scholarly journals Expanded (Black) Cork for the Development of an Eco-Friendly Surfboard: Environmental Impact and Mechanical Properties

2022 ◽  
Vol 14 (2) ◽  
pp. 668
Author(s):  
José M. D. Correia ◽  
Gabriel F. Serra ◽  
Ricardo J. Alves de Sousa ◽  
António B. Pereira ◽  
Fábio A. O. Fernandes
Keyword(s):  
Mechanical Properties ◽  
Numerical Models ◽  
Uniaxial Tensile ◽  
Prototype Model ◽  
Environmental Footprint ◽  
Compression Tests ◽  
Experimental Conditions ◽  
Bending Tests ◽  
Excellent Candidate ◽  
Sustainable Materials

Based on global needs for sustainable development, finding new sustainable materials that can replace oil-based ones for mass products is crucial nowadays. This paper focuses on employing an expanded cork-based composite to produce a surfboard. To evaluate the mechanical properties, uniaxial tensile and compression tests were performed on the skin and core materials, respectively. Bending tests were performed on the entire representative composite structure. Numerical models of the tests were arranged and validated from experimental results. From that, a surfboard prototype model was used to simulate some experimental conditions, permitting us to draw promising conclusions. An actual prototype was also produced. It was found that expanded cork performs very well when sandwiched between wood and polyester resin/glass fibre, being able to hold substantial loads and at the same time reduce weight and the environmental footprint of the composite by 62.8%. It can be concluded that expanded cork is an excellent candidate to replace oil-based foams in surfboard manufacturing. Despite a slight increase in weight, this sustainable material aligns with all the philosophies of surf practice worldwide.

Experimental investigation of the mechanical behavior of glass fiber/high fluidity polyamide-based composites for automotive market

2021 ◽  
pp. 073168442110140
Author(s):  
Hossein Ramezani-Dana ◽  
Moussa Gomina ◽  
Joël Bréard ◽  
Gilles Orange
Keyword(s):  
Mechanical Properties ◽  
Glass Fiber ◽  
Mechanical Performance ◽  
Physical And Mechanical Properties ◽  
Ultimate Strain ◽  
Uniaxial Tensile ◽  
Compression Tests ◽  
Automotive Market ◽  
Glass Fiber Reinforced ◽  
Glass Fiber Reinforcement

In this work, we examine the relationships between the microstructure and the mechanical properties of glass fiber–reinforced polyamide 6,6 composite materials ( V f = 54%). These materials made by thermocompression incorporate different grades of high fluidity polyamide-based polymers and two types of quasi-UD glass fiber reinforcement. One is a classic commercial fabric, while the other specially designed and manufactured incorporates weaker tex glass yarns (the spacer) to increase the planar permeability of the preform. The effects of the viscosity of the polymers and their composition on the wettability of the reinforcements were analyzed by scanning electron microscopy observations of the microstructure. The respective influences of the polymers and the spacer on the mechanical performance were determined by uniaxial tensile and compression tests in the directions parallel and transverse to the warp yarns. Not only does the spacer enhance permeability but it also improves physical and mechanical properties: tensile longitudinal Young’s modulus increased from 38.2 GPa to 42.9 GPa (13% growth), tensile strength increased from 618.9 MPa to 697 MPa (3% growth), and decrease in ultimate strain from 1.8% to 1.7% (5% reduction). The correlation of these results with the damage observed post mortem confirms those acquired from analyses of the microstructure of composites and the rheological behaviors of polymers.

scholarly journals Formation conditions and mechanical properties of aggregates produced in tephra–water–snow flows

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Hirofumi Niiya ◽  
Kenichi Oda ◽  
Daisuke Tsuji ◽  
Hiroaki Katsuragi
Keyword(s):  
Mechanical Properties ◽  
Mixing Time ◽  
Testing Machine ◽  
Small Scale ◽  
Scaling Analysis ◽  
Compression Tests ◽  
Ice Slurry ◽  
Experimental Conditions ◽  
Formation Conditions ◽  
Snow And Ice

