Modern Engineering Applications Research Articles

A combined experimental and numerical study on droplet-impact induced breakup and ejection behaviors in vertical electric field

Droplet impact on solid surface in the electric field is a fundamental process widely existing in our daily life and in engineering applications. Here, we investigated the dynamic behavior after droplet impact on the electrode plate in the electric field both experimentally and numerically. Particularly, the breakup or ejection behaviors were systematically studied. One key finding from the experiments is that the applied electric field can significantly affect the droplet stretching behavior, leading to two different breakup modes near the droplet top. We reproduced the two modes in the OpenFOAM simulation to reveal the intricate trade-off among the electrostatic force, surface tension and droplet gravity. Furthermore, the relationship between the impact Weber number, the applied electric field and the breakup modes was obtained. This work contributes to a thorough understanding of the droplet impact behavior and provides useful guidance for the development of modern droplet-related engineering applications.

Wave propagation across a functionally graded interphase between soft and hard solids: Insight from a dynamic surface elasticity model

Joining soft to hard materials is a challenging problem in modern engineering applications. In order to alleviate stress concentrations at the interface between materials with such a mismatch in mechanical properties, the use of functionally graded interphases is becoming more widespread in the design of the new generation of engineered composite materials. However, current macroscale models that aim at mimicking the mechanical behavior of such complex systems generally fail in incorporating the impact of microstructural details across the interphase because of computational burden. In this paper we propose to replace the thin, but yet finite, functionally graded interphase by a zero-thickness interface. This is achieved by means of an original model developed in the framework of surface elasticity, which accounts for both the elastic and inertial behavior of the actual interphase. The performance of the proposed equivalent model is evaluated in the context of elastic wave propagation, by comparing the calculated reflection coefficient to that obtained using different baseline models. Numerical results show that our dynamic surface elasticity model provides an accurate approximation of the reference interphase model over a broad frequency range. We demonstrate application of this modeling approach for the characterization of the graded tissue system at the tendon-to-bone interphase, which fulfills the challenging task of integrating soft to hard tissues over a submillimeter-wide region.

Group Design Project in Control Engineering: Adapting to COVID-19 Pandemic.

Group Design Project (GDP) is a common education strategy in engineering. However, due to the COVID-19 pandemic, GDP cannot be fulfilled in a typical lab condition. The paper describes an example of delivering intensive hands-on, group project-based engineering course Autonomous Vehicle Dynamics and Control at Cranfield University. The project was designed to be implemented using modern simulation tools. As a result, students have not only obtained a better understanding of the engineering areas but also learned the usage of essential engineering and IT tools. The students obtained skillsets useful in modern engineering applications, where a simulation environment could improve the quality of the system before deployment and reduce a development cost.

Quasi-3D Hyperbolic Shear Deformation Theory for the Free Vibration Study of Honeycomb Microplates with Graphene Nanoplatelets-Reinforced Epoxy Skins.

A novel quasi-3D hyperbolic shear deformation theory (QHSDT) with five unknowns is here employed, together with the Hamilton’s principle and the modified couple stress theory (MCST) to analyze the vibrational behavior of rectangular micro-scale sandwich plates resting on a visco-Pasternak foundation. The sandwich structure features a Nomex or Glass phenolic honeycomb core, and two composite face sheets reinforced with graphene nanoplatelets (GPLs). The effective properties of both face sheets are evaluated by means of the Halpin-Tsai and extended rule of mixture (ERM) micromechanical schemes. The governing equations of the problem are derived by applying the Hamilton’s principle, whose solutions are determined theoretically according to a classical Navier-type procedure. A parametric study checks for the effect of different material properties, length-scale parameters, foundation parameters and geometrical properties of the honeycomb cells, and the reinforcing GPLs, on the vibration response of the layered structure, which can be of great interest for many modern engineering applications and their optimization design.

Manufacturing processes & recent applications of aluminium metal matrix composite materials: A review

Composite Materials are formed by two or more distinct metals to achieve the superior physical and mechanical properties to enhance the modern engineering applications and industrial needs. These needs can be archived by the Metal Matrix Composites. This also satisfies the consumers’ demands like light-weight material, low cost-effective, less production cost, higher flexibility with major strength. Now a days the Aluminium Metal Matrix Composites are widely used and also newer developments are made to get light-weight, high strength, high stiffness and the required properties. This paper gives the overview discussion about the manufacturing of Aluminium Metal Matrix Composite, manufacturing processes with related advantages and limitations, properties of various Aluminium Composition with its reinforcement and at last the various applications in different areas.

