Optimization of Sandwich Composites Fuselages Under Flight Loads

Fiber reinforced sandwich structures are widely used as structural elements due to their lightweight and high load-bearing capacity. In this paper, effort is taken to fabricate fiber facesheet (0°/90° orientation) and corrugated cores (trapezoidal vertical pillared, core-1 and sinusoidal vertical pillared, core-2) of the sandwich structure using fused filament fabrication and Inkjet printing techniques, respectively. Firstly, the quasi-static indentation properties of the additively manufactured facesheet, cores, and sandwich structures were investigated. In addition, acoustic emission signals were monitored during quasi-static indentation testing and the resulting hits data were correlated with quasi-static indentation test results. The quasi-static indentation test results showed that sinusoidal sandwich structures have the highest load-bearing capacity of 1.79 kN until crack initiation and a total energy-absorption capacity of 20.05 J. Acoustic emission hits recorded in the range of 1–30, 30–100, and above 100 represented crack initiation, crack propagation, and specimen failure, respectively. Lastly, micro-computed tomography analysis was performed on the sandwich structures at intermediate indentation displacements, thus leading to the identification of hard to detect failure points and damage propagation. Fracture surface morphology of the sandwich structures showed that fiber pullout and core shear were the dominant damage mechanisms.

Section: Introductionmentioning

confidence: 99%

Quasi-static indentation analysis on three-dimensional printed continuous-fiber sandwich composites

Dikshit

Nagalingam

Goh

et al. 2019

“…The mechanical properties of honeycomb sandwich structures (e.g. bending deformation, buckling/ultimate strength and dynamical properties) were investigated by simplified theories models and FEM [13–16]. For grid sandwich structures, typically smeared approaches were developed to predict its structural performances, which was valuable for parametric studies and initial design of grid configurations [17–18].…”

Section: Introductionmentioning

confidence: 99%

Equivalent properties of composite sandwich panels with honeycomb–grid hybrid core

Shi

Chen

Sun

2018

Combining the complementary properties of honeycomb cores and grid cores, a composite sandwich panel with honeycomb–grid hybrid core was proposed to enhance the structural performance of composite sandwich panels. However, important gaps remain in calculating the structural performance of the composite sandwich panels. In this paper, an equivalent stiffness model was proposed to analytically estimate the stiffness matrix of composite sandwich panels with honeycomb–grid hybrid core. The reliability and accuracy of the equivalent stiffness model were verified by experimental measurements from three-point bending tests. Furthermore, the effects of face-sheet thickness, core height, grid spacing, rib width and material properties on structural stiffness were investigated for the design of sandwich structures with hybrid core. The parameter studies demonstrated that core height had the most significant influence on the specific bending stiffness, while grid spacing was most important for specific in-plane stiffness of sandwich panels with carbon-fiber grid. Moreover, using carbon-fiber grid, although increases manufacturing cost, could further enhance the specific stiffness.

“…During the last century, the use of sandwich composites has steadily increased in the industrial sector [1–4]. The high potential of this solution for structural applications, as an alternative to traditional materials, stems from their lightness, with better strength and rigidity ratio weight and durability [5–8].…”

Section: Introductionmentioning

confidence: 99%

Viscoelastic behaviour investigation and new developed laboratory slamming test on foam core sandwich

Alila

Fajoui

Gérard

et al. 2018

In the first part of this paper, a viscoelastic model is used to numerically study the cellular foam core fatigue behaviour. Material’s temperature evolution is quantified with a numerical/experimental confrontation. In the second part, the slamming phenomenon is discussed by measuring the panel flexural strain on a racing sailboat during navigation. Making use of these results, a new slamming test rig was developed to evaluate the fatigue of sandwich structure under realistic loading. Four-point bending and slamming tests were performed on sandwich beams in order to compare their fatigue life and to discuss the physical parameters.