The paper describes a probabilistic model capturing the multiple-cracking behavior of unidirectional brittle-matrix composites loaded in tension. The approach to modeling of composite fragmentation introduces two salient features that enhance both efficiency and flexibility compared to existing simulation methods: First, the algorithm identifies the emerging cracks one by one within a minimum number

In this paper an (r,Q) stock policy is used to control an inventory system with deterministic demand and defective items. The fraction of defective items in a batch is a random variable whose variance maybe dependent and independent of the order quantity. Considering the numerous benefits of selling high quality items (noting the vital importance for firms like medical device companies), a full inspection

The rapidly increasing data volume produced daily is encouraging to generate novel procedures for extracting suitable information from such data. Machine learning is an application of artificial intelligence which is employed to provide relevant knowledge extracted from data, due to such characteristics, the adoption of machine learning approaches is one of the most accepted alternatives for this purpose

The feed system of machine tool has complex nonlinear dynamic behaviors in the process of machining, which will affect the machining accuracy of parts. The two-degrees-of-freedom dynamical model of the feed system with clearance and friction is established, where the torsion and load disturbance are considered. By using the averaging method, the approximate analytical solution of the feed system of

In this paper, nonlinear vibrations of fractional viscoelastic functionally graded micro-beam are studied based on the fractional calculus. The Modified Couple Stress Theory (MCST) is utilized for considering the effect of the micro-scale. The micro-beam is modeled based on the Euler-Bernoulli theory and the Von Karman’s nonlinear strain relations. The viscoelastic part of the micro-beam is considered

External factors, such as increasing environmental awareness among consumers and introduction of environmental regulations by governments, have stimulated manufacturers to produce new green products. Cost factors, on the other hand, encourage the continuation of older generation products and hinder the launch of new green products. To study this dilemma, we consider a single manufacturer with the ability

The availability of wildland fire propagation models with parameters estimated in an accurate way starting from measurements of fire fronts is crucial to predict the evolution of fire and allocate resources for firefighting. Thus, we propose an approach to estimate the parameters of a wildland fire propagation model combining an empirical rate of spread and level set methods to describe the evolution

This study is intended for investigating the linear and nonlinear responses of carbon nanotube-based mass sensors in thermal and magnetic environment. For accurate modeling, the carbon nanotube rippling deformation effect is considered and various representations for the thermal expansion are examined and compared to each other. By utilizing Euler-Bernoulli beam theory assumptions and Eringen's nonlocal

In this paper, a variational approach is developed to solve the exterior acoustic-structure interaction problem. The Reissner-Naghdi's thin shell theory and Helmholtz equation are adopted to formulate the energy functionals for structural and acoustic domains, respectively. With introduced Lagrangian multipliers, a domain partitioning technique for both structural and acoustic domains is developed

Eliminating defects related to molten pool geometry such as lack of fusion and keyhole effects, is an urgent issue in selective laser melting (SLM). A practical and effective method for predicting molten pool geometry becomes necessary to optimize process conditions and upgrade printing quality. In this study, a novel analytical model predicting molten pool geometry of SLM is proposed. The key of the

A top-down strategy is proposed for analyzing the elliptic eigenvalue problems of the hierarchically perforated materials with three-scale periodic configurations. The heterogeneous structure considered is composed of perforated cells in the mesoscopic scale and composite cells in the microscopic scale, and Neumann boundary conditions are imposed on the boundaries of the cavities. By using the classical

In the present study, the flow and heat transfer of a power-law non-Newtonian fluid in a cavity are addressed. The top and bottom walls of the cavity as well insulated, the left vertical wall is at a hot temperature, and the right wall is at a low temperature. A flexible elastic fin is mounted at the hot wall of the cavity. The non-Newtonian fluid circulates inside the cavity due to the buoyancy forces

Classic mean value methods of performance measure approach in reliability-based design optimization may become computationally challenging due to their instability and inefficiency as the degree of nonlinearity grows in problems. In this paper, sequential quadratic programming method associated with the Broyden-Fletcher-Goldfarb-Shanno algorithm is introduced to take information about the curvature

This paper reports the first attempt to extend a novel localized boundary knot method to the 2D and 3D acoustic problems with complicated geometry. The solution of original partial differential equation with inhomogeneous term is firstly described as a sum of a particular solution and a homogeneous one. Secondly, the Chebyshev interpolation technique is applied to the approximation of particular solution

A Y-shaped bifurcated beam that is comprised of one tapered part and two uniform parts is investigated in this article. The wave propagation method and Timoshenko beam theory are utilized to investigate the characteristics of energy transfer of flexural vibration. Transmission and reflection matrices at Y-shaped bifurcated interface with variable propagation directions of flexural incident wave are

