Abstract The main aim of this paper is to define the interfacial stress transfer parameter s in the Callister model using the Pukanszky model. The parameter s is expressed by the polymer strength, carbon nanotube (CNT) size, and interfacial shear strength. The developed equation is applied to plot the roles of all parameters in the value of s. The reasonable outputs of the developed equation show its

Abstract The abnormal behavior of monotonic stress-strain curves of aluminum alloys induced by the yield drop with increasing strain rate or decreasing temperature is considered based on the relaxation model of plasticity. The plastic deformation of 2519A and 2519A-T87 aluminum alloys within the strain rate range from 0.001 to 6000 s–1 and temperature range from –45 to 450°С is analyzed from the standpoint

Abstract The study explores the effect of helical rolling on the low-temperature impact toughness of pearlitic steel 09G2S. Helical rolling in two modes was performed at T = 850°C in six passes through rolls of varied diameters with air cooling (mode I) and water quenching (mode II). The tensile σ–ε curves at room temperature are characterized by parabolic strain hardening, without any specific behavior

Abstract The operating conditions of current highways require the development and implementation of new testing standards for pavement materials with regard to dynamic impact. Pavement materials have a complex hierarchical structure exhibiting a self-consistent response to load at different scale levels. The corresponding parameters of the phenomenological models used for macroscopic objects essentially

Abstract This paper deals with a mesomechanical modeling of fracture in concrete like quasi-brittle materials. The paper seeks to provide insight regarding the variation of the fracture process zone (FPZ) length during the cracking process. The correlation between the FPZ length and the crack extension is also investigated. The FPZ variation is investigated through the evolution of cohesive tangential

Abstract The paper studies the effect of the temperature of helical rolling, which creates nanoscale mesoscopic structural states in lattice curvature zones, on the low-temperature impact toughness of Ti–6Al–4V alloy. The polymorphic transformation temperature Tс = 950°C is shown to play the decisive role in this effect. The impact toughness is very high at helical rolling temperatures above Tс, while

Abstract The work studies the mechanical properties of chiral metallic nanotubes by the molecular statics method. The atomic structure of nanotubes was obtained by rolling up thin nanoplates from cubic crystals of copper, iron, aluminum, and cobalt with the (010) orientation at various chiral angles. It is shown that such nanotubes can experience torsion under tension and their Poisson’s ratio decreases

Abstract This study examines TiAlN and CrAlSiN coatings with a thickness of 0.8–4.0 μm deposited by plasma-assisted physical vapor deposition in vacuum on nitrided and carburized steel substrates. The coatings have different structural morphologies: a homogeneous monolayer structure, a multilayer structure with different-thickness layers, and a heterogeneous multiphase structure. A range of coating

Abstract The paper is a theoretical study of mechanically activated processes in tribocontact, which lead to the formation of a lubricating film between rubbing bodies. The adhesive aspect of tribofilm formation is considered using the condition of the mechanical activation of the friction surface. This condition is satisfied when the adhesion energy becomes greater than the cohesion energy. The Hamaker

Abstract The paper analyzes the evolution of microcracks in austenitic and carbon steels on evidence from our studies and literature data. The well-known Lotka–Volterra model, applied to competing processes of various nature, and the percolation model are used to describe the alternation of microcrack formation, growth, and coalescence providing a hierarchical damage structure.

