Abstract
A modified estimation method for the dynamic mechanical properties of viscoelastic materials via asymmetrical sandwich specimens is presented. In contrast to the traditional vibrating cantilever beam test method (VCBTM), the proposed method allows asymmetrical base beams in sandwich specimens. Based on the complex stiffness method, complex parameters are introduced for general sandwich configurations. Calculation formulas for loss factor and shear modulus of the core material are presented. The effectiveness of this approach is validated numerically and experimentally by analysis of one symmetrical sandwich beam specimen and two specimens with asymmetrical thicknesses and materials. It is shown that dynamic mechanical parameters of the core material can be obtained regardless of sandwiches’ symmetry. The proposed method breaks the symmetrical criteria for sandwich specimens and may provide a wider application to measure viscoelastic materials’ dynamic properties.
Highlights
Benefiting from the high damping performance, viscoelastic materials have been widely utilized in aerospace and vehicle transport industries
A modified evaluation method has been presented in this paper for the dynamic mechanical properties of viscoelastic materials via asymmetrical sandwich specimens, and some improvement has been made for the vibrating cantilever beam test method (VCBTM)
With the asymmetry of thickness and material of base beams taken into account, 5
Summary
Benefiting from the high damping performance, viscoelastic materials have been widely utilized in aerospace and vehicle transport industries. Ghidelli et al [23] extracted the elastic moduli of both layers of bilayer microcantilevers from stiffness measurements by nanoindentation technique They determined the residual stress of double clamped bilayer micro beams, which plays an important role in surface effects on microscale structures. For bulk-like materials, the VCBTM is a convenient and effective method by which both loss factors and moduli can be extracted from modal vibration data using bilayer or sandwich beam specimens. As an extension of the VCBTM, residual stress in the interface of different layers will not be considered since shear deformation in the viscoelastic core is predominant during the vibration of sandwiches This method will be helpful to avoid the waste in the process of specimen preparation and can enrich the experimental data. Comparisons and discussions of the experimental results are presented
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