In this study, a novel analytical method for predicting bending and springback behaviours of hexagonal close-packed (HCP) sheet metals is presented. The proposed analytical approach is developed by using the Cazacu-Barlat 2004 asymmetric yield function and isotropic plastic hardening rule. This model can be used to determine bending moment-curvature relationships and springback of HCP metals under

In the present paper, we use the concept of virtual age to propose a periodic switching policy for assessing the reliability of a two-unit cold standby system. This approach is suitable for units that recover with discontinuous activity and get younger. To restore the units and bring back the state of the system to a desirable condition, the active unit and cold standby unit are periodically replaced

It is a phenomenon well-known to professional and private users of complex machines: in most situations these machines do not deliver their full performance. This difference between the actual achieved performance and some maximal performance obtained in benchmarks varies between different use cases but poses crucial questions concerning the resulting gap in any case. Is it possible to reduce this

This paper proposes the notion of a fractional generalised integral transform (Fractional G-transform) using modified Riemann-Liouville derivative with the Mittag-Leffler function as a kernel. We investigate the basic properties of the Fractional G-transform. In addition, the homotopy analysis is incorporated to introduce a hybrid Fractional Generalised Homotopy Analysis Method using Modified Riemann-Liouville

This work develops a comprehensive population balance modeling of the spray fluidized bed aggregation process based on the process specific microscopic mechanisms. A sophisticated constant number Monte Carlo algorithm is used to virtually simulate all important micro-mechanisms (e.g., droplet addition, droplet drying, volume dependent particle collisions, aggregation, and rebound, etc.) of spray fluidized

In many cable-driven compliant mechanisms, the need for controlled motion in the flexible structure often demands the actuation cables to pass through a fixed point (e.g. a cable routing channel in a segment disk or a fixed pulley) to constrain the force angle on the cable. This condition can be modeled as the large deflection problem of a cantilever beam with two parameters, namely the distal slope

Direct numerical simulation of diffusion through heterogeneous media can be difficult due to the computational cost of resolving fine-scale heterogeneities. One method to overcome this difficulty is to homogenize the model by replacing the spatially-varying fine-scale diffusivity with an effective diffusivity calculated from the solution of an appropriate boundary value problem. In this paper, we present

In this paper, a continuum mathematical electro-mechanical model of ultrasonic Langevin transducers has been developed by considering three factors: 3D vibrations, piezoelectric effects, and elements damping. Since the equivalent-circuit methods simulate a continuous system with discrete components, they are valid near one resonance frequency. However, a continuum model is valid in broader frequency

Many large-scale applications of regression models have correlated data. Although a variety of methods have been developed for this modeling problem, yet it is still challenging to keep an accurate estimation. We propose an adaptive and “reversed” penalty, which focuses on removing the shrinking bias and encouraging the grouping effect. Combining the L1 penalty and the Minimax Concave Penalty, we propose

In this paper, composites with multi-directional ellipsoidal fillers of arbitrary aspect ratio, and an interphase layer surrounding the filler, accommodating smoothly the differences in the filler and the matrix's properties, is taken into account. Each constituent of the fiber reinforced composite (FRC) is regarded to be isotropic and linear elastic, and the property of interphase is assumed to be

Green closed-loop supply chain (GCLSC) is a supply chain that encompasses forward and reverse flows of components and products in logistic networks with a focus on economic and environmental performance. In the decision-making process of GCLSC, the presence of uncertainty and risk originating from the size and complexity of network is crucial to consider, and the distribution of uncertain parameter

This paper adopts concepts of systems’ theory and multidimensional scaling to study the competitiveness in soccer leagues of four countries. A season for a given league is read as a dynamical system with states that are measured at discrete time samples corresponding to the rounds. The system state is inferred from the accumulated points won and lost by each team. These data series are interpreted

PID control is widely used in vibration control systems. However, there are various uncertainties present in practical engineering, and the PID parameters obtained from a deterministic system may fail. Thus, reliability estimation is necessary to solve this problem. To avoid the disadvantages of traditional probabilistic methods, a non-probability based method to calculate time-dependent reliability

Rotor active magnetic bearing is one of the preferable supporting techniques for the high-speed rotating machinery. This article proposes a comparison between two different control strategies for the constant stiffness coefficients 16-pole rotor active magnetic bearings system (16-pole Rotor-AMBs). The first strategy is the Cartesian control in which the applied currents on the poles depend on the

