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This paper presents two approaches to modelling the vibrations of three-layer beams with asymmetric faces. Two sets of differential equations of motion for such composite are derived. Despite sharing a common displacement hypothesis, they differ significantly. The first is based on fundamental equilibrium conditions that must be satisfied at every beam cross-section (EE). The second is the result of applying a variational approach (VAR) and minimizing the composite’s energy in a global scale. In the presented computational example, both models are used to investigate the free vibration frequencies of a specific set of layered beams, and the obtained results are compared with FEM results. It should be emphasized that FEM models do not require any a priori assumed deformation hypothesis. Consequently, the presented calculations demonstrate not only the correctness and applicability of the presented modelling approaches but also the usefulness of the assumed hypothesis. The presented analysis shows that both the EE and VAR systems of motion are applicable to vibration analysis of sandwich beams in a wide range of typical design cases. As ‘typical’ composites one should consider asymmetric sandwich beams with relatively thin faces, where the core thickness is at least 25 times greater than thickness of any outer layers, and with any ratio of material properties of all layers. In less typical design cases, where the faces of the composite are only 10 times thinner than its core, the presented analytical solutions are still applicable to vibration analysis, but they may generate higher relative errors when compared to FEM. Based on the presented results, assessing such ‘unusual’ composites using VAR is not recommended. In such case the EE approach results should be considered as more predictable and closer to those obtained with FEM.
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Allen, H. G. (1969). Analysis and design of structural sandwich panels. Pergamon Press. (Crossref)
Birman, V. & Kardomateas, G. A. (2018). Review of current trends in research and applications of sandwich structures. Composites Part B: Engineering, 142, 221‒240. https://doi.org/10.1016/j.compositesb.2018.01.027 (Crossref)
Burton, W., & Noor, A. K. (1995). Assessment of computational models for sandwich panels and shells. Computer Methods in Applied Mechanics and Engineering, 124(1), 125‒151. https://doi.org/10.1016/0045-7825(94)00750-H (Crossref)
Carrera, E. (2000). An assessment of mixed and classical theories on global and local response of multilayered orthotropic plates. Composite Structures, 50(2), 183‒198. https://doi.org/10.1016/S0263-8223(00)00099-4 (Crossref)
Carrera, E. (2001). Developments, ideas, and evaluations based upon Reissner’s Mixed Variational Theorem in the modeling of multilayered plates and shells. Applied Mechanics Reviews, 54(4), 301‒329. https://doi.org/10.1115/1.1385512 (Crossref)
Carrera, E., & Brischetto, S. A. (2009). A Survey with Numerical Assessment of Classical and Refined Theories for the Analysis of Sandwich Plates. Applied Mechanics Reviews, 62(1), 010803. https://doi.org/10.1115/1.3013824 (Crossref)
Castanie, B. & Bouvet, C. & Ginot, M. (2020). Review of composite sandwich structure in aeronautic applications. Composites Part C: Open Access, 1, 100004. https://doi.org/10.1016/j.jcomc.2020.100004 (Crossref)
Chen, D., Li, X., Qu, Y., Yuan, H., Li, X. & Li, Y. (2026). Dynamic stiffness-based modelling for bandgap characteristics of corrugated-core sandwich meta-plate. International Journal of Mechanics Sciences, 311, 111261. https://doi.org/10.1016/j.ijmecsci.2026.111216 (Crossref)
Frostig, Y., & Shenhar, Y. (1995). High-order bending of sandwich beams with a transversely flexible core and unsymmetrical laminated composite skins. Composites Engineering, 5(4), 405‒414. https://doi.org/10.1016/0961-9526(95)93440-7 (Crossref)
Gajjala, R. R., & Jana, P. (2026). Optimization of sandwich plate with re-entrant auxetic core for improved performance under transverse impact loads. International Journal of Solids and Structures, 326, 113764. https://doi.org/10.1016/j.ijsolstr.2025.113764 (Crossref)
Galos, J., Das, R., Sutcliffe, M. P., & Mouritz, A. P. (2022). Review of balsa core sandwich composite structures. Materials & Design, 221, 111013. https://doi.org/10.1016/j.matdes.2022.111013 (Crossref)
Hu, H., Belouettar, S., Potier-Ferry, M., & Daya, E. M. (2008). Review and assessment of various theories for modeling sandwich composites. Composite Structures, 84, 282‒292. https://doi.org/10.1016/j.compstruct.2007.08.007 (Crossref)
Islami, D. P., Muzaqih, A. F., Adiputra, R., Prabowo, A. R., Firdaus, N., Ehlers, S., Braun, M., Jurkovic, M., Smaradhana, D. F., & Carvalho, H. (2024). Structural design parameters of laminated composites for marine applications: Milestone study and extended review on current technology and engineering. Results in Engineering, 24, 103195. https://doi.org/10.1016/j.rineng.2024.103195 (Crossref)
Kączkowski, Z. (2000). Płyty. Obliczenia statyczne. Arkady.
