Determination Of Elastic Properties Research Articles

On the Determination of Elastic Properties of Single-Walled Nitride Nanotubes Using Numerical Simulation.

In recent years, tubular nanostructures have been related to immense advances in various fields of science and technology. Considerable research efforts have been centred on the theoretical prediction and manufacturing of non-carbon nanotubes (NTs), which meet modern requirements for the development of novel devices and systems. In this context, diatomic inorganic nanotubes formed by atoms of elements from the 13th group of the periodic table (B, Al, Ga, In, Tl) and nitrogen (N) have received much research attention. In this study, the elastic properties of single-walled boron nitride, aluminium nitride, gallium nitride, indium nitride, and thallium nitride nanotubes were assessed numerically using the nanoscale continuum modelling approach (also called molecular structural mechanics). The elastic properties (rigidities, surface Young's and shear moduli, and Poisson's ratio) of nitride nanotubes are discussed with respect to the bond length of the corresponding diatomic hexagonal lattice. The results obtained contribute to a better understanding of the mechanical response of nitride compound-based nanotubes, covering a broad range, from the well-studied boron nitride NTs to the hypothetical thallium nitride NTs.

Machine Learning and Data Fusion Approach for Elastic Rock Properties Estimation and Fracturability Evaluation

Accurate rock elastic property determination is vital for effective hydraulic fracturing, particularly Young's modulus due to its link to rock brittleness. This study integrates interdisciplinary data for better predictions of elastic modulus, combining data mining, experiments, and calibrated synthetics. We used the microstructural insights extracted from rock images for geomechanical facies analysis. Additionally, the petrophysical data and well logs were correlated with shear wave velocity (Vs) and Young's modulus. We developed a machine-learning workflow to predict Young's modulus and assess rock fracturability, considering mineral composition, geomechanics, and microstructure. Our findings indicate that artificial neural networks effectively predict Young's modulus, while K-Means clustering and hierarchical support vector machines excel in identifying rock and geomechanical facies. Utilizing Microscale thin section analysis in conjunction with fracture modeling enhances our understanding of fracture geometries and facilitates fracturability assessment. Notably, fracturability is controlled by specific geomechanical facies during initiation and propagation and influenced by continuity of geomechanical facies in small depth intervals. In conclusion, this study demonstrates data mining and machine learning potential for predicting rock properties and assessing fracturability, aiding hydraulic fracturing design optimization through diverse data and advanced methods.

Determination of Elastic Properties of Soils around a Typical Erosion-Prone Area in Benin City, South-South Nigeria

Soil properties play a crucial role in understanding the mechanisms of erosion and consequently developing appropriate mitigation strategies. The aim of this study is to determine the elastic parameters of soil in an erosion-prone area using the Multichannel Analysis of Surface Wave (MASW) method of geophysical exploration. The active method MASW was adopted for this study. Data were acquired using a 24-channel ABEM Terralock MATK-6 seismograph with geophones of frequency 14Hz. An 8 Kg hammer was used as a source to generate seismic energy. Data acquired were processed with SeisImager2D refraction software developed by Geometric Earth Science Ltd and 2-D shear wave (Vs) and P-wave (Vp) velocities were generated alongside 2-D profiles of Shear Modulus, Young’s Modulus, Bulk Modulus, and Poison’s Ratio. The result of this study reveals soft to medium-stiff saturated clay/dry sand/wet sand and medium-stiff to stiff saturated clays/dry sand/wet sand with shear wave velocity values ranging from 84 m/s to 504 m/s. The bulk modulus, shear modulus, poison’s ratio, and Young’s modulus range from 3.4 GPa to 5.9 GPa, 20 kPa to 440 kPa, 0.448 to 0.498, and 50 kPa to 1.05 GPa respectively.

