scholarly journals Fabrication and Characterization of Polyetherimide Electrospun Scaffolds Modified with Graphene Nano-Platelets and Hydroxyapatite Nano-Particles

2020 ◽  
Vol 21 (2) ◽  
pp. 583
Author(s):  
Vassilis Kostopoulos ◽  
Athanasios Kotrotsos ◽  
Kalliopi Fouriki ◽  
Alexandros Kalarakis ◽  
Diana Portan
Keyword(s):  
Mechanical Performance ◽  
Morphological Characteristics ◽  
Tensile Tests ◽  
Electrospinning Process ◽  
Nano Particles ◽  
Uniaxial Tensile ◽  
Porous Scaffolds ◽  
Potential Candidate ◽  
Fibrous Materials ◽  
Wide Range

Solution electrospinning process (SEP) is a versatile technique for generating non-woven fibrous materials intended to a wide range of applications. One of them is the production of fibrous and porous scaffolds aiming to mimic bone tissue, as artificial extracellular matrices (ECM). In the present work, pure and nano-modified electrospun polyetherimide (PEI) scaffolds have been successfully fabricated. The nano-modified ones include (a) graphene nano-platelets (GNPs), (b) hydroxyapatite (HAP), and (c) mixture of both. After fabrication, the morphological characteristics of these scaffolds were revealed by using scanning electron (SEM) and transmission electron (TEM) microscopies, while porosity and mean fiber diameter were also calculated. In parallel, contact angle experiments were conducted so that the hydrophilicity level of these materials to be determined. Finally, the mechanical performance of the fabricated scaffolds was investigated by conducting uniaxial tensile tests. Ιn future work, the fabricated scaffolds will be further utilized for investigation as potential candidate materials for cell culture with perspective in orthopedic applications.

scholarly journals Fabrication of Nanopore in MoS2-Graphene vdW Heterostructure by Ion Beam Irradiation and the Mechanical Performance

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 196
Author(s):  
Xin Wu ◽  
Ruxue Yang ◽  
Xiyue Chen ◽  
Wei Liu
Keyword(s):  
Mechanical Performance ◽  
Ion Irradiation ◽  
Ion Beam ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Beam Irradiation ◽  
Ion Beam Irradiation ◽  
Stacking Order ◽  
Vdw Heterostructure ◽  
Nanopore Structure

Nanopore structure presents great application potential especially in the area of biosensing. The two-dimensional (2D) vdW heterostructure nanopore shows unique features, while research around its fabrication is very limited. This paper proposes for the first time the use of ion beam irradiation for creating nanopore structure in 2D vdW graphene-MoS2 heterostructures. The formation process of the heterostructure nanopore is discussed first. Then, the influence of ion irradiation parameters (ion energy and ion dose) is illustrated, based on which the optimal irradiation parameters are derived. In particular, the effect of stacking order of the heterostructure 2D layers on the induced phenomena and optimal parameters are taken into consideration. Finally, uniaxial tensile tests are conducted by taking the effect of irradiation parameters, nanopore size and stacking order into account to demonstrate the mechanical performance of the heterostructure for use under a loading condition. The results would be meaningful for expanding the applications of heterostructure nanopore structure, and can arouse more research interest in this area.

Tensile Properties at High and Low Temperatures and at Room Temperature after High-Temperature Exposure

2004 ◽  
pp. 211-242
Keyword(s):  
High Temperatures ◽  
Room Temperature ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Data Set ◽  
Casting Alloys ◽  
Subzero Temperatures ◽  
Wide Range ◽  
Temperature Exposure ◽  
High And Low Temperatures

Abstract This data set contains the results of uniaxial tensile tests of a wide range of aluminum casting alloys conducted at high temperatures from 100 to 370 deg C, subzero temperatures from -269 to -28 deg C, and room temperature after holding at high temperatures from 100 to 370 deg C. In most cases, tests were made of several lots of material of each alloy and temper. The results for the several lots were then analyzed together graphically and statistically, and the averages were normalized to the room-temperature typical values. For some alloys, "representative" values (raw data) rather than typical values are provided.

