Simultaneous Modeling of Young’s Modulus, Yield Stress, and Rupture Strain of Gelatin/Cellulose Acetate Microfibrous/Nanofibrous Scaffolds Using RSM

Electrospinning is a promising method to fabricate bioengineered scaffolds, thanks to utilizing various types of biopolymers, flexible structures, and also the diversity of output properties. Mechanical properties are one of the major components of scaffold design to fabricate an efficacious artificial substitute for the natural extracellular matrix. Additionally, fiber orientations, as one of the scaffold structural parameters, could play a crucial role in the application of fabricated fibrous scaffolds. In this study, gelatin was used as a highly biocompatible polymer in blend with cellulose acetate (CA), a polysaccharide, to enhance the achievable range of mechanical characteristics to fabricated fibrous electrospun scaffolds. By altering input variables, such as polymers concentration, weight ratio, and mandrel rotation speed, scaffolds with various mechanical and morphological properties could be achieved. As expected, the electrospun scaffold with a higher mandrel rotation speed shows higher fiber alignment. A wide range of mechanical properties were gained through different values of polymer ratio and total concentration. A general improvement in mechanical strength was observed by increasing the concentration and CA content in the solution, but contradictory effects, such as high viscosity in more concentrated solutions, influenced the mechanical characteristics as well. A response surface method was applied on experimental results in order to describe a continuous variation of Young’s modulus, yield stress, and strain at rupture. A full quadratic version of equations with the 95% confidence level was applied for the response modeling. This model would be an aid for engineers to adjust mandrel rotation speed, solution concentration, and gelatin/CA ratio to achieve desired mechanical and structural properties.

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Evaluating Mechanical Properties of Thin Layers using Nanoindentation and Finite-Element Modeling: Implanted Metals and Deposited Layers

MRS Proceedings ◽

10.1557/proc-438-617 ◽

1996 ◽

Vol 438 ◽

Cited By ~ 14

Author(s):

J. A. Knapp ◽

D. M. Follstaedt ◽

J. C. Barbour ◽

S. M. Myers ◽

J. W. Ager ◽

...

Keyword(s):

Mechanical Properties ◽

Finite Element ◽

Finite Element Modeling ◽

Yield Stress ◽

Young’S Modulus ◽

Layer Thickness ◽

Young's Modulus ◽

Thin Layers ◽

Element Modeling ◽

Surface Modified

AbstractWe present a methodology based on finite-element modeling of nanoindentation data to extract reliable and accurate mechanical properties from thin, hard films and surface-modified layers on softer substrates. The method deduces the yield stress, Young's modulus, and hardness from indentations as deep as 50% of the layer thickness.

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Effects of cross-sessional area and aspect ratio coupled with orientation on mechanical properties and deformation behavior of Cu nanowires

Nanotechnology ◽

10.1088/1361-6528/ac3e32 ◽

2021 ◽

Author(s):

Hui Cao ◽

Wenke Chen ◽

Zhiyuan Rui ◽

Changfeng Yan

Keyword(s):

Mechanical Properties ◽

Aspect Ratio ◽

Yield Stress ◽

Young’S Modulus ◽

Young's Modulus ◽

Cross Sectional Area ◽

Sectional Area ◽

Cross Sectional ◽

Cu Nanowires ◽

The Cross

Abstract Metal nanomaterials exhibit excellent mechanical properties compared with corresponding bulk materials and have potential applications in various areas. Despite a number of studies of the size effect on Cu nanowires mechanical properties with square cross-sectional, investigations of them in rectangular cross-sectional with various sizes at constant volume are rare, and lack of multifactor coupling effect on mechanical properties and quantitative investigation. In this work, the dependence of mechanical properties and deformation mechanisms of Cu nanowires/nanoplates under tension on cross-sessional area, aspect ratio of cross-sectional coupled with orientation were investigated using molecular dynamics simulations and the semi-empirical expressions related to mechanical properties were proposed. The simulation results show that the Young’s modulus and the yield stress sharply increase with the aspect ratio except for the <110>{110}{001} Cu nanowires/nanoplates at the same cross-sectional area. And the Young’s modulus increases while the yield stress decreases with the cross-sectional area of Cu nanowires. However, both of them increase with the cross-sectional area of Cu nanoplates. Besides, the Young’s modulus increases with the cross-sectional area at all the orientations. The yield stress shows a mildly downward trend except for the <111> Cu nanowires with increased cross-sectional area. For the Cu nanowires with a small cross-sectional area, the surface force increases with the aspect ratio. In contrast, it decreases with the aspect ratio increase at a large cross-sectional area. At the cross-sectional area of 13.068 nm2, the surface force decreases with the aspect ratio of the <110> Cu nanowires while it increases at other orientations. The surface force is a linearly decreasing function of the cross-sectional area at different orientations. Quantitative studies show that Young’s modulus and yield stress to the aspect ratio of the Cu nanowires satisfy exponent relationship. In addition, the main deformation mechanism of Cu nanowires is the nucleation and propagation of partial dislocations while it is the twinning-dominated reorientation for Cu nanoplates.

