Vibration characteristics of circular composite sandwich cylindrical shells with soft core

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In this paper, the dynamic performance of Multi‐layered Sandwich Composite Cylindrical Open Shells (MSCCOS) with double‐layered soft cores is analyzed for the first time by adopting the First‐order Shear Deformation Theory (FSDT). For accomplishing this aim, vibration differential equations of MSCCOS are derived based on Hamilton's variance principle. Then, the closed‐form Navier solution is introduced to obtain the numerical results of differential equations. Subsequently, the effectiveness and accuracy are discussed by several comparisons. Ultimately, the dramatic effect of different structural and material parameters on natural frequencies and associated loss factors is investigated and described vividly. Because shear deformation and rotary inertia of all layers are considered in vibration differential equations, thin and moderately thick MSCCOS could be researched, and some interesting discoveries for the dynamic performance of MSCCOS are derived.Highlights A vibration model of five‐layered composite open shell was obtained. The optimal structure parameters maximizing the damping properties are shown. Dynamics properties of five‐layered composite open shell are presented.

“…The equations of motion of the MSCCOS are derived based on the Hamilton principle 40

\int_{t_{0}}^{t_{1}} ((), italicδT goodbreak- italicδU) goodbreak= 0

where the expressions of U and T are:

U goodbreak= \frac{1}{2} \sum_{i = 1}^{5} \int_{0}^{θ_{0}} \int_{0}^{a} \int_{- h_{i} / 2}^{h_{i} / 2} ((), ε_{xx}^{(i)} σ_{xx}^{(i)} goodbreak+ ε_{θθ}^{(i)} σ_{θθ}^{(i)} goodbreak+ ε_{xθ}^{(i)} σ_{xθ}^{(i)} goodbreak+ γ_{θz}^{(i)} τ_{θz}^{(i)} goodbreak+ γ_{xz}^{(i)} τ_{xz}^{(i)}) R_{i} italicdzdxdθ

T goodbreak= \frac{1}{2} \sum_{i = 1}^{5} \int_{0}^{θ_{0}} \int_{0}^{a} R_{i} ρ_{i} h_{i} ([], {(\frac{\partial w}{\partial t})}^{2} goodbreak+ {(\frac{\partial u_{i}}{\partial t})}^{2} goodbreak+ {(\frac{\partial v_{i}}{\partial t})}^{2} goodbreak+ \frac{h_{i}^{2}}{12} ([], {(\frac{\partial α_{i}}{\partial t})}^{2} goodbreak+ {(\frac{\partial β_{i}}{\partial t})}^{2}))

…”

Section: Equation Of Motionmentioning

confidence: 99%

Dynamic performance of multi‐layered composite sandwich open cylindrical shells with double‐layered soft cores

Zhai,

Chang

2024

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“…Compared with the equivalent monolayer theory, LW theory was more appropriate for the analysis of composite component with medium and above thickness. [ 23 ] A LW model consisting of multiple interacting shell units was established to capture the intralaminar in‐plane tension distribution under different compaction conditions, as shown in Figure 1. U‐shaped shells were stacked in a column and each shell unit represented a layer of material with a given thickness of 0.1 mm.…”

Section: Layerwise Shell Modelingmentioning

confidence: 99%

Composite component incremental consolidation for fiber waviness inhibition and its effect on damage progression of curved beams

Zhang

et al. 2023

Severe fiber waviness defect often occurs during the consolidation process of fiber reinforced polymer composite component, which arises from that multiple interactional plies start to slide simultaneously and out‐of‐control under sufficient pressure. In this study, based on the significant in‐plane tension gradient along thickness of viscoelastic composite, a concept of incremental consolidation was proposed to actively inhibit fiber waviness in prepreg‐based composite component. Via applying a series of tiny step pressures continuously, plies were triggered to slide and consolidate layer by layer from top to bottom with a just‐right in‐plane tension and concurrent stresses relaxation. Incremental consolidation avoided the complex interaction among plies and allowed in‐plane tension to be significantly reduced by 165 times compared with autoclave processing with a constant pressure. The fiber waviness defects in a typical wing spar were successfully inhibited by the proposed method. The failure load of the component increased by 1.5 times and curved beam strength increased by 1.1 times while elastic displacement increased by 75%. The inhibition method was highly effective, easy to implement and affordable, which showed considerable promise to improve the manufacturability of the primary structural composite components.

“…A regular sandwich construction consists of a core embedded with a couple of face layers. 1 Numerous core designs have been used in sandwich structures, including honeycomb, 2 soft cores, 3 elastomers, 4 and bio-inspired cores .5 In composite sandwich structures, the core layer transfers the shear stress throughout the structure, boosting the composite's damping property and high bending stiffness. Generally, it has high stiffness in out-of-plane direction and the greatest shear strength in longitudinal conditions.…”

Section: Introductionmentioning

confidence: 99%

Free and forced vibration response of a laminated composite sandwich beam with dual honeycomb core: Numerical and experimental study

Thanikasalam,

Ramamoorthy

2023

Free and forced vibration characteristics of composite sandwich beams with single‐core (SC) and dual‐core (DC) are investigated in this study. The wet hand‐layup technique is followed to make the composite face sheet, and honeycomb cores are 3D printed using the fused filament fabrication method. The natural frequencies of SC and DC sandwich beams were measured using experimental modal tests and validated through a three‐dimensional finite‐element model. Also, parametric studies on the geometry of composite structures are performed to scrutinize the effect of DC sandwich beams with different ply orientations, length‐to‐breadth ratios, core thickness, and core cell wall thickness. In addition, the transverse vibration responses of SC and DC sandwich beams are examined under harmonic force excitations at different end conditions. The study result shows that the sandwich beam's vibration behavior is enhanced by the inclusion of a core.