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Showing papers on "Young's modulus published in 2017"


Journal ArticleDOI
TL;DR: In this article, the authors investigated the properties of blended low-calcium fly ash geopolymer concrete cured in ambient condition, and they found that the density of hardened GPC mixtures is similar to that of normal-weight OPC concrete.

295 citations


Journal ArticleDOI
TL;DR: In this article, two types of distinct texture control were achieved in low-modulus beta-type Ti-15Mo-5Zr-3Al alloy products using selective laser melting.

241 citations


Journal ArticleDOI
TL;DR: In this paper, the effects of the design parameters on the Poisson's ratio (PR), coefficient of thermal expansion (CTE), Young's modulus and relative density are systematically investigated using unit cell-based finite element simulations that incorporate periodic boundary conditions.

130 citations


Journal ArticleDOI
TL;DR: A comparison of two characterization techniques for determining the mechanical properties of thin-film organic semiconductors for applications in soft electronics provides mechanistic insight into fracture modes in this class of materials.
Abstract: This paper describes a comparison of two characterization techniques for determining the mechanical properties of thin-film organic semiconductors for applications in soft electronics. In the first method, the film is supported by water (film-on-water, FOW), and a stress–strain curve is obtained using a direct tensile test. In the second method, the film is supported by an elastomer (film-on-elastomer, FOE), and is subjected to three tests to reconstruct the key features of the stress–strain curve: the buckling test (tensile modulus), the onset of buckling (yield point), and the crack-onset strain (strain at fracture). The specimens used for the comparison are four poly(3-hexylthiophene) (P3HT) samples of increasing molecular weight (Mn = 15, 40, 63, and 80 kDa). The methods produced qualitatively similar results for mechanical properties including the tensile modulus, the yield point, and the strain at fracture. The agreement was not quantitative because of differences in mode of loading (tension vs comp...

122 citations


Journal ArticleDOI
TL;DR: The results indicate that strong and tough cellulose long fiber can be produced by using ionic crosslinking, controlling spinning speed, stretching and drying.
Abstract: Cellulose nanofiber (CNF) with high crystallinity has great mechanical stiffness and strength. However, its length is too short to be used for fibers of environmentally friendly structural composites. This paper presents a fabrication process of cellulose long fiber from CNF suspension by spinning, stretching and drying. Isolation of CNF from the hardwood pulp is done by using (2, 2, 6, 6-tetramethylpiperidine-1-yl) oxidanyl (TEMPO) oxidation. The effect of spinning speed and stretching ratio on mechanical properties of the fabricated fibers are investigated. The modulus of the fabricated fibers increases with the spinning speed as well as the stretching ratio because of the orientation of CNFs. The fabricated long fiber exhibits the maximum tensile modulus of 23.9 GPa with the maximum tensile strength of 383.3 MPa. Moreover, the fabricated long fiber exhibits high strain at break, which indicates high toughness. The results indicate that strong and tough cellulose long fiber can be produced by using ionic crosslinking, controlling spinning speed, stretching and drying.

112 citations


Journal ArticleDOI
TL;DR: An analytical model is established to estimate the quasi-static bending displacement of the pneumatic actuators made of two different elastomeric silicones and the effective modulus of elasticity of the actuators is estimated from a blocking force model.
Abstract: In this article, we have established an analytical model to estimate the quasi-static bending displacement (i.e., angle) of the pneumatic actuators made of two different elastomeric silicones (Elastosil M4601 with a bulk modulus of elasticity of 262 kPa and Translucent Soft silicone with a bulk modulus of elasticity of 48 kPa—both experimentally determined) and of discrete chambers, partially separated from each other with a gap in between the chambers to increase the magnitude of their bending angle. The numerical bending angle results from the proposed gray-box model, and the corresponding experimental results match well that the model is accurate enough to predict the bending behavior of this class of pneumatic soft actuators. Further, by using the experimental bending angle results and blocking force results, the effective modulus of elasticity of the actuators is estimated from a blocking force model. The numerical and experimental results presented show that the bending angle and blocking f...

