Articles
Ghatreh samani s., ,
Beheshti, H.,
Akbarzadeh a.h., ,
Kiani y., International Journal of Structural Stability and Dynamics (02194554)25(15)
In this paper, the free vibration of a sandwich plate with an anisogrid core and two face sheets reinforced with graphene platelets (GPLs) is investigated. A continuous approach is considered for the lattice core and the equivalent properties are calculated. Adopting the Halpin–Tsai micromechanics, the effective Young’s modulus of the nanocomposites/graphene platelets is extracted. Also, mass density and Poisson’s ratio are earned with the simple rule of mixtures. A quasi-3D theory is applied to model the kinematics of the sandwich plate with simply supported boundary conditions. Hamilton’s principle is implemented to obtain the equations of motion that are solved based on the Navier solution. The validity of the results of this study is confirmed by comparing the analytical results with those presented in other researches and also a finite element model. The effect of the parameters of the lattice core such as the width of ribs, the number of helical ribs in one direction, and the ratio of thickness of face sheets to core on the natural frequencies of the sandwich plate was investigated. Additionally, the impact of the pattern of graphene platelets and their weight fraction on the natural frequencies were investigated. The results show that by decreasing the ratio of the thickness of face sheets to the thickness of core and increasing the number of ribs and their width, the natural frequencies will decrease. Moreover, the patterns FG-V and FG-A have the highest and the lowest natural frequencies, respectively, among the other distribution of graphene platelets. © 2025 World Scientific Publishing Company.
Mechanics of Advanced Materials and Structures (15210596)31(18)pp. 4295-4308
In this study, a novel micromechanics-based damage model is proposed for the damage evolution of a two-component microencapsulated-based self-healing polymer composite. In this way, a representative volume element (RVE) including an epoxy matrix with randomly distributed poly(methyl methacrylate) (PMMA) microcapsules is modeled in DigimatTM software and analyzed in Abaqus®. A new technique is developed to investigate the progressive damage by pre-inserted cohesive elements along all element boundaries of the epoxy matrix, PMMA shell, and capsule-matrix interfaces with the bilinear traction–separation law. Moreover, the impact of interface bonding strength, interface fracture energy, and PMMA microcapsules volume fraction on the load-carrying capacity of the RVEs under uniaxial tension loading was studied. The results indicated that the tensile strength of the self-healing polymer composite increased as the interfacial strength and fracture energy increased from 10 to 60 MPa and 100 to 1000 J/m2, respectively. Furthermore, the higher volume fraction of 5% PMMA microcapsules results in a lower load-carrying capacity of self-healing polymer composite with a strength of 4.9 N. A similar trend of Young’s modulus was observed for microcapsule-loaded epoxy composite compared to the pristine epoxy matrix. The micromechanical model has proper accuracy in predicting the tension behavior of self-healing composite in comparison to experimental results. Finally, two healing strategies are considered for the damaged RVE. © 2023 Taylor & Francis Group, LLC.
Journal of Composite Materials (00219983)57(30)pp. 4675-4686
One of the most important applications of electromagnetic wave absorption is in stealth aircrafts and electromagnetic protection of avionic systems. The main limitations in the design of these structures are aerodynamics, thickness or weight, mechanical strength, manufacturing process, and reasonable cost. In this study, a novel three-layer woven fabric composite laminate (with a total thickness of about 3 mm) is proposed which each layer is reinforced by individual polyaniline, carbonyl iron, or (PANI + CI) core-shell fillers. The developed Non-dominated Sorting Genetic Algorithm II optimization algorithm suggests the stacking sequence of layers, the appropriate thickness of each layer, and the filler weight fraction in each layer to achieve a broadband absorption. Due to using both dielectric and magnetic absorbing fillers, this structure shows well-impedance matching and approximately absorbs 80% of the X-band (8-12 GHz) electromagnetic waves. The maximum reflection loss is about −14dB. Finally, the effect of the addition of absorbent particles on the mechanical properties has been investigated. Experimental results showed that the tensile modulus and strength decrease by about 21.5% and 20.6%, respectively, and the flexural modulus and strength reduce by 21.7% and 19.7%, respectively. However, the (PANI + CI) core-shell filler can be introduced as a high performance absorber filler because it suggests maximum reflection loss with low weight fraction compared to other fillers and consequently the minimum reduction in mechanical properties. © The Author(s) 2023.
