Free vibrational characteristics of grid-stiffened truncated composite conical shells

Zarei, Masoumeh; Rahimi, Gholam Hossein; Hemmatnezhad, M.

doi:10.1016/j.ast.2020.105717

Cited by 42 publications

(10 citation statements)

References 43 publications

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“…Experimental studies are expensive, time-consuming and require manpower while theoretical studies reduce the cost, time and manpower. Therefore, further theoretical studies are required for characterizing the vibration performance of different fiber orientations of FRPCs [ 44 ]. In this section, the challenges associated with the existing theoretical models and the better possible ways to enhance those challenges are discussed.…”

Section: Theoretical Modelingmentioning

confidence: 99%

Temperature-Frequency–Dependent Viscoelastic Properties of Neat Epoxy and Fiber Reinforced Polymer Composites: Experimental Characterization and Theoretical Predictions

et al. 2020

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In general, aerospace structures manufactured using fiber reinforced polymer composites are exposed to fluctuating temperatures and subjected to cyclic loading during their service life. Therefore, studying the temperature-frequency dependent properties of composites for different fiber orientations is essential. However, such experiments are expensive, time-consuming and labor-intensive while theoretical models minimize these issues, but temperature-frequency-dependent viscoelastic models for predicting the full-range of the storage and loss moduli curves of composites are limited. In this study, the dynamic mechanical properties of a neat epoxy resin, unidirectional ([0°]6, [45°]6 and [90°]6), symmetric angle-ply [+45°/−45°/+45°]s and quasi-isotropic [±45°/0°/90°]s carbon/epoxy and glass/epoxy composite panels were investigated. Experiments were performed from room temperature (approximately 35 °C) to 160 °C at five different frequencies (1, 10, 20, 33 and 50 Hz). Two parameter viscoelastic models as function of temperature and frequency were used, and their applicability in predicting the storage and loss moduli for the entire region of the temperature curve is shown. The storage modulus values were compared and validated against the static flexural modulus values coupled with scanning electron microscopy analysis. The flexural and storage moduli values were found to be higher for [0°]6 carbon/epoxy composites, while the activation energy values were found to be higher in the case of [+45°/−45°/+45°]s carbon/epoxy composites compared with epoxy resin and other laminates in different orientations. The predicted results were in reasonably good agreement with the experiments. Both experimental and modeling approaches used in this study are highly valuable for designing aerospace composites for harsh in-service loading conditions.

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Section: Theoretical Modelingmentioning

confidence: 99%

Temperature-Frequency–Dependent Viscoelastic Properties of Neat Epoxy and Fiber Reinforced Polymer Composites: Experimental Characterization and Theoretical Predictions

et al. 2020

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“…Recently Zarei et al. 40 investigated vibrational behavior of the grid stiffened conical shell using experimental, numerical, and analytical methods.…”

Section: Introductionmentioning

confidence: 99%

Buckling behavior of grid stiffened composite conical shells subjected to the lateral pressure

Zarei

Rahimi

2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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This paper presents the buckling behavior of the grid stiffened composite conical shell subjected to the lateral pressure. A smeared method is employed to equivalent grid structure into a layer. For this purpose, a typical unit cell is chosen for analyzing forces and moments on it. Therefore equivalent stiffness parameters due to the grid structure are determined. By determining the stiffness parameters of the shell and superimposing with those of the stiffeners, equivalent stiffness of the whole structure is obtained. Governing equations are established based on the Donnell shell theory. The power series method is used to extract the buckling load of the stiffened shell. To validate obtained results, a 3 D finite element model is built using ABAQUS software. The comparison showed that the analytical solution is qualified enough to study the buckling behavior of the grid stiffened composite conical shell. Through this study, the effect of a set of important parameters due to stiffeners like stiffener orientation angle, the number of stiffeners, and due to due to shell like lamination angle and semi-vertex angle are investigated, and finally are presented based on this study results.

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“…It was shown that Compositesandwich cylindrical shells with circumferential grid cores are the most efficient structures. Recently, the free vibrational behavior of composite conical shells stiffened by bevel stiffeners is analytically, numerically and experimentally studied by Zarei et al [37].…”

Section: Introductionmentioning

confidence: 99%

Investigation on the free vibration behavior of sandwich conical shells with reinforced cores

Zarei

Rahimi

Shahgholian‐Ghahfarokhi

2021

Jnl of Sandwich Structures & Materials

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The free vibration behavior of sandwich conical shells with reinforced cores is investigated in the present study using experimental, analytical, and numerical methods. A new effective smeared method is employed to superimpose the stiffness contribution of skins with those of the stiffener in order to achieve equivalent stiffness of the whole structure. The stiffeners are also considered as a beam to support shear forces and bending moments in addition to the axial forces. Using Donnell’s shell theory and Galerkin method, the natural frequencies of the sandwich shell are subsequently derived. To validate analytical results, experimental modal analysis (EMA) is further conducted on the conical sandwich shell. For this purpose, a method is designed for manufacturing specimens through the filament winding process. For more validation, a finite element model (FEM) is built. The results revealed that all the validations were in good agreement with each other. Based on these analyses, the influence of the cross-sectional area of the stiffeners, the semi-vertex angle of the cone, stiffener orientation angle, and the number of stiffeners are investigated as well. The results achieved are novel and can be thus employed as a benchmark for further studies.

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Free vibrational characteristics of grid-stiffened truncated composite conical shells

Cited by 42 publications

References 43 publications

Temperature-Frequency–Dependent Viscoelastic Properties of Neat Epoxy and Fiber Reinforced Polymer Composites: Experimental Characterization and Theoretical Predictions

Temperature-Frequency–Dependent Viscoelastic Properties of Neat Epoxy and Fiber Reinforced Polymer Composites: Experimental Characterization and Theoretical Predictions

Buckling behavior of grid stiffened composite conical shells subjected to the lateral pressure

Investigation on the free vibration behavior of sandwich conical shells with reinforced cores

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