On the Determination of Elastic Properties of Indium Nitride Nanosheets and Nanotubes by Numerical Simulation

Among the semiconductors formed by a 13th group element and nitrogen, indium nitride (InN) has promising electronic and optical properties, which make it an appropriate material for light-emitting devices and high-speed electronic applications. One-dimensional and two-dimensional InN structures, such as nanotubes and nanosheets, respectively, are expected to present novel advanced characteristics different from those of bulk InN, bringing new prospects in the designs of electronic and optical nanodevices. Despite the difficulties in the synthesis and mass production of the indium nitride nanotubes and nanosheets, the understanding of their properties, including mechanical ones, deserves more research attention, taking into account future perspectives. In this context, the present work is an exploratory study on the numerical evaluation of elastic properties of InN nanosheets and nanotubes, using the nanoscale continuum modelling (also called molecular structural mechanics) approach. The results obtained constitute a solid base for further investigation on the mechanical behaviour of the InN nanostructures, where studies are at an early stage or almost absent.

Analysis of Texture and Anisotropic Elastic Properties of Additively Manufactured Ni-Base Alloys

Additive manufacturing of metallic materials generates strong crystallographic textures, leading to anisotropic elastic properties on the macroscopic scale. The impact of the processing parameters on the resulting texture requires suitable techniques for the prediction and the experimental determination of elastic properties to exploit the anisotropy in the design process. Within this study mechanical as well as microstructure based approaches are applied on a batch of specimens manufactured from IN718 by selective laser melting to assess the elastic behavior on macroscropic scale. Tensile loading experiments and the impulse excitation technique are applied for the determination of elastic properties without additional constitutive data. Furthermore, the elastic behavior is estimated from single-crystal elastic properties and texture data measured by electron backscatter diffraction and high energy X-ray diffraction. The results of the applied approaches are discussed and compared, allowing also to assess the homogeneity of the elastic properties within the batch of specimens.

The impact of overbalance pressure on the alteration of sandstone geomechanical properties

The overbalance pressure drilling technique is well common and practiced during the drilling operations in the petroleum field. This parameter is very critical and affects the drilled formation characteristics, and therefore, the main objective of the current study is to evaluate the impact of overbalance pressure that is applied during the drilling operation on the rock elastic and strength characteristics by employing integrated lab experimental work. Berea Buff sandstone rock type was utilized to interact with water-based drilling fluid (barite-weighted) under an extended range of overbalance pressure [300 to 1000 psi]. The current research presents extensive lab analyses that cover filtration tests for rock-mud interaction, scratch testing for determining the rock strength profile, sonic data acquisition, elastic properties determination, and spectrometry of scanning electron microscope and nuclear magnetic resonance spectrometry to study the internal pore structure changes. The analysis was performed before the mud interaction for the saturated samples (base case) and after applying different overbalance pressure (pre-mud interaction) to evaluate the rock properties alterations. The obtained results showed the high degree of impact of the overbalance pressure on the sonic wave propagation as the compressional and shear wave velocities increased by 17 and 6%, respectively with increasing the overbalance pressure. Poisson’s ratio showed a stable trend, while Young’s modulus showed an increasing trend by 23% increase with the extended range of the overbalance pressure. The rock strength showed deterioration behavior with increasing the overbalance pressure. The unconfined compression strength decreased by 10% and the tensile strength showed a 9% reduction. The internal pore spectrometry showed the rock structure alterations due to mud solids precipitations and filtrate fluid impact on the rock integrity during the rock-mud interaction. In addition, statistical analysis illustrated the high degree of relationship between the recorded rock characteristics with the overbalance pressure as a controlling factor on the rock and mud interaction.

Single-ply elastic properties determination in CFRP laminates using a combined ultrasonic method

Estimation of the elastic properties in composite laminates is very important. Researchers usually consider the laminate as a whole and identify its equivalent stiffness properties. However, determining the elastic properties of each layer within a laminate can provide more comprehensive information to the users. In this paper, an ultrasonic method is proposed to reconstruct the single-ply elastic properties by combing bulk and guided waves. Herein, a novel double-side-transmitted bulk wave method is developed to identify the stacking sequences, providing the necessary information for further evaluation of the single-ply elastic properties. The double-side-transmitted bulk wave method is demonstrated under various layup scenarios, allowing the detection of more layers than conventional techniques. The laser-generated guided wave velocities are then inverted by genetic algorithms (GAs) to reconstruct the single-ply elastic properties. An effective indicator, the coefficient of variation, is designed to represent the accuracy of the identified single-ply material properties. And the experimental dispersion curves are in good agreement with the theoretical dispersion curves under the identified material properties.

IETeasy: An open source and low-cost instrument for impulse excitation technique, applied to materials classification by acoustical and mechanical properties assessment.

