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This paper aims to apply the novel numerical model to analyze the effect of pillar material on the response of compound quartz crystal resonator (QCR) with an array of pillars. The performance of the proposed device compared to conventional QCR method was also investigated.

A finite element method model was developed to analyze the behavior of QCR coupled with an array of pillars. The model was composed of an elastic pillar, a solution and a perfectly matched layer. The validation of the model was performed through a comparison between its predictions and previous experimental measurements. Notably, a good agreement was observed between the predicted results and the experimental data.

The effect of pillar Young’s modulus on the coupled QCR and pillars with a diameter of 20 µm, a center-to-center spacing of 40 µm and a density of 2,500 kg/m³ was investigated. The results indicate that multiple vibration modes can be obtained based on Young’s modulus. Notably, in the case of the QCR–pillar in air, the second vibration mode occurred at a critical Young’s modulus of 0.2 MPa, whereas the first mode was observed at 3.75 Mpa. The vibration phase analysis revealed phase-veering behavior at the critical Young’s modulus, which resulted in a sudden jump-and-drop frequency shift. In addition, the results show that the critical Young’s modulus is dependent on the surrounding environment of the pillar. For instance, the critical Young’s modulus for the first mode of the pillar is approximately 3.75 Mpa in air, whereas it increases to 6.5 Mpa in water.

It was concluded that the performance of coupled QCR–pillar devices significantly depends on the pillar material. Therefore, choosing pillar material at critical Young’s modulus can lead to the maximum frequency shift of coupled QCR–pillar devices. The model developed in this work helps the researchers design pillars to achieve maximum frequency shift in their measurements using coupled QCR–pillar.

The purpose of this paper is to study elastic properties of III-V nitride nanotubes (NNTs) using second generation (REBO) potential.

In the present research paper elastic properties of BN, AlN and GaN nanotubes have been investigated, using the second generation REBO potential by Brenner and co-workers, which is a bond order potential earlier used for carbon nanostructures successfully. In the present calculation, the same form of potential is used with adjusted parameters for h-BN, h-AlN and h-GaN. In all these cases the authors have considered graphite like network and strongly polar nature of these atoms so electrostatic forces are expected to play an important role in determining elastic properties of these nanotubes. The authors generate the coordinates of nanotubes of different chirality’s and size. Each and every structure thus generated is allowed to relax till the authors obtain minima of energy. The authors then apply the requisite compressions, elongations and twists to the structures and compute the elastic moduli. Young’s Modulus, Shear Modulus and Poisson’s ratio for single-walled armchair and zigzag tubes of different chirality’s and size have been calculated. The computational results show the variation of Young’s Modulus, Poisson’s ratio and Shear Modulus for these NNTs with nanotube diameter. The results have been compared with available data, experimental as well as theoretical.

The authors have calculated bond length, cohesive energy/bond, Strain energy, Young’s Modulus, Shear Modulus and Poisson’s ratio.

To the best of the knowledge this work is the first attempt to study elastic properties of III-V NNTs using second generation REBO potential

Microstereolithography is capable of producing millimeter-scale polymer parts having micron-scale features. Material properties of the cured polymers can vary depending on build parameters such as exposure. Current techniques for determining the material properties of these polymers are limited to static measurements via micro/nanoindentation, leaving the dynamic response undetermined. The purpose of this paper is to demonstrate a method to measure the dynamic response of additively manufactured parts to infer the dynamic modulus of the material in the ultrasonic range.

Frequency-dependent material parameters, such as the complex Young’s modulus, have been determined for other relaxing materials by measuring the wave speed and attenuation of an ultrasonic pulse traveling through the materials. This work uses laser Doppler velocimetry to measure propagating ultrasonic waves in a solid cylindrical waveguide produced using microstereolithography to determine the frequency-dependent material parameters of the polymer. Because the ultrasonic wavelength is comparable with the part size, a model that accounts for both geometric and viscoelastic dispersive effects is used to determine the material properties using experimental data.

The dynamic modulus in the ultrasonic range of 0.4-1.3 MHz was determined for a microstereolithography part. Results were corroborated by using the same experimental method for an acrylic part with known properties and by evaluating the natural frequency and storage modulus of the same microstereolithography part with a shaker table experiment.

The paper demonstrates a method for determining the dynamic modulus of additively manufactured parts, including relatively small parts fabricated with microstereolithography.