Validation of the Hardening Behaviors for Metallic Materials at High Strain Rate and Temperature by Using the Taylor Impact Test

2016 ◽  
Vol 715 ◽  
pp. 153-158
Author(s):  
Ming Jun Piao ◽  
Hoon Huh ◽  
Ik Jin Lee ◽  
Hyung Won Kim ◽  
Lee Ju Park
Keyword(s):  
Tensile Tests ◽  
Thermal Softening ◽  
Experimental Results ◽  
Uniaxial Tensile ◽  
Strain Rates ◽  
Metallic Materials ◽  
Softening Effect ◽  
Impact Tests ◽  
Wide Range ◽  
Taylor Impact

This paper is concerned with the validation of the dynamic hardening behaviors of metallic materials by comparing numerical and experimental results of the Taylor impact tests. Several uniaxial tensile tests are performed at different strain rates and temperatures by using three kinds of materials: 4130 steel (BCC); OFHC copper (FCC); and Ti6Al4V alloy (HCP). Uniaxial material tests are performed at a wide range of strain rates from 10−3 s−1 to 103 s−1. Moreover, tensile tests are performed at temperature of 25 °C and 200 °C at strain rates of 10−3 s−1, 10−1 s−1, and 102 s−1, respectively. A modified Johnson–Cook type thermal softening model is utilized for the accurate application of the thermal softening effect at different strain rates. The hardening behaviors of the three materials are characterized by comparing the seven sequentially deformed shapes of the projectile from numerical and experimental results of Taylor impact tests.

scholarly journals TO THE QUESTION OF AN INTEGRATED RESEARCH OF BIOLOGICAL DAMAGE TO FIBROUS MATERIALS BY THE METHOD OF RASTER ELECTRON MICROSCOPY

2019 ◽  
Vol 20 (2) ◽  
pp. 522-534
Author(s):  
T. Balinyan ◽  
L. Derecha ◽  
Yu. Nosatenko
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Higher Plants ◽  
Morphological Characteristics ◽  
Fibrous Materials ◽  
Blue Green Algae ◽  
Biological Damage ◽  
Wide Range ◽  
Scanning Electron ◽  
Comprehensive Study

The article considers the need for a comprehensive study of biological damage to fibrous materials by scanning electron microscopy. The main types and characteristics of fibers and fibrous materials, their types of damage, in particular, biological, and the mechanism of their formation are described. It is shown that with modern methods for studying morphological characteristics, the most effective is the method of scanning electron microscopy, which makes it possible to directly study the object in a wide range of magnifications. The use of scanning electron microscopy makes it possible to identify qualitatively new volumetric microsigns when conducting studies of fibrous materials. Biological damage agents (biofactors) are considered — microbiological (bacteria, microbes, fungi, blue-green algae), phytological (mosses, lichens, higher plants, algae), zoological (insects, birds, mammals). Attention is focused on the study of injuries caused by mold caused by moths, dogs, etc. Conducting a comprehensive study of various types of damage to materials of various fibrous nature allows us to obtain an information database, the possibility of differentiating chemical, mechanical, thermal and biological damage, identifying microsigns that individualize one or another object (factor) of action, influence, increasing the potential for obtaining trace information about the actual data and circumstances of the event in those cases when only by external morphological features of the diagnosis It is not possible to repair damage. The data obtained indicate the effectiveness of the chosen research area. The results of the studies are positive for creating the optimal research scheme, methods of microscopic studies of damage to materials of fibrous nature in order to solve diagnostic, identification and situational tasks of forensic examination.

scholarly journals Optimisation of optical fibre using micro-braiding for structural health monitoring

2018 ◽  
Vol 30 (2) ◽  
pp. 171-185 ◽  
Author(s):  
Olubukola Rufai ◽  
Mayank Gautam ◽  
Prasad Potluri ◽  
Matthieu Gresil
Keyword(s):  
Structural Health Monitoring ◽  
Optical Fibre ◽  
Health Monitoring ◽  
Mechanical Performance ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Optical Fibres ◽  
Structural Health ◽  
Three Point Bend Test ◽  
Point Bend