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Optimized CNT-PDMS Flexible Composite for Attachable Health-Care Device

Sensors ◽

10.3390/s20164523 ◽

2020 ◽

Vol 20 (16) ◽

pp. 4523 ◽

Cited By ~ 1

Author(s):

Jian Du ◽

Li Wang ◽

Yanbin Shi ◽

Feng Zhang ◽

Shiheng Hu ◽

...

Keyword(s):

Composite Material ◽

Percolation Threshold ◽

Young’S Modulus ◽

Cross Section ◽

Young's Modulus ◽

Large Strain ◽

Weight Ratio ◽

Linear Range ◽

Wide Range ◽

The Cross

The CNT-PDMS composite has been widely adopted in flexible devices due to its high elasticity, piezoresistivity, and biocompatibility. In a wide range of applications, CNT-PDMS composite sensors were used for resistive strain measurement. Accordingly, the percolation threshold 2%~4% of the CNT weight ratio in the CNT-PDMS composite was commonly selected, which is expected to achieve the optimized piezoresistive sensitivity. However, the linear range around the percolation threshold weight ratio (2%~4%) limits its application in a stable output of large strain (>20%). Therefore, comprehensive understanding of the electromechanical, mechanical, and electrical properties for the CNT-PDMS composite with different CNT weight ratios was expected. In this paper, a systematic study was conducted on the piezoresistivity, Young’s modulus, conductivity, impedance, and the cross-section morphology of different CNT weight ratios (1 to 10 wt%) of the CNT-PDMS composite material. It was experimentally observed that the piezo-resistive sensitivity of CNT-PDMS negatively correlated with the increase in the CNT weight ratio. However, the electrical conductivity, Young’s modulus, tensile strength, and the linear range of piezoresistive response of the CNT-PDMS composite positively correlated with the increase in CNT weight ratio. Furthermore, the mechanism of these phenomena was analyzed through the cross-section morphology of the CNT-PDMS composite material by using SEM imaging. From this analysis, a guideline was proposed for large strain (40%) measurement applications (e.g., motion monitoring of the human body of the finger, arm, foot, etc.), the CNT weight ratio 8 wt% was suggested to achieve the best piezoresistive sensitivity in the linear range.

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A Model for the Conductivity and Compliance of Unpropped and Natural Fractures

SPE Journal ◽

10.2118/184852-pa ◽

2017 ◽

Vol 22 (06) ◽

pp. 1893-1914 ◽

Cited By ~ 8

Author(s):

Weiwei Wu ◽

Mukul M. Sharma

Keyword(s):

Plastic Deformation ◽

Yield Stress ◽

Young’S Modulus ◽

Correlation Length ◽

Young's Modulus ◽

Heterogeneous Surfaces ◽

Natural Fractures ◽

Wide Range ◽

Fracture Closure ◽

Deformation Interaction

Summary Fluid flow in unpropped and natural fractures is critical in many geophysical processes and engineering applications. The flow conductivity in these fractures depends on their closure under stress, which is a complicated mechanical process that is challenging to model. The challenges come from the deformation interaction and the close coupling among the fracture geometry, pressure, and deformation, making the closure computationally expensive to describe. Hence, most of the previous models either use a small grid system or disregard deformation interaction or plastic deformation. In this study, a numerical model is developed to simulate the stress-driven closure and the conductivity for fractures with rough surfaces. The model integrates elastoplastic deformation and deformation interaction, and can handle contact between heterogeneous surfaces. Computation is optimized and accelerated by use of an algorithm that combines the conjugate-gradient (CG) method and the fast-Fourier-transform (FFT) technique. Computation time is significantly reduced compared with traditional methods. For example, a speedup of five orders of magnitude is obtained for a grid size of 512 × 512. The model is validated against analytical problems and experiments, for both elastic-only and elastoplastic scenarios. It is shown that interaction between asperities and plastic deformation cannot be ignored when modeling fracture closure. By applying our model, roughness and yield stress are found to have a larger effect on fracture closure and compliance than Young's modulus. Plastic deformation is a dominant contributor to closure and can make up more than 70% of the total closure in some shales. The plastic deformation also significantly alters the relationship between fracture stiffness and conductivity. Surfaces with reduced correlation length produce greater conductivity because of their larger apertures, despite more fracture closure. They have a similar fraction of area in contact as compared with surfaces with longer fracture length, but the pattern of area in contact is more scattered. Contact between heterogeneous surfaces with more soft minerals leads to increased plastic deformation and fracture closure, and results in lower fracture conductivity. Fracture compliance appears not to be as sensitive to the distribution pattern of hard and soft minerals. Our model compares well with experimental data for fracture closure, and can be applied to unpropped or natural fractures. These results are obtained for a wide range of conditions: surface profile following Gaussian distribution with correlation length of 50 µm and roughness of 4 to 50 µm, yield stress of 100 to 1500 MPa, and Young's modulus of 20 to 60 GPa. The results may be different for situations outside this range of parameters.