Le, V. T. & Ha, N. S. & Goo, N. S. (2021). Advanced sandwich structures for thermal protection systems in hypersonic vehicles: A review. Composites Part B: Engineering, 226, 109301. https://doi.org/10.1016/j.compositesb.2021.109301 (Crossref)
Li, M., Yu, J., Li, X., Chen, W., Xu, S., Shen, W., Zhao, Y., & Qiu, Y. (2026). A novel analytical model for vibration analysis of 3D-printed sandwich plate with graded pyramid lattice cores. Engineering Structures, 353(A), 122152. https://doi.org/10.1016/j.engstruct.2026.122152 (Crossref)
Magnucka-Blandzi, E., Kędzia, P., & Smyczyński, M. J. (2018). Unsymmetrical sandwich beams under three-point bending – Analytical studies. Composite Structures, 202, 539‒544. https://doi.org/10.1016/j.compstruct.2018.02.086 (Crossref)
Magnucki, K., & Szyc, W. (2012). Wytrzymałość i stateczność belek i płyt trójwarstwowych z rdzeniem z pianki aluminiowej. Wydawnictwo Politechniki Poznańskiej.
Magnucki, K., Magnucka-Blandzi, E., & Sowiński, K. (2024). Buckling and free flexural vibration of an asymmetric sandwich beam with a functionally graded core. Archives of Mechanics, 76(4), 335‒355. https://doi.org/10.24423/aom.4532
Magnucki, K., Magnucka-Blandzi, E., Lewiński, J., & Milecki, S. (2019). Analytical and numerical studies of an unsymmetrical sandwich beam – bending, buckling and free vibration. Engineering Transactions, 67(4), 491‒512. https://doi.org/10.24423/EngTrans.1015.20190725
Mouritz, A., Gellert, E., Burchill, P., & Challis, K. (2001). Review of advanced composite structures for naval ships and submarines. Composite Structures, 53(1), 21‒42. https://doi.org/10.1016/S0263-8223(00)00175-6 (Crossref)
Noor, A. K. & Burton, W. S. & Bert, C. W. (1996). Computational Models for Sandwich Panels and Shells. Applied Mechanics Reviews, 49(3), 155‒199. https://doi.org/10.1115/1.3101923 (Crossref)
Plantema, F. J. (1966). Sandwich Construction: The Bending and Buckling of Sandwich Beams, Plates and Shells. John Wiley & Sons.
Vu, V. T., & Tran T. T. (2026) Dynamic response of honeycomb core sandwich plates assuming sinusoidal top face sheet subjected to half-car moving load resting on elastic foundation. Thin-Walled Structures, 221, 114486. https://doi.org/10.1016/j.tws.2026.114486 (Crossref)
Yuan, H. & Wu, X. & Bai, J. & Zhang, J. (2025) Piercing failure behaviour of foam core sandwich plates. Engineering Structures, 345(B), 121538. https://doi.org/10.1016/j.engstruct.2025.121538 (Crossref)
Zenkert, D. (1995). An introduction to sandwich structures. Chameleon
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