Structural health monitoring is a fast growing area used to assess the state of various structures such as aircraft, building, bridge, wind turbine, pipe, automobile through appropriate data processing and interpretation. This article presents a novel technique of optimising the conventional optical fibres used for structural health monitoring, in order to improve their mechanical properties, and handling during the manufacturing process by micro-braiding the optical fibres. This study investigates and compares the tensile properties of the both micro-braided optical fibre and conventional optical fibres through uniaxial tensile tests. Experimental results show 85% improvement in strain at failure for the micro-braided optical fibre when compared to the optical fibres. Moreover, interfacial shear strength comparison, of the braiding yarn, between optical fibres and micro-braided optical fibre (carried out through micro-bond test) has also been conducted. In addition, the effect of embedding both micro-braided and conventional optical fibre in composite was also investigated by three-point bend test. Overall, the mechanical performance of the composite was not affected by the presence of micro-braided optical fibre. This article will also discuss the process and the advantage of micro-braided optical fibre for structural health monitoring.

scholarly journals Effect of microstructure on the formability of Ti21S alloy

2021 ◽  
Author(s):  
Cai Hu ◽  
Lionel Leotoing ◽  
Philippe Castany ◽  
Dominique Guines ◽  
Thierry Gloriant
Keyword(s):  
Titanium Alloys ◽  
Weight Ratio ◽  
Tensile Tests ◽  
Forming Limit ◽  
Uniaxial Tensile ◽  
Β Phase ◽  
Wide Range ◽  
Tension State ◽  
And Performance ◽  
Effect Of Microstructure

Titanium alloys find a wide range of uses, especially in the aeronautic industry because of a combination of favorable specifications in terms of strength-to-weight ratio, corrosion resistance and performance at high temperature. If many works are interested in mechanical properties, as well as microstructure, few of them studied the effect of microstructure on formability. The aim of this work is to study the influence of the microstructure on the formability of β metastable titanium alloys (Ti21S) which are increasingly used in aeronautical applications. For this purpose, two different heat treatments are performed on Ti21S alloy in order to propose different microstructures. Based on uniaxial tensile tests, the elastoplastic hardening behavior and the limit strain in the uniaxial tension state are obtained and allow to determine one point of the forming limit curve (FLC). From these experimental observations, it is shown that the microstructure has an important effect on the formability: precipitation of α phase reduces the formability in comparison with full β phase microstructure. Finally, a finite element M-K model is used and calibrated to predict the whole FLC for the different investigated microstructures.

scholarly journals Research on the Homogenized Postirradiation Elastoplastic Constitutive Relations for Composite Nuclear Fuels

2021 ◽  
Vol 8 ◽  
Author(s):  
Jing Zhang ◽  
Jingyu Zhang ◽  
Haoyu Wang ◽  
Hongyang Wei ◽  
Changbing Tang ◽  
...  
Keyword(s):  
Metal Matrix ◽  
Volume Fraction ◽  
Constitutive Relations ◽  
Particle Volume Fraction ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Particle Volume ◽  
Plastic Deformations ◽  
Wide Range ◽  
Irradiation Process

A multi-scale finite element method is developed to simulate the irradiation process and postirradiation uniaxial tensile tests for metal-matrix composite fuels with representative volume elements (RVEs). The simulations of irradiation process are implemented under a wide range of burnup levels, with the irradiation effects on the mechanical constitutive relations of fuel particles and matrix taken into account comprehensively. The simulation results for the macroscopic postirradiation true stress/strain curves are obtained, excluding the irradiation-induced macroscopic deformations. The effects of particle fission density, temperature, and initial particle volume fraction are investigated and analyzed. The research results indicate that 1) a quasi-elastic stage appears during the postirradiation tension, which is mainly induced by the creation of high residual compressive stresses in the particles and matrix after irradiation; 2) with the increase of effective strains, new plastic deformations increase in the particles and matrix to result in the macroscale plastic stage; 3) the macroscale irradiation softening and hardening phenomena appear, which mainly stem from the weakened deformation resistance by the irradiation-induced plastic deformations in the matrix, the enlarged particle volume fraction after irradiation, and the irradiation hardening effects of metal matrix.

