The authors regret to have made an implementation error in their simulation code.

In this study, the squeezing flows between parallel disks, which one disk is impermeable and the other is porous, in the presence of magnetic field are investigated by Gegenbauer Wavelet Collocation Method (GWCM). Appropriate similarity transformations may be used to convert the governing non-linear partial differential equations into non-linear ordinary differential equations. The resultant non-linear

In this paper, the formulation of post-buckling of end-supported nanorods under self-weight was developed by the variational method. The surface stress effect was considered following the surface elasticity theory of Gurtin–Murdoch. The variational formulation involving the strain energy in the bulk material, the strain energy of the surface layer, and the potential energy due to self-weight was expressed

Scale-dependent stress intensity factors in an anti-plane cracked orthotropic material layer are evaluated using strain gradient theory. Both volumetric and surface strain gradient material characteristic lengths represented as l and \(l^{'}\), respectively, are employed to obtain semi-analytical solutions. The surface strain gradient effect is considered for both positive and negative \(l^{'}\) values

As is known, limit analysis is a common way to study stability and failure mechanism of geotechnical engineering. This paper presents an upper bound finite element limit analysis (UB-FELA) formulation for non-homogeneous clays using discontinuous quadratic displacement fields and second-order cone programming (SOCP). The details are provided about the application of SOCP to the UB-FELA formulation

In this paper, we present a new approach for solving equations of motion for the trapped motion of the infinitesimal mass m in case of the elliptic restricted problem of three bodies (ER3BP) (primaries \(M_\mathrm{Sun}\) and \(m_\mathrm{planet}\) are rotating around their common centre of masses on elliptic orbit): a new type of the solving procedure is implemented here for solving equations of motion

The authors regret to have made an implementation error in their simulation code.

The purpose of this study was to investigate the effect of the number of spiral paths on the spray cone angle, discharge coefficient and droplet diameter in pressure-swirl atomizer with spiral paths using numerical and experimental methods. Initially, the injector was designed and manufactured based on some assumptions such as operating fluid type, pressure difference, spray cone angle and mass flow

In hydromechanical applications, Darcy, Brinkman, Forchheimer and Richards equations play a central role when porous media flow under saturated and unsaturated conditions has to be investigated. While Darcy, Brinkman, Forchheimer and Richards found their equations mainly on the basis of flow observations in field and laboratory experiments, the modern Theory of Porous Media allows for a scientific

In this work, we studied the peristaltic motion of steady non-Newtonian nanofluid flow with heat transfer through a non-uniform inclined channel. The flow in this discussion obeys the power law model through a non-Darcy porous medium. Moreover, the effects of thermal radiation, heat generation, Ohmic dissipation and a uniform external magnetic field are taken in consideration. The governing equations

Certain frequency ranges where waves do not propagate, and thus, vibrations are suppressed, are called band gaps. In the present paper, the appearance and the behavior of such areas are investigated on star-shaped auxetic microstructures, which are equipped with shunted piezoelectric elements. The optimal position of the piezoelectric patches is found using genetic algorithms, considering the maximization

The main motive of this work is to study the effects of nonlinear radiation and mixed convection for the Casson nanofluid through the thin needle. Mass transfer is further characterized by activation energy. Temperature-dependent viscosity and a variable magnetic field are assumed for the current problem. The consequences of the physical framework on the velocity, temperature and species including

This paper focuses on the nonlinear dynamic responses of a functionally graded material (FGM) truncated conical shell under 1:2 internal resonance relation. The FGM truncated conical shell is subjected to the in-plane load and the aerodynamic load along the meridian direction. According to a power-law distribution, the material properties are assumed to be modified along the thickness direction smoothly

The objective of this paper is to provide a computational method to analyze free vibrations of advanced composite plates in thermal environments according to a recently developed higher-order shear deformation theory. This method is based upon the assumptions that displacements field include just four unknowns and considers a combination of trigonometric and exponential shear shape functions which

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Nonlinear viscoelastic behaviour of –COOH functionalized multi-walled carbon nanotubes reinforced polypropylene nanocomposites is examined up to 2% MWCNT concentration. Isochronal creep and strain recovery experiments are conducted in dynamic mechanical analyser with oscillatory inputs. Creep stress level of 5 MPa is selected and successive creep and recovery experiments are performed at \(-\,20\,^\circ

A simple boundary method is developed for the solution of isotropic thick plates with in-plane arbitrarily variable material properties or thickness. Equilibrated basis functions which have proved to be effective in a variety of problems, are adopted for the bending problem of thick plates. The bases are created through a weighted residual approach over a fictitious rectangular domain so as to approximately

