PSI - Issue 72

H.G.E. da Silva et al. / Procedia Structural Integrity 72 (2025) 26–33

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Table 6. Numerical and experimental values of t and sf for each configuration during 3PB tests. Configuration  (MPa)  f (MPa)

Experimental average

1.11 1.29

119.50 141.33 18.3% 100.90 141.51 40.2%

1

Numerical

Relative deviation Experimental average

16.2%

1.20 1.29 7.5%

2

Numerical

Relative deviation

4. Conclusions This study addressed the experimental and numerical behavior of composite sandwich structures subjected to 3PB tests. Experimental results revealed minimal differences in performance between the two skin configurations studied, with configuration 2 showing marginally better overall mechanical properties. Stress analysis revealed that maximum adhesive shear stresses occurred near the punch area but remained uniform along significant portions of the structure. Similarly, the Von Mises stresses and Tsai-Wu criteria highlighted localized failures in both the skins and the core under peak loads, with no significant differences between configurations. Numerical and experimental P -  curves closely matched, validating the CZM approach by achieving deviations of less than 20% for critical parameters. From a design perspective, the findings emphasize the negligible impact of skin ply orientation on the adhesive and core stress distributions. The findings contribute to advancing lightweight, high-performance materials in industries such as aerospace, automotive, and energy, where optimized material usage and structural efficiency are critical. Future work could explore dynamic loading conditions, environmental factors, and alternative material configurations. References Allen, H. G., 1969. Analysis and design of structural sandwich panels: the commonwealth and international library: structures and solid body mechanics division. London, Pergamon Press Ltd. Barenblatt, G. I., 1959. The formation of equilibrium cracks during brittle fracture. General ideas and hypothesis. Axisymmetrical cracks. Journal of Applied Mathematics and Mechanics 23: 622-636 Barenblatt, G. I., 1962. The Mathematical Theory of Equilibrium Cracks in Brittle Fracture. Advances in Applied Mechanics 7: 55-129 Djama, K., Michel, L., Ferrier, E., Gabor, A., 2020. Numerical modelling of a truss core sandwich panel: Influence of the con nectors’ geometry and mechanical parameters on the mechanical response. Composite Structures 245 Dugdale, D. S., 1960. Yielding of steel sheets containing slits. Journal of the Mechanics Physics of Solids 8(2): 100-104 Farrokhabadi, A., Ahmad Taghizadeh, S., Madadi, H., Norouzi, H., Ataei, A., 2020. Experimental and numerical analysis of novel multi-layer sandwich panels under three point bending load. Composite Structures 250 Gao, X., Zhang, M., Huang, Y., Sang, L., Hou, W., 2020. Experimental and numerical investigation of thermoplastic honeycomb sandwich structures under bending loading. Thin-Walled Structures 155: 106961 Gupta, A. K., Velmurugan, R., Joshi, M., 2017. Numerical and experimental study of multimode failure phenomena in GFRP laminates of different lay-ups. International Journal of Crashworthiness 23(1): 87-99 Lacy, T. E., Hwang, Y., 2003. Numerical modeling of impact-damaged sandwich composites subjected to compression-after-impact loading. Composite Structures 61(1-2): 115-128 Magnucki, K., Lewinski, J., Far, M., Michalak, P., 2020. Three-point bending of an expanded-tapered sandwich beam — Analytical and numerical FEM study. Mechanics Research Communications 103: 103471 Mohammadkhani, P., Jalali, S. S., Safarabadi, M., 2021. Experimental and numerical investigation of Low-Velocity impact on steel wire reinforced foam Core/Composite skin sandwich panels. Composite Structures 256: 112992 Mostafa, A., Shankar, K., Morozov, E. V., 2014. Behaviour of PU-foam/glass-fibre composite sandwich panels under flexural static load. Materials and Structures 48(5): 1545-1559 Olsson, K. J. P. i. D., 1987. GRP-Sandwich Design and Production in Sweden. Development and Evaluation. 3 Thiagarajan, S., Munusamy, R., 2020. Experimental and numerical study of composite sandwich panels for lightweight structural design. International Journal of Crashworthiness: 1-12 Upreti, S., Singh, V. K., Kamal, S. K., Jain, A., Dixit, A., 2020. Modelling and analysis of honeycomb sandwich structure using finite element method. Materials Today: Proceedings 25: 620-625 Vinson, J. R. (1999). The behavior of sandwich structures of isotropic and composite materials. London, Taylor and Francis Routledge Wang, Z., Li, Z., Xiong, W., 2019. Numerical study on three-point bending behavior of honeycomb sandwich with ceramic tile. Composites Part B: Engineering 167: 63-70 Zenkert, D. (1997). The handbook of sandwich construction, Engineering Materials Advisory Services