Prediction of residual stresses of second kind in deep drawing using an incremental two-scale material model

ABSTRACT For modern engineering applications, the prediction of residual stresses is a starting-point for the subsequent optimisation of the design with regard to the process induced stresses on the macro and the grain scale. In this paper, a new approach for the numerically efficient prediction of phase-specific residual stresses (residual stresses of second kind) in two-phase materials is presented. The proposed model allows for a two-scale simulation of complex forming processes, solely based on the phase-specific constitutive equations. This enables the calculation of the average stresses and strains in each phase during the entire process and the prediction of the macroscopic material response. The numerical results are compared to experimental diffraction-based data of a bending bar and a deep drawn cup and are aligned better compared to existing models.

Mechanical and Wear Behavior of Al7075 - Graphite Self-Lubricating Composite Reinforced by Nano-WO<sub>3</sub> Particles

Al7075 hybrid nanocomposites considered one of the most material utilized in modern engineering applications that required a combination of superior properties such as lightweight, high strength, excellent corrosion resistance, and high thermal conductivity. In the current study, Al7075 – 5 vol % graphite self-lubricating composite was reinforced by 0, 1.5, 2.5, 3.5, and 4.5 vol % WO3 nanoparticles in order to study the microstructural, mechanical, and wear characteristics. The classical powder metallurgy route was employed to fabricate the hybrid nanocomposites specimens. The microstructural analysis of the nanocomposites was characterized by utilizing a Field Emission Scanning Electron Microscope (FESEM) and Energy-Dispersive X-ray (EDX) analyses. Mechanical properties such as micro-hardness and diametral compressive strength were studied. Dry sliding wear test was performed under the various loads of 10, 15, 20, and 25 N at a sliding distance and sliding speed of 1810 m and 1.5 m/s, respectively. Results have revealed that the microhardness and diametral compressive strength considerably improved by increasing the WO3 content until 3.5 vol % and then slightly decreased. Besides, both the values of the wear rate and friction coefficient gradually reduced by increment the reinforcement content up to 3.5 vol % and then suddenly increases for all the applied loads. Nevertheless, the wear rate and friction coefficient were correlated positively with the applied loads. From the results obtained, graphite as solid lubricating material with WO3 nanoparticles was successfully combined into the Al7075 alloy matrix. The optimum mechanical and wear performance of the hybrid nanocomposite were revealed at 3.5 vol % content of WO3 nanoparticles.

Characterization of hydrogel structural damping

Gels are composed of crosslinked polymer networks and solvent molecules imbibed into the networks. Gels are both ubiquitous in nature and important engineering materials widely used in many applications. Due to their biocompatibility, stimuli-responsiveness, and compliance, gels gain an edge over traditional materials, such as metals and composites in many modern engineering applications. In the past, the static and kinetic properties of gels have been widely studied. However, the dynamic properties of gels, particularly their structural damping, remain largely unknown even though gels are often under dynamic conditions in various applications. The literature of soft materials is lacking both damping data for hydrogels and a standard testing method to that end. This work reports experimentally identified structural damping data for a set of hydrogel samples via resonant vibration tests for the first bending mode. Beam-shaped samples of rectangular cross-section are clamped vertically at both ends and tested under linear base excitation. An analysis of the frequency response functions based on the Euler–Bernoulli beam theory is conducted to extract Young’s modulus and structural damping values. In the experiments, polyacrylamide gels of three different compositions and polydimethylsiloxane (PDMS) elastomers of two different compositions are prepared and tested. The remarkable result is that the hydrogels have 80% less damping than PDMS, even though hydrogels are an order of magnitude softer than PDMS. The molecular origins of the damping in hydrogels and PDMS are discussed. The low damping of gels may open new avenues of research and applications of soft materials in structural dynamics and wave propagation, such as metamaterials and topological insulators, among others.

