Characterization tests for predicting the mechanical performance of SFRC floors: identification of fibre distribution and orientation effects

AbstractIn the context of the evaluation of the load-bearing capacity of a steel fibre reinforced concrete (SFRC) elevated slab recently built in northern Italy, this paper presents the study addressing the effects of fibre distribution and orientation. An extensive experimental programme was carried out in a collaboration between Politecnico di Milano and Universitat Politècnica de Catalunya. The programme included mechanical tests on four shallow beams and six notched standard beams. Additionally, uniaxial tensile tests (UTTs), double edge wedge splitting tests (DEWSTs) and double punching tests (DPTs) on 192 drilled core samples extracted from the shallow beams were performed. Inductive tests, measuring the self-induction change that occurs when a SFRC sample is placed inside a coil, were performed on all samples subjected to DPTs to assess fibre distribution. This paper compares direct and indirect tensile tests for the definition of the FRC post-cracking constitutive law, highlighting advantages and disadvantages of each test type. A comparison between standard and non-standard mechanical tests is also presented. Mechanical and non-destructive tests on drilled core samples extracted in different directions and at different locations have allowed the evaluation of the effects of fibre distribution and fibre orientation which provide an estimation of the possibility of using these tests as simplified tests for production control.

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

Nanomaterials ◽

10.3390/nano12020196 ◽

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.

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Study for Performance Increase of a Extractor Device by Steel Replacement of AISI 304 Steel for AISI 420 Steel

Materials ◽

10.3390/ma15010280 ◽

2021 ◽

Vol 15 (1) ◽

pp. 280

Author(s):

Francisco Alves de Lima Júnior ◽

Ricardo Artur Sanguinetti Ferreira ◽

Rômulo Rocha de Araújo Lima

Keyword(s):

Stainless Steel ◽

Service Life ◽

Tensile Tests ◽

Mechanical Tests ◽

Uniaxial Tensile ◽

Manufacturing Cost ◽

Aisi 304 ◽

Aisi 420 ◽

Hardness Tests ◽

Steel Aisi

The performance of an extractor device used in the food industry was studied from the development of structural analysis through computational modeling based on finite elements. These analyses considered the mechanical properties of AISI 304 and 420 stainless steels, in addition to the tribological aspects of the device in operation. Initially, uniaxial tensile tests were carried out according to the ABNT NBR 6892 standard and hardness tests were carried out according to ASTM E384, E92, and E18 standards. From the mechanical tests, structural analyses were carried out numerically on each of the components of the extractor device. After analyzing all the components, the device was assembled to be tested in operation. The wear and service life of devices made from these two materials were evaluated. From this study, it could be concluded that the extractor device made with AISI 420 stainless steel, in addition to having a lower manufacturing cost, suffered less wear and had an increase in service life of up to 650% compared to the extractor device made with steel stainless steel AISI 304.

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

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x18810805 ◽

2018 ◽

Vol 30 (2) ◽

pp. 171-185 ◽

Cited By ~ 2

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.

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Durable and Highly Dissipative Fibrous Composites for Strengthening Coastal Military Constructions

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.893.75 ◽

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.

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Degradation Mechanisms of Underfills Subjected to Isothermal Long-Term Aging From 150°C to 200°C

ASME 2020 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems ◽

10.1115/ipack2020-2677 ◽

2020 ◽

Author(s):

Pradeep Lall ◽

Yunli Zhang ◽

Haotian Wu ◽

Ed Davis ◽

Jeff Suhling

Keyword(s):

High Temperature ◽

Tensile Tests ◽

Optical Microscope ◽

Mechanical Tests ◽

Uniaxial Tensile ◽

Cross Section Area ◽

Section Area ◽

Before And After ◽

Damage Tolerant ◽

High Temperature Operation

Abstract FCBGAs are finding applications in automotive underhood environments where they may be subjected to sustained temperatures of 125–200°C for sustained periods during operation. While, FCGBAs have been previously used in consumer applications where operating temperatures typically range in 55–85°C, relatively little is known on methods to design damage-tolerant packages in automotive underhood environments. There is insufficient information on plastic encapsulated electronic components capable of surviving high temperatures for long periods (> 100,000 hours). In this paper, four different types of underfills has been cured and aged. Mechanical tests have been performed on all the four types of underfills too understand the degradation in properties under extended high temperature operation. Uniaxial tensile tests are conducted to study the elastic modulus, ultimate tensile strength and percentage elongation of the underfills. After uniaxial tensile tests, Optical Microscope, SEM and EDS are applied to study the microstructure behaviors of the cross-section area of the underfills. The experimental results are compared before and after aging tests, including pristine, 30 days, 60 days, 90days, 120 days and 240 days. The research focuses on microstructure-property-processing-performance relationships, building the relation between the microstructure evolution and macro-mechanical properties. Reliability physics of high temperature degradation of packaging material is studied.

