A four-unknown higher-order shear deformation theory for the analysis of bending in sigmoid-FGM plates
Abstract
An In this paper, the bending analysis of sigmoid functionally graded materials (S-FGM) plates is presented using four-variable high-order shear deformation theory. In this present theory, the number of unknown functions has simply been reduced from five to four compared to other shear deformation theories, it does not require shear correction factors and satisfies the conditions of zero shear stresses for the top and bottom surface of the plate, knowing that the variation of shear stresses is parabolic through the thickness. The equilibrium equations of this present theory are derived from the principle of virtual work, and the Navier solution is used to solve these equations. For this S-FGM plate, according to the power law, the materials are distributed in terms of volume fractions of the constituents, and their properties are gradually varied in the thickness direction. This analytical study gave very satisfactory results, and the comparison between the numerical results obtained from the present theory and those obtained from the classical plate theory (CPT) and high-order shear deformation theories (HSDTs) demonstrated the simplicity, accuracy, and reliability of this presented theory in analyzing the static bending behavior of thick S-FGM plates.
References
Abdulrazzaq, M., A., Fenjan, R., M., Ahmed, R., A., Faleh, N., M. 2020. Thermal buckling of nonlocal clamped exponentially graded plate according to a secant function based refined theory. Steel Compos Struct, 35(1), pp.147-157. Available at: https://doi:10.12989/scs.2020.35.1.147
Ahmed, R., A., Fenjan, R., M., Faleh, N., M. 2019. Analyzing post-buckling behavior of continuously graded FG nanobeams with geometrical imperfections. Geomechanics and Engineering, 17(2), pp.175-180. Available at: https://doi: 10.12989/gae.2019.17.2.175
Avcar, M. 2015. Effects of rotary inertia shear deformation and non-homogeneity on frequencies of beam. Struct. Eng. Mech,55(4), pp.871-884. Available at: https://doi:10.12989/sem.2015.55.4.871
Beldjelili, Y., Tounsi, A., Mahmoud, S., R. 2016. Hygro-thermo-mechanical bending of S-FGM plates resting on variable elastic foundations using a four-variable trigonometric plate theory. Smart Structures and Systems, 18(4), pp.755-786. Available at: https://doi: 10.12989/sss.2016.18.4.755
Birman, V., Keil, T., Hosder, S. 2013. Functionally graded materials in engineering. In: S Thomopoulus, V Birman and GM Genin (eds) Structural interfaces and attachments in biology. New York: Springer, pp.19–41. Available at: https://doi: 10.1007/978-1-4614-3317-0_2
Boukhari, A., Ait Atmane, H., Houari, M., S., A., Tounsi, A., AddBedia, E., A., Mahmoud, S., R. 2016. An efficient sheadeformation theory for wave propagation of functionally gradedmaterial plates. Struct. Eng. Mech, 57(5), pp.837-859. Available at: https://doi: 10.12989/sem.2016.57.5.837
Dai, H., L., Rao, Y., N., Dai, T. 2016. A review of recent researches on FGM cylindrical structures under coupled physical interactions. Compos Struct,152, pp.199–225. Available at: https://doi: 10.1016/j.compstruct.2016.05.042
Dehshahri, K., Nejad, M., Z., Ziaee, S., Niknejad, A., Hadi, A. 2020. Free vibrations analysis of arbitrary threedimensionally FGM nanoplates. Adv. Nano Res, 8(2), pp.115-134. Available at: https://doi: 10.12989/anr.2020.8.2.115
Duc, N., D., Quang, V., D., Anh, V., T., T. 2017. The nonlinear dynamic and vibration of the S-FGM shallow spherical shells resting on an elastic foundations including temperature effects. Int. J. Mech. Sci, 123,pp. 54–63. Available at: https://doi: 10.1016/j.ijmecsci.2017.01.043
Eltaher, M., A., Alshorbagy, A., E., Mahmoud, F., F. 2013. Determination of neutral axis position and its effect on natural frequencies of functionally graded macro/nanobeams. Composite Structures, 99, pp.193-201. Available at: https://doi: 10.1016/j.compstruct.2012.11.039
Fallah, A., Aghdam, M., M., Kargarnovin, M., H. 2013. Free vibration analysis of moderately thick functionally graded plates on elastic foundation using the extended Kantorovich method. Arch. Appl. Mech, 83(2), pp.177-191. Available at: https://doi: 10.1007/s00419-012-0645-1
Hosseini-Hashemi, S., Rokni Damavandi Taher, H., Akhavan, H., Omidi, M. 2010. Free vibration of functionally graded rectangular plates using first-order shear deformation plate theory. Appl. Math. Model, 34(5), pp.1276-1291. Available at: https://doi: 10.1016/j.apm.2009.08.008
Hosseini-Hashemi, S., Fadaee, M., Atashipour, S., R. 2011. A new exact analytical approach for free vibration of ReissnerMindlin functionally graded rectangular plates. Int. J. Mech.Sci,53(1), pp.11-22. Available at: https://doi: 10.1016/j.ijmecsci.2010.10.002
