Analysis of Effective Mechanical Properties and Anisotropy of Structured Porous Materials

2014 ◽  
Author(s):  
Efrain De la Rosa Dávila ◽  
Dirk F. de Lange ◽  
Hugo I. Medellín Castillo ◽  
Gilberto Mejía Rodríguez
Keyword(s):  
Mechanical Properties ◽  
Pore Structure ◽  
Porous Materials ◽  
Porous Structures ◽  
Binary Function ◽  
Fem Model ◽  
Anisotropic Properties ◽  
Practical Applications ◽  
Proper Design ◽  
Effective Mechanical Properties

Many natural and modern man-made materials are porous materials. In many cases, for practical applications and for the proper design of products it is necessary to understand the effective mechanical properties of the porous structure. Even though some general applicable theories exist to estimate the mechanical properties in function of the porosity fraction, or apparent density, the relation between the pore structure and size distribution is not clear. In particular, in case of structured porosity the mechanical properties demonstrate anisotropic behavior. For specialized applications there is an interest to be able to design materials with specified anisotropic properties or with properties varying in space. In order to design and optimize porous structures with specific anisotropic properties, a flexible simulation model is developed and tested to predict and understand the mechanical anisotropic properties of a large variety of porous structures. In order to be able to change the geometric pore structure without recreating a new model, the pore structure is implemented into a space dependent smoothed binary function. A comparison is made between results obtained with FEM models with a fully defined geometry and the FEM model with the porosity function to describe the pore structure in order to evaluate and quantify the error that is introduced by the latter implementation and investigate the possibility to mitigate the error. The model results are also compared with experimental en numerical results reported in literature.

scholarly journals Mechanical analysis of heterogeneous materials with higher-order parameters

2021 ◽  
Author(s):  
Bozo Vazic ◽  
Bilen Emek Abali ◽  
Hua Yang ◽  
Pania Newell
Keyword(s):  
Mechanical Properties ◽  
Porous Materials ◽  
Higher Order ◽  
Order Parameters ◽  
Constitutive Law ◽  
Porous System ◽  
First Order ◽  
Bio Engineering ◽  
The Relationship ◽  
Effective Mechanical Properties

AbstractEven though heterogeneous porous materials are widely used in a variety of engineering and scientific fields, such as aerospace, energy-storage technology, and bio-engineering, the relationship between effective material properties of porous materials and their underlying morphology is still not fully understood. To contribute to this knowledge gap, this paper adopts a higher-order asymptotic homogenization method to numerically investigate the effect of complex micropore morphology on the effective mechanical properties of a porous system. Specifically, we use the second-order scheme that is an extension of the first-order computational homogenization framework, where a generalized continuum enables us to introduce length scale into the material constitutive law and capture both pore size and pore distribution. Through several numerical case studies with different combinations of porosity, pore shapes, and distributions, we systematically studied the relationship between the underlying morphology and effective mechanical properties. The results highlight the necessity of higher-order homogenization in understanding the mechanical properties and reveal that higher-order parameters are required to capture the role of realistic pore morphologies on effective mechanical properties. Furthermore, for specific pore shapes, higher-order parameters exhibit dominant influence over the first-order continuum.

scholarly journals Finite element analysis of Ti6Al4V porous structures for low-stiff hip implant application

2021 ◽  
Vol 12 ◽  
pp. 12
Author(s):  
Porika Rakesh ◽  
Bidyut Pal
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Hip Implants ◽  
Porous Structures ◽  
Element Analysis ◽  
Hip Implant ◽  
Femur Bone ◽  
Body Center Cubic ◽  
Effective Mechanical Properties

Solid metallic hip implants have much higher stiffness than the femur bone, causing stress-shielding and subsequent implant loosening. The development of low-stiff implants using metallic porous structures has been reported in the literature. Ti6Al4V alloy is a commonly used biomaterial for hip implants. In this work, Body-Center-Cubic (BCC), Cubic, and Spherical porous structures of four different porosities (82%, 76%, 70%, and 67%) were investigated to establish the range of ideal porosities of Ti6Al4V porous structures that can match the stiffness of the femur bone. The effective mechanical properties have been determined through Finite Element Analysis (FEA) under uniaxial compressive displacement of 0.32 mm. FEA predictions were validated with the analytical calculations obtained using Gibson and Ashby method. The effective mechanical properties of 82%, 76%, 70%, and 67% porous BCC and Cubic structures were found to match the mechanical properties of cortical bone closely. They were also well comparable to the Gibson-Ashby method-based calculations. BCC and Cubic porous structures with 67–82% porosity can mimic the stiffness of the femur bone and are suitable for low-stiff hip implant applications.

scholarly journals Enhancing Density-Based Mining Waste Alkali-Activated Foamed Materials Incorporating Expanded Cork

CivilEng ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 523-540
Author(s):  
Imed Beghoura ◽  
Joao Castro-Gomes
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Pore Size ◽  
Physical And Mechanical Properties ◽  
Critical Parameters ◽  
Porous Structures ◽  
Foaming Agent ◽  
Al Powder ◽  
Highly Porous ◽  
Alkali Activated

