.045

Cited by 37 publications

(45 citation statements)

References 19 publications

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“…Stemple and Lee developed an element that directly utilises the laminate stiffness matrix (

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) and incorporates shear effects by prescribing warping displacements parallel to deformed axis that are then superimposed over the cross section . Saravanos et al formulate a shear beam element for hollow, closed cross sections, with an arbitrary skin laminate lay‐up, with a focus on capturing the damping effects of the composite lay‐up . Kim et al formulated an element that with an arbitrary higher order polynomial displacement assumption, followed by minimising the elastic energy of the entire beam to obtain a solution .…”

Section: Computational Modelmentioning

confidence: 99%

“…22 Saravanos et al formulate a shear beam element for hollow, closed cross sections, with an arbitrary skin laminate lay-up, with a focus on capturing the damping effects of the composite lay-up. 23 Kim et al formulated an element that with an arbitrary higher order polynomial displacement assumption, followed by minimising the elastic energy of the entire beam to obtain a solution. 24 Kennedy et al use a homogenisation-based theory that expresses the stress and strains as a linear combination of the solution of pre-chosen solutions shapes, along with the contribution from the strain residual that accounts for the solution parts not captured by the fundamental solution.…”

Section: Structural Modelling Of Composite Kite Wingsmentioning

confidence: 99%

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Structural analysis and optimization of a tethered swept wing for airborne wind energy generation

Candade

Ranneberg

Schmehl³

2020

Wind Energy

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In this paper, we present an aero‐structural model of a tethered swept wing for airborne wind energy generation. The carbon composite wing has neither fuselage nor actuated aerodynamic control surfaces and is controlled entirely from the ground using three separate tethers. The computational model is efficient enough to be used for weight optimisation at the initial design stage. The main load‐bearing wing component is a nontypical “D”‐shaped wing‐box, which is represented as a slender carbon composite shell and further idealised as a stack of two‐dimensional cross section models arranged along an anisotropic one‐dimensional beam model. This reduced 2+1D finite element model is then combined with a nonlinear vortex step method that determines the aerodynamic load. A bridle model is utilised to calculate the individual forces as a function of the aerodynamic load in the bridle lines that connect the main tether to the wing. The entire computational model is used to explore the influence of the bride on the D‐box structure. Considering a reference D‐box design along with a reference aerodynamic load case, the structural response is analysed for typical bridle configurations. Subsequently, an optimisation of the internal geometry and laminate fibre orientations is carried out using the structural computation models, for a fixed aerodynamic and bridle configuration. Aiming at a minimal weight of the wing structure, we find that for the typical load case of the system, an overall weight savings of approximately 20% can be achieved compared with the initial reference design.

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“…Stemple and Lee developed an element that directly utilises the laminate stiffness matrix (

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Section: Computational Modelmentioning

confidence: 99%

Section: Structural Modelling Of Composite Kite Wingsmentioning

confidence: 99%

Structural analysis and optimization of a tethered swept wing for airborne wind energy generation

Candade

Ranneberg

Schmehl³

2020

Wind Energy

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“…Note that structural damping is a characteristic of the structure itself, so Equation (8) does not contain rotational effects. The modal damping ratio η in Equation (8) can be defined as the ratio of dissipation (damping) energy and maximum strain energy in each vibration period [27]:…”

Section: Calculation Of Structural Dampingmentioning

confidence: 99%

Sliding Mode Control of Active Trailing-Edge Flap Based on Adaptive Reaching Law and Minimum Parameter Learning of Neural Networks

et al. 2020

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Theoretical modeling and the sliding mode control (SMC) of an active trailing-edge flap of a wind turbine blade based on the adaptive reaching law are investigated. The blade is a single-celled thin-walled composite structure using circumferentially asymmetric stiffness (CAS) design, exhibiting displacements of flap-wise/twist coupling. A reduced structural model originated from the variation method is used to model the structure of the blade, the structural damping of which is computed. The trailing-edge flap is a rigid structure that is embedded in and hinged to the blade host structure, and it is driven by two pairs of pneumatic cylinders moving in reverse. Flutter suppression for the large-amplitude vibration of the blade tip is investigated based on an active trailing-edge flap structure and SMC algorithm using the adaptive reaching law. The controlled responses of flap-wise/twist displacements and control inputs (the angles of the trailing-edge flap) are illustrated, with obvious simulation effects demonstrated. An experimental platform for driving the pneumatic cylinders verifies the effectiveness of the control algorithm using the adaptive reaching law and the effectiveness of the selected pneumatic transmission scheme controlled by another adaptive SMC based on the minimum parameter learning of neural networks.

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“…[22]. The stiffness matrices K s1 ½ and K s2 ½ include the first-and second-order nonlinear terms, respectively, …”

Section: Sectionmentioning

confidence: 99%

“…Damping mechanics and specialty finite elements based on high-order layerwise kinematic assumptions capable of predicting damping in thick composite plates, and sandwich laminates and damped plates with constrained damping layers were subsequently reported by Saravanos and coworkers [20,21]. A theoretical framework for predicting the linear section damping matrices of composite blades with hollow laminated cross-sections was reported by Saravanos et al [22] and incorporated into a shear beam finite element of the so-called DAMPBEAM blade analysis code. The work was extended to include material coupling effects on the damping of composite blade structures [23].…”

Section: Introductionmentioning

confidence: 99%

Linearized Frequencies and Damping in Composite Laminated Beams Subject to Buckling

Chortis¹,

Varelis

Saravanos

2013

Journal of Vibration and Acoustics

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This paper considers the damped small-amplitude free-vibration of composite laminated strips subject to large in-plane forces and rotations. A theoretical framework is formulated for the prediction of the nonlinear damping of composite laminates subject to large Green-Lagrange axial strains and assuming a Kelvin viscoelastic solid. An extended beam finite element is developed capable of providing the nonlinear stiffness and damping matrices of the system. The linearized damped free-vibration equations associated with the deflected strip shape in the pre-and postbuckling region are presented. Numerical results quantify the strong geometric nonlinear effect of compressive in-plane loads on the modal damping and frequencies of composite strips. Measurements of the modal damping of a cross-ply glass/epoxy beam subject to buckling were also conducted and correlate well with the finite element predictions.

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A shear beam finite element for the damping analysis of tubular laminated composite beams

Cited by 37 publications

References 19 publications

Structural analysis and optimization of a tethered swept wing for airborne wind energy generation

Structural analysis and optimization of a tethered swept wing for airborne wind energy generation

Sliding Mode Control of Active Trailing-Edge Flap Based on Adaptive Reaching Law and Minimum Parameter Learning of Neural Networks

Linearized Frequencies and Damping in Composite Laminated Beams Subject to Buckling

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