Rohollah Fallah Madvari¹, Mohammad Reza Monazzam², Mohsen Niknam Sharak³, Mohsen Mosa Farkhani^4,*

Sound & Vibration, Vol.54, No.2, pp. 127-137, 2020, DOI:10.32604/sv.2020.08158

Abstract Honeycomb structures have recently, replaced with conventional homogeneous materials. Given the fact that sandwich panels containing a honeycomb core are able to adjust geometric parameters, including internal angles, they are suitable for acoustic control applications. The main objective of this study was to obtain a transmission loss curve in a specific honeycomb frequency range along with same overall dimensions and weight. In this study, a finite element model (FEM) in ABAQUS software was used to simulate honeycomb panels, evaluate resonant frequencies, and for acoustic analysis. This model was used to obtain acoustic pressure and then to calculate the sound transmission… More >

Haiyang Zhou^1,2, Xiaoyu Wang³, Xiaolong Hao^1,2, Qingwen Wang^1,2,*, Rongxian Ou^1,2,*

Journal of Renewable Materials, Vol.8, No.5, pp. 485-498, 2020, DOI:10.32604/jrm.2020.010263

Abstract The mechanical properties of wood flour/high-density polyethylene composites (WPC) were improved by adding a small amount of nano-SiO₂ to obtain a network-structured WPC with a continuous honeycomb-like nano-SiO₂ network. The wood flour was modified with a fire retardant (a mixture of sodium octabonate and amidine urea phosphate) to improve its fire retardancy. The flexural properties, creep resistance, thermal expansion, and fire retardancy of the WPC were compared to a control (WPC_CTRL) without nano-SiO₂ or fire retardant. The flexural strength and modulus of the WPC containing only 0.55 wt.% nano-SiO₂ were 6.6% and 9.1% higher than the control, respectively, while the… More >

J. Li, Z. H. Xiang, M. D. Xue¹

CMC-Computers, Materials & Continua, Vol.2, No.2, pp. 139-150, 2005, DOI:10.3970/cmc.2005.002.139

Abstract This paper investigates the buckling response of honeycomb sandwich composite shells with cutouts under axial compression. The Wilson's incompatible solid Finite Element (FE) is used around cutouts to obtain the detail stress distribution there. While to reduce the computational expense, a special multilayered relative degrees-of-freedom (DOF) shell FE is used to model the regions far from the cutouts. The efficiency and accuracy of this modeling scheme are illustrated by two benchmarks. Then parametric studies are carried out to reveal how the buckling response is influenced by the area, the shape and the orientation of cutouts. More >

C. Wang¹, J.H. Qiu^1,2, R. Nie¹, H.L. Ji¹, W. Deng¹

CMC-Computers, Materials & Continua, Vol.32, No.1, pp. 61-80, 2012, DOI:10.3970/cmc.2012.032.061

Abstract The morphing skin has been a main obstacle in the real-world implementation of morphing aircrafts. This paper presents a morphing skin made of the elastomer reinforced by the honeycomb structure. A matrix made from elastomer provides possibilities to configure the morphing skin and the honeycomb structure with smaller in-plane modulus and larger out-of-plane modulus is thought to be suitable to reinforce the elastomer. The polyurethane elastomer is selected and synthesized by the casting method with the prepolymer approach, after which a tensile test is conducted to get its stress-strain relationship. To decrease the skin depth and diminish the local deformation… More >

D. H. Pahr¹, F.G. Rammerstorfer¹

CMES-Computer Modeling in Engineering & Sciences, Vol.12, No.3, pp. 229-242, 2006, DOI:10.3970/cmes.2006.012.229

Abstract Sandwich structures are efficient lightweight materials. Due to there design they exhibit very special failure modes such as global buckling, shear crimping, facesheet wrinkling, facesheet dimpling, and face/core yielding. The core of the sandwich is usually made of foams or cellular materials, e.g., honeycombs. Especially in the case of honeycomb cores the correlation between analytical buckling predictions and experiments might be poor (Ley, Lin, and Uy (1999)). The reason for this lies in the fact that analytical formulae typically assume a homogeneous core (continuous support of the facesheets). This work highlights problems of honeycomb core sandwiches in a parameter regime,… More >

Zhenyu Xue¹, Ashkan Vaziri¹, John W. Hutchinson¹

CMES-Computer Modeling in Engineering & Sciences, Vol.10, No.1, pp. 79-96, 2005, DOI:10.3970/cmes.2005.010.079

Abstract A constitutive model for the elastic-plastic behavior of plastically compressible orthotropic materials is proposed based on an ellipsoidal yield surface with evolving ellipticity to accommodate non-uniform hardening or softening associated with stressing in different directions. The model incorporates rate-dependence arising from material rate-dependence and micro-inertial effects. The basic inputs are the stress-strain responses under the six fundamental stress histories in the orthotropic axes. Special limits of the model include classical isotropic hardening theory, the Hill model for incompressible orthotropic solids, and the Deshpande-Fleck model for highly porous isotropic foam metals. A primary motivation is application to metal core structure in… More >

L. Gornet¹, S. Marguet², G. Marckmann³

CMC-Computers, Materials & Continua, Vol.4, No.2, pp. 63-74, 2006, DOI:10.3970/cmc.2006.004.063

Abstract The purpose of the present study is to determine the components of the effective elasticity tensor and the failure properties of Nomex^® honeycomb cores. In order to carry out this study, the NidaCore software, a program dedicated to Nomex®Cores predictions, has been developed using the Finite Element tool Cast3M-CEA. This software is based on periodic homogenization techniques and on the modelling of structural instability phenomena. The homogenization of the periodic microstructure is realized thanks to a strain energy approach. It assumes the mechanical equivalence between the microstructures of a RVE and a similar homogeneous macroscopic volume. The key point of… More >

Lianhua Ma¹, Qingsheng Yang²

CMC-Computers, Materials & Continua, Vol.40, No.2, pp. 79-98, 2014, DOI:10.3970/cmc.2014.040.079

Abstract Honeycombs are widely used in aerospace structures due to their low density and high specific strength. In this paper, effective electromagnetic properties of irregular honeycombs are investigated, by using the three dimensional homogenization theory and corresponding computational procedure. This homogenization method, being the extension of two-scale asymptotic approach, is employed to determine the expressions of the effective dielectric permittivity, magnetic permeability and electrical conductivity. To verify and validate the proposed model and procedure, effective permittivities of a typical irregular honeycomb are studied and compared with those of semi-empirical formulae. Moreover, the effect of geometry of honeycomb's unit cell on effective… More >