111 citations


Journal ArticleDOI
TL;DR: In this article, a study of CFF FFF parts produced on desktop 3D printers using commercially available filament was presented, and the results showed that CFF coupons in general yield higher tensile modulus at all print orientations.
Abstract: Fused Filament Fabrication (FFF) is a widely used Additive Manufacturing (AM) technique. Recently, mechanical properties of plastic FFF parts have been enhanced by adding short carbon fibers to the thermoplastic polymer filament to form a carbon fiber filled (CFF) polymer composite. Unfortunately, improvements to the material properties of commercially available CFF filament are not well understood. This paper presents a study of CFF FFF parts produced on desktop 3D printers using commercially available filament. Tensile test samples fabricated with CFF polymer composite and unfilled polymer were printed and then tested following ASTM D3039M. Test bars were printed with FFF bead orientations aligned with the direction of the applied load at 0 °, and also at 45°, ±45°, and normal to the loading axis at 90°. The filament considered here was purchased from filament suppliers and included both CFF and unfilled PLA, ABS, PETG and Amphora. Results for tensile strength and tensile modulus show that CFF coupons in general yield higher tensile modulus at all print orientations and higher tensile strength at 0 ° print orientation. The addition of carbon fiber was shown to decrease tensile strength for some materials when printed with beads not aligned with the loading direction. Additionally, CFF samples are evaluated for fiber length distribution (FLD) and fiber weight fraction, where it was found that the filament extrusion process contributes very little to fiber breakage. Finally, fracture surfaces evaluated under SEM show that voids between the beads are reduced with CFF coupons, and poor interfacial bonding between fibers and polymer become a prominent failure mechanism.

111 citations


Journal ArticleDOI
TL;DR: In this paper, the authors synthesized all relevant experimental data in the literature to propose a new equation for predicting the modulus of elasticity (MOE) at different ages.

106 citations


Journal ArticleDOI
TL;DR: In this article, the effect of elevated temperatures on the mechanical properties of limestone, quartzite and granite concrete was investigated, and the results indicated that the mechanical property of concrete are largely affected from elevated temperatures and the type of coarse aggregate used.
Abstract: Although concrete is a noncombustible material, high temperatures such as those experienced during a fire have a negative effect on the mechanical properties. This paper studies the effect of elevated temperatures on the mechanical properties of limestone, quartzite and granite concrete. Samples from three different concrete mixes with limestone, quartzite and granite coarse aggregates were prepared. The test samples were subjected to temperatures ranging from 25 to 650 °C for a duration of 2 h. Mechanical properties of concrete including the compressive and tensile strength, modulus of elasticity, and ultimate strain in compression were obtained. Effects of temperature on resistance to degradation, thermal expansion and phase compositions of the aggregates were investigated. The results indicated that the mechanical properties of concrete are largely affected from elevated temperatures and the type of coarse aggregate used. The compressive and split tensile strength, and modulus of elasticity decreased with increasing temperature, while the ultimate strain in compression increased. Concrete made of granite coarse aggregate showed higher mechanical properties at all temperatures, followed by quartzite and limestone concretes. In addition to decomposition of cement paste, the imparity in thermal expansion behavior between cement paste and aggregates, and degradation and phase decomposition (and/or transition) of aggregates under high temperature were considered as main factors impacting the mechanical properties of concrete. The novelty of this research stems from the fact that three different aggregate types are comparatively evaluated, mechanisms are systemically analyzed, and empirical relationships are established to predict the residual compressive and tensile strength, elastic modulus, and ultimate compressive strain for concretes subjected to high temperatures.

105 citations


Journal ArticleDOI
TL;DR: In this article, two types of carbon fillers were added to polypropylene - carbon nanotubes and synthetic graphite -to improve the thermal and electrical conductivities of polymer composites but will also have a significant effect on the flexural and tensile behavior.

105 citations


Journal ArticleDOI
TL;DR: In this paper, the authors combined static and dynamic mechanical analysis on purpose-designed microstructures (microbending of pillar-like structures and picometer-sensitive laser Doppler vibrometry of drumlike structures) to viably and nondestructively estimate Young's modulus, Poisson's ratio, and density of materials for 2P lithography.
Abstract: Two-photon (2P) lithography shows great potential for the fabrication of three-dimensional (3-D) micro- and nanomechanical elements, for applications ranging from microelectromechanical systems to tissue engineering, by virtue of its high resolution (<100 nm) and biocompatibility of the photosensitive resists. However, there is a considerable lack of quantitative data on mechanical properties of materials for 2P lithography and of structures obtained through this technique. In this paper, we combined static and dynamic mechanical analysis on purpose-designed microstructures (microbending of pillar-like structures and picometer-sensitive laser Doppler vibrometry of drum-like structures) to viably and nondestructively estimate Young's modulus, Poisson's ratio, and density of materials for 2P lithography. This allowed us to analyze several polymeric photoresists, including acrylates and epoxy-based materials. The experiments reveal that the 2P exposure power is a key parameter to define the stiffness of the realized structures, with hyperelasticity clearly observable for high-power polymerization. In the linear elastic regime, some of the investigated materials are characterized by a quasi-linear dependence of Young's modulus on the used exposure power, a yet unknown behavior that adds a new degree of freedom to engineer complex 3-D micro- and nanomechanical elements.