Additive manufacturing (AM) methods such as material extrusion (ME) are becoming widely used by engineers, designers and hobbyists alike for a wide variety of applications. Successfully manufacturing objects using ME three-dimensional printers can often require numerous iterations to attain predictable performance because the exact mechanical behavior of parts fabricated via additive processes are difficult to predict. One of that factors that contributes to this difficulty is the wide variety of ME feed stock materials currently available in the marketplace. These build materials are often sold based on their base polymer material such as acrylonitrile butadiene styrene or polylactic acid (PLA), but are produced by numerous different commercial suppliers in a wide variety of colors using typically undisclosed additive feed stocks and base polymer formulations. This paper aims to present the results from an experimental study concerned with quantifying how these sources of polymer variability can affect the mechanical behavior of three-dimensional printed objects. Specifically, the set of experiments conducted in this study focused on following: several different colors of PLA filament from a single commercial supplier to explore the effect of color additives and three filaments of the same color but produced by three different suppliers to account for potential variations in polymer formulation.

A set of five common mechanical and material characterization tests were performed on 11 commercially available PLA filaments in an effort to gain insight into the variations in mechanical response that stem from variances in filament manufacturer, feed stock polymer, additives and processing. Three black PLA filaments were purchased from three different commercial suppliers to consider the variations introduced by use of different feed stock polymers and filament processing by different manufacturers. An additional eight PLA filaments in varying colors were purchased from one of the three suppliers to focus on how color additives lead to property variations. Some tests were performed on unprocessed filament samples, while others were performed on objects three-dimensional printed from the various filaments. This study looked specifically at four mechanical properties (Young’s modulus, storage modulus, yield strength and toughness) as a function of numerous material properties (e.g. additive loading, molecular weight, molecular weight dispersity, enthalpy of melting and crystallinity).

For the 11 filaments tested the following mean values and standard deviations were observed for the material properties considered: p_a = 1.3 ± 0.9% (percent additives), M_w = 98.6 ± 16.4 kDa (molecular weight), Ð = 1.33 ± 0.1 (molecular weight dispersity), H_m = 37.4 ± 7.2 J/g (enthalpy of melting) and = 19.6 ± 2.1% (crystallinity). The corresponding mean values and standard deviations for the resulting mechanical behaviors were: E = 2,790 ± 145 MPa (Young’s modulus), E’ = 1,050 ± 125 MPa (storage modulus), S_y = 49.6 ± 4.93 MPa (yield strength) and U_t = 1.87 ± 0.354 MJ/m^³ (toughness). These variations were observed in filaments that were all manufactured from the same base polymer (e.g. PLA) and are only different in terms of the additives used by the manufacturers to produce different colors or different three-dimensional printing performance. Unfortunately, while the observed variations were significant, no definitive strong correlations were found between these observed variations in the mechanical behavior of the filaments studied and the considered material properties.

These variations in mechanical behavior and material properties could not be ascribed to any specific factor, but rather show that the mechanical of three-dimensional printed parts are potentially affected by variations in base polymer properties, additive usage and filament processing choices in complex ways that can be difficult to predict.

These results emphasize the need to take processing and thereby even filament color, into account when using ME printers, they emphasize the need for designers to use AM with caution when the mechanical behavior of a printed part is critical and they highlight the need for continued research in this important area. While all filaments used were marked as PLA, the feedstock materials, additives and processing conditions created significant differences in the mechanical behavior of the printed objects evaluated, but these differences could not be accurately and reliably predicted as function of the observed material properties that were the focus of this study.

The testing methods used in the study can be used by engineers and creators alike to better analyze the material properties of their filament printed objects, to increase success in print and mechanical design. Furthermore, the results clearly show that as AM continues to evolve and grow as a manufacturing method, standardization of feedstock processing conditions and additives would enable more reliable and repeatable printed objects and would better assist designers in effectively implementing AM methods.

In this paper, the main factors influencing the structure stiffness will be analyzed by studying the tangent stiffness matrix based on different requirement in engineering practice. The authors can obtain the deformation of three-bar tensegrity basic unit in different load, and gain the primary factor by comparing the deformation, which will provide reference to concrete structure design in the engineering.