Abstract The formation of aggregates consisting of snow, water, and tephra has been reported in small-scale experiments on three-phase flows containing tephra, water, and snow, representing lahars triggered by snowmelt. Such aggregates reduce the mobility of mud flow. However, the formation mechanism of such aggregates under various conditions has not been investigated. To elucidate the formation conditions and mechanical properties of the aggregates, we performed mixing experiments with materials on a rotating table and compression tests on the resulting aggregates with a universal testing machine in a low-temperature room at $$0\,^{\circ }\text {C}$$ 0 ∘ C . From experiments with varying component ratios of the mixture and tephra diameter, the following results were obtained: (i) the aggregate grew rapidly and reached maturity after a mixing time of 5 min; (ii) the mass of aggregates increased with snow concentration, exhibiting an approximately linear relationship; (iii) single aggregates with large mass formed at lower and higher tephra concentrations, whereas multiple aggregates with smaller mass were observed at intermediate concentrations; (iv) the shape of the aggregate satisfied the similarity law for an ellipsoid; (v) the compressive mechanical behavior could be modeled by an empirical nonlinear model. The obtained mechanical properties of the aggregates were independent of the experimental conditions; (vi) scaling analysis based on the Reynolds number and the strength of the aggregates showed that the aggregates cannot form in ice-slurry lahars. Our findings suggest that low-speed lahars containing snow and ice are likely to generate aggregates, but snow and ice in the ice-slurry lahars are dispersed without such aggregates.

scholarly journals Microstructure and Mechanical Properties of Hypo- and Hypereutectic Cast Mg/Mg2Si Composites

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3591
Author(s):  
Katarzyna N. Braszczyńska-Malik ◽  
Marcin A. Malik
Keyword(s):  
Mechanical Properties ◽  
Compression Strength ◽  
Eutectic Mixture ◽  
Weight Fraction ◽  
Uniaxial Tensile ◽  
Compression Tests ◽  
Magnesium Matrix ◽  
Magnesium Matrix Composites ◽  
Mg2si Phase ◽  
Microstructure And Mechanical Properties

In this paper, the microstructure and mechanical properties of two magnesium matrix composites—a hypoeutectic with 1.9 wt% Mg2Si phase and a hypereutectic with 19 wt% Mg2Si compound—were analyzed. The investigated materials were prepared using the gravity casting method. Microstructure analyses of the fabricated composites were carried out by XRD and light microscopy. The tensile and compression strength as well as yield strength of the composites were examined in both uniaxial tensile and compression tests. The microstructure of the hypoeutectic composite was in agreement with the phase diagram and composed of primary Mg dendrites and an Mg–Mg2Si eutectic mixture. For the hypereutectic composite, besides the primary Mg2Si phase and eutectic mixture, additional magnesium dendrites surrounding the Mg2Si compound were observed due to nonequilibrium solidification conditions. The composites exhibited a rise in the examined mechanical properties with an increase in the Mg2Si weight fraction and also a higher tensile and compression strength in comparison to the pure magnesium matrix (cast in the same conditions). Additionally, analyses of fracture surfaces of the composites carried out using scanning electron microscopy (SEM + EDX) are presented.

Research Progress of Strain-Rate Effect on Mechanical Properties of Concrete

2014 ◽  
Vol 638-640 ◽  
pp. 1391-1396
Author(s):  
Hong Yu Zhou ◽  
Yi Bo Chen ◽  
Ya Ran Zhang ◽  
Hai Qian Wang
Keyword(s):  
Mechanical Properties ◽  
Strain Rate ◽  
Concrete Strength ◽  
Strain Rate Effect ◽  
Rate Effect ◽  
Research Progress ◽  
Uniaxial Tensile ◽  
Compression Tests ◽  
Strain Rate Effects ◽  
Deformation Properties

Introducing research progress of rate-dependent tests by domestic and foreign scholars, strain-rate effect on dynamic mechanical properties of concrete are reviewed. Classified descriptions of research results on dynamic load tests of concrete at home and abroad are provided, including uniaxial compression tests, uniaxial tensile tests, and multi-axis tests; strain-rate effects on concrete strength and deformation properties in each test are respectively discussed; and strain-rate effect on concrete energy absorption capability are described.

Influence of Experimental Protocols on the Mechanical Properties of the Intervertebral Disc in Unconfined Compression

2011 ◽  
Vol 133 (7) ◽  
Author(s):  
Maximilien Recuerda ◽  
Simon-Pierre Coté ◽  
Isabelle Villemure ◽  
Delphine Périé
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Nucleus Pulposus ◽  
Annulus Fibrosus ◽  
Young's Modulus ◽  
Viscoelastic Model ◽  
Compression Tests ◽  
Unconfined Compression ◽  
Experimental Conditions ◽  
Experimental Protocols