In the past twenty years, impulse excitation technique (IET) has become a widely diffused non-destructive technique in metal industry field. This success resides in its capability to determine with high precision and accuracy some elastic properties of materials, such as Young’s modulus, shear modulus and Poisson’s ratio. The technique, which is very fast and non-destructive, consists in exciting a sample by a mechanical input and registering the acoustic output that, once analyzed by Fast Fourier-Transformation (FFT), provides the resonant frequencies of the sample, with a fast data analysis procedure. The approach is thus very easy to be applied to most materials and cost and time effective. Despite these many advantages, IET is still an under exploited technique in academic research centres, that mainly rely on traditional destructive methods for the evaluation of such properties, for instance by the measurement of strain-stress curves. Commercial IET instruments, similarly to traditional ones, have costs spanning from many hundreds to thousands of dollars, limiting their diffusion in academic world but also in small companies with limited R&D or quality control expenses. Non-professional instruments can also give very precise results and can be successfully used in basic research and in quality control even if not certified as commercial ones. Moreover they can be easily customized according to specific user needs and sample features. Since no examples of low cost IET designs can still be found in the scientific literature, we fill the gap in this paper, giving instructions for a self-assembled instrument for IET analysis, with a cost in the range of 70–85 USD. Moreover, the collected calibration data are analyzed to prove that the instrument can be used for other purposes than the common elastic properties determination, but also for a fast and cheap material characterization exploiting a multivariate analysis approach. Calibration results show that IETeasy can be used in both academic and industrial field for quality control purposes as a low-cost, fast and efficient alternative to tensometers. Principal component analysis, applied in this paper for the first time to IET data analysis, was able to distinguish and classify steel from Al or Cu alloys from polymers, but also different steel grades, demonstrating its potential in massive and eventually automatic IET data analysis. Calculated mechanical properties fitted with good approximation the ranges expected for each sample.

Comparison of Mechanical Properties of Gypsum with and without Polypropylene Fibers

Gypsum is a mineral belonging to the group of sulfates, i.e., sulfuric acid, which is often found in Earth's crust. In this paper, two main types of gypsum, gypsum α and gypsum β, with different water content were prepared. Samples with and without polypropylene fibers, with different fiber content and different fiber lengths during preparation, produced in a gypsum factory located in the Debar region, North Macedonia, were studied. Physical properties such as density, porosity, water absorption capability and their kinetics, packing factor, hardening and others were examined using different methods. The main goal of this paper was the determination of mechanical properties of gypsum such as the compressive and flexure strength and the module of elasticity of the gypsum prisms. For the determination of elastic properties, the nondestructive method of ultrasound testing was used. In this test, the strength and quality of a prism is assessed by measuring the velocity of an ultrasonic pulse passing through a gypsum structure. This test is conducted by passing a pulse of ultrasonic wave through a prism and by measuring the time taken by the pulse to get through the structure. Higher velocities indicate good quality and continuity of the material, while slower velocities may indicate gypsum with many cracks or voids. The comparison of the obtained results from these two types of gypsum shows different mechanical and other physical properties.

On the Determination of Elastic Properties of Single-Walled Boron Nitride Nanotubes by Numerical Simulation.

The elastic properties of chiral and non-chiral single-walled boron nitride nanotubes in a wide range of their chiral indices and diameters were studied. With this aim, a three-dimensional finite element model was used to assess their rigidities and, subsequently, elastic moduli and Poisson’s ratio. An extensive study was performed to understand the impact of the input parameters on the results obtained by numerical simulation. For comparison, the elastic properties of single-walled boron nitride nanotubes are shown together with those obtained for single-walled carbon nanotubes.

A downhole uniaxial pressure gauge to determine elastic properties of hard rocks

The paper presents experimental equipment meant for determination of elastic properties in hard rocks by means of creation of adjustable uniaxial pressure on open well walls perpendicular to the well axis, measurement of deformations in a wide range of loads and for automatic recording of the observed data.