The mathematical model of tensegrity structure was built by establishing generalized node coordinates and connective matrix. Three main factors that affect the structure deformation can be obtained by analyzing the stiffness matrix, which is preload, Young's modulus, and cross-sectional area, the thinking of deformation also be sorted out. The deformation analysis of the concrete structure is carried out, and it is concluded that increasing the cross-sectional area can quickly improve the stiffness of the structure, which provides a reference for the structural variable stiffness design in practical engineering.

(1) When the axial external force is applied to the structure, the torsion-angle deformation of the structure is the largest, and the radial deformation of the structure is the smallest. (2) The structure stiffness can be rapidly enhanced by increasing the cross-sectional area. But the cross-sectional area can't be increased indefinitely. Because the mass will be increased once increasing the cross-sectional area, which will destroy the structure of the advantages of light weight in engineering practice.

The deformation analysis of the concrete structure is carried out, and it is concluded that increasing the cross-sectional area can quickly improve the stiffness of the structure, which provides a reference for the structural variable stiffness design in practical engineering.

Evaluating mechanical properties of simply made samples by 3D printing technology at nanoscale provides a clear path to better understand larger-scale responses of complex natural rocks. Therefore, to realize the similarity between synthetically manufactured materials and natural geomaterials, this study focused on nanoscale mechanical characterization of a 3D printed object with only two constituent components (gypsum powder and infiltrant).

The study method includes nanoindentation technique combined with numerical simulation via discrete element method (DEM).

Four typical load-displacement curves were identified from nanoindentation of total test points indicating a typical elastic-plastic behavior of the 3D printed gypsum rock sample. Mechanical parameters such as Young’s modulus and hardness were calculated by energy-based methods and a positive correlation was observed. The infiltrant was found to considerably be responsible for the majority of the sample nano-mechanical behavior rather than the gypsum particles, thus expected to control macroscale properties. This was decided from deconvolution and clustering of elastic modulus data. Particle flow modeling in DEM was used to simulate the nanoindentation process in a porous media yielding rock-alike mechanical behavior.

The results show a matching load-displacement response between experimental and simulation results, which verified the credibility of simulation modeling for mechanical behavior of 3D printed gypsum rock at nanoscale. Finally, differential effective medium theory was used to upscale the nanoindentation results to the macroscale mechanical properties, which provided an insight into the geomechanical modeling at multiscale.

This study aims to investigate the structural, mechanical, thermal and electrical properties of tin–silver–nickel (Sn-Ag-Ni) melt-spun solder alloys. So, it aims to improve the mechanical properties of the eutectic tin–silver (Sn-Ag) such as tensile strength, plasticity and creep resistance by adding different concentrations of Ni content.

Ternary melt-spun Sn-Ag-Ni alloys were investigated using x-ray diffractions, scanning electron microscope, dynamic resonance technique (DRT), Instron machine, Vickers hardness tester and differential scanning calorimetry.

The results revealed that the Ni additions 0.1, 0.3, 0.5, 0.7, 1, 3 and 5 Wt.% to the eutectic Sn-Ag melt-spun solder were added. The “0.3wt.%” of Ni was significantly improved its mechanical properties to efficiently serve under high strain rate applications. Moreover, the uniform distribution of Ag₃Sn intermetallic compound with “0.3wt.%” of Ni offered the potential benefits, such as high strength, good plasticity consequently and good mechanical performance through a lack of dislocations and microvoids. The tensile results showed improvement in 17.63 per cent tensile strength (26 MPa), 21 per cent toughness (1001 J/m³), 22.83 per cent critical shear stress (25.074 MPa) and 11 per cent thermal diffusivity (2.065 × 10⁻⁷ m²/s) when compared with the tensile strength (21.416 MPa), toughness (790 J/m³), critical shear stress (19.348 MPa) and thermal diffusivity (1.487 × 10⁻⁷ m²/s) of the eutectic Sn-Ag. Slight increments have been shown for the melting temperature of Sn_96.2-Ag_3.5-Ni_0.3 (222.62°C) and electrical resistivity to (1.612 × 10⁻⁷ Ω.m). It can be said that the eutectic Sn-Ag solder alloy has been mechanically improved with “0.3wt.%” of Ni to become a suitable alloy for high strain rate applications. The dislocation movement deformation mechanism (n = 4.5) without Ni additions changed to grain boundary sliding deformation mechanism (n = 3.5) with Ni additions. On the other hand, the elastic modulus, creep rate and strain rate sensitivity with “0.3wt.%” of Ni have been decreased. The optimum Ni-doped concentration is “0.7wt.%” of Ni in terms of refined microstructure, electrical resistivity, Young’s Modulus, bulk modulus, shear modulus, thermal diffusivity, maximum shear stress, tensile strength and average creep rate.