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The Mechanical Properties of Electroplated Cu Thin Films Measured by means of the Bulge Test Technique

MRS Proceedings ◽

10.1557/proc-695-l4.9.1 ◽

2001 ◽

Vol 695 ◽

Cited By ~ 29

Author(s):

Yong Xiang ◽

Xi Chen ◽

Joost J. Vlassak

Keyword(s):

Mechanical Properties ◽

Film Thickness ◽

Yield Stress ◽

Young’S Modulus ◽

Young's Modulus ◽

Bulge Test ◽

X Ray Diffraction ◽

Test Technique ◽

Cu Films ◽

Analytical Formulae

ABSTRACTThe mechanical properties of freestanding electroplated Cu films were determined by measuring the deflection of Si-framed, pressurized membranes. The films were deformed under plane-strain conditions. The pressure-deflection data are converted into stress-strain curves by means of simple analytical formulae. The microstructure of the Cu films was characterized using scanning electron microscopy and x-ray diffraction. The yield stress, Young's modulus, and residual stress were determined as a function of film thickness and microstructure. Both yield stress and Young's modulus increase with decreasing film thickness and correlate well with changes in the microstructure and texture of the films.

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Interfacial Effect on Mechanical Properties of Polypropylene Ternary Nanocomposites

Materials Science Forum ◽

10.4028/www.scientific.net/msf.913.564 ◽

2018 ◽

Vol 913 ◽

pp. 564-570 ◽

Cited By ~ 1

Author(s):

Wei Wang ◽

Dong Lv ◽

Jing Shen Wu

Keyword(s):

Mechanical Properties ◽

Yield Stress ◽

Young’S Modulus ◽

Young's Modulus ◽

Vital Role ◽

Enhancement Effect ◽

Weak Interface ◽

The Matrix ◽

Grafted Nanoparticles ◽

The Impact

The matrix/filler interface plays a vital role in mechanical properties of polypropylene (PP)/rigid nanoparticles composites. In general, the use of spherical stearic acid modified CaCO3 (SA-CaCO3) can induce a weak interfacewhich facilitatesparticle debonding from the matrix under loading and reduces plastic resistance, enhancing the toughness of nanocomposites, while the use of polymer-grafted nanoparticles (PGS) can improve the Young’s modulus and yield stress because of strong interfacial binding between particle and matrix. With the objective to simultaneously improve the modulus, yield stress and toughness, the ternary nanocomposites, PP/PGS/CaCO3 (PPSC), were prepared and the morphology, crystallization, and mechanical behavior were investigated and compared to their binary nanocomposites. The results show that Young’s modulus is enhanced as the particle loading, and the yield stress is balanced by two interactions, i.e. the decreasing effect of the weak interface and the enhancement effect of the strong interface. The impact strength of the ternary nanocomposites shows insignificant improvement compared with neat PP, which is attributed to the brittle effect of the weak interface in the particle cluster of SA-CaCO3 and PGS.

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Influence of calcium ions on the mechanical properties of a model biofilm of mucoid Pseudomonas aeruginosa

Water Science & Technology ◽

10.2166/wst.2001.0338 ◽

2001 ◽

Vol 43 (6) ◽

pp. 49-57 ◽

Cited By ~ 133

Author(s):

V. Körstgens ◽

H.-C. Flemming ◽

J. Wingender ◽

W. Borchard

Keyword(s):

Mechanical Properties ◽

Pseudomonas Aeruginosa ◽

Yield Stress ◽

Young’S Modulus ◽

Calcium Ions ◽

Extracellular Polymeric Substances ◽

Young's Modulus ◽

Critical Concentration ◽

Strain Diagram ◽

Stress Strain

The mechanical properties of biofilms and in particular their mechanical strength is of great importance for both biofilm reactors and for the removal of undesired biofilms as in cases of biofouling and biocorrosion. By uniaxial compression measurements, it is possible to determine the apparent elastic or Young's modulus and the yield stress as parameters for mechanical stability. This was performed with a recently developed device, using model biofilms of mucoid strain Pseudomonas aeruginosa SG81. The biofilms were grown on membrane filters placed on nutrient agar medium with different concentrations of calcium ions. The compressive stress - strain behaviour up to failure was recorded at a compression speed of 1 μm s-1. The apparent Young's modulus, representing the stiffness of the biofilm, and the yield stress obtained from the stress - strain diagram were used for the description of mechanical properties of biofilms. A certain critical concentration of calcium ions was found where the Young's modulus of the P. aeruginosa biofilms increases strongly and subsequently remains constant for higher calcium concentrations. This behaviour is explained by the presence of calcium ions crosslinking alginate, which is the major component of the extracellular polymeric substances produced by the mucoid P. aeruginosa strain used in this investigation.