Kar, V., R., Panda, S., K. 2015. Nonlinear flexural vibration of shear deformable functionally graded spherical shell panel. Steel Compos. Struct, Int. J., 18(3), pp.693-709. Available at: https://doi: 10.12989/scs.2015.18.3.693
Karakoti, A., Pandey, S., Kar, V., R. 2022. Nonlinear transient analysis of porous P-FGM and S-FGM sandwich plates and shell panels under blast loading and thermal environment. Thin-Walled Structures,173, 108985. Available at: https://doi: 10.1016/j.tws.2022.108985
Karami, B., Karami, S. 2019. Buckling analysis of nanoplate-type temperature-dependent heterogeneous materials. Advances in Nano Research, 7(1), pp.51-61. Available at: https://doi: 10.12989/anr.2019.7.1.051
Kumar, A., Pandey, S. 2024. Transient analysis of size-dependent S-FGM micro-folded plates based on exact shear correction factor in the thermal environment. Arch Appl Mech, 94, pp.1335–1357. Available at: https://doi: 10.1007/s00419-024-02578-6
Kurpa, L., Shmatko, T., Awrejcewicz, J., Timchenko, G., Morachkovska, I. 2023, Analysis of Free Vibration of Porous Power-law and Sigmoid Functionally Graded Sandwich Plates by the R-functions Method. Journal of Applied and Computational Mechanics,9(4), pp.1144-1155. Available at: https://doi: 10.22055/jacm.2023.43435.4082
Mechab, I., Ait Atmane, H., Tounsi, A., Belhadj, H., A., Adda Bedia, El-A. 2010. A two variable refined plate theory for the bending analysis of functionally graded plates. Acta Mech Sin, 26, pp.941–949. Available at: https://doi: 10.1007/s10409-010-0372-1
Pandey, H., K., Agrawal, H., Panda, S., K., Hirwani, C., K., Katariya, P., V., Dewangan, H., C. 2020. Experimental and numerical bending deflection of cenosphere filled hybrid (Glass/Cenosphere/Epoxy) composite. Struct. Eng.Mech,73(6),pp.715-724.Available at: https://doi: 10.12989/sem.2020.73.6.715
Reddy, J., N.2000. Analysis of functionally graded plates. Int. J. Numer. Method. Eng, 47(1-3), pp.663-684. Available at: https://doi: 10.1002/(SICI)1097-0207(20000110/30)47:1/3<663::AID-NME787>3.0.CO;2-8
Reddy, J., N. 1984. A simple higher-order theory for laminated composite plates. J Appl Mech,51, pp.745–52. Available at: https://doi: 10.1115/1.3167719
Selmi, A.2020. Dynamic behavior of axially functionally graded simply supported beams. Smart Struct. Syst, 25(6), pp.669-678. Available at: https://doi: 10.12989/sss.2020.25.6.669
Singh, S., J., Harsha, S., P.2019. Nonlinear dynamic analysis of sandwich S-FGM plate resting on pasternak foundation under thermal environment. European Journal of Mechanics - A/Solids,76, pp.155-179. Available at: https://doi: 10.1016/j.euromechsol.2019.04.005
Singh, S., J., Harsha, S., P.2020.Thermo-mechanical analysis of porous sandwich S-FGM plate for different boundary conditions using Galerkin Vlasov's method: A semi-analytical approach. Thin-Walled Structures, 150, 106668. Available at: https://doi: 10.1016/j.tws.2020.106668
Sobhy, M. 2013. Buckling and free vibration of exponentially graded sandwich plates resting on elastic foundations under various boundary conditions. Compos. Struct, 99, pp.76-87. Available at: https://doi: 10.1016/j.compstruct.2012.11.018
Taczała, M., Buczkowski, R., Kleiber, M. 2022. Analysis of FGM plates based on physical neutral surface using general third-order plate theory. Composite Structures,301, 116218. Available at: https://doi: 10.1016/j.compstruct.2022.116218
Tao, C., Dai, T. 2021. Analyses of thermal buckling and secondary instability of post-buckled S-FGM plates with porosities based on a meshfree method. Applied Mathematical Modelling, 89, pp.268-284. Available at: https://doi: 10.1016/j.apm.2020.07.032
Thai, H., T., Choi, D., H.2012.A refined shear deformation theory for free vibration of functionally graded plates on elastic foundation. Compos. Part B: Eng, 43(5), pp.2335-2347. Available at: https://doi: 10.1016/j.compositesb.2011.11.062
Thai, H., T., Kim, S., E. 2013. A simple quasi-3D sinusoidal shear deformation theory for functionally graded plates. Compos. Struct, 99, pp.172-180. Available at: https://doi: 10.1016/j.compstruct.2012.11.030
Touratier, M. 1991. An efficient standard plate theory. Int J Eng Sci. 29(8): 901–16. Available at: https://doi:10.1016/0020-7225(91)90165-Y
Copyright (c) 2025 Fatima Zohra Djidar, Habib Hebali

This work is licensed under a Creative Commons Attribution 4.0 International License.
Proposed Creative Commons Copyright Notices
Proposed Policy for Military Technical Courier (Journals That Offer Open Access)
Authors who publish with this journal agree to the following terms:
Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).