The lack of standardization in experimental protocols for unconfined compression tests of intervertebral discs (IVD) tissues is a major issue in the quantification of their mechanical properties. Our hypothesis is that the experimental protocols influence the mechanical properties of both annulus fibrosus and nucleus pulposus. IVD extracted from bovine tails were tested in unconfined compression stress-relaxation experiments according to six different protocols, where for each protocol, the initial swelling of the samples and the applied preload were different. The Young’s modulus was calculated from a viscoelastic model, and the permeability from a linear biphasic poroviscoelastic model. Important differences were observed in the prediction of the mechanical properties of the IVD according to the initial experimental conditions, in agreement with our hypothesis. The protocol including an initial swelling, a 5% strain preload, and a 5% strain ramp is the most relevant protocol to test the annulus fibrosus in unconfined compression, and provides a permeability of 5.0 ± 4.2e−14m4/N·s and a Young’s modulus of 7.6 ± 4.7 kPa. The protocol with semi confined swelling and a 5% strain ramp is the most relevant protocol for the nucleus pulposus and provides a permeability of 10.7 ± 3.1 e−14m4/N·s and a Young’s modulus of 6.0 ± 2.5 kPa.

scholarly journals Mechanical properties of solid glass bricks

2019 ◽  
Author(s):  
Jiří Fíla ◽  
Martina Eliášová ◽  
Zdeněk Sokol
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
Building Materials ◽  
Flat Glass ◽  
Structural Elements ◽  
Compression Tests ◽  
Bending Tests ◽  
Load Bearing ◽  
Three Point Bending ◽  
Solid Glass

Glass as one of the oldest building materials has been used for centuries to fill window openings. In recent years is it increasingly used also for load-bearing structural elements such as beams, columns, ribs, railings, etc. In addition to flat glass and hollow glass blocks, which have been used historically for non-load-bearing partitions and facades, new load bearing structures from solid glass bricks are arising. Their greater use is hampered by a lack of knowledge of their material properties. Also, their joining is difficult, as can be seen from the realized structures and published works focused on the glass bricks masonry. Most often, transparent adhesives or special mortars are used on the joint between glass bricks. In addition to some examples of completed glass brick structures, the paper is aimed at determining the material properties of glass bricks, which are a prerequisite for the design of safe structures. Two sets of experiments were performed. There were made three-point bending tests and compression tests to determine the bending tensile strength, modulus of elasticity and compressive strength of glass bricks.

Characterizing of Anisotropy and Asymmetry of Tubular Materials

2018 ◽  
Vol 920 ◽  
pp. 211-216
Author(s):  
Heng Li ◽  
Heng Yang ◽  
Jun Ma ◽  
Zhen Yong Feng
Keyword(s):  
Mechanical Properties ◽  
Pure Titanium ◽  
Hollow Structure ◽  
High Strength ◽  
Axial Direction ◽  
Uniaxial Tensile ◽  
Compression Tests ◽  
Tension And Compression ◽  
Deformation Behaviors ◽  
Thin Walled

Titanium tubular materials with high strength, long-lifetime and light weight has attracted wide attention in many industries such as aerospace, energy and chemistry. While, titanium tubular materials are subjected to complex multiple thermal-mechanical processing, and generally present pronounced anisotropy/asymmetry properties, which greatly affects the formability and the performance of the tubular materials. Meanwhile, thin-walled tubular materials are difficult-to-characterizing materials. Thus, how to accurately and comprehensively characterize the mechanical properties is the most vital issue and precondition for innovative design of the fabricating and forming of the tubular materials and components. However, the hollow structure of tubular materials, especially thin-walled geometry, makes the testing and characterizing of the mechanical properties a challenge. In this research, a general testing and characterizing framework is developed to determine anisotropic and asymmetrical mechanical properties for tubular materials. In the framework, Knoop microhardness is first employed to qualitatively identify anisotropy and asymmetry of titanium tubes. The basic tension and compression mechanical properties along axial direction are determined by mean of uniaxial tensile and compressive tests. Combined with tension and compression tests, the viscoplastic self-consistent crystal plasticity (VPSC) is calibrated to complement the deformation behaviors along other different loading directions. Taking Ti-3Al-2.5V titanium tube and commercial pure titanium (CP-Ti) tube as the case materials, the application of the above framework for the mandrel bending demonstrates the feasibility of the proposed methodology.

scholarly journals Mycocomposites: looking for a viable alternative to EPS

2021 ◽  
Author(s):  
Vithoria Réggia Gomes Pessanha ◽  
Maria das Graças Machado Freire ◽  
Michel Picanço Oliveira ◽  
Bárbara Ferreira de Oliveira
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Compression Tests ◽  
Bending Tests ◽  
Three Point Bending ◽  
Synthetic Materials ◽  
Significant Difference ◽  
The Mean ◽  
Compressive Resistance ◽  
Base Substrate