Abstract The ball on beam system is a highly nonlinear laboratory model which helps to understand the modern and classical control theory. This paper emphasizes the position control of a ball on beam system which is actuated by shape memory alloy wires in an antagonistic configuration. The shape memory alloy actuator provides the necessary force to actuate the beam in the left and right directions

Abstract Equal channel angular extrusion is an extrusion to refine the microstructure of metals and alloys. This paper presents for the first time the experimental results on effects of the equal channel angular pressing (ECAP) on tensile mechanical properties and ductile fracture strength of 7075 Al alloy. The 7075 Al was subjected to equal channel angular pressing after solution treatment, and significant

Abstract Nonlocal elasticity assumes integral stress constitutive equation, takes into account interatomic long-range forces, reduces to the classical theory of elasticity in the long wave-length limit and to the atomic lattice theory in the short wave-length limit. In this paper, we propose the nonlocal elasticity theory with the kernel (the weight function in the integral stress constitutive equation)

Abstract In this study, the thermal stress distribution surrounding a quasi-triangular hole within a symmetric composite laminate made of various composite materials was investigated. A composite laminate exposed to uniform heat flux was analyzed using the complex variable method as a thermo-elastic two-dimensional problem under a steady state condition. The analytical solution was achieved with the

Abstract Acoustic emission activity under static loading of Pb–Sn alloys was studied in a wide range of alloy element concentrations. The strain rate dependences of the acoustic emission count rate were plotted in mechanical tests. The obtained experimental data revealed a significant change in the type of recorded acoustic emission signals depending on the alloy structure, determined by the content

Abstract Frictional damping in elastic contact of a parabolic indenter subjected to a combination of oscillations in normal and tangential directions is numerically simulated. The dissipated energy first increases linearly with coefficient of friction, then decreases linearly, and finally reaches a constant value. These three regions correspond to the states of complete slip, partial slip and complete

Abstract In this article, several models are applied to reveal the effects of volume fraction, thickness, strength and modulus of interphase region between polymer matrix and nanofiller on the Young’s modulus and yield strength of polymer nanocomposites. The properties of interphase are calculated for several samples by experimental data of mechanical properties. It is found that the concentration

Abstract This paper investigates the bending, buckling and free vibration behaviors of porous functionally graded curved nanobeams with different boundary conditions via a nonlocal strain gradient theory. The stresses are dependent on the strain gradients according to the nonlocal strain gradient theory. This theory contains both nonlocal and material length-scale parameters. The three-variable sinusoidal

Abstract The effect of hydrogen charging, ultrasonic treatment, and hydrogen charging after ultrasonic treatment on the fatigue life of VT6 alloy is investigated. Ultrasonic treatment causes the formation of a continuous nonetching α2(Ti3Al) layer within the surface layer, which reduces the fatigue life. Below this layer there are bands of the α2(Ti3Al) phase which, on the contrary, increase the fatigue

Abstract This paper presents the design, physical modelling and testing of electromechanical logic elements using shape memory alloy (SMA) wire actuated hinged beam switches. Microelectromechanical system logic devices actuated by electrostatic, pneumatic and electrothermal actuation mechanisms are used as alternatives to the conventional logic systems for harsh operating conditions such as ionizing

Abstract The kinematic equations of the multiplicative model of large elastoplastic deformations are generalized for hardening materials with different principal directions of the stress and plastic strain rate tensors. By taking into account the intermediate configuration, an algorithm is proposed for analyzing dynamic elastic processes in a medium with preliminary irreversible deformations. The use

Abstract In this work, two simple but effective strategies were proposed to optimize friction-stir welding of 6061-T6 aluminum alloy. The first one involved an optimization of welding variables to provide a combination of a relatively high welding temperature and the shortest possible thermal cycle during friction-stir welding. This inhibited precipitation coarsening in the heat-affected zone and resulted

Abstract In this research, the prevalent mode fracture of V-notches with end holes (VO-notch) in tungsten–copper functionally graded material (W–Cu FGM) was studied experimentally and theoretically. W–Cu FGM specimens were made by powder metallurgy technique in the experimental part. Several fracture tests were done on VO-notched W–Cu FGM specimens under prevalent mode loading for different notch tip

Abstract The paper analyzes the nature of constant low-temperature impact toughness in low-carbon low-alloy 10Mn2VNbAl steel after helical rolling at 850°C. The analysis shows that when rolled, the steel changes the electronic spectrum via shifting its low-energy states in the reciprocal space of lattice curvature to higher levels which are vacant in the initial material. Such interstitial states provide