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Preparation and Properties of Paper Yarn from Mulberry

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.175-176.575 ◽

2011 ◽

Vol 175-176 ◽

pp. 575-579 ◽

Cited By ~ 3

Author(s):

Midori Takasaki ◽

Rie Ogura ◽

Hideaki Morikawa ◽

Seiji Chino ◽

Hisanaga Tsuiki

Keyword(s):

Mechanical Properties ◽

Young’S Modulus ◽

Molecular Orientation ◽

Young's Modulus ◽

Weight Ratio

We examined the molecular orientation of paper and mechanical properties of prepared paper yarn by twisting strips of paper made from various ratios of mulberry bast and Manila hemp. The molecular orientation of paper in direction of the strip was highest for paper with a mulberry bast weight ratio of 30 wt% as measured by a microwave molecular orientation analyzer. In contrast, the paper yarn sample with a mulberry bast weight ratio of 100 wt% showed a low molecular orientation of paper in direction of the strip. For mechanical properties, paper yarn with mulberry bast weight ratio of 30 wt% had the highest strength and Young’s modulus and the lowest elongation. These results show that the mechanical properties of the paper yarn depend on the molecular orientation of the paper in direction of strip.

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Relationship between Thermal Diffusivity and Mechanical Properties of Wood

Materials ◽

10.3390/ma15020632 ◽

2022 ◽

Vol 15 (2) ◽

pp. 632

Author(s):

Yuri I. Golovin ◽

Alexander I. Tyurin ◽

Dmitry Yu. Golovin ◽

Alexander A. Samodurov ◽

Sergey M. Matveev ◽

...

Keyword(s):

Mechanical Properties ◽

Thermal Diffusivity ◽

Young’S Modulus ◽

Mechanical Characteristics ◽

Young's Modulus ◽

Brinell Hardness ◽

Mechanical Tests ◽

Pedunculate Oak ◽

Young’S Moduli ◽

Diffusivity Tensor

This paper describes an experimental study of the relationships between thermal diffusivity and mechanical characteristics including Brinell hardness, microhardness, and Young’s modulus of common pine (Pinus sylvestris L.), pedunculate oak (Quercus robur L.), and small-leaf lime (Tilia cordata Mill.) wood. A dependence of Brinell hardness and thermal diffusivity tensor components upon humidity for common pine wood is found. The results of the measurement of Brinell hardness, microhardness, Young’s modulus, and main components of thermal diffusivity tensor for three perpendicular cuts are found to be correlated. It is shown that the mechanical properties correlate better with the ratio of longitude to transversal thermal diffusivity coefficients than with the respective individual absolute values. The mechanical characteristics with the highest correlation with the abovementioned ratio are found to be the ratio of Young’s moduli in longitude and transversal directions. Our technique allows a comparative express assessment of wood mechanical properties by means of a contactless non-destructive measurement of its thermal properties using dynamic thermal imaging instead of laborious and material-consuming destructive mechanical tests.

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Young's Modulus and Dynamic Mechanical Properties of San Resins Modified with Ethylene-Propylene Rubber

Rubber Chemistry and Technology ◽

10.5254/1.3535753 ◽

1978 ◽

Vol 51 (4) ◽

pp. 655-667 ◽

Cited By ~ 2

Author(s):

A. Brancaccio ◽

L. Gargani ◽

G. P. Giuliani

Keyword(s):

Mechanical Properties ◽

Young’S Modulus ◽

Young's Modulus ◽

Dynamic Mechanical Properties ◽

Ethylene Propylene ◽

Dynamic Mechanical ◽

Styrene Copolymer ◽

Wide Range ◽

Main Transition ◽

The Relationship

Abstract The dependence of Young's modulus and dynamic mechanical properties of a new high impact resin, ATS (acrylonitrile-styrene copolymer polymerized in the presence of ethylene-propylene-triene terpolymer), on the composition and morphology of the dispersed phase is examined and compared to that of ABS resins (acrylonitrile-styrene copolymer polymerized in presence of polybutadiene). The relationship between modulus and composition is different for the two resins because of the different morphology of the rubbery phases. The experimental results are compared to the predictions of several mathematical models. This analysis is extended to the dynamic moduli E′ and E″, measured over a wide range of temperatures covering the main transition of the rubbery phases.

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