Journal ArticleDOI
TL;DR: The elastic modulus calculated for metals was more than 50 Gigapascals (GPa) and had significantly higher modulus values compared to poly-ether- ether-ketone (PEEK) materials and allograft bone.
Abstract: Background: The modulus of elasticity of an assortment of materials used in spinal surgery, as well as cortical and cancellous bones, is determined by direct measurements and plotting of the appropriate curves. When utilized in spine surgery, the stiffness of a surgical implant can affect its material characteristics. The modulus of elasticity, or Young’s modulus, measures the stiffness of a material by calculating the slope of the material’s stress-strain curve. While many papers and presentations refer to the modulus of elasticity as a reason for the choice of a particular spinal implant, no peer-reviewed surgical journal article has previously been published where the Young’s modulus values of interbody implants have been measured. Methods: Materials were tested under pure compression at the rate of 2 mm/min. A maximum of 45 kilonewtons (kN) compressive force was applied. Stress-strain characteristics under compressive force were plotted and this plot was used to calculate the elastic modulus. Results: The elastic modulus calculated for metals was more than 50 Gigapascals (GPa) and had significantly higher modulus values compared to poly-ether-ether-ketone (PEEK) materials and allograft bone. Conclusions: The data generated in this paper may facilitate surgeons to make informed decisions on their choices of interbody implants with specific attention to the stiffness of the implant chosen.

Journal ArticleDOI
TL;DR: In this paper, the fracture toughness of iron borides was measured by microindentation technique using a Vickers diamond indenter under load of 100 gf (about 0.981 n).
Abstract: FeB and Fe2B hard ceramic phases were produced in Armco iron using gas-boriding in N2–H2–BCl3 atmosphere. This process was carried out at 920 °C (1193 K) for 3 h and caused acceleration in the diffusion of boron into the surface of a base material in comparison with other acceptable methods of diffusion boriding. FeB and Fe2B layers were characterized by a strong zonation, obtaining the average thickness of 32 μm and 125 μm, respectively. Young's moduli and hardness of iron borides were measured using the nanoindenter with a Berkovich diamond tip under load of 50 mN. The higher average indentation hardness (HIT = 20.95 ± 0.93 GPa) and Young's modulus (EIT = 308.86 ± 26.44 GPa) were characteristic of FeB phase. Fe2B boride was characterized by HIT = 17.42 ± 0.80 GPa, and EIT = 252.96 ± 15.57 GPa. The fracture toughness of iron borides was measured by microindentation technique using a Vickers diamond indenter under load of 100 gf (about 0.981 N). The average fracture toughness (Kc), measured in FeB zone, was equal to 1.79 ± 0.70 MPa·m1/2. Fe2B phase was characterized by higher fracture toughness, obtaining Kc = 2.42 ± 0.66 MPa·m1/2. However, at FeB/Fe2B interface the increase in brittleness was detected. Such a situation was caused by the differences in coefficients of thermal expansion of both iron borides and their mechanical properties. It could provide the preliminary cracks at this interface after cooling. During indentation, the value of shear stress probably exceeded the value of normal compressive stress. It could cause the failure at this interface, facilitating cracks' propagation.

Journal ArticleDOI
TL;DR: In this article, the influence of pore aspect ratio on strength and Young's modulus of porous sandstones has been investigated in two-dimensional numerical simulations (RFPA 2D ).

Journal ArticleDOI
TL;DR: In this paper, a detailed analysis has been undertaken of the mechanisms of reinforcement of polypropylene (PP) by the addition of graphene nanoplatelets (GNP) and it was found that the GNPs increased the thermal stability of the PP and aided crystal nucleation.
Abstract: A detailed analysis has been undertaken of the mechanisms of reinforcement of polypropylene (PP) by the addition of graphene nanoplatelets (GNP) The PP/GNP nanocomposites were processed by melt mixing followed by injection moulding and microstructure was fully characterized It was found that the GNPs increased the thermal stability of the PP and aided crystal nucleation The mechanical properties of the nanocomposites were evaluated using both tensile testing and dynamic mechanical thermal analysis The addition of GNPs led to a significant increase in the Young’s modulus of the PP, coupled with a decrease in the yield stress and a reduction in the elongation to failure Stress transfer from the PP matrix to the GNP reinforcement was followed from stress-induced shifts of the 2D Raman band and the effective Young’s modulus of the GNPs in the nanocomposites was found to be about 100 GPa, shown to be consistent with the expected value

Journal ArticleDOI
TL;DR: In this article, two 3D cross chiral structures with negative Poisson's ratios were proposed based on the Timoshenko beam theory, and the Young's modulus and Poisson ratio of the cellular structures were obtained in all principal directions.