Dual heterogeneous structures lead to ultrahigh strength and uniform ductility in a Co-Cr-Ni medium-entropy alloy

Alloys with ultra-high strength and sufficient ductility are highly desired for modern engineering applications but difficult to develop. Here we report that, by a careful controlling alloy composition, thermomechanical process, and microstructural feature, a Co-Cr-Ni-based medium-entropy alloy (MEA) with a dual heterogeneous structure of both matrix and precipitates can be designed to provide an ultra-high tensile strength of 2.2 GPa and uniform elongation of 13% at ambient temperature, properties that are much improved over their counterparts without the heterogeneous structure. Electron microscopy characterizations reveal that the dual heterogeneous structures are composed of a heterogeneous matrix with both coarse grains (10∼30 μm) and ultra-fine grains (0.5∼2 μm), together with heterogeneous L12-structured nanoprecipitates ranging from several to hundreds of nanometers. The heterogeneous L12 nanoprecipitates are fully coherent with the matrix, minimizing the elastic misfit strain of interfaces, relieving the stress concentration during deformation, and playing an active role in enhanced ductility.

Perturbation approach to Eringen’s local/non-local constitutive equation with applications to 1-D structures

Eringen’s two-phase local/non-local constitutive equation is preferred over its full non-local counterpart due to mathematical simplifications it provides. Then again, an integro-differential equation must be solved, which requires rigorous examination of the existence of an exact solution in certain forms. For this purpose, some additional constraints are attained to strain field for the sake of an exact solution which may be in contrast with the balance equations. It is the aim of this study to look for possible approximated solutions in series by a perturbation approach. Indeed, we find that response of structures with non-local constitutive relation may be approximated by a set of local elasticity problems, the existence and uniqueness of which are ensured. The present approach does not require any more conditions than physical boundary conditions, such as constitutive boundary conditions. It is applied to simple one-dimensional structural elements, and numerical evidence on possible convergence of the series expansion is provided. Some structural problems of bars and beams, which may be the simplified models of nanostructures in modern engineering applications, are discussed and solutions to them are given in closed-form.

An Energy‐Efficient, Wood‐Derived Structural Material Enabled by Pore Structure Engineering towards Building Efficiency

AbstractThe development of high‐performance structural materials for high‐rise building applications is critical in achieving the energy conservation goal mandated by the Department of Energy (DOE). However, there is usually a trade‐off between the mechanical strength and thermal insulation properties for these materials. Here, the optimization is demonstrated of natural wood to simultaneously improve the mechanical properties and thermal insulation for energy efficient high‐rise wood buildings. The improved wood material (strong white wood) features a complete delignification followed by a partial densification process (pore structure control), which enables substantially enhanced mechanical properties (≈3.4× in tensile strength, ≈3.2× in toughness) and reduced thermal conductivity (≈44% decrease in the transverse direction). The complete delignification process removes all lignin and partial hemicellulose from the cell walls of the wood structure, leading to an all‐cellulose microstructure with numerous aligned cellulose nanofibers. The partial densification optimizes the porosity of the delignified cellulose scaffold while enhancing the effectiveness of hydrogen bonding among aligned cellulose nanofibers. The simultaneously improved mechanical and thermal insulation properties of the wood material render it highly desirable for a wide range of modern engineering applications, especially as an energy‐efficient, strong, lightweight, environmentally‐benign, scalable, and low‐cost building material.

From nature and basic scientific results to modern engineering applications

From nature and basic scientific results to modern engineering applications

Powell–Eyring fluid flow towards an isothermal sphere in a non-Darcy porous medium

Non-Newtonian viscoelastic fluid flow past an isothermal sphere embedded in non-Darcy porous medium is examined numerically in this work. To be specific, the non-Newtonian Powell–Eyring fluid in the presence of both the heat and mass characteristics is mathematically modelled in terms of differential system. A non-Darcy drag force model is employed to simulate the effects of linear porous media drag and second-order Forchheimer drag. The surface of the sphere is maintained at a constant temperature and concentration. The numerical solution of the resultant system is reported via the Keller box method. Both tabular and graphical forms are adopted to identify the variations in Powell–Eyring fluid velocity, Powell–Eyring fluid temperature, and Powell–Eyring fluid concentration. In addition, the surface physical quantities, namely, skin friction and heat and mass transfer rates, are explored. The obtained observations are validated with earlier Newtonian studies. We found an excellent match in this regard. It is found that the velocity is reduced with increasing fluid parameter (ε), Forchheimer parameter (Λ), and tangential coordinate (ξ). In contrast, the temperature and concentration are increasing with increasing value of ε. A very slight increase in velocity is seen with an increase in the local non-Newtonian parameter, δ. But the temperature and concentration decrease slightly with an increase in δ. An increase in Darcy parameter enhances velocity but reduces both temperature and concentration. The present study finds an extensive array of applications in modern nuclear engineering, mineral and chemical process engineering, nuclear waste in geomaterial repositories, petroleum product filtration, and insulation systems.