Mycocomposites have received special attention from both academic and commercial environments. These materials give a new purpose to agricultural residues, bringing benefits to companies, society and the environment. Currently, they have been studied to replace synthetic materials such as polyester. However, its field of application is still very limited, making it necessary for more research to be carried out. In this work, mycocomposites were produced in two configurations: without jute and with two jute arranged at 1/3 of the thickness in relation to the surfaces perpendicular to loading plains during bending and compression tests. The base substrate used consisted of coconut mesocarp, white wood sawdust and wheat grain pre-myceliated by the fungus Pycnopurus sanguineus. Analysis by confocal microscopy showed that the fungus produced a network of mycelial hyphae capable of uniting substrate components and incorporated jute. Composites’ mechanical properties were evaluated from three-point bending tests and compression tests. The Shapiro-Wilk tests showed that all determined mechanical properties are normally distributed. The highest compressive resistance (10% deformation) was found in the mycocomposite without jute. The analysis of variance showed that the mean flexural strength of the two configurations analyzed did not present any statistically significant difference; despite this, the composite without jute proved to be more rigid. It was verified that the flexural strength of the produced mycocomposites is located between the values found for the expanded polystyrenes EPS 100 and EPS 150, but that their compressive strength was lower. At first, the materials produced in this work exhibited the necessary properties to be applied in simple pieces such as lampshades, packaging, and plant vases. However, it is still necessary that new studies are carried out to verify the feasibility of its application in the field of engineering, such as in civil construction panels, where EPS are used.

Plastic Formability and Auto Demonstration Parts of Mg-Nd-Zn-Zr Magnesium Alloy

2011 ◽  
Vol 690 ◽  
pp. 455-458 ◽  
Author(s):  
Jie Dong ◽  
Xing Wei Zheng ◽  
Zhen Yan Zhang ◽  
Yin Xing Wang ◽  
Li Jin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Strain Ratio ◽  
Direct Chill ◽  
Instrument Panel ◽  
Uniaxial Tensile ◽  
Compression Tests ◽  
High Toughness ◽  
Transmission Case ◽  
Dc Casting ◽  
Rectangular Tubes

Mg-3.0Nd-0.2Zn-0.4Zr (wt.%, NZ30K) alloy shows middle strength and high toughness, potentially being applied as a wrought alloy. In this paper, this alloy is first successfully cast into some billets in a diameter of 100mm by direct chill (DC) casting. The optimal casting temperature is 700°C and casting speed is 90mm/min. Then, the deformability of NZ30K alloy billets was modeled by using uniaxial tensile and compression tests at different process parameters. The results show that the optimum deformation temperature of the as-cast NZ30K alloy is between 350 and 400 °C and strain ratio ranges from 0.01 to 1 s-1. Finally some round and rectangular tubes (which are also bent and weld into a support frame for an auto instrument panel) are successfully extruded, and an end cover for auto transmission case is successfully forged. Both the extruded and forged demo parts show good mechanical properties. The maximum ultimate tensile strength, yield strength and elongation of the T5 state alloy are 323 MPa, 318MPa and 11.2%, respectively.

scholarly journals Nonlinear modelling of the seismic response of masonry structures: Calibration strategies

2021 ◽  
Author(s):  
Antonio Maria D’Altri ◽  
Francesco Cannizzaro ◽  
Massimo Petracca ◽  
Diego Alejandro Talledo
Keyword(s):  
Mechanical Properties ◽  
Numerical Models ◽  
Shear Stiffness ◽  
Model Material ◽  
National Standards ◽  
National Standard ◽  
Masonry Structures ◽  
Nonlinear Modelling ◽  
Various Boundary Conditions ◽  
Panel Stiffness

AbstractIn this paper, a simple and practitioners-friendly calibration strategy to consistently link target panel-scale mechanical properties (that can be found in national standards) to model material-scale mechanical properties is presented. Simple masonry panel geometries, with various boundary conditions, are utilized to test numerical models and calibrate their mechanical properties. The calibration is successfully conducted through five different numerical models (most of them available in commercial software packages) suitable for nonlinear modelling of masonry structures, using nonlinear static analyses. Firstly, the panel stiffness calibration is performed, focusing the attention to the shear stiffness. Secondly, the panel strength calibration is conducted for several axial load ratios by attempts using as reference the target panel strength deduced by well-known analytical strength criteria. The results in terms of panel strength for the five different models show that this calibration strategy appears effective in obtaining model properties coherent with Italian National Standard and Eurocode. Open issues remain for the calibration of the post-peak response of masonry panels, which still appears highly conventional in the standards.

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