This paper presents the results of an experimental and numerical study on aluminium honeycomb sandwich structures under low-velocity impact loadings. In order to investigate the impact behavior of honeycomb sandwich structures, which is consisted of two identical aluminium facesheets and an aluminium honeycomb core, an experimental study was carried out by using a drop-weight impact test system. Using this system, the contact forces and absorbed energies were measured to determine the influence of impact energy for one configuration of the sandwich structure. According to these results, a numerical model by finite element method of sandwich structures was developed, which is in good agreement with experimental results in terms of contact forces and deformations. Later, the effect of the cell size and the height variation of aluminum honeycomb core on the impact response of sandwich structures were investigated using the improved numerical model. The obtained numerical and experimental results were interpreted in detail.

The aim of this study is to determine the ballistic impact response of a novel sandwich structure consisting of aluminum honeycomb and Al/SiC functionally graded face sheets and develop a compatible numerical model with experiments. The experiments were carried out by a single-stage gas gun system and numerical simulations were performed using the explicit finite element code, LS-DYNA®. The mechanical properties of the functionally graded face sheets through the thickness were considered in accordance with a power-law distribution. The Mori–Tanaka scheme was used in order to determine the effective material properties of the functionally graded face sheets at a local point. In order to simulate the elastoplastic behavior of the functionally graded face sheets, Tamura–Tomota–Ozawa model was implemented in the numerical model. The ballistic performance of the sandwich structure was investigated for metal-rich ( n = 0.1), linear ( n = 1.0), and ceramic-rich ( n = 10.0) compositions of the functionally graded face sheets. The results indicated that the ceramic fraction of the functionally graded face sheets was quite influential on energy absorption capability, damage mechanism, and impact resistance of the sandwich structure. The sandwich structure with linear functionally graded face sheets showed the highest ballistic performance in terms of damage and deformation shapes of the entire sandwich structure among investigated material compositions.

This study investigates damage mechanisms and deformation of honeycomb sandwich structures reinforced by functionally graded face plates under ballistic impact. The honeycomb sandwich structure consists of two identical functionally graded face sheets, having different material compositions through the thickness, and an aluminum honeycomb core. The functionally graded face sheets consist of ceramic (SiC) and aluminum (Al 6061) phases. The through-thickness mechanical properties of face sheets are assumed to vary according to a power-law. The locally effective material properties are evaluated using the Mori–Tanaka scheme. The effect of material composition of functionally graded face sheets on the ballistic performance of honeycomb sandwich structures was investigated using the finite element method and the penetration and perforation threshold energy values on ballistic performance and ballistic limit of the sandwich structures are determined. The contribution of the honeycomb core on the ballistic performance of the sandwich structure was evaluated by comparing with spaced plates (without honeycomb core) in terms of the residual velocity, kinetic energy, and damage area.

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This study investigates damage mechanism and deformation of honeycomb sandwich structures reinforced by functionally graded plates under ballistic impact effect by means of explicit dynamic analysis using ANSYS LS-DYNA. The honeycomb sandwich structures consisted of two identical functionally graded (FG) facesheets having different material compositions through the plate thickness and an aluminum honeycomb core. The functionally graded facesheets were composed of ceramic (SiC) and metal (Al6061) phases. The through-thickness mechanical properties of facesheets were determined based on a power-law distribution of the volume fraction of the constituents. The locally effective material properties were evaluated using homogenization method which based on the Mori-Tanaka scheme. In the analyses, theoretical models which based on micro structural model of functionally graded materials were used. The effect of material composition of functionally graded facesheets on the ballistic performance of honeycomb sandwich structures was investigated and the penetration and perforation threshold energy values which are the most considerable parameters on ballistic performance and ballistic limit of the sandwich structures were determined.

A comparative numerical investigation on low-velocity impact response of a metal/ ceramic functionally graded sandwich beam (FGSB) is performed by the commercial finite element (FE) software, LS-DYNA[Formula: see text]. The mechanical properties of the FG core are represented by a power-law depending on the volume fractions of the constituents. The effective elastic properties and elastoplastic behavior of the FG core are defined by Mori–Tanaka method and TTO (Tamura–Tomota–Ozawa) model, respectively. The effects of number of layers, compositional gradient, impact energy, and impact side are investigated. The simulation results indicated that both number of layers and compositional gradient have almost no effect on the kinetic energy history. In other respects, the compositional gradient exhibits a considerable effect, and the number of layers has a minor effect on the contact force history. Increasing impact energy does not have a considerable effect in terms of number of layers whereas it exhibits a significant effect in terms of compositional gradient on the percentage difference between the peak contact forces. Finally, the impact side does not influence the contact force history for all number of layers and compositional gradients.

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