To reduce the drag of fluid on a surface, the parameterized structure of the mantis shrimp abdominal segment was analyzed to design the airfoil profile, and a calculation model was established based on the biological characteristics of the mantis shrimp. By using a numerical simulation method, the change in the viscous sublayer and drag reduction of the biological surface under different flow velocities

This study used a wavelet-based technique with variable modal scales to achieve the identification of modal parameters. Combined with the correlation technique or random decrement algorithm, the stationary response can be transformed into a quasi-free response, which can be employed to estimate the number of excited modes of structures and determine the modal scale corresponding to the major modes

During gas measurement, there is a mass change of resonator in a micro-resonant gas sensor. If the design parameters are not selected rightly, there will be obvious vibration state change or even chaotic vibration during gas measurement. Here, using multi-field coupled nonlinear dynamics model considering mass change during gas adsorption and desorption, the nonlinear dynamics performance and chaotic

This study aims to examine the effect of the diameter, number, and location of the circular cutout on the free vibration response and buckling loads of the laminated composites. Eigen-buckling and free vibrations analyses are performed for the laminated composite plates by using the finite element software ANSYS. Numerical results obtained by the finite element method are compared to the experimental

Angular contact ball bearings are widely used in rotary machines for their combined loads capacity, i.e., simultaneously acting radial and axial loads. Spall defect is one of the most important potential failure modes of the rolling element bearings. The main motivation of this study is to achieve a true perception of the spall defect influence on the angular contact ball bearing to predict bearing

The steady-state response of a strongly nonlinear system often has multiple solutions under harmonic excitation, which includes both multiple response amplitudes and multiple phases. Taking advantage of the force dropout phenomenon of electrodynamic shakers near resonance, a fixed frequency test method was proposed previously to measure the multivalued amplitude curves continuously. This method is

During final typesetting, the copy-editor introduced an error and ignored the corresponding correction remark by the authors, which lead to a significant bias in the first sentence on page 12 of the original paper [1].

In the existence of an aligned magnetic field over the inclined shrinking/stretching stratified sheet in a non-Darcy porous medium, the two-dimensional boundary layer flow of an upper-convected Maxwell fluid is analyzed. The heat transfer effects are acknowledged by using the nonlinear convection. The system of partial differential equations, which administrates the distinctive properties of flow and

Based on fracture extreme theory (FET), the size effect on initial fracture toughness \(K_{\mathrm{I}}^{\mathrm{ini}}\) and unstable fracture toughness \(K_{\mathrm{I}}^{\mathrm{un}}\) of concrete for three-point bending beam was investigated. Nine groups of geometrically similar specimen were simulated to obtain peak load and critical crack mouth opening displacement, of which specimen depth was from

The present study analysed the characteristics of a moving Griffith crack in a self-reinforced strip of finite thickness and infinite extent with the moving parallel punches of constant load acting on the boundaries of the strip at both sides due to the propagation of magnetoelastic plane waves under mechanical point loading. With the aid of integral transform technique, problem has been reduced to

The modified couple stress theory (MCST) is used to capture size effect on dynamic response in multiple-layer microbeams in the present article. Governing equations of the system are obtained based on the MCST and using Hamilton’s principle. The natural frequencies of the multiple-layer microbeam are calculated using the analytical method. Then, the results of the natural frequencies are presented

This article theoretically demonstrates the reciprocity and uniqueness theorems for generalized theory of thermo-viscoelasticity involving memory-dependent derivative (MDD). To prove the theorems, a thermo-viscoelastic initial-boundary value problem under the domain of three-phase-lag (TPL) model is taken into consideration for an isotropic, homogeneous medium. The theorems are proved with the help

The main purpose of this paper is to perform dynamic analysis of a viscoelastic laminated composite rotor shaft considering various asymmetries. Equivalent modulus theory (EMT) is employed to derive the finite element based mathematical model of the composite shaft considering the shear effect and compared with other method known as direct procedure technique (DPT). The material damping behaviour of

Deformation of thin elastic sheet due to electrostatic forces play important role in engineering and biological systems. In this work, we analyze the deformation of thin elastic sheet, while interacting with a rigid curved domain in the presence of dielectric fluid. Mechanical deformation of the sheet is coupled with the electrostatic interaction in its equilibrium configuration. We consider small