Abstract Tandon–Weng model based on Mori–Tanaka idea for tensile modulus of conventional composites is currently used for various polymer nanocomposites, but some complex terms in this model may limit the calculations. In this article, this model is simplified and developed for ternary polymer nanocomposites containing layered and spherical nanofillers. The calculations of developed model are compared

Abstract An analytical relaxation model of plasticity is proposed for predicting the deformation characteristics of cyclically stabilized materials. The model is modified for cyclic deformation conditions and involves the determination of the structural-temporal and relaxation characteristics of the material. It is shown that the earlier developed relaxation model of plastic deformation for single

Abstract A mathematical model of Green–Naghdi photothermal theory is given to study the wave propagation in a two-dimensional semiconducting material due to moving heat source. By using the Fourier and Laplace transformations with the eigenvalues method, the physical quantities are obtained analytically. Initially, it is assumed that the medium is at rest and it is subject to a heat source in motion

Abstract In this work, a simple technique is suggested applying the simple models for Young’s modulus of polymer nanocomposites to calculate the Y interphase parameter and interphase modulus for multilayered interphase in polymer nanocomposites. The developed model is compared to the experimental results of several samples to examine its correctness. The effects of Y on the Young’s moduli of interphase

Abstract A model based on the concept of interface crack bridging and thermofluctuation theory is proposed for analyzing the efficiency of crack self-healing in composite materials in view of three main stages: (1) crack initiation and growth under external load, (2) self-healing activation, and (3) self-healing with partial or complete bond recovery between crack faces. A system of singular integro-differential

Abstract The present paper deals with the study of the wave propagation in a homogeneous transversely isotropic magneto-thermo-piezoelectric cylindrical material, under the influence of rotation, in the context of the linear theory of thermoelasticity. The displacement, electric potential, magnetic potential, electrostatic displacement, and magnetic induction functions are introduced to uncouple the

Abstract The plastic flow behavior of tensile specimens of ultrafine-grained 08G2B steel prone to strain aging was studied using digital image correlation, electron backscatter diffraction, and microindentation. Standard flat tensile specimens were tested with a constant strain rate in the initial state (after controlled rolling) and after controlled rolling + heating to 680°C for 30 min followed by

Abstract A model of in-plane graphene deformation is developed by considering a linear chain of atoms with regard to the independent moment interaction and noncentral force interaction between atoms. A discrete and continuous beam models of the linear chain of atoms are constructed. Assuming that each graphene atom interacts only with its nearest neighbors, the atomic system is replaced by a beam system

Abstract The paper analyzes the nucleation and growth of bainite in low-carbon low-alloy 09Mn2Si steel doped with titanium carbonitride nanoparticles in impact toughness testing. The analysis shows that such particles segregate at low-angle boundaries, retarding the formation of high-angle ones, and when impacted into the steel, they curve the lattice and generate a new bainite phase at the curvature

Abstract This study explores the effect of the radius of silver nanospheres and temperature on the total potential energy of the system as well as on the surface energy and energy of bulk atoms and binding energy of surface and bulk atoms. An approach is developed for calculating the surface energy of spherical nanoclusters. The investigation is performed for silver nanospheres with a radius of 2 to

Abstract The possibility of the structural turbulence of plastic flow and ductile fracture in low-carbon and low-alloy steel 09Mn2Si is shown by fracture toughness measurements and uniaxial tension of chevron-notched specimens at 20°C. The conditions for the structural turbulence of plastic deformation of solids are determined which provide high fracture toughness. The decisive functional role is played

Abstract This paper investigates whether the Weibull parameters of the new local approach model for cleavage fractures are affected by the geometric size of the specimen. Based on the fracture test data of A508-C steel, low temperature round notched bar tensile specimens of A508-C steel with two different notch sizes are numerically simulated by using finite element analysis software ABAQUS, and the