This study focuses on the development of an alkali-activated lightweight foamed material (AA-LFM) with enhanced density. Several mixes of tungsten waste mud (TWM), grounded waste glass (WG), and metakaolin (MK) were produced. Al powder as a foaming agent was added, varying from 0.009 w.% to 0.05 w.% of precursor weight. Expanded granulated cork (EGC) particles were incorporated (10% to 40% of the total volume of precursors). The physical and mechanical properties of the foamed materials obtained, the effects of the amount of the foaming agent and the percentage of cork particles added varying from 10 vol.% to 40% are presented and discussed. Highly porous structures were obtained, Pore size and cork particles distribution are critical parameters in determining the density and strength of the foams. The compressive strength results with different densities of AA-LFM obtained by modifying the foaming agent and cork particles are also presented and discussed. Mechanical properties of the cured structure are adequate for lightweight prefabricated building elements and components.

scholarly journals Characteristics of Lightweight Cellular Concrete and Effects on Mechanical Properties

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2678 ◽  
Author(s):  
Wei Yu ◽  
Xu Liang ◽  
Frank Mi-Way Ni ◽  
Abimbola Grace Oyeyi ◽  
Susan Tighe
Keyword(s):  
Mechanical Properties ◽  
Pore Structure ◽  
High Definition ◽  
Pore Characteristics ◽  
Software Applications ◽  
Solid Part ◽  
Electron Microscopes ◽  
Lab Test ◽  
Scanning Electron Microscopes ◽  
Cellular Concrete

This study investigated the pore structure and its effects on mechanical properties of lightweight cellular concrete (LCC) in order to understand more and detailed characteristics of such structure. As part of investigation, environment scanning electron microscopes (ESEM) and industrial high-definition (HD) macro photography camera were separately used to capture and compare images of specimens. Physical properties of the pore structure, including pore area, size, perimeter, fit ellipse, and shape descriptors, were studied based on the image processing technology and software applications. Specimens with three different densities (400, 475, and 600 kg/m3) were prepared in the laboratory. Firstly, the effects of density on the characteristics of pore structure were investigated; furthermore, mechanical properties (compressive strength, modulus of elasticity and Poisson’s ratio, flexural strength and splitting tensile strength of LCC) were tested. The relationships among pore characteristics, density, and mechanical properties were analyzed. Based on the results obtained from the lab test—comparisons made between specimens with high-densities and those with low-densities—it was found significant variability in bubble size, thickness, and irregularity of pores. Furthermore, the increase of density is accompanied by better mechanical properties, and the main influencing factors are the thickness of the solid part and the shape of the bubble. The thicker of solid part and more regular pores of LCC has, the better mechanical properties are.

The characterization and preparation of porous low dielectric films using various cyclodextrins as template materials

2003 ◽  
Vol 766 ◽  
Author(s):  
Jin-Heong Yim ◽  
Jung-Bae Kim ◽  
Hyun-Dam Jeong ◽  
Yi-Yeoul Lyu ◽  
Sang Kook Mah ◽  
...  
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Dielectric Constant ◽  
Pore Structure ◽  
Pore Diameter ◽  
Dielectric Films ◽  
Low Dielectric Constant ◽  
Cyclodextrin Derivatives ◽  
Low Dielectric ◽  
Low K

AbstractPorous low dielectric films containing nano pores (∼20Å) with low dielectric constant (<2.2), have been prepared by using various kinds of cyclodextrin derivatives as porogenic materials. The pore structure such as pore size and interconnectivity can be controlled by changing functional groups of the cyclodextrin derivatives. We found that mechanical properties of porous low-k thin film prepared with mCSSQ (modified cyclic silsesquioxane) precursor and cyclodextrin derivatives were correlated with the pore interconnection length. The longer the interconnection length of nanopores in the thin film, the worse the mechanical properties of the thin film (such as hardness and modulus) even though the pore diameter of the films were microporous (∼2nm).

Effects of graphene oxide on pore structure and mechanical properties of cementitious composites

2020 ◽  
Vol 234 ◽  
pp. 111709 ◽  
Author(s):  
Su-Jin Lee ◽  
Seong-Hoon Jeong ◽  
Dong-Uk Kim ◽  
Jong-Pil Won
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Pore Structure ◽  
Cementitious Composites

The Structure and Mechanical Properties of Aluminum Cellular Metal With Periodic Cubic Cells

2016 ◽  
Author(s):  
Xiaobing Dang ◽  
Ruxu Du ◽  
Kai He ◽  
Qiyang Zuo
Keyword(s):  
Mechanical Properties ◽  
Relative Density ◽  
Sheet Metal ◽  
Light Weight ◽  
Practical Applications ◽  
Sheet Metal Stamping ◽  
High Stiffness ◽  
The Past ◽  
Cellular Metal ◽  
Metal Stamping

As a light-weight material with high stiffness and strength, cellular metal has attracted a lot of attentions in the past two decades. In this paper, the structure and mechanical properties of aluminum cellular metal with periodic cubic cells are studied. The aluminum cellular metal is fabricated by sheet metal stamping and simple adhesion. Two sizes of specimens with cell sizes of 3mm and 5mm are fabricated. Their relative density and mechanical properties are tested by means of experiments. The results show that the cubic-cell cellular metal has high and predictable strength and hence, can be used for many practical applications.

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