Stress-Strain State of an Unsymmetrical Three-Layer Beam

Introduction. A three-layer structure, though having a small weight, possesses enough rigidity and strength to withstand various force and physical impacts of both static and dynamic nature. By altering the combination of materials and thicknesses of the loadbearing layers and the core, it is possible to achieve the desired physical and mechanical properties of a three-layer structure. In this regard, this paper investigates the stress-strain state of a three-layer beam of different thickness of loadbearing layers and height of the core.

Materials and Methods. The three-layer beam design based on the well-known calculation methodology is presented. A three-layer 70 cm long beam was examined as an example, its width was altered depending on the face size of the hexagonal cell of the core. The thickness of loadbearing layers was altered from 1 to 1.5 mm and the thickness of the core from 0.12 to 0.30 mm. The loadbearing layers were made of the AMG2-H (АМГ2-Н) aluminium alloy, and the hexagonal honeycomb core – of the D16-AT (Д16-АТ) aluminium alloy.

Results. Based on the obtained data, the graphs of the stresses and strains (deflections) alteration dependence on the distributed load were plotted for each of the tested specimens. The graphical dependences were given for the symmetrical and unsymmetrical three-layer beams.

Discussion and Conclusion. The obtained theoretical data on deformations (deflections) and stresses allowed determining the efficient combination of the loadbearing layers, which would make a three-layer beam efficient. Based on the analysis of this data, the conclusions on enhancing the three-layer beam efficiency were made. 

1. Kobelev VN, Kovarskiy LM, Timofeev SI. Calculation of Three-Layer Structures. Moscow: Mashino-stroenie; 1984. 304 р.

2. Dvoeglazov IV., Khaliulin VI. To the Question of Experimental Research of Strength of Folded Aggregates of Z-gofr Type on Transverse Compression. Bulletin of Samara State Aerospace University named after Academician S.P. Korolev (National Research University). 2012;11(5–2):275–280. https://doi.org/10.18287/2541-7533-2012-0-52(36)-275-281 (in Russ.).

3. Ivanov AA., Gofin MYa. Mechanics of Honeycomb Aggregates. Moscow: Moscow Forest Engineering Institute; 1989. 315 p. (in Russ.).

4. Ildiyarov EV. Experimental-Theoretical Studies of Stress-Strain State of three-Layer Roof Panel With Orthotropic Middle Layer. Structural Mechanics and Calculation of Structures. 2011;(6):11–15. (in Russ.).

5. Panin VF, Gladkov YuA. Constructions With Filler. Moscow: Mashinostroenie; 1991. P. 15–60. (in Russ.).

6. Paimushin VN. Theory of Stability of Three-Layer Plates and Shells (Stages of Development, Present State and Directions of Further Research). Izvestia RAS, Mechanics of Solid State. 2001;(2):148–162. URL: https://mtt.ipmnet.ru/ru/Issues/2001/2/148 (accessed: 04.09.2023). (in Russ.).

7. Vishtalov RI, Muselemov HM, Ustarkhanov OM. Determination of the Reduced Characteristics of Honeycomb Aggregates of Different Shapes. Bulletin of Dagestan State Technical University. Technical Sciences. 2016;42(3):155– 166. https://doi.org/10.21822/2073-6185-2016-42-3-155-166 (in Russ.).

8. Ustarkhanov OM, Alibekov MS, Ustarkhanov TO. Experimental Study of the Strength of Cone Filler for ThreeLayer Structures. Izvestiya of Higher Educational Institutions. Mechanical Engineering. 2014;(9):54–59. https://doi.org/10.18698/0536-1044-2014-9-54-59 (in Russ.).

9. Ustarkhanov OM, Muselemov HM, Ustarkhanov TO. Experimental Studies of Three-Layer Beams With Pyramidal Discrete Filler. Izvestiya of Higher Educational Institutions. Mechanical Engineering. 2016;(2):59–64. https://doi.org/10.18698/0536-1044-2016-2-59-64 (in Russ.).

10. Ustarkhanov OM, Kobelev VN, Kobelev VV, Abrosimov NA. Analysis of experimental study of three-layer beams with metal honeycomb filler and composite bearing layers. In: Collection of the International Scientific and Technical Conference "Modern Scientific and Technical Problems of Civil Aviation". Moscow: MGTUGA; 1999. P. 32–33. (in Russ.).