scholarly journals Model-Assisted Guided-Wave-Based Approach for Disbond Detection and Size Estimation in Honeycomb Sandwich Composites

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8183
Author(s):  
Piotr Fiborek ◽  
Paweł Kudela
Keyword(s):  
Spectral Element ◽  
Guided Wave ◽  
Composite Panel ◽  
Sandwich Composite ◽  
Size Estimation ◽  
Honeycomb Core ◽  
Propagating Waves ◽  
Honeycomb Sandwich ◽  
Honeycomb Sandwich Composite ◽  
The Time Domain

One of the axioms of structural health monitoring states that the severity of damage assessment can only be done in a learning mode under the supervision of an expert. Therefore, a numerical analysis was conducted to gain knowledge regarding the influence of the damage size on the propagation of elastic waves in a honeycomb sandwich composite panel. Core-skin debonding was considered as damage. For this purpose, a panel was modelled taking into account the real geometry of the honeycomb core using the time-domain spectral element method and two-dimensional elements. The presented model was compared with the homogenized model of the honeycomb core and validated in the experimental investigation. The result of the parametric study is a function of the influence of damage on the amplitude and energy of propagating waves.

Prediction of Elastic Properties of Honeycomb Core Materials and Analysis of Interlaminar Stress of Honeycomb Sandwich Composite Plate

2006 ◽  
Vol 306-308 ◽  
pp. 763-768
Author(s):  
Hyoung Gu Kim ◽  
Hoong Soo Yoon ◽  
Nak Sam Choi
Keyword(s):  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Sandwich Composite ◽  
Plate Model ◽  
Honeycomb Core ◽  
Interlaminar Stresses ◽  
Honeycomb Sandwich ◽  
Honeycomb Sandwich Composite ◽  
Theoretical Results ◽  
Core Materials

Theoretical formulas for effective elastic modulus and Poisson's ratio of honeycomb core materials were proposed considering the bending, axial and shear deformations of cell walls. Theoretical results obtained by the formulas showed orthotropic elasticity and large Poisson’s ratio, which were comparable to results by finite element analysis(FEA). Tensile test of honeycomb sandwich composite(HSC) plates was performed for analysis of their deformation behaviors and interlaminar stresses. Equivalent plate model using the theoretical results of honeycomb core layer show that interlaminar shear stress occurring due to large difference of Poisson’s ratio between skin and honeycomb core layers led to the delamination in HSC plate under tensile loading. Load-displacement behavior of HSC specimen simulated by equivalent plate model coincided fairly with that of detailed FEA model similar to experimental results.

Investigation on Nonlinear Constitutive Relationship for a Honeycomb Sandwich Composite

2011 ◽  
Vol 291-294 ◽  
pp. 1025-1038
Author(s):  
Qiang Liu ◽  
Zheng Ming Huang
Keyword(s):  
Constitutive Relationship ◽  
Sandwich Composite ◽  
Sandwich Composites ◽  
Honeycomb Core ◽  
Stress Strain ◽  
Nonlinear Responses ◽  
Nonlinear Stress ◽  
Honeycomb Sandwich ◽  
Aluminum Honeycomb ◽  
Honeycomb Sandwich Composite

This paper investigates nonlinear responses of honeycomb sandwich composite under externally applied loads theoretically and experimentally. In the experimental work, honeycomb sandwich composites made of an aluminum honeycomb core and glass fiber reinforced polymer (FRP) laminate surfaces were loaded under in-plane tension and out-of plane bending up to failure. Stress-strain curves or load deflection plot together with elastic moduli and ultimate strengths were obtained. An energy approach was used to establish a nonlinear constitutive relationship for the honeycomb sandwich composites. Making use of the superimposition ability of the strain energies of all of the walls of the RVE, a nonlinear constitutive relationship for the honeycomb core was obtained. The thus obtained relationship was incorporated with a laminate theory and the bridging model to analyze nonlinear responses of the honeycomb core and FRP surface sandwich composites up to failure. The composite failure was detected micromechanically, i.e., based on the failure status of its constituent aluminum core, reinforcing fiber, polymer matrix, and adhesion layer. Stiffness discount was applied respectively to the failed composing element. The predicted nonlinear stress-strain curves under tension and load-deflection relationship under three-point bending were compared with the experimental measurements. Favorable correlations have been obtained.

scholarly journals NDE Detection Techniques and Characterization of Aluminum Wires Embedded in Honeycomb Sandwich Composite Panels Using Terahertz Waves

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1264 ◽  
Author(s):  
Kwang-Hee Im ◽  
Sun-Kyu Kim ◽  
Jong-An Jung ◽  
Young-Tae Cho ◽  
Yong-Deuck Woo ◽  
...  
Keyword(s):  
Carbon Fibers ◽  
Sandwich Panels ◽  
Sandwich Composite ◽  
Composite Panels ◽  
Fiber Reinforced ◽  
Terahertz Waves ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Honeycomb Sandwich ◽  
Honeycomb Sandwich Composite

For many years, scientists have been aware of the importance of terahertz waves (T-rays), which have now emerged as an NDE (nondestructive evaluation) technique for certain ranges of the electronic spectrum. The present study deals with T-ray scanning techniques of honeycomb sandwich composite panels with a carbon-fiber-reinforced plastic (CFRP) skin as well as the refractive index (n), and the electrical conductivity (α) of glass fiber-reinforced plastic (GFRP) composites. For this experiment, the degree of penetration to FRP composites is investigated for the THz transmitted power based on the angle in the electric field (E-field) direction vs. the direction of the unidirectional carbon fibers. Also, when CFRP skin honeycomb sandwich panels are manufactured for use in aerospace applications, aluminum wires are twisted together into the one-sided surface of the honeycomb sandwich panels to protect against thunderstorms. The aluminum wires are partly visible because they are embedded in the CFRP skin on the honeycomb sandwich panels. After finishing work with a paintjob, the wires become invisible. Thus, detecting the aluminum wires is a key issue for product monitoring. Based on a simple resistor model, an optimal scanning method is proposed to determine the preferred scan orientation on the baseline of the E-field in the direction of fibers to evaluate the level of transmission of T-rays according to the frequency bandwidth. Thus, the combination of angles required to detect the aluminum wires embedded with carbon fibers on the surface of the composite panels can be determined.

Study on Ballistic Energy Absorption of Laminated and Sandwich Composites

2006 ◽  
Vol 306-308 ◽  
pp. 739-744 ◽  
Author(s):  
Xiao Dong Cui ◽  
Tao Zeng ◽  
Dai Ning Fang
Keyword(s):  
Energy Absorption ◽  
Impact Response ◽  
Sandwich Composite ◽  
Sandwich Composites ◽  
Ballistic Resistance ◽  
Honeycomb Sandwich ◽  
Honeycomb Sandwich Composite ◽  
Improved Model ◽  
Energy Absorbing ◽  
The Impact

The impact response and energy absorbing characteristics of laminated, foam sandwich and honeycomb sandwich composites under ballistic impact have been studied in this investigation. An improved model is proposed in this paper to predict the ballistic property of the laminated composites. In this model, the material structures related to fiber lamination angles are designed in terms of their anti-impacting energy absorption capability. The ballistic limit speed and energy absorption per unit thickness of the three composites under different conditions are calculated. It is shown that honeycomb sandwich composite has the best ballistic resistance capability and energy absorption property among the three composites.

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