A point interpolation meshfree method based on polynomial basic function is employed to analyze static behavior of sandwich beams with functionally graded face sheets and porous core whose mechanical properties vary continuously in the depth-direction. Transverse shear deformation is taken into account with the context of third-order beam theory which satisfies the vanishing of shear stress at the

This paper studies the free vibration behavior of hybrid laminated plates using a layer-wise formulation. The laminated structures are made of graphite fiber-reinforced composite (GFRC) and multilayer functionally graded carbon nanotube-reinforced composite (FG-CNTRC) plies. The internal single-walled carbon nanotubes (SWCNTs) are distributed in layer-wise form along the ply thickness direction either

Unsupervised learning methods are effective and suitable tools for damage detection. The main reason for the popularity of these methods in structural health monitoring originates from the fact that the process of learning can be implemented by information of the only normal condition called training data. In contrast, supervised learning methods require information of both normal and current conditions

The current contribution is concerned with the development of novel constitutive equations for anisotropic magnetoactive elastomers (MAEs). A hyperelastic material model for an incompressible magnetoelastic medium representing transversely isotropic MAEs has been developed to investigate their response behavior in the presence of the applied magnetic field while undergoing finite deformation. Transversely

Vibration attenuation and dynamic control of the piezolaminated plate actuated with coupled electromechanical loading are aimed and achieved in the present work. Efficient finite element methodology with higher-order shear deformation theory is assisted to blend the effects of shear strains in the computational model. An isoperimetric eight-noded rectangular element is implemented through linear electric

This paper presents a study of the stability and collapse modes of a system made up of a masonry arch resting on two piers subject to its own weight. It examines both semicircular arches and three different types of pointed arches commonly found in architecture, namely low-pointed, equilateral, and lancet-pointed arches. The collapse modes characterizing each type of arch-piers systems are then compared

This work deals w ith the development and extension of higher-order models for delaminated doubly curved composite shells with constant radii of curvatures. The mechanical model is based on the method of four equivalent single layers and the system of exact kinematic conditions. A remarkable addition of this work compared to some previous ones, is a modified and improved continuity condition between

In the present paper, the non-conservative instability of a cantilever single-walled carbon nanotube (SWCNT) through nonlocal theory is investigated. The nanotube is modeled as clamped-free beam carrying a concentrated mass, located at a generic position, or in the presence of crack, and subjected to a compressive axial load, at the free end. Nonlocal Euler–Bernoulli beam theory is used in the formulation

Models for analyzing squeeze film air damping depending on the oscillation mode of cantilever and double-clamped micro/nanobeam resonators are presented. The models are obtained from the damping theory of a rigid rectangular plate moving parallelly to a nearby object in viscous and molecular flow regime and electrostatic theory. The analysis results based on the models show that the influence of oscillation

Crack can significantly affect the performance of structures and is one of the crucial indicators of damage in structural health monitoring. In this paper, the deflection behaviors of Euler–Bernoulli beams with arbitrary open edge cracks under arbitrary elastic boundary conditions are investigated. A continuous diffused stiffness reduction crack model is implemented to simulate the cracks in beams

Polygonal finite elements offer an increased freedom in terms of mesh generation at the price of more complex, often rational, shape functions. Thus, the numerical integration of rational interpolants over polygonal domains is one of the challenges that needs to be solved. If, additionally, strong discontinuities are present in the integrand, e.g., when employing fictitious domain methods, special

The aim of this work is to analyze the axial nonlinear dynamics of a drilling tool. The force at four impact surfaces are analyzed. Then, a parametric analysis is performed to investigate the effect that some parameters have on the dynamic behavior of the axial nonlinear dynamics of a drilling tool. Furthermore, a measure is proposed to evaluate the efficiency of the process, and used for design modifications

Numerical parametric analysis is carried out to study the force-local deformation \((F-\delta )\) behavior of circular hollow section X-joints under brace axial force (including compression and tension) and chord stress. An exponential model is proposed to describe the \(F-\delta \) curves of the X-joints. Parameters of the proposed model including two intercept forces and three joints stiffness (initial

Hydrodynamic bearings are commonly used to support fast rotating rotors. Due to their nonlinear bearing properties, they strongly influence the rotor response behaviour, which can be observed by the occurrence of sub-harmonic oscillations. The appearance of sub-synchronous vibrations depends on the operating bearing conditions, which are determined by the kinematics of bearing partners, the thermodynamic

Based on the modified couple stress and non-classical Timoshenko beam theories, the nonlinear forced vibration of an elastically connected double nanobeam system subjected to a moving particle is assessed here. This system is assumed to be resting on an elastic medium. Hamilton’s principle and the Galerkin method are applied to govern the equations of system motion and corresponding boundary conditions