Evaluation of elastic properties of graphene nanoplatelet/epoxy nanocomposites

Abstract The present work deals with the determination of elastic properties of graphene nanoplatelet (GNP) reinforced epoxy nanocomposites. The elastic properties of GNP/epoxy nanocomposite at different fiber volume fractions have been determined. Different analytical models such as the rule of mixture, Halpin-Tsai model, Tandon-Weng model, and Chamis model have been considered to determine the elastic properties of the nanocomposites. The variation of elastic properties with volume fraction of GNP has been observed for all the four analytical models. It has been observed that the longitudinal Young’s modulus and Poisson’s ratio obtained by using all the models show good agreement with each other. Transverse Young’s modulus and in-plane shear modulus obtained by using all the models show an acceptable agreement with each other. The elastic properties of GNP/epoxy nanocomposites have also been compared with the conventional glass/epoxy composites as well as advanced carbon nanotube/epoxy nanocomposites and a similar trend of results have been observed. With the increase in volume fraction of GNP, the longitudinal Young’s modulus increases and Poisson’s ratio decreases linearly of the nanocomposite. But with the increase in volume fraction of GNP, both the transverse Young’s modulus and in-plane shear modulus of the nanocomposite increases nonlinearly. It can be concluded from the present study that the Halpin-Tsai model gives better results than the other three analytical models.

Влияние пористости слоя кремния на упругие свойства гибридных подложек SiC/Si

In this work, the influence of porosity of silicon layer with macropores on elastic and thermomechanical properties of SiC/Si substrates synthesized by the atom substitution method has been studied. Calculation of elastic constants of porous silicon has been performed by the finite element method. The results of calculation of the Young’s modulus in [111] direction are in agreement with the estimates obtained by the nanoindentation method of SiC/Si(111) substrates. The proposed theoretical model can be used for determination of elastic properties of SiC/Si substrates of different orientation.

Determination of Elastic Properties of Beech Plywood by Analytical, Experimental and Numerical Methods

This research article examines the application of various methods to determine the effective elastic properties of beech veneer-wood composites. Using laminate theory, the theoretically calculated effective values of the in-plane and out-of-plane modulus of elasticity as well as shear modulus are compared with the values determined from the natural frequencies of flexural, torsional and longitudinal vibrations of samples having different orientations and numbers of composite layers. The samples are also modelled using the finite element method, and their natural frequencies are calculated by the modal analysis. Research has shown that the laminate theory, which is well established and applied in the world of synthetic composites, can also be applied to beech plywood composites, where the theoretically calculated effective values can be up to 15% higher. Similarly, due to the higher calculated effective elastic properties, higher natural frequencies of flexural, torsional and longitudinal vibrations are also calculated by the finite element method.

Experimental determination of elastic properties of the loose materials in the field of high pressures after heating

This article presents a physical study of materials’ elastic response (asbestos, slag microspheres, fireclay and corundum powders) at the pressure up to 70 MPa. The research is carried out after heating the samples up to 500 °C and exposure to crimping pressure up to 105 MPa. The graphical dependencies are given for each materials of relative strain from the pressure level. The original research technique of elastic response for materials samples having a loose aggregate state is proposed in laboratory. This technique is based on the use of a special laboratory equipment relatively simple and efficient design which combines power and measurement components. A detailed description of the scheme and principle of operation equipment is given. The calibration of dynamometer component of the special equipment is carried out and graphs of its work are presented. A technique for calculating the elastic moduli of material samples is proposed. The elastic moduli and the relative residual deformation of the material samples are determined. The ability of materials to preserve their loose properties are studied (dismantling ability). The conclusion about the possibility of using materials in the housing of pressure vessels is made as a means of protecting their load-bearing structural elements from unwanted heating and reducing in their strength characteristics.

Representative Volume Element for Mechanical Properties of Carbon Nanotube Nanocomposites Using Stochastic Finite Element Analysis

AbstractThe aim of this study is to present a representative volume element (RVE) for nanocomposites with different microstructural features using a stochastic finite element approach. To that end, computer-simulated microstructures of nanocomposites were generated to include a variety of uncertainty present in geometry, orientation, and distribution of carbon nanotubes. Microstructures were converted into finite element models based on an image-based approach for the determination of elastic properties. For each microstructure type, 50 realizations of synthetic microstructures were generated to capture the variability as well as the average values. Computer-simulated microstructures were generated at different length scales to determine the change in mechanical properties as a function of length scale. A representative volume element is defined at a length scale beyond which no change in variability is observed. The results show that there is no universal RVE applicable to all properties and microstructures; however, the RVE size is highly dependent on microstructural features. Microstructures with agglomeration tend to require larger RVE. Similarly, random microstructures require larger RVE when compared with aligned microstructures.

