scholarly journals Inverse Identification of the Frequency-Dependent Mechanical Parameters of a Viscoelastic Core Layer Based on the Vibration Response

2017 ◽  
Vol 7 (5) ◽  
pp. 455 ◽  
Author(s):  
Wei Sun ◽  
Zhuo Wang ◽  
Rong Liu ◽  
Xianfei Yan
Keyword(s):  
Core Layer ◽  
Vibration Response ◽  
Mechanical Parameters ◽  
Inverse Identification ◽  
Frequency Dependent ◽  
Viscoelastic Core

Versatile hybrid sandwich composite combining large stiffness and high damping: spatial patterning of the viscoelastic core layer

2017 ◽  
Vol 141 (5) ◽  
pp. 3643-3643
Author(s):  
Marta Gallo ◽  
Renaud G. Rinaldi ◽  
Laurent Chazeau ◽  
Jean-Marc Chenal ◽  
François Ganachaud ◽  
...  
Keyword(s):  
Core Layer ◽  
Sandwich Composite ◽  
Spatial Patterning ◽  
Viscoelastic Core

Dynamic analysis of three-layer cylindrical shells with fractional viscoelastic core and functionally graded face layers

2020 ◽  
pp. 107754632096622
Author(s):  
Meisam Shakouri ◽  
Mohammad Reza Permoon ◽  
Abdolreza Askarian ◽  
Hassan Haddadpour
Keyword(s):  
Natural Frequency ◽  
Equations Of Motion ◽  
Cylindrical Shells ◽  
Ritz Method ◽  
Shear Deformation Theory ◽  
Core Layer ◽  
Functionally Graded ◽  
Viscoelastic Layer ◽  
Viscoelastic Core ◽  
Graded Layers

Natural frequency and damping behavior of three-layer cylindrical shells with a viscoelastic core layer and functionally graded face layers are studied in this article. Using functionally graded face layers can reduce the stress discontinuity in the face–core interface that causes a catastrophic failure in sandwich structures. The viscoelastic layer is expressed using a fractional-order model, and the functionally graded layers are defined by a power law function. Assuming the classical shell theory for functionally graded layers and the first-order shear deformation theory for the viscoelastic core, equations of motion are derived using Lagrange’s equation and then solved via Rayleigh–Ritz method. The obtained results are validated with those in the literature, and finally, the effects of some geometrical and material parameters such as length-to-radius ratio, functionally graded properties, radius and thickness of viscoelastic layer on the natural frequency, and loss factor of the system are considered, and some conclusions are drawn.

A four-node quadrilateral element for vibration and damping analysis of sandwich plates with viscoelastic core

2017 ◽  
Vol 21 (3) ◽  
pp. 1072-1118 ◽  
Author(s):  
Shanhong Ren ◽  
Guozhong Zhao
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Element Formulation ◽  
Sandwich Plates ◽  
Complex Eigenvalue ◽  
Constrained Layer Damping ◽  
Quadrilateral Element ◽  
Frequency Dependent ◽  
Viscoelastic Core ◽  
Rectangular Element

Constrained layer damping treatments have been widely used as an effective way for vibration control and noise reduction of thin-walled plates and shells. Despite extensive application in vibration and damping analysis of sandwich plates with viscoelastic core, the rectangular element is challenged by irregular structural forms in practical engineering. In this paper, a three-layer four-node quadrilateral element with seven degrees of freedom at each node is presented. Compared with classical rectangular element, the four-node quadrilateral element has stronger adaptability in complex structural forms and boundary conditions. Based on the layer-wise theory where the constrained layer and the base layer meet Kirchhoff theory and the viscoelastic layer satisfies first-order shear deformation theory, the finite element formulation of the sandwich plate with viscoelastic core is derived by the Hamilton principle in variational form and based on the generalization of the discrete Kirchhoff Quadrilateral plate element. The complex modulus model is employed to describe the viscoelastic core of sandwich plates, allowing for the material’s frequency dependent characteristics. The natural frequencies and associated modal loss factors are computed based on the complex eigenvalue problems. The frequency dependent characteristic of the viscoelastic core is considered and an iterative procedure is introduced to solve the nonlinear eigenvalue problem. At last, six verification numerical examples that include three sandwich beam-plates and three sandwich plates are provided to compare present method with experiment, analytical method, Galerkin method, finite element methods and commercial software (NASTRAN). The results show that the proposed finite element can accurately and efficiently simulate the sandwich plates treated with constrained layer damping with a variety of structural forms and boundary conditions.

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