This study provides nickel effects on the structural of the eutectic Sn-Ag rapidly solidified by melt-spinning technique. In this paper, the authors have compared the elastic modulus of the melt-spun compositions which has been resulted from the tensile strength tester with these results from the DRT for the first time to best of the authors’ knowledge. This paper presents new improvements in mechanical and electrical performance.

The limit elastic speed of rotating disk is an important design criterion, as it defines the limit before onset of yielding initiates. The purpose of this paper is to establish the limit elastic speeds for S-FG disks and report the stresses induced at such speeds.

For S-FGM disk, effective Young’s modulus is calculated using modified rule of mixture and subsequently effective yield stress is also calculated by taking into consideration of stress-strain transfer ratio. The S-FGM disk is subject to centrifugal loading and the stress and deformation characteristics are investigated using variational principle wherein the solution is obtained by Galerkin’s error minimization principle. Based on von-Mises yield criteria, equivalent stress is calculated at different angular speeds till the equivalent stress at any given location in the disk attains the value of effective yield stress at the given location (location of yield initiation). This defines the limit elastic speed for the S-FGM disk (for given n).

The limit elastic speed of S-FGM disks for a range of grading index (n) and corresponding stresses within the disk are reported. Results are reported for uniform disks of different aspect ratio and the results reported could be used as practical design data.

Functional grading of material in structures opens a new horizon to explore the possibility of manufacturing high strength component at low weight. Material grading plays a significant role in achieving desired material properties, and literature review reveals reporting of numerous grading functions to approximate material distribution in structure.

The work has not been addressed earlier and findings provide a pioneering insight into the performance of S-FG disks.

The purpose of this study was carried out to explore the potential use of carrageenan extracted from marine red seaweed (Kappaphycus alvarezii) collected from Munaikadu, Mandapam region, Ramanathapuram district, Tamil Nadu.

Biodegradable film was developed by using carrageenan extracted by using alcohol extraction method. To improve the mechanical properties of the film, rice starch was incorporated. The biodegradable films were made by phase inversion method with varied carrageenan concentration of 1%, 1.5% and 2% (w/v) and rice starch with concentration of 0%, 1%, 1.5% and 2% (w/v). Physical properties, optical properties, mechanical properties and other properties such as biodegradability, solubility and water vapor permeability of the developed biodegradable films were characterized. The results were analyzed in design expert software using Box–Behnken design.

Results show that the biodegradable film’s mechanical and water vapor permeability increases with an increase in carrageenan and rice starch concentration. The optimized film structure was obtained with carrageenan and rice starch composition of 1.5% and 2%, respectively.

The results shown a broad spectrum of commercial applications and future rice starch possibilities incorporated in the carrageenan-based biodegradable film.

The purpose of this paper is to analyze various properties of anatase titanium dioxide (TiO₂) nanoparticles. Further, it proposes to implement Linear Combinations of Atomic Orbitals (LCAO) basis set under the framework of density functional theory and outline how LCAO is able to provide improved results in terms of various mechanical properties rather than plane wave and other theoretical results.

This paper provides an exploratory study on anatase TiO₂ by implementing OLCAO–DFT–LDA–LBFGS–EOS–PZ algorithms to find out various ground-level properties. The data so obtained are complemented by various analysis using mathematical expressions, description of internal processes occurred and comparison to others’ analytical results.

The paper provides some empirical insights on how mechanical properties of anatase TiO₂ improved by implementing LCAO methodology. From the analysis of electronic properties, it is seen that the anatase TiO₂ supports the inter band indirect transition from O-2p in valence region to Ti-3d in the conduction region.

Most of the electronic properties are underestimated because a single exchange-correlation potential is not continuous across the gap. This gap can be enhanced by implementing Green’s function in place of DFT and the other way is to implement self-interaction correction.

The use of anatase TiO₂ is primarily used for catalytic applications. This is also used to enhance the quality of paper in the paper industry. Additionally, this is used as a prime ingredient in cosmetic industry.

This paper fulfills an identified need to study how LCAO, another basis set, plays an important role in improving material properties.