The Hertzian contact model is prominent for characterizing the contact behaviors of particles in three dimensions (3D), while its two-dimensional (2D) version in the tangential direction has not been well-established yet. In this work, a semianalytical Hertzian frictional contact model in 2D is developed, with an analytical solution for the normal contact behavior and a semianalytical solution with

Most of the existing research on gyrostat systems uses the Melnikov method to analyze chaotic dynamic characteristics. The mechanism of chaotic motion from the energy perspective of gyrostat systems has rarely been analyzed. The gyrostat system with positive damping disturbance is modeled in this paper. Casimir energy and power are given. The mechanism of the orbital expansion and contraction of the

This study examines a one-dimensional Stefan problem describing the sorption of a finite amount of swelling solvent in a glassy polymer. The polymer is initially in a dry non-swollen state, where the polymer network is dense. The polymer is then injected with a critical concentration of a swelling solvent, causing polymer chain relaxation to occur. A moving boundary separating the swollen rubbery polymer

This paper is focused on the application of a novel reproducing kernel particle finite strip method (RKP-FSM) for the static, mechanical and thermal buckling, and free vibration analyses of rectangular functionally graded (FG) plates with different boundary conditions and internal supports. Conventional reproducing kernel particle method (RKPM) is incorporated into the finite strip method (FSM), and

Mesh stiffness calculation is critically important for gear dynamic analysis, and many mesh stiffness models have been developed for its convenience and efficiency. However, for a long time, how to properly consider the influence of gear body flexibility and tooth profile error during modeling process has been a challenging problem. The existing mesh stiffness models may either ignore the coupling

An interface capturing scheme called modified switching technique for advection and capturing of surfaces (MSTACS) has been proposed. The proposed interface capturing scheme utilizes a basic switching technique for advection and capturing of surfaces (STACS) for solution of the volume fraction advection equation. MSTACS has been compared against three interface capturing schemes with the help of various

Peridynamics was originally developed to model spontaneously emerged discontinuities such as crack propagation and progressive failure. In this paper, contrary to typical peridynamic applications in the realm of modeling of discontinuities, a modeling approach is proposed in the framework of non-ordinary state-based peridynamics to simulate impact-driven solid-state welding processes that can effectively

A novel efficient methodology for probabilistic material reliability analysis considering fine-scale microstructure stochasticity is proposed in this paper. Integrated computational material engineering requires efficient multiscale computational capabilities to enable computational design and validation. Two critical challenges are identified: handling uncertainties from microstructures and material

The piezoelectric unimorph circular diaphragm is a valuable configuration in many applications of smart structures and smart martials. Piezoelectric energy harvesting, sensing and actuating in a pressure-load system are main applications of this configuration. Structural optimization could be used to improve the performance of this configuration. In this paper, a piezoelectric unimorph energy harvester

Aiming to increase successful transfers at stations for late-night passengers, we first propose an efficient dwell time adjustment strategy for the last-train coordination planning problem under transfer-passenger flows uncertainty. Unlike the traditional robust optimization model, we present a novel distributionally robust chance-constrained program to model this problem, where the probability distributions

Majority of the existing dam deformation monitoring models focus on the prediction of individual displacement, and ignore the spatial correlation of data. In this study, we propose a method dealing with multi-target prediction called the Maximum Correlated Stacking of Single-Target. The proposed method can provide reliable predictions of multi-target simultaneously, while fully exploiting the internal

A dynamic modeling method for a multi-panel structure connected with flexible hinges is proposed in this paper. For the solar array composed of several flexible rectangular panels, the global explicit modal functions of spatial coordinates are obtained by employing the Rayleigh-Ritz method, which are in favor of deriving the lower-dimension discrete dynamic equations and the design of controllers for

Two-phase flows in oil reservoirs can be modeled by a coupled system of elliptic and hyperbolic partial differential equations. The transport velocity of the multiphase fluid system is related to the pressure through Darcy’s law and it is coupled to a conservation law for the saturation variable of one of the phases. A time step of the classical IMPES (IMplicit Pressure Explicit Saturation) method

The present paper investigates the nonlinear static bending behavior of infinite length cylindrical panels made of functionally graded porous (FGP) materials. The shell with clamped edges is subjected to uniform temperature rise and transverse pressure loading. Thermomechanical properties of the shell with even distributed porosities are temperature-dependent and are graded along the thickness. The

An explicit analytical solution is obtained to an old problem of a potential steady-state 2-D saturated Darcian flow in a homogeneous isotropic soil towards systematic drains modeled as line sinks (submerged drains under an overhanging of a phreatic surface), placed on a horizontal impervious substratum, with a constant-rate infiltration from the vadose zone. The corresponding boundary-value problem

