Prediction of orthotropic mechanical properties of plain-weave composites with matrix voids using unit cells at multi-scales

2012 ◽  
pp. n/a-n/a ◽  
Author(s):  
Hongzhou Li ◽  
Xinyu Fan ◽  
Chun Yan
Keyword(s):  
Mechanical Properties ◽  
Plain Weave ◽  
Unit Cells ◽  
Multi Scales

Flame Retardation of Plain Weave Fabrics Made of Polyacrylonitrile Pre-Oxidized Yarns

2011 ◽  
Vol 175-176 ◽  
pp. 465-468 ◽  
Author(s):  
Lei Shi ◽  
Hua Wu Liu ◽  
Ping Xu ◽  
Dang Feng Zhao
Keyword(s):  
Mechanical Properties ◽  
Flame Retardant ◽  
Oxygen Index ◽  
Limiting Oxygen Index ◽  
Plain Weave ◽  
Weave Fabric ◽  
Short Period ◽  
Flame Retardation ◽  
Fabric Structures

Plain weave fabrics of polyacrylonitrile pre-oxidation yarns (PANOF) were prepared by small rapier loom. The flame retardation properties, mechanical properties and wear behaviors of PANOF plain weave fabrics were tested. The limiting oxygen index (LOI) of these PANOF plain weave fabric samples was 31%, which meets the criterion of flame-retardant fabrics. These fabrics neither melt nor shrunk when left in flame for a short period of time and the fabric structures were well maintained. Compared with flammable polyacrylonitrile fabrics, the polyacrylonitrile pre-oxidation fabrics exhibited excellent flame retardation properties, with satisfactory mechanical properties and comfortable handle.

Evaluation methods for predicting the elastic constants of C/Epoxy plain-weave composites by considering the realistic mesostructures

2018 ◽  
Vol 53 (2) ◽  
pp. 197-208 ◽  
Author(s):  
Shan-yuan Jiang ◽  
Hao Wang ◽  
Zhong-wei Wang
Keyword(s):  
Mechanical Properties ◽  
Elastic Constants ◽  
Stochastic Theory ◽  
Textile Composites ◽  
Analytical Models ◽  
Plane Shear ◽  
Elliptical Cross ◽  
Variable Metric ◽  
Plain Weave ◽  
Feature Parameters

Variabilities of mesostructures existing in textile composites can affect their mechanical properties. Most of the deterministic mechanical models are based on the assumptions of ideal Representative Volume Element, which cannot predict the mechanical properties accurately. Two analytical models predicting the elastic constants of C/Epoxy plain-weave composites by considering the realistic mesostructures are presented in this paper. These models utilize the variable metric stochastic theory to introduce the fluctuations of yarn feature parameters (yarn path and elliptical cross-section parameters) into the model of macro elastic properties. C/Epoxy plain-weave composite is taken as an example to quantify the influences of realistic yarn feature parameters on the elastic constants of the composite. The predicted elastic constants by analytical models and finite element method are verified by the results of mechanical experiments. It can be concluded that for C/Epoxy plain-weave composite the stochastic fluctuations of yarn feature parameters reduce in-plane elastic moduli by a maximum of 4%, and increase the in-plane shear modulus and Poisson’s ratio by a maximum of 15% and 33%, respectively.

scholarly journals Development of PLA Fibers as an Antimicrobial Agent with Enhanced Infection Resistance using Electrospinning/Plasma Technology

2020 ◽  
Author(s):  
Abdelrahman Mahmoud ◽  
Mohammed Naser ◽  
Mahmoud Abdelrasool ◽  
Khalid Jama ◽  
Mohamed Hussein ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Three Dimensional ◽  
Plasma Technology ◽  
Energy Increase ◽  
The Past ◽  
Unit Cells ◽  
Infection Resistance ◽  
Dimensional Shape ◽  
Fiber Dimensions ◽  
Three Dimensional Shape