Local-Basis-Function Equation of State for Ice VII–X to 450 GPa at 300 K

Helmholtz energy of ice VII–X is determined in a pressure regime extending to 450 GPa at 300 K using local-basis-functions in the form of b-splines. The new representation for the equation of state is embedded in a physics-based inverse theory framework of parameter estimation. Selected pressures as a function of volume from 14 prior experimental studies and two theoretical studies constrain the behavior of Helmholtz energy. Separately measured bulk moduli, not used to construct the representation, are accurately replicated below about 20 GPa and above 60 GPa. In the intermediate range of pressure, the experimentally determined moduli are larger and have greater scatter than values predicted using the Helmholtz representation. Although systematic error in the determination of elastic moduli is possible and likely, the alternative hypothesis is a slow relaxation time associated with changes in proton mobility or the ice VII to X transition. A correlation is observed between anomalies in the pressure derivative of the predicted bulk modulus and previously suggested higher-order phase transitions. Improved determinations of elastic properties at high pressure would allow refinement of the current equation of state. More generally, the current method of data assimilation is broadly applicable to other materials in high-pressure studies and for investigations of planetary interiors.

Micro-Macro Relationships in the Simulation of Wave Propagation Phenomenon Using the Discrete Element Method.

The present work is aimed to investigate the capability of the discrete element method (DEM) to model properly wave propagation in solid materials, with special focus on the determination of elastic properties through wave velocities. Reference micro–macro relationships for elastic constitutive parameters have been based on the kinematic hypothesis as well as obtained numerically by simulation of a quasistatic uniaxial compression test. The validity of these relationships in the dynamic analysis of the wave propagation has been checked. Propagation of the longitudinal and shear wave pulse in rectangular sample discretized with discs has been analysed. Wave propagation velocities obtained in the analysis have been used to determine elastic properties. Elastic properties obtained in the dynamic analysis have been compared with those determined by simulation of the quasistatic compression test.

Evaluation of Bridge Abutment with Ultraseismic Waveform Tomography: Field Data Application

This paper presents an application of ultraseismic waveform tomography for condition evaluation (determination of elastic properties) and the unknown depth of a concrete bridge abutment. A newly developed waveform tomography technique for bounded medium (e.g. thin plate) was applied to an ultraseismic dataset collected on a 30-m long bridge in New York City. The dataset was measured on the top of abutment using 24 100-Hz vertical geophones uniformly spaced at 1.2 m apart, and a 3-lb hammer source to induce wave energy. The results revealed that the waveform analysis was able to characterize both the S-wave and P-wave velocities (Vs and Vp) of the abutments and the supporting soils. The true abutment depth of 5.7 m was generally identified in both inverted Vs and Vp profiles. The main advantages of this approach include: (1) data acquisition on top of the abutment is more convenient and cost effective compared to measurements from the ground, boreholes, or river-beds for water bridges; and (2) abutment concrete physical elastic properties are characterized at high resolution in cells. To our best understanding, this is the first reported study using the waveform tomography on field data for assessment of concrete abutments or wall-type structures.

Elastic property determination of nanostructured W/Cu multilayer films on a flexible substrate

An experimental method for a single layer is extended to determine the elastic properties of nanostructured W/Cu multilayers on a flexible substrate. The strain difference between the W/Cu-polyimide-W/Cu composite and the uncoated substrate, measured by dual digital image correlation, allows us to extract the effective Young’s modulus of W/Cu multilayers (20 periods) equaling $$216 \pm 13\hbox { GPa}$$. Finite element method is then performed, which agrees well with the experiment and classical rule of mixture (ROM) theory demonstrating that the extension to multilayers is effective and reliable. The numerical analysis also interestingly shows that the strain difference is linearly related to the thickness ratio (W/Cu), periods and sublayer thickness, respectively. In contrast to ROM theory, this approach could potentially be used for the evaluation of properties and design of emerging/unknown functional multilayers, whether or not they are crystalline or amorphous.