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  • Open Access

    ARTICLE

    Enhancing Sound Absorption in Micro-Perforated Panel and Porous Material Composite in Low Frequencies: A Numerical Study Using FEM

    Mohammad Javad SheikhMozafari*

    Sound & Vibration, Vol.58, pp. 81-100, 2024, DOI:10.32604/sv.2024.048897

    Abstract Mitigating low-frequency noise poses a significant challenge for acoustic engineers, due to their long wavelength, with conventional porous sound absorbers showing limitations in attenuating such noise. An effective strategy involves combining porous materials with micro-perforated plates (MPP) to address this issue. Given the significant impact of structural variables like panel thickness, hole diameter, and air gap on the acoustic characteristics of MPP, achieving the optimal condition demands numerous sample iterations. The impedance tube’s considerable expense for sound absorption measurement and the substantial cost involved in fabricating each sample using a 3D printer underscore the advantage of utilizing simulation methods to… More > Graphic Abstract

    Enhancing Sound Absorption in Micro-Perforated Panel and Porous Material Composite in Low Frequencies: A Numerical Study Using FEM

  • Open Access

    ARTICLE

    Parameter Study on a Composite Sound-Absorbing Structure Liner in Elevator Shafts

    Ting Qu, Bo Wang, Hequn Min*

    Journal of Renewable Materials, Vol.11, No.9, pp. 3433-3446, 2023, DOI:10.32604/jrm.2023.027136

    Abstract With the growing global environmental awareness, the development of renewable and green materials has gained increased worldwide interest to substitute conventional materials and are favorable for sustainable economic development. This paper proposed a novel eco-friendly sound absorbing structure (NSAS) liner for noise reduction in elevator shafts. The base layer integrated with the shaft walls is a damping gypsum mortarboard, and a rock wool board and a perforated cement mortarboard are used to compose the NSAS. Based on the acoustic impedance theory of porous materials and perforated panels, the sound absorption theory of the NSAS was proposed; the parameter effects of… More >

  • Open Access

    ARTICLE

    Preparation of Porous Materials Derived from Waste Mussel Shell with High Removal Performance for Tableware Oil

    Yi Yang1, Zhaodi Wu1, Lili Ji2, Shiyao Lu2, Hua Jing2, Jiaxing Sun2, Jian Guo1, Wendong Song3, Yaning Wang2, Lu Cai4,*

    Journal of Renewable Materials, Vol.9, No.11, pp. 1869-1881, 2021, DOI:10.32604/jrm.2021.015952

    Abstract In this work, carbonized mussel shell powder (CMSP) was modified by alkyl polyglucosides (APG) and rhamnolipid (RL) to render porous biomass a lipophilic surface, which was innovatively utilized as an environmentally friendly tableware cleaning material. The modified method was two-step hydrotherm-assisted synthesis. A contact angle meter was used to determine the surface hydrophobic property of modified samples (MTAR). The pore and the surface structure of CMSP and MTAR were characterized by BET, SEM, XRD, FTIR and XPS. The effect of removing oil was tested by gravimetric method. The results showed that the surface of MTAR was more porous and fluffier… More > Graphic Abstract

    Preparation of Porous Materials Derived from Waste Mussel Shell with High Removal Performance for Tableware Oil

  • Open Access

    ARTICLE

    Statistical Multiscale Analysis of Transient Conduction and Radiation Heat Transfer Problem in Random Inhomogeneous Porous Materials

    Yiqiang Li1, Liang Ma2, Zhiqiang Yang3, Xiaofei Guan4, Yufeng Nie1, Zihao Yang1, 2

    CMES-Computer Modeling in Engineering & Sciences, Vol.115, No.1, pp. 1-24, 2018, DOI:10.3970/cmes.2018.115.001

    Abstract This paper is devoted to the homogenization and statistical multiscale analysis of a transient heat conduction problem in random porous materials with a nonlinear radiation boundary condition. A novel statistical multiscale analysis method based on the two-scale asymptotic expansion is proposed. In the statistical multiscale formulations, a unified linear homogenization procedure is established and the second-order correctors are introduced for modeling the nonlinear radiative heat transfer in random perforations, which are our main contributions. Besides, a numerical algorithm based on the statistical multiscale method is given in details. Numerical results prove the accuracy and efficiency of our method for multiscale… More >

  • Open Access

    ARTICLE

    Characterization and modeling of the multiscale pore structures for porous materials

    X.F. Guan1, X. Liu2, J.Z. Cui3

    CMES-Computer Modeling in Engineering & Sciences, Vol.91, No.6, pp. 425-444, 2013, DOI:10.3970/cmes.2013.091.425

    Abstract In this paper, a stochastic geometrical modeling method for reconstructing three dimensional multiscale pore structures of porous materials is presented. In this method, the pore structure in porous materials is represented by a random but spatially correlated pore-network, in which the results of the Mercury Intrusion Porosimetry (MIP) experiment are used as the basic input information. Beside that, based on the Monte Carlo techniques, an effective computer generation algorithm is developed, and the quantities to evaluate the properties of porous materials are defined and described. Furthermore, numerical implementations are conducted based on experimental data afterwards. This method can be used… More >