Humans are vulnerable and easily prone to all kind of injuries, diseases, and traumas that can be damaging to their tissues (including its building unit, cells), bones, or even organs. Therefore, they would need assistance in healing or re-growing once again. Medical scaffolds have emerged over the past decades as one of the most important concepts in the tissue-engineering field as they enable and aide the re-growth of tissues and their successors. An optimal medical scaffold should be addressing the following factors: biocompatibility, biodegradability, mechanical properties, scaffold architecture/porosity, precise three-dimensional shape and manufacturing technology. There are several materials utilized in the fabrication of medical scaffolds, but one of the most extensively studied polymers is polylactic acid (PLA). PLA is biodegradable thermoplastic aliphatic polyester that is derived from naturally produced lactic acid. PLA is characterized with its excellent mechanical properties, biodegradability, promising eco-friendly, and excellent biocompatibility. PLA can be fabricated into nanofibers for medical scaffolds used through many techniques; electrospinning is one of the widely used methods for such fabrication. Electrospinning is a favorable technique because in the preparation of scaffolds, some parameters such as fiber dimensions, morphology, and porosity are easily controlled. A problem that is associated with medical scaffolds, such as inflammation and infection, was reported in many cases resulting in a degradation of tissues. Therefore, a surface modification was thought of as a needed solution which mostly focuses on an incorporation of extra functionalities responsible for the surface free energy increase (wettability). Therefore, plasma technique was a favorable solution for the surface treatment and modification. Plasma treatment enables the formation of free radicals. These radicals can be easily utilized for grafting process. Subsequently, ascorbic acid (ASA) could be incorporated as anti-inflammatory and anti-infection agent on the plasma pretreated surface of scaffolds.

scholarly journals Non-Auxetic Mechanical Metamaterials

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 635 ◽  
Author(s):  
Christa de Jonge ◽  
Helena Kolken ◽  
Amir Zadpoor
Keyword(s):  
Mechanical Properties ◽  
Yield Stress ◽  
Fatigue Behavior ◽  
Analytical Data ◽  
Three Dimensional ◽  
Mechanical Metamaterials ◽  
Macro Scale ◽  
Unit Cells ◽  
Poisson's Ratios ◽  
Poisson’S Ratios

The concept of “mechanical metamaterials” has become increasingly popular, since their macro-scale characteristics can be designed to exhibit unusual combinations of mechanical properties on the micro-scale. The advances in additive manufacturing (AM, three-dimensional printing) techniques have boosted the fabrication of these mechanical metamaterials by facilitating a precise control over their micro-architecture. Although mechanical metamaterials with negative Poisson’s ratios (i.e., auxetic metamaterials) have received much attention before and have been reviewed multiple times, no comparable review exists for architected materials with positive Poisson’s ratios. Therefore, this review will focus on the topology-property relationships of non-auxetic mechanical metamaterials in general and five topological designs in particular. These include the designs based on the diamond, cube, truncated cube, rhombic dodecahedron, and the truncated cuboctahedron unit cells. We reviewed the mechanical properties and fatigue behavior of these architected materials, while considering the effects of other factors such as those of the AM process. In addition, we systematically analyzed the experimental, computational, and analytical data and solutions available in the literature for the titanium alloy Ti-6Al-4V. Compression dominated lattices, such as the (truncated) cube, showed the highest mechanical properties. All of the proposed unit cells showed a normalized fatigue strength below that of solid titanium (i.e., 40% of the yield stress), in the range of 12–36% of their yield stress. The unit cells discussed in this review could potentially be applied in bone-mimicking porous structures.

scholarly journals Extreme Mechanical Properties of Regular Tensegrity Unit Cells in 3D Lattice Metamaterials

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4845
Author(s):  
Anna Al Sabouni-Zawadzka
Keyword(s):  
Mechanical Properties ◽  
Continuum Model ◽  
Soft Mode ◽  
Point Of View ◽  
Unit Cells ◽  
Deformation Modes