Abstract This paper studies the formation of cermet coatings by a combined additive manufacturing technology on the basis of cold gas dynamic spraying and subsequent laser irradiation. The coatings are made of titanium and nickel metal powders with ceramic particles of tungsten carbide and boron carbide. Optimal energy parameters are determined for coating deposition by cold gas dynamic spraying and

AbstractIn this study, the conventional Chow model for the tensile modulus of polymer composites containing fully aligned particles is simplified and developed for polymer nanocomposites, taking into account the effects of interphase and particle arrangement. The results obtained from the developed model are compared to the experimental results of several samples containing spherical, layered, and

AbstractAdditive manufacturing techniques are known for the unrivalled geometric freedom they offer to designers. It is one of the mainstays of “metal 3D-printing”, compared to casting, which, in contrast, implies more restrictions because some shapes do not cool evenly or may need moulds or forms. Despite the possible presence of defects inside additive manufactured components, such as oxide films

AbstractThe paper investigates a model simulating crustal fault dynamics and strain wave generation in a fault block geological medium, the parameters determining sliding regimes in faults, and the physics of transitions between different deformation regimes. The model comprises the most important mechanisms responsible for the interaction of fault walls: friction, geometric irregularities (roughness

AbstractThis paper examines the distribution of the tangential and normal components of the magnetic leakage fields in pole-magnetized sheet materials, such as cold-worked structural steels St3, 09G2S, and 08G2B, as well as electrical steel with different grain structure and coarse-grained magnetically soft alloy Alfer, which have different types of texture induced by rolling and uniaxial tension.

AbstractIn the paper, the plastic deformation of heterogeneous materials is analyzed by direct numerical simulation based on the theory of an elastic-plastic orthotropic Cosserat continuum, with the plasticity condition taking into account both the shear and rotational mode of irreversible deformation. With the assumption of a block structure of a material with elastic blocks interacting through compliant

AbstractThe deformation behavior of St3 steel was studied to show that the stress-strain state of a structure can be estimated using Rayleigh surface waves in both the elastic and plastic region. The most informative parameters in the analysis of the limit state associated with the onset of plastic deformation are the dispersion and shape of the probing signal. If the processes governing the effect

AbstractThreshold modes of multiscale dynamic deformation were identified for 1561 aluminum alloy by conducting two series of impact tests in the velocity range of 250–750 m/s: under uniaxial deformation and with high-speed penetration of elongated impactors. It was found that the scale of deformation changes at the same strain rate in the spall fracture zone under uniaxial deformation and on the lateral

AbstractA discrete model in a generalized rectangular-pulse space is proposed for dislocation cores in a crystal with its undeformed perfect structure taken as a Hilbert space of Schrödinger wave functions and with the core of a dislocation as a rigged Hilbert space of step functions of opposite sign separated by a time interval. The model suggests Vlasov equations for cation and electron distribution

AbstractThe paper considers the problem of elastic wave reflection from a free surface moving with a constant velocity. Analytical expressions in the approximation of geometrical acoustics are derived for the frequency shifts, angles of reflection, and reflection coefficients of P, SV, and SH waves to estimate the strain state at the free surface. Based on respective calculations, the reflection coefficients

AbstractThis paper is an experimental and theoretical study of changes in a laser-induced photoacoustic signal near a hole in metal plates of D16 aluminum alloy. The process of photoacoustic signal generation from metals is analyzed within the classical thermoelasticity framework, with account for only the thermal effect of laser irradiation on metal lattice deformation. A comparison is made of photoacoustic

AbstractThe paper analyzes how the elastic properties of titanium and its alloys vary as their structure is transformed from coarse- to ultrafine-grained under severe plastic deformation. The analysis includes acoustic measurements of the elastic modulus of Ti materials with a piezoelectric composite oscillator over a wide amplitude range, a detailed examination of their microstructure by electron

AbstractA method based on molecular dynamics and embedded atom potential is proposed for estimating the Laplace pressure, thermal expansion coefficient, and surface tension coefficient in spherical nanoobjects in relation to their size and temperature. The method is applied to silver nanospheres of radius 2–8 nm for analyzing their size and temperature effect on the thermodynamic parameters.