Durable and Highly Dissipative Fibrous Composites for Strengthening Coastal Military Constructions

2021 ◽  
Vol 893 ◽  
pp. 75-83
Author(s):  
Cesare Signorini
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
High Resistance ◽  
Mechanical Performance ◽  
Fibrous Composite ◽  
Degradation Process ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Viable Solution ◽  
Organic Fibre

Reinforced concrete strategic structures for military purposes are often established in coastalor offshore areas, widely subjected to chemical attacks, mainly due to an aggressive saline and acidenvironments. Porosity of cementitious conglomerates favour penetration of chlorides, which tend tocorrode the internal metallic rebar. The reinforcement of structures with fibrous composite materialsis a viable solution to restore the initial requirements of the building, especially when it exerts defence purposes. Among synthetic fibres, polyphenylenebenzobisoxazole (PBO) is an organic fibre based on linked aromatic structures with high elastic modulus and tensile strength and highly dissipative attitudes. In this work, the assessment of durability of continuous fibrereinforced cementitious mortar (FRCM) composites is carried out comparing the mechanical performance of laminates subjected to uniaxial tensile tests. It is found that PBOFRCM presents high resistance against aggressive environments and specifically preserve its mechanical strength in the presence of saltwater, where other reinforcing materials undergo to a dramatic degradation process.

scholarly journals Lime-cement textile reinforced mortar (TRM) with modified interphase

2019 ◽  
Vol 17 (1) ◽  
pp. 228080001982782
Author(s):  
Cesare Signorini ◽  
Antonella Sola ◽  
Andrea Nobili ◽  
Cristina Siligardi
Keyword(s):  
Mechanical Performance ◽  
Tensile Tests ◽  
Pozzolanic Reaction ◽  
Woven Fabric ◽  
Uniaxial Tensile ◽  
Coated Fabric ◽  
The Matrix ◽  
Micro Silica ◽  
Hybrid Carbon ◽  
Textile Reinforced Mortar

Background: Lack of interphase compatibility between the fabric and the matrix significantly impairs the load-bearing capacity of textile reinforced mortar (TRM). In this study, we consider the application of two inorganic surface coatings for enhancing the interphase bond properties. Methods: Either of two silica-based coatings, namely nano- and micro-silica, were applied to alkali-resistant glass (ARG) and to hybrid carbon–ARG woven fabric. Mechanical performance of TRM reinforced with the uncoated and the coated fabric was compared in uniaxial tensile tests. Results: Mechanical testing provides evidence of a remarkable enhancement in terms of ultimate strength and deformability for the coated specimens. This effect can be ascribed to the improved hydrophilicity of the fibers’ surface and to the activation of pozzolanic reaction at the interphase. In addition, penetration of nano- and microparticles in the bundle of the textile yarns reduces the occurrence of telescopic failure.

scholarly journals Experimental Research and Simulation on the Mechanical Performance Degradation of Corroded Stud Shear Connectors

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Bing Wang ◽  
Xiaoling Liu ◽  
Jiantao Du
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Corrosion Rate ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Tensile Tests ◽  
Tensile Behavior ◽  
Uniaxial Tensile ◽  
Element Analysis ◽  
Gtn Model

Electrochemical accelerated corrosion and tensile tests were conducted on six series of 30 stud specimens in this study to assess the various mechanical properties in corroded stud connectors. The results indicate that there is a gradual decline in mechanical properties (e.g., yield strength, ultimate strength, and plasticity) as stud corrosion rate increases. Degradation equations for these parameters were established via fitting analysis on the test data. A Gurson–Tvergaard–Needleman (GTN) constitutive model describing the tensile behavior of corroded studs was established based on mesodamage mechanics and finite element analysis. In the GTN model, the corrosion rate equals the original void volume fraction; the trial-and-error method was adopted to determine the relationship between the corrosion rate and material failure parameters. The finite element simulation results are in good agreement with the experimental results. The GTN model accurately simulates the uniaxial tensile behavior of the corroded stud.

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