Recurrent approach to effective material properties with application to anisotropic binarized random fields

AbstractMetamaterials can possess extraordinary properties not readily available in nature. While most of the early metamaterials had narrow frequency bandwidth of operation, many recent works have focused on how to implement exotic properties and functions over broad bandwidth for practical applications. Here, we provide two definitions of broadband operation in terms of effective material properties and device functionality, suitable for describing materials and devices, respectively, and overview existing broadband metamaterial designs in such two categories. Broadband metamaterials with nearly constant effective material properties are discussed in the materials part, and broadband absorbers, lens, and hologram devices based on metamaterials and metasurfaces are discussed in the devices part.

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A computational modeling approach based on random fields for short fiber-reinforced composites with experimental verification by nanoindentation and tensile tests

Computational Mechanics ◽

10.1007/s00466-020-01958-3 ◽

2021 ◽

Author(s):

Natalie Rauter

Keyword(s):

Numerical Simulations ◽

Correlation Functions ◽

Material Properties ◽

Random Fields ◽

Tensile Tests ◽

Short Fiber ◽

Fiber Reinforced Composites ◽

Reinforced Composites ◽

Fiber Reinforced ◽

Component Level

AbstractIn this study a modeling approach for short fiber-reinforced composites is presented which allows one to consider information from the microstructure of the compound while modeling on the component level. The proposed technique is based on the determination of correlation functions by the moving window method. Using these correlation functions random fields are generated by the Karhunen–Loève expansion. Linear elastic numerical simulations are conducted on the mesoscale and component level based on the probabilistic characteristics of the microstructure derived from a two-dimensional micrograph. The experimental validation by nanoindentation on the mesoscale shows good conformity with the numerical simulations. For the numerical modeling on the component level the comparison of experimentally obtained Young’s modulus by tensile tests with numerical simulations indicate that the presented approach requires three-dimensional information of the probabilistic characteristics of the microstructure. Using this information not only the overall material properties are approximated sufficiently, but also the local distribution of the material properties shows the same trend as the results of conducted tensile tests.

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Structural optimization in ESAC: annals 2011

International Journal for Simulation and Multidisciplinary Design Optimization ◽

10.1051/smdo/2013013 ◽

2014 ◽

Vol 5 ◽

pp. A09

Author(s):

Ji-Hong Zhu ◽

Wei-Hong Zhang

Keyword(s):

Topology Optimization ◽

Structural Optimization ◽

Material Properties ◽

Numerical Results ◽

Multiphase Materials ◽

And Topology ◽

Effective Material Properties

The purpose of this paper is to give an overall introduction of the structural optimization research works in ESAC group in 2011. Four main topics are involved, i.e. 1) topology optimization with multiphase materials, 2) integrated layout and topology optimization, 3) prediction of effective material properties and 4) composite design. More detailed techniques and some numerical results are also presented and discussed here.

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Effects of Shear Deformation of Struts in Hexagonal Lattices on their Effective In-Plane Material Properties

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1034.193 ◽

2021 ◽

Vol 1034 ◽

pp. 193-198

Author(s):

Pana Suttakul ◽

Thongchai Fongsamootr ◽

Duy Vo ◽

Pruettha Nanakorn

Keyword(s):

Shear Deformation ◽

Material Properties ◽

Strain Energy ◽

Equivalent Strain ◽

Homogenization Method ◽

Two Dimensional ◽

Engineering Applications ◽

Large Numbers ◽

Effective Material Properties ◽

Unit Cells

Two-dimensional lattices are widely used in many engineering applications. If 2D lattices have large numbers of unit cells, they can be accurately modeled as 2D homogeneous solids having effective material properties. When the slenderness ratios of struts in these 2D lattices are low, the effects of shear deformation on the values of the effective material properties can be significant. This study aims to investigate the effects of shear deformation on the effective material properties of 2D lattices with hexagonal unit cells, by using the homogenization method based on equivalent strain energy. Several topologies of hexagonal unit cells and several slenderness ratios of struts are considered. The effects of struts’ shear deformation on the effective material properties are examined by comparing the results of the present study, in which shear deformation is neglected, with those from the literature, in which shear deformation is included.

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