In recent years, it became possible to use different methods for the analysis of mechanical systems with the help of computers to learn like humans and by increasing their interaction with the world by observing autonomously. One of these mechanical analyzes is the fracture mechanics in which the behavior of the laminated composites having a crack is examined. In this study, experimental methods, finite

Earthquakes generate a series of waves that penetrate the Earth. Depending on proximity to the epicenter of an earthquake, different types of seismic waves dominate at the surface of the Earth. Distinct kinds of seismic waves shake the ground in various ways. Love and Rayleigh waves both produce ground shaking at the surface of the Earth, which exponentially attenuates with depth. Surface waves can

In this paper, the new application of the generalized trigonometric function (GTF) and of the Ateb function in strong nonlinear dynamic systems is considered. It is found that the GTF and the Ateb function represent the closed-form solution of the purely nonlinear one-degree of freedom oscillator with specific initial conditions. Definition of the GTF and Ateb functions is introduced. In spite of the

This study deals with a novel model of forced vibrational analysis of nonlocal transversely isotropic thermoelastic nanobeam resonators due to ramp-type heating and due to time varying exponentially decaying load with multi-dual-phase-lag theory of thermoelasticity. The mathematical model is prepared for the nanobeam in a closed form with the application of Euler–Bernoulli (E–B) beam theory using nonlocal

In this article, we discuss measures for fibers having a curvilinear shape. This is the case, for example, for man-made cellulose fibers having a weak stiffness. The fibers are bent during the injection molding process of short fiber reinforced plastics. For this purpose, \(\mu \)-CT data can be evaluated and several measures can be introduced defining the geometrical orientation of the fibers. These

The analytic free vibration solutions of triangular plates are important for both rapid analyses and preliminary designs of similar structures. Due to the difficulty in solving the complex boundary value problems of the governing high-order partial differential equations, the current knowledge about the analytic solutions is limited. This study presents a first attempt to explore an up-to-date symplectic

In the present study, a recently developed non-polynomial zigzag theory by the authors is assessed for the buckling analysis of the laminated composite and sandwich plates. This theory assumes a nonlinear distribution for the transverse shear stresses. The model satisfies the transverse shear stress free boundary conditions at top and bottom surfaces of the laminate obviating the need for a shear correction

We study the near-tip singular fields for an interface anticrack between dissimilar anisotropic elastic materials using the sextic Stroh formalism. The stress and strain fields exhibit an oscillatory singularity and a square root singularity at the anticrack tip. A complex and a real strain/rotation intensity factors are introduced to scale, respectively, the two singularities. An explicit expression

Ferroelectric phase field models based on the Ginzburg–Landau–Devonshire theory are characterized by a large number of material parameters with problematic physical interpretation. In this study, we systematically address the relationship between these parameters and the main properties of ferroelectric domain walls. A variational approach is used to derive closed form solutions for the polarization

In the modelling of fibre-reinforced composites, it is well established to consider the fibre direction in the stored energy in order to account for the transverse isotropy of the overall material, induced by a single family of fibres. However, this approach does not include any length scale and therefore lacks in the prediction of size effects that may occur from the fibre diameter or spacing. By

The aim of the work is to analyse the effective elastic properties of composites with randomly distributed thin rigid fibres. The matrix is linear-elastic, homogenous and isotropic, and the fibres are perfectly connected to the matrix. Two-dimensional models of composites are analysed using the boundary element method (BEM). The method requires division of fibres and external boundaries of the plate

In this contribution, a variational diffuse modeling framework for cracks in heterogeneous media is presented. A static order parameter smoothly bridges the discontinuity at material interfaces, while an evolving phase-field captures the regularized crack. The key novelty is the combination of a strain energy split with a partial rank-I relaxation in the vicinity of the diffuse interface. The former

To isolate low-frequency vibration, a novel single-degree-of-freedom vibration isolation system with quasi-zero stiffness (QZS) and nonlinear damping using geometric nonlinearity is proposed in this study. One of the remarkable features of this system is the use of scissor-like structures (SLSs) to achieve the nonlinear stiffness and damping. The length difference between the connecting rods in SLS

Strong initial and induced anisotropies, observed in the deformation of Mg alloys, have restricted their industrial applications. The initial anisotropic behavior is caused by the initial texture of Mg sheets which are fabricated by successive rolling operations. This behavior could be well described by appropriate yield criteria. However, the texture evolution inside the material induces the distortion