Heru Suryanto^1,2,*, Muhamad Muhajir¹, Bili Darnanto Susilo¹, Yanuar Rohmat Aji Pradana¹, Husni Wahyu Wijaya^2,3, Abu Saad Ansari⁴, Uun Yanuhar⁵

Journal of Renewable Materials, Vol.9, No.10, pp. 1717-1728, 2021, DOI:10.32604/jrm.2021.015312

Abstract The microstructure of bacterial cellulose nanofibers (BCNs) film affects its characteristic. One of several means to engineer the microstructure is by changing the BCNs size and fiber distribution through a high-pressure homogenizer (HPH) process. This research aimed to find out the effects of repetition cycles on HPH process towards BCNs film characteristics. To prepare BCNs films, a pellicle from the fermentation of pineapple peels waste with Acetobacter xylinum (A. xylinum) was extracted, followed by crushing the pellicle with a high-speed blender, thereafter, homogenized using HPH at 150 bar pressure with variations of 5, 10, 15, and 20 cycles. The BCNs… More >

Marco Lo Cascio¹, Marco Grifò¹, Alberto Milazzo¹, Ivano Benedetti^1,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.23, No.1, pp. 13-13, 2021, DOI:10.32604/icces.2021.08335

Abstract The Virtual Element Method (VEM) [1] is a recent numerical technique that is capable of dealing with very general polygonal and polyhedral mesh elements, including irregular or non-convex ones. Because of this feature, the VEM ensures noticeable simplification in the data preparation stage of the analysis, especially for problems whose analysis domain features complex geometries, as in the case of computational micromechanics problems [2]. The Boundary Element Method (BEM) [3] is a well-known, extensively used and efficient numerical technique that has been successfully employed for the computational homogenization of materials with complex morphologies [4]. Due to its underlying formulation, the… More >

Jurica Sorić^*, Tomislav Lesičar, Zdenko Tonković

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.3, pp. 915-934, 2021, DOI:10.32604/cmes.2021.014142

Abstract The paper deals with the numerical modelling of ductile damage responses in heterogeneous materials using the classical second-order homogenization approach. The scale transition methodology in the multiscale framework is described. The structure at the macrolevel is discretized by the triangular C¹ finite elements obeying nonlocal continuum theory, while the discretization of microstructural volume element at the microscale is conducted by means of the mixed type quadrilateral finite element with the nonlocal equivalent plastic strain as an additional nodal variable. The ductile damage evolution at the microlevel is modelled by using the gradient enhanced elastoplasticity. The macrolevel softening is governed by… More >

Kai Long^1,*, Xiaoyu Yang¹, Nouman Saeed¹, Zhuo Chen¹, Yi Min Xie²

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.1, pp. 293-310, 2021, DOI:10.32604/cmes.2021.012734

Abstract A methodology for achieving the maximum bulk or shear modulus in an elastic composite composed of two isotropic phases with distinct Poisson’s ratios is proposed. A topology optimization algorithm is developed which is capable of nding microstructures with extreme properties very close to theoretical upper bounds. The effective mechanical properties of the designed composite are determined by a numerical homogenization technique. The sensitivities with respect to design variables are derived by simultaneously interpolating Young’s modulus and Poisson’s ratio using different parameters. The so-called solid isotropic material with penalization method is developed to establish the optimization formulation. Maximum bulk or shear… More >

Dimitra Papagianni^{1, 2}, Magd Abdel Wahab^{3, 4, *}

CMC-Computers, Materials & Continua, Vol.62, No.1, pp. 79-97, 2020, DOI:10.32604/cmc.2020.07988

Abstract This paper deals with modeling of the phenomenon of fretting fatigue in heterogeneous materials using the multi-scale computational homogenization technique and finite element analysis (FEA). The heterogeneous material for the specimens consists of a single hole model (25% void/cell, 16% void/cell and 10% void/cell) and a four-hole model (25% void/cell). Using a representative volume element (RVE), we try to produce the equivalent homogenized properties and work on a homogeneous specimen for the study of fretting fatigue. Next, the fretting fatigue contact problem is performed for 3 new cases of models that consist of a homogeneous and a heterogeneous part (single… More >