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

Journal of Applied Biomaterials & Functional Materials ◽

10.1177/2280800019827823 ◽

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.

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

Mathematical Problems in Engineering ◽

10.1155/2019/2846467 ◽

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

International Journal of Molecular Sciences ◽

10.3390/ijms21020583 ◽

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.

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Experimental, Computational, and Dimensional Analysis of the Mechanical Performance of Fused Filament Fabrication Parts

Polymers ◽

10.3390/polym13111766 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1766

Author(s):

Iván Rivet ◽

Narges Dialami ◽

Miguel Cervera ◽

Michele Chiumenti ◽

Guillermo Reyes ◽

...

Keyword(s):

Dimensional Analysis ◽

Mechanical Performance ◽

Cost Savings ◽

Acrylonitrile Butadiene Styrene ◽

Tensile Tests ◽

Uniaxial Tensile ◽

Zone Model ◽

Key Factors ◽

Fused Filament Fabrication ◽

3D Printed

Process parameters in Additive Manufacturing (AM) are key factors in the mechanical performance of 3D-printed parts. In order to study their effect, a three-zone model based on the printing pattern was developed. This modelization distinguished three different zones of the 3D-printed part, namely cover, contour, and inner; each zone was treated as a different material. The cover and contour zones were characterized via uniaxial tensile tests and the inner zones via computational homogenization. The model was then validated by means of bending tests and their corresponding computational simulations. To reduce the number of required characterization experiments, a relationship between the raw and 3D-printed material was established by dimensional analysis. This allowed describing the mechanical properties of the printed part with a reduced set of the most influential non-dimensional relationships. The influence on the performance of the parts of inter-layer adhesion was also addressed in this work via the characterization of samples made of Polycarbonate Acrylonitrile Butadiene Styrene (ABS/PC), a polymeric material well known for its poor adhesion strength. It was concluded that by using this approach, the number of required testing configurations could be reduced by two thirds, which implies considerable cost savings.

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Development of a Global Indicator to Assess Mechanical Tests

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.651-653.883 ◽

2015 ◽

Vol 651-653 ◽

pp. 883-888

Author(s):

Nelson Souto ◽

Sandrine Thuillier ◽

António Andrade-Campos

Keyword(s):

Plane Strain ◽

Simple Shear ◽

Kinematic Hardening ◽

Tensile Tests ◽

Mechanical Tests ◽

Material Behavior ◽

Uniaxial Tensile ◽

Strain Fields ◽

Global Indicator

Full-field measurement methods have emerged in the last years and these methods are characterized by directly providing displacement and strain fields for all points over the specimen surface. Thus, the design of heterogeneous tests can be performed for material parameter identification purposes since the inhomogeneous strain fields can be measured. However, (i) no defined criterion yet exists for designing new heterogeneous tests, (ii) it is rather difficult to compare and rate different tests and (iii) a quantitative way to define the best test for material behavior characterization of sheet metals has yet to be proposed. Due to this, the goal of this work is the development of a global indicator able to assess mechanical tests. The proposed indicator quantifies the strain state range, the deformation heterogeneity and the strain level achieved in the test, based on a continuous evaluation of the strain field up to rupture. This global indicator was applied to rank some classical tests, such as uniaxial tensile, simple shear, plane strain and biaxial tensile tests. These tests were carried out numerically by reproducing the virtual behavior of DC04 mild steel. A constitutive model composed by the non-quadratic Yld2004-18p yield criterion combined with a mixed isotropic-kinematic hardening law and a macroscopic rupture criterion was used. The performance of the tests was compared with the indicator and a ranking was established. The results obtained show that biaxial tension is the test providing more information for the mechanical behavior characterization of the material. It was also verified that plane strain test presents a better performance than simple shear and uniaxial tensile tests.

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