Mechanical performance of micro-Cu and nano-Ag reinforced Al-CNT composite prepared by powder metallurgy technique

Nanoparticles of metal and other materials are a proved reinforcing material for producing a high-performance aluminum composite utilized in modern engineering applications. In the present work, two different hybrid composites were fabricated and compared based on mechanical performance and physical properties. The aluminum hybrid nanocomposites were fabricated using powder metallurgy technique with 1 vol% constant content of Multi-Wall Carbon Nano Tubes (MWCNTs) and different volume fraction 0, 1, 2, 3, and 4 vol% of Micro-copper and Nano-silver particles. To ensure goodness of preparation, the hybrid nanocomposites were characterized using Field Emission Scanning Electron Microscope (FESEM), Energy-Dispersive x-ray (EDX) analyses, and elemental mapping analysis. An enhancement in microhardness and diametral compressive strength was observed with improving the reinforcement content. On studying mechanical properties, the wear behaviour of hybrid nanocomposites was studied against a constant distance of 1810 m and different normal loads of 5, 10, 15 and 20 N. Upon examination of wear map and compared to several literatures, it is observed that, during dry sliding wear, a decrease in the wear rate continues by adding more reinforcement particles up to 2 vol% Nano-Ag and up to 3 vol% Micro-Cu then increased, and the wear rate for all hybrid nanocomposites content have increased with increasing normal load. In conclusion, the results revealed that the hybrid nanocomposites with Micro-Cu particles showed better mechanical performance from Nano-Ag particles. In addition, it was confirmed that the Micro-Cu composite can be applied in various applications if the nanoparticles was networked enough with the Micro-Cu.

Size‐dependent free vibration of sandwich micro beam with porous core subjected to thermal load based on SSDBT

AbstractIn this study, free vibration of the sandwich microbeam with porous core and FG carbon nanotubes reinforced composite face sheets which is rested on Winkler‐Pasternak substrate is investigated. It is assumed the beam is in thermal environment and is subjected to thermal load and the displacement components are described based on sinusoidal shear deformation beam theory. The small scale effects are taken into account according to the modified couple stress theory. The core and face sheets properties are diffused through the thickness. The motion equations are derived and solved using Hamilton's principle and Navier's method, respectively. Effect of different parameters such as porosity coefficient and distributions, different types of CNTs distribution, small scale and geometrical size of the beam is considered. The results show by enhancing the porosity, the frequency decreased. The findings of the current study can be used to design prominent role in modern engineering applications.

Six-dimensional basins of attraction computation on small clusters with semi-parallelized SCM method

In modern engineering applications it is needed to determine the robustness of stable steady states, which depends on the shape and size of the associated basins of attraction. Once the basins are known, the quantitative measures can be computed by means of dynamical integrity tools and arguments. Those numerical techniques applied to strongly nonlinear systems, with six of more phase-space variables, demand considerable amounts of computing power, available only on High Performance Computing platforms. With the aim to minimize utilization of computer resources, we developed a software to adapt basin computations to small, affordable, clusters. It is based on Simple Cell Mapping method, modified to reduce the memory load, adjust integration time and overcome discretization discontinuities. Resource intensive part of computations is parallelized with Message Passing Interface and less demanding operations are kept serial, due to their inherit sequential nature. As intended, the program computes full six-dimensional basins of attraction at the adequate accuracy to distinguish compact parts of basins, but not to fully disclose fractalities or chaos. Disadvantages of the SCM method are addressed and the effectiveness of proposed solutions are demonstrated and discussed by the paradigmatic example composed of three coupled Duffing oscillators.