Journal ArticleDOI
TL;DR: In this article, a laser assisted additive manufacturing (AM) methodology that utilizes prepreg composites (glass fiber-polypropylene) with continuous fiber reinforcement to fabricate 3D objects by implementing laser assisted bonding and laser cutting.

Journal ArticleDOI
TL;DR: In this article, the influence of fiber on the mechanical properties and impact resistance of oil palm shell geopolymer concrete (OPSGPC) prepared with ground granulated blast-furnace slag and palm oil fuel ash (POFA) as binders is reported.

Journal ArticleDOI
TL;DR: In this article, the effect of steel and Forta-ferro fibers on the mechanical properties of high-strength concrete was investigated, including compressive strength, tensile strength, modulus of elasticity, water absorption, and density.

Journal ArticleDOI
TL;DR: In this article, the authors examined the mechanical behavior of a novel class of mechanical metamaterials alternating pentamode lattices and stiffening plates, and showed that the effective compression modulus of the analyzed structures is equal to two thirds of the Young modulus for the stiffest isotropic elastic networks.
Abstract: This study examines the mechanical behavior of a novel class of mechanical metamaterials alternating pentamode lattices and stiffening plates. The unit cell of such lattices consists of a sub-lattice of the face cubic-centered unit cell typically analyzed in the current literature on pentamode materials. The studied systems exhibit only three soft deformation modes in the infinitesimal stretch-dominated regime, as opposed to the five zero-energy modes of unconfined pentamode lattices. We develop analytical formulae for the vertical and bending stiffness properties and study the dependence of such quantities on the main design parameters: the lattice constant, the solid volume fraction, the cross-section area of the rods, and the layer thickness. A noteworthy result is that the effective compression modulus of the analyzed structures is equal to two thirds of the Young modulus of the stiffest isotropic elastic networks currently available in the literature, being accompanied by zero-rigidity against infinitesimal shear and twisting mechanisms. The use of the proposed metamaterials as novel seismic-isolation devices and impact-protection equipment is discussed by drawing comparisons with the response of alternative devices already available or under development.

Journal ArticleDOI
TL;DR: In this article, the effective inverse aspect ratio (αeff) and volume fraction ( φ e f f ) of nanoparticles in polymer/CNT nanocomposites are defined accounting imperfect interfacial adhesion between polymer matrix and nanoparticles and percolation of interfacial regions as interphase percoation.

Journal ArticleDOI
TL;DR: In this article, the Young's modulus of suspended 2D material membranes from their nonlinear dynamic response is determined using the solutions of the Duffing equation using only one fit parameter.
Abstract: Due to their atomic-scale thickness, the resonances of 2D material membranes show signatures of nonlinearities at amplitudes of only a few nanometers. While the linear dynamics of membranes is well understood, the exact relation between the nonlinear response and the resonator's material properties has remained elusive. In this work, we propose a method to determine the Young's modulus of suspended 2D material membranes from their nonlinear dynamic response. The method is demonstrated by interferometric measurements on graphene and MoS2 resonators, which are electrostatically driven into the nonlinear regime at multiple driving forces. It is shown that a set of response curves can be fitted by the solutions of the Duffing equation using only one fit parameter, from which the Young's modulus is extracted using membrane theory. Our method is fast, contactless, and provides a platform for high-frequency characterization of the mechanical properties of 2D materials.