The study focuses on the identification of extreme mechanical properties of 3D lattice metamaterials based on regular tensegrity modules: 4-strut simplex, 3-strut simplex, expanded octahedron, truncated tetrahedron and X-module. The basis of the analysis is a continuum model which is used to find the equivalent elasticity matrices of the unit cells. For each examined tensegrity module a line of extreme properties is determined, which indicates the occurrence of the soft mode of deformation. Moreover, the eigenvectors corresponding to soft and stiff deformation modes are calculated and presented graphically. The obtained results are promising from the point of view of future creation of tensegrity lattices and metamaterials with extreme mechanical properties. One of the analysed materials is identified as quasi bimode, two as quasi trimodes, another one as a trimode and one more as a unimode.

Mechanical properties of partially pyrolysed composites with plain weave basalt fibre reinforcement

2014 ◽  
Vol 40 (5) ◽  
pp. 7507-7521 ◽  
Author(s):  
Martin Černý ◽  
Martina Halasová ◽  
Jana Schwaigstillová ◽  
Zdeneˇk Chlup ◽  
Zbyneˇk Sucharda ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fibre Reinforcement ◽  
Basalt Fibre ◽  
Plain Weave

A general micromechanical model to predict elastic and strength properties of balanced plain weave fabric composites

2017 ◽  
Vol 51 (20) ◽  
pp. 2863-2878 ◽  
Author(s):  
MM Shokrieh ◽  
R Ghasemi ◽  
R Mosalmani
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Elastic Properties ◽  
Present Model ◽  
Micromechanical Model ◽  
Homogenization Method ◽  
Plain Weave ◽  
Weave Fabric ◽  
Fabric Composites ◽  
Out Of Plane

In the present research, a micromechanical-analytical model was developed to predict the elastic properties and strength of balanced plain weave fabric composites. In this way, a new homogenization method has been developed by using a laminate analogy method for the balanced plain weave fabric composites. The proposed homogenization method is a multi-scale homogenization procedure. This model divides the representative volume element to several sub-elements, in a way that the combination of the sub-elements can be considered as a laminated composite. To determine the mechanical properties of laminates, instead of using an iso-strain assumption, the assumptions of constant in-plane strains and constant out-of-plane stress have been considered. The applied assumptions improve the accuracy of prediction of mechanical properties of balanced plain weave fabrics composites, especially the out-of-plane elastic properties. Also, the stress analysis for prediction of strain–stress behavior and strength has been implemented in a similar manner. In addition, the nonlinear mechanical behavior of balanced plain weave composite is studied by considering the inelastic mechanical behavior of its polymeric matrix. To assess the accuracy of the present model, the results were compared with available results in the literature. The results, including of engineering constants (elastic modulus and Poisson’s ratio) and stress–strain behavior show the accuracy of the present model.

Microstructure-Mechanical Properties Correlations in Composite Grid Structures

2013 ◽  
Vol 668 ◽  
pp. 630-634
Author(s):  
Xai Mei Lu ◽  
Yun Fei Ma
Keyword(s):  
Mechanical Properties ◽  
Impact Resistance ◽  
High Strength ◽  
Light Weight ◽  
Load Testing ◽  
Mechanical Behaviors ◽  
Grid Structure ◽  
Unit Cells ◽  
Composite Grid ◽  
Energy Absorbing

The composite grid structure, which is highly efficient and strongly designable, posses a variety of excellent performances， such as light weight, high strength, and inherent impact resistance. This paper used experimental methods to investigate the composite grid structure consisting of quadrilateral unit cells. The authors made nine specimens composed of different unit-cell sizes of the grid structure, through a series of static and dynamic load testing on them, examined and further analyzed their mechanical behaviors and energy-absorbing capabilities, as well as compared their mechanical properties, thus found specific (new) correlations between microstructures and mechanical properties in composite grid structures.

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