Stability Analysis of a Tapered Symmetric Sandwich Beam Resting on a Variable Pasternak Foundation

The static and dynamic stability analysis of a three-layered, tapered and symmetric sandwich beam resting on a variable Pasternak foundation and undergoing a periodic axial load has been carried out for two different boundary conditions by using a computational method. The governing equation of motion has been derived by using Hamilton’s principle along with generalized Galerkin’s method. The effects of elastic foundation parameter, core-loss factor, the ratio of length of the beam to the thickness of the elastic layer, the ratio of thickness of shear-layer of Pasternak foundation to the length of the beam, different modulus ratios, taper parameter, core thickness parameter, core-density parameter and geometric parameter on the non-dimensional static buckling load and on the regions of parametric instability are studied. This type of study will help the designers to achieve a system with high strength to weight ratio and better stability which are the desirable parameters for many modern engineering applications, such as in the attitude stability of spinning satellites, stability of helicopter components, stability of space vehicles etc.

Interior penalty discontinuous Galerkin FEMs for a gradient beam and CNTs

Carbon nanotubes (CNTs) are widely employed to modern engineering applications. The structural beam element is an acceptable model that has been used to simulate the CNTs' response. At the same time the gradient elasticity theory, taking into account the size effect phenomena, can be considered a viable option to study the mechanical response of CNTs through a generalized gradient beam model. Given that the constitutive equations of this theory produce a boundary layer, the hp-version interior penalty discontinuous Galerkin finite element methods (IPDGFEMs) are developed in this work for the solution of a static, tensile or compressive, gradient elastic beam in macro- and micro-structure (CNT), respectively. An a priori error analysis of the aforementioned methods is performed and numerical simulations that verify the analytical findings are carried out. The consistency, the stability and the convergence of the IPDGFEMs are proved. A priori error estimates established also indicate an optimal convergence in the meshsize h, yet a slightly suboptimal convergence in the polynomial degree p.

Evolutionary intelligence in wireless sensor network: routing, clustering, localization and coverage

Evolutionary intelligence has become one of the most important directions that improve the performance and effectiveness of automated systems such as communication systems, robotics and engineering industries. Today, there are many applications of evolutionary intelligence in many engineering fields and the most important fields related to computation and informatics engineering as a part of electrical and communication engineering, as modern engineering applications are involved in these fields. The sensor network is the main data source in the world of smart systems nowadays. Additionally, it has become a field of science used in the development of the rest of scientific applications. The need to use evolutionary intelligence in sensor networks has emerged because of the problems encountered by different types of sensor networks. This paper represents a comprehensive scientific review of the role of evolutionary intelligence in sensor networks and its implications for this important part of engineering applications. This paper discusses the theoretical, mathematical and practical application of evolutionary computing with the use of evolutionary algorithms and the improvements resulting from the application of evolutionary intelligence in sensor networks. The content of this paper will review the most important of the evolutionary intelligence from principles, algorithms and applications. The problems facing the types of sensor network has been solved using evolutionary algorithms. After reviewing the evolutionary intelligence and its details in the sensor network, a performance evaluation is presented in the paper at the end of each of the targeted areas of the sensor network. This performance evaluation represents the measure of the quality of improvements provided by evolutionary intelligence in sensor network field with graphical analysis studies to demonstrate the effect of evolutionary algorithms on the sensor network.

Structure and Transport Properties of Water and Hydrated Ions in Nano‐Confined Channels

AbstractNano‐confined flow is ubiquitous in modern engineering and biomedical applications. As the peculiar phenomena of nano‐confined flow were continuously reported and traditional theories failed to describe them accurately, simulation efforts have been made to gain deeper insight. The objective of this paper is to provide an overview of the recent progress on nano‐confined flow, including water flow and hydrated ions transport. This report starts with the water behavior under nano‐confinement, summarizing the water structures, flow properties and their dependence on wall wettability, channel size, etc. The report also presents the efforts made to modify the existing theories to describe nano‐confined flows. Then, the report goes to the hydrated ions. The dehydration process of hydrated ions and ions sieving are discussed in detail, and the effects of membrane surface charge, grafting functional groups, and external field on ions transport are reviewed. In this Progress Report, the transport properties of water and hydrated ions in nano‐confined channels are highlighted, which is critical to the design and application of nanofluidic devices, such as nanofiltration membranes, biosensors, and other related fields.