AbstractIn this work, the interphase in polymer nanocomposites is modeled as a multilayered part in which the Young’s modulus of each layer Ek continuously changes from nanoparticle surface (xk = 0) to polymer matrix (xk = t). The dependency of Ek onxk is analyzed by linear, exponential and power functions. The average interphase modulus is determined by the Ji model for several samples and the accurate

AbstractThis work suggests a modeling method based on micromechanical models such as Pukanszky one to determine the interphase properties in ternary polymer nanocomposites containing two nanofillers. The developed models can calculate the volume fraction, thickness and strength of interphases between nanoparticles and polymer matrix using the experimental data of Young’s modulus and yield strength

AbstractAttempts to improve the osteointegration, fixation and stability of Ti-base implants have been focused by producing a significative surface roughness that enhances the surface area available for bone/ implant apposition. In this research study, it shows the experimental data by synchrotron radiation X-ray diffraction (SR-XRD) of the main material surface properties (residual stress and cold

AbstractIn this article, the generalized model for photothermal wave under dual-phase-lag model is utilized to compute the increment of temperature, the components of displacement, the carrier density and the stress components in a two-dimension semiconducting media. By using Fourier and Laplace transformations with the eigenvalue techniques methodology, the exact solutions of all physical quantities

AbstractThe paper proposes a finite element approach with a mathematical model and an algorithm for simulating the wear of polymer composites in friction joints with account of temperature. The polymer interaction with a counterpart is modeled by solving a stress-strain contact problem with regard for the physical nonlinearity of deformation in polymer composites. The contact temperature is estimated

AbstractThis paper numerically investigates the mechanical behavior of an aluminum specimen with a TiC–Al6061 composite coating. The strain localization and fracture patterns are determined for different scale levels. The effects of the loading type, distance between titanium carbide particles, and metal matrix coating thickness are studied. A numerical method based on the experimental data is proposed

AbstractThe present paper deals with the development of dense Fe–Ag and Fe–Cu high-strength nanocomposites from blends of nanocomposite powders employing cold sintering (high-pressure consolidation). Nanocomposite powders were obtained by high-energy attrition milling of micron-scale powder of carbonyl iron (Fe) and nanosized silver oxide powder (Ag2O) as well as of nanopowders of Fe and cuprous oxide

AbstractA closed system of differential equations has been derived to describe thermal processes in a one-dimensional harmonic crystal on an elastic foundation. It is shown that the evolution of thermal perturbation in such a crystal is described by a discrete unsteady-state equation, a special case of which is the hyperbolic equation of ballistic heat conduction. This equation remains valid with negative

AbstractThe paper analyzes the scale hierarchy of transitions from very high to high and low cycle fatigue which are taken as fatigue limit according to the Wöhler concept. The analysis shows that the life distribution in the transition range 106–108 cycles is multimodal. From relations between the fatigue limit σ–1 and mechanical characteristics σU and σ0.2 in aircraft materials based on Fe, Al, Mg

AbstractControl over the inelastic deformation of polycrystals aimed at achieving desired performance characteristics of finished products is impossible without analyzing the structural evolution of the material at different scale levels. A major task in this respect is to develop physically sound mathematical models for describing the internal structure evolution as it determines the material properties

The use of NiBrAl casting alloy for the construction of marine propellers is expanding due to the resistance to fatigue, corrosion and wear under the effect of particles suspended in fluid. In this study, the nanostructure of the Ni-B coating is created by the electroless plating method on the NiBrAl alloy surface. After plating, the specimens are heat-treated, and the temperature and optimum time