  • Open Access

    ARTICLE

    The Second-Order Two-Scale Method for Heat Transfer Performances of Periodic Porous Materials with Interior Surface Radiation

    Zhiqiang Yang1, Junzhi Cui2, Yufeng Nie1, Qiang Ma2

    CMES-Computer Modeling in Engineering & Sciences, Vol.88, No.5, pp. 419-442, 2012, DOI:10.3970/cmes.2012.088.419

    Abstract In this paper, a new second-order two-scale (SOTS) method is developed to predict heat transfer performances of periodic porous materials with interior surface radiation. Firstly, the second-order two-scale formulation for computing temperature field of the problem is given by means of construction way. Then, the error estimation of the second-order two-scale approximate solution is derived on some regularity hypothesis. Finally, the corresponding finite element algorithms are proposed and some numerical results are presented. They show that the SOTS method in this paper is feasible and valid for predicting the heat transfer performances of periodic porous materials. More >

  • Open Access

    ARTICLE

    T-Trefftz Voronoi Cell Finite Elements with Elastic/Rigid Inclusions or Voids for Micromechanical Analysis of Composite and Porous Materials

    L. Dong1, S. N. Atluri2

    CMES-Computer Modeling in Engineering & Sciences, Vol.83, No.2, pp. 183-220, 2012, DOI:10.32604/cmes.2012.083.183

    Abstract In this paper, we develop T-Trefftz Voronoi Cell Finite Elements (VCF -EM-TTs) for micromechanical modeling of composite and porous materials. In addition to a homogenous matrix in each polygon-shaped element, three types of arbitrarily-shaped heterogeneities are considered in each element: an elastic inclusion, a rigid inclusion, or a void. In all of these three cases, an inter-element compatible displacement field is assumed along the element outer-boundary, and interior displacement fields in the matrix as well as in the inclusion are independently assumed as T-Trefftz trial functions. Characteristic lengths are used for each element to scale the T-Trefftz trial functions, in… More >

  • Open Access

    ARTICLE

    3D Higher-OrderX-FEM Model for the Simulation of Cohesive Cracks in Cementitious Materials Considering Hygro-Mechanical Couplings

    C. Becker1, S. Jox2, G. Meschke3

    CMES-Computer Modeling in Engineering & Sciences, Vol.57, No.3, pp. 245-278, 2010, DOI:10.3970/cmes.2010.057.245

    Abstract A three-dimensional numerical model based on the Extended Finite Element Method (X-FEM) is presented for the simulation of cohesive cracks in cementitious materials, such as concrete, in a hygro-mechanical framework. Enhancement functions for the small scale resolution of the displacement jump across cracks in the context of the X-FEM is used in conjunction with a higher order family of hierarchical shape functions for the representation of the large scale displacement field of the investigated structure. Besides the theoretical and computational formulation in a multiphase context, aspects of the implementation, such as integration and crack tracking algorithms, are discussed. Representative numerical… More >

  • Open Access

    ARTICLE

    Numerical Characterization of Porous Solids and Performance Evaluation of Theoretical Models via the Precorrected-FFT Accelerated BEM

    Z. Y. Yan1,2, J. Zhang1, W. Ye1, T.X. Yu1

    CMES-Computer Modeling in Engineering & Sciences, Vol.55, No.1, pp. 33-60, 2010, DOI:10.3970/cmes.2010.055.033

    Abstract An 3-D precorrected-FFT accelerated BEM approach for the linear elastic analysis of porous solids with randomly distributed pores of arbitrary shape and size is described in this paper. Both the upper bound and the lower bound of elastic properties of solids with spherical pores are obtained using the developed fast BEM code. Effects of porosity and pore shape on the elastic properties are investigated. The performance of several theoretical models is evaluated by comparing the theoretical predictions with the numerical results. It is found that for porous solids with spherical pores, the performances of the generalized self-consistent method and Mori-Tanaka… More >

  • Open Access

    ARTICLE

    A Unified Approach to Numerical Modeling of Fully and Partially Saturated Porous Materials by Considering Air Dissolved in Water

    D. Gawin1, L. Sanavia2

    CMES-Computer Modeling in Engineering & Sciences, Vol.53, No.3, pp. 255-302, 2009, DOI:10.3970/cmes.2009.053.255

    Abstract This paper presents a unified mathematical approach to model the hydro-thermo-mechanical behavior of saturated and partially saturated porous media by considering the effects of air dissolved in liquid water. The model equations are discretized by means of the Finite Element method. A correspondingly updated code is used to analyze two examples; the first one is the well known Liakopoulos test, i.e. the drainage of liquid water from a 1m column of sand, which is used to validate numerically the model here developed. As second example, a biaxial compression test of undrained dense sands where cavitation takes place at strain localization… More >

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