This paper presents analytical travel time models for the computation of cycle times and throughput performance of Automated Vehicles Storage and Retrieval Systems (AVS/RS) with multiple-tier shuttle vehicles. The proposed analytical travel time models consider the multiple-tier shuttle vehicle with the condition of simultaneously travelling in a horizontal and moving in a vertical direction in the

In this paper, a manufacturer of automotive springs is studied in order to reduce inventory costs and losses in the steel bar cutting process. For that, a mathematical model is proposed considering parallel machines and operational constraints, besides the demand, inventory costs and limits for items and final products. This one-dimensional integrated lot sizing and cutting stock problem is solved

In this paper, a third-order reconstructed discontinuous Galerkin (DG) method based on a weighted variational minimization principle, which is denoted as P1P2(WVr) method, is presented for solving the incompressible flows on unstructured grids. In this method, the first-order degrees of freedom (DoFs) are obtained directly from the underlying second-order DG method, while the second-order DoFs are

In this investigation, the system of equations governing the thermoelastic behavior of a rotating viscoelastic microbeam has been derived based on the non-Fourier heat conduction model. The viscoelastic properties of the material are incorporated in terms of the Kelvin-Voigt scheme. This considered microbeam is axially compressed and rotated at a uniform angular velocity in addition to exposing it

The problem of pull-in instability of a cantilever micro- or nano-switch under electrostatic forces has attracted considerable attention in the literature, given its importance in designing micro- and nano-electromechanical systems (MEMS and NEMS). The non-linear nature of the problem supports the typical approach that relies on numerical or semi-analytical tools to approximate the solution. By contrast

This paper points out a number of mathematical inaccuracies in the recent paper ”FPGA Realization of Fractional Order Neuron” by S.A.Malik and A.H.Mir. The comments in this paper pertain mainly with the errors presented in Section 3 of that paper referencing the discretization of the fractional operator. Proposed corrections to the formulas and figures are presented along with a sample Maple code to

In this paper, we introduce an extended version of hub location problem, called bi-objective hierarchical multimodal hub location problem to simultaneously minimize the overall system-wide costs and the maximum delivery time. This problem is distinct from the classic hub location problem in designing a hierarchical multimodal hub-and-spoke network involving multiple transportation modes, multi-class

Material handling systems are progressively becoming robotized in e-commerce distribution centers. Mobile material handling solutions cut labor costs, work 24/7, and improve system efficiency. These and many other merits make them a perfect fit for e-commerce fulfillment centers. This paper presents analytical models for Last-Mile-Delivery and Meet-in-Aisle mobile solutions and compares them with traditional

The paper reports the new forms of the fundamental solutions for 3D magnetoelectroelasticity equations. The state-of-art presented in the paper shows that the fundamental solutions for magnetoelectroelasticity equations take complex forms, especially considering their applications in the boundary element method. In the paper, the magnetoelectroelastic continuum serves as a homogenized model of the

The Brachistochrone problems with various penalties for fuel expense for a mass moving in a vertical plane in a uniform field of gravity are considered. The resistance of the medium is considered viscous. The lift force or normal component of the reaction force of the curve and thrust are considered as control variables. The optimal control problems are reduced to a boundary value problems for a system

In this paper, a resolved CFD-DEM method based on the immersed boundary method is proposed to simulate the proppant transport process, which is a multi-phase problem with strong fluid-particle coupling mechanisms in the oil and gas industry. A multi-sphere model is integrated into this method to describe complex particle shapes, in which Lagrangian points uniformly distributed on the particle surface

This work presents a method dedicated to the simultaneous identification of the thermal diffusivities of coatings or thin film materials. To ensure non-destructive thermal characterization of the coating, the present method also implies the identification of the substrate thermal properties, which may be orthotropic. The estimation of thermal diffusivities is based on the resolution of an inverse problem

The interface failure (micro-annulus and de-bonding) at the first interface between cement sheath and formation, or at the second interface between cement sheath and casing can be easily caused by alternating change of internal pressure and temperature in the casing during large-scale multistage hydraulic fracturing in shale-gas well. It is likely to have a great impact on casing stress and pose a

The different loading conditions often occur in polymer matrix composites during their service life. In order to use effectively the materials in high-performance applications, analyzing the effect of hygrothermal effects on a ballistic impact event is necessary. This paper considers a heat sink and humidity sink for the hygrothermal diffusion in the composites and solves the Luikov equations by means

Dynamic-based methods for detecting the location of damage in structures are generally based on changes caused by damage in the dynamic properties of structures such as modal frequencies and mode shapes. Mode shape curvature damage detection method is one of these techniques in which the difference in mode shape curvatures between undamaged and damaged structures is used to identify the location of