G. Milani¹, T. Rotunno², E. Sacco³, A. Tralli^1,4

Structural Durability & Health Monitoring, Vol.2, No.1, pp. 29-50, 2006, DOI:10.3970/sdhm.2006.002.029

Abstract Aim of the present work is the evaluation of the ultimate load bearing capacity of masonry panels reinforced with FRP strips. The investigation is developed performing both experimental and numerical studies. In particular, several panels subjected to different loading conditions are tested in the Tests Laboratory of the University of Florence (Italy). Then, numerical models based on combined homogenization and limit analysis techniques are proposed. The results obtained by numerical simulations are compared with experimental data. The good agreement obtained shows that the proposed numerical model can be applied for the evaluation of the ultimate load bearing capacity of reinforced… More >

J.T. Verbis¹, S.V. Tsinopoulos², D. Polyzos²

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.6, pp. 803-814, 2002, DOI:10.3970/cmes.2002.003.803

Abstract In the present work the iterative effective medium approximation (IEMA) is appropriately used for wave dispersion and attenuation predictions in fiber-reinforced composites that microscopically exhibit a non-uniform fiber distribution. Two types of composites with such irregular topology of fibers are considered. The first contains a regular distribution of clusters of fibers embedded in a composite matrix with uniformly distributed fibers, and the second a uniform distribution of matrix-rich inclusions embedded in a fiber-rich regular composite medium. The resulting from the application of the IEMA scattering problems are solved numerically by means of a two dimensional boundary element method. The obtained… More >

T. Asada¹, N. Ohno¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.4, No.4, pp. 201-206, 2007, DOI:10.3970/icces.2007.004.201

Abstract In this study, to determine incremental, perturbed displacement fields in periodic inelastic solids, an incremental homogenization problem is fully implicitly formulated, and an algorithm is developed to solve the homogenization problem. It is shown that the homogenization problem can be iteratively solved with quadratic convergences by successively updating strain increments in unit cells, and that the present formulation allows versatility in the initial setting of strain increments in contrast to previous studies. The homogenization algorithm developed is then examined by analyzing a holed plate, with an elastoplastic micro-structure, subjected to tensile loading. It is thus demonstrated that the convergence in… More >

Harald Berger¹, Ulrich Gabbert², Reinaldo Rodriguez-Ramos³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.9, No.2, pp. 127-129, 2009, DOI:10.3970/icces.2009.009.127

Abstract Piezoelectric materials have the property of converting electrical energy into mechanical energy and vice versa. This reciprocity in the energy conversion makes piezoelectric ceramics very attractive for use as sensors and actuators. By combining piezoelectric fibers with passive non-piezoelectric polymer composites with superior properties can be created. But for design of such smart micro-macro structures homogenization techniques are necessary to describe the overall behavior of piezocomposites expressed by effective material coefficients.
A number o fnumerical and analytical methods have been developed to estimate the effective coefficients. Although analytical homogenization methods provide excellent results it is difficult to extend them to… More >

Hiroshi Okada¹, Yasuyoshi Fukui¹, Noriyoshi Kumazawa¹

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.2, pp. 135-150, 2004, DOI:10.3970/cmes.2004.005.135

Abstract A method to obtain the effective mechanical properties of particulate composite materials is presented in this paper. The methodology is based on the boundary element method (BEM) coupled with analytical solutions for ellipsoidal inclusions such as Eshelby's tensor. There is no numerical integration for the surfaces or the domains of distributed particles, and, therefore, proposed technique is very efficient. Homogenization analysis based on representative volume element (RVE) is carried out considering a unit cell containing many particles (up to 1000). By using a conventional BEM approach (i.e., multi-region BEM), it would be extremely difficult to analyze such a large RVE,… More >