Journal ArticleDOI
TL;DR: The result of the present study indicates that the modulus of elasticity of soil can reliably be estimated from the indirect method using ANN analysis with greater confidence.
Abstract: The elastic modulus of soil is a key parameter for geotechnical projects, transportation engineering, engineering geology and geotechnics, but its estimation in laboratory or field is complex and difficult task due to instrument handling problems, high cost, and it being a time consuming process. For this reason, the predictive models are useful tool for indirect estimation of elastic modulus. In this study, to determine the modulus of elasticity of soil, a rapid, less expensive, and reliable predictive model was proposed using artificial neural network (ANN). For this purpose, a series of laboratory tests were conducted to estimate the index properties (i.e., particle size fractions, plastic limit, liquid limit, unit weight, and specific gravity) and the modulus of elasticity of soils collected from Mahabaleshwar (Maharashtra), Malshej Ghat (Maharashtra), and Lucknow (Uttar Pradesh), in India. The input parameters in the developed ANN model are gravel, sand, fines, plastic limit, liquid limit, unit weight, and specific gravity, and the output is modulus of elasticity. The accuracy of the obtained ANN model was also compared with the multiple regression model based on coefficient of determination (R 2), the mean absolute error (MAE), and the variance account for (VAF). The ANN predictive model had the R 2, MAE, and VAF equal to 0.98, 5.07, and 97.64 %, respectively, superseding the performance of the multiple regression model. The performance comparison revealed that ANN model has more reliable predictive performance than multiple regression and it can be applied for predicting the modulus of elasticity of soil with more confidence. Thus, the result of the present study indicates that the modulus of elasticity of soil can reliably be estimated from the indirect method using ANN analysis with greater confidence.

Journal ArticleDOI
15 Jan 2017
TL;DR: The developed model suggests the accurate results compared to experimental data assuming the interphase role and the best modulus of PCN is achieved by the thinnest clay layers and the thickest interphase between polymer and clay.
Abstract: The effect of percolation threshold on the mechanical properties of insulate polymer nanocomposites has been briefly investigated in literature. In this work, an approach is suggested to study the percolation threshold and interphase role in polymer/clay nanocomposites (PCN) by a model for tensile modulus. The percolation threshold is related to the aspect ratio of clay layers and the predictions of the suggested methodology are compared with the experimental data. A low percolation threshold is obtained by high aspect ratio of clay layers which increases the modulus. Also, the developed model suggests the accurate results compared to experimental data assuming the interphase role. According to the calculations, the best modulus of PCN is achieved by the thinnest clay layers and the thickest interphase between polymer and clay.

Journal ArticleDOI
TL;DR: In this paper, the elastic behavior of polypropylene fibers with carbon nanotubes was analyzed in terms of both experimental mechanical properties and numerical non-local models, showing that the tensile properties of nanocomposite fibers vary significantly with the filler content.

Journal ArticleDOI
TL;DR: In this article, the authors compared the tensile strength and ductility properties of waste steel fiber and engineered steel fiber, and found that the latter is more robust than the former.

Journal ArticleDOI
TL;DR: The Hui-Shia model, which considers the complete stress transfer between polymer matrix and particles (perfect interfacial adhesion), overpredicts the Young's modulus of clay/polymer nanocomposites (CPN) as discussed by the authors.

Journal ArticleDOI
TL;DR: In this paper, the authors measured Young's modulus and thermal conductivity of nanocrystalline diamond films with average grain sizes ranging from 6 to 15nm, considering the thermal boundary conductance between grains as well as a grain size effect on the phonon mean free path.

Journal ArticleDOI
TL;DR: In this paper, the authors present a study on the relationship between Young's modulus and DEM results, where the transverse mixing of particles within a rotating drum in rolling regime was considered.

Journal ArticleDOI
15 Nov 2017
TL;DR: Thinner and longer CNT in addition to thicker interphase enhance the volume fraction of interphase which shifts the connectivity of inter phase regions to smaller nanoparticle fraction and improves the modulus of PCNT.
Abstract: In this paper, conventional Ouali model for tensile modulus of composites is developed for polymer/carbon nanotubes (CNT) nanocomposites (PCNT) assuming the influences of filler network and dispersed nanoparticles above percolation threshold as well as the interphases between polymer host and nanoparticles which reinforce the nanocomposite and facilitate the networking. The developed model is simplified, because the characteristics of dispersed nanoparticles and surrounding interphase cannot significantly change the modulus of PCNT. The suggested model is compared to the experimentally measured modulus of some samples, which can calculate the percolation threshold of interphase regions and the possessions of interphase and filler network. The suggested model correctly predicts the influences of all parameters on the modulus. Thinner and longer CNT in addition to thicker interphase enhance the volume fraction of interphase which shifts the connectivity of interphase regions to smaller nanoparticle fraction and improves the modulus of PCNT. A very low level of percolation threshold significantly develops the modulus, but its high ranges have not any role. Among the studied parameters, the thickness and modulus of interphase between polymer host and networked nanoparticles play the most important roles in the modulus of PCNT.