PSI - Issue 72

Muhammad Zainnal Mutaqin et al. / Procedia Structural Integrity 72 (2025) 445–452

451

= ( + ) 2 2 =

(6)

where J (mm 4 ) is the second moment of the sectional area of the laminated beam. For three-point bending with force F (N) the maximum bending moment M = 1/4 FL (Nmm) is in the midpoint of the beam span L (mm), and the corresponding maximum stress in the facing σ fx (MPa) is given by the Equation 7. = 1 2 ( + )= 12 4 2 ( + ) 2 ( + )= 4 ( + ) (7) Based on the experimental three-point bending test, the structure of the panel sandwich is independent of the strain rate results (Palomba et al., 2019). The core layer damage did not exhibit significant changes prior to the failure stage, and the residual stiffness damage variable was unable to predict the fatigue time of the sandwich structure (Ma et al., 2021). The core damage caused by the crack density is independent of the external load, and the damage is minimal. The core damage caused by the crack length depends only on the load ratio, and a lower load ratio leads to a severe damage state (Ma et al., 2021). For honeycomb-corrugation hybrid core sandwich beams under three-point bending, four possible collapse modes are studied in analytical models: (a) face yielding or face wrinkling, (b) core shear, and (c) indentation (Zhang et al., 2022c). The failure of the sandwich beam is generally dictated by one of the competing collapse modes that depend on the given geometry parameter of the sandwich beam and the mechanical properties of the face sheet and hybrid core materials (Zhang et al., 2022c). 4. Conclusions Honeycomb sandwich panels have advantages in terms of strength, including high stiffness, high energy absorption, and excellent tensile and compressive properties. In the application as a leisure boat, the hull material has good potential. In the review of impact and bending testing, the variation in the combination of materials that make up the honeycomb sandwich panel greatly influences the overall strength of the sandwich structures. Several previous studies have demonstrated that the thickness and type of face sheet significantly influence the overall stiffness and strength of the honeycomb sandwich panel. Most structures in the honeycomb sandwich core are susceptible to shear and buckling damage. Additionally, honeycomb sandwich panels often experience debonding failure between the core layer and the face sheet. To increase the peeling strength of each layer of a sandwich structure, subsequent research is needed on the variations of the adhesive layer. A careful review of the material composition is required when selecting materials for constructing leisure boat hulls. Honeycomb sandwich panel material is subjected to an extreme working environment when used as a construction material on the hull of a leisure boat. Therefore, further research is necessary to investigate the corrosion and creep properties of this material. Additionally, research is also needed on the behavior of honeycomb sandwich panels in relevant environments, such as those with corrosive conditions and high humidity. 5. Acknowledgments This work was supported by the RKAT Universitas Sebelas Maret Year 2025, under the Research Scheme of “PENELITIAN KOLABORASI INTERNASIONAL” (KI -UNS), with research grant/contract no. 369/UN27.22/PT.01.03/2025. The authors highly acknowledge this support. References Abbadi, A., Azari, Z., Belouettar, S., Gilgert, J., Freres, P., 2010. Modelling the fatigue behaviour of composites honeycomb materials (aluminium/aramide fibre core) using four-point bending tests. Int. J. Fatigue 32, 1739 – 1747 Bulatović, S., Aleksić, V., Mladenović, M., 2023. Influe nce of temperature on impact toughness of hsla steels. Struct. Integ. Life 23, S91-S94 Carreño, A., Lloret, J., 2021. Environmental impacts of increasing leisure boating activity in Mediterranean coastal waters. Ocean Coast. Manag. 209, 105693 Chen, D., Lu, X., Wang, Z., Qu, Y., Ding, Q., 2024. Durability test study of laminated specimens for large glass fiber protective structures in