Modeling, evaluation and prediction of slab track damage and its evolution are nowadays challenge and hot topics, in which the computer modeling program lies a foundation for vehicle-track dynamic analysis subject to slab track damage except the experimental research. In this work, the finite element modeling methods and related computer modules are presented to compile a simulation program to evaluate

On-site observations show that several damages have occurred in CRTS II slab-type ballastless track system, such as crack and interface debonding between different structural layers, which will trigger the occurrence of some failure modes of CRTS II track slab. As the damages are the prior for specific failure modes, time-dependent reliability of CRTS II track slab should be conducted considering the

The problem as to whether an inclusion when embedded in an elastic infinite matrix with a perfectly bonded interface could achieve uniform internal stress has been studied extensively in the literature. It has been shown that in almost all cases ellipsoidal shape (including elliptical shape for two-dimensional deformation) is the only inclusion shape ensuring the uniformity of the stress inside the

Eliminating substantial energy dissipation and achieve precise tracking accuracy are both vital for the hydraulic actuated servo system, especially in the face of the global energy crisis and energy exhaustion. When an asymmetric hydraulic cylinder moves symmetrically back and forth, the pressure and flow in the two chambers differ a lot, resulting in huge energy loss. To reduce the throttle loss and

It is a challenge to determine the crack-tip stress intensity factors (SIFs) of ferroelectrics under large-scale domain switching. An I-integral method has been previously established for an impermeable crack. In order to investigate the influences of crack-face electric boundary conditions on domain switching and the SIFs, this paper develops the I-integral for permeable and conducting cracks to extract

Cracks are vitally detrimental to the load-bearing capacity of materials and further to the durability and service-life of various structures. Autonomous self-healing via embedded capsules or hollow fibres with healing agent has recently become more popular to repair the damage of structural materials. Figuring out the exact amount of capsules required to repair the cracks is indispensable to develop

An effective approach is proposed to predict the remaining fatigue life (RFL) of structures with stochastic parameters. The extended finite element method (XFEM) was firstly used to produce a large amount of datasets associated with structural responses and RFL. Then, a RFL prediction model was developed using the ensemble learning algorithm, which employed multiple machine-learning algorithms to learn

Since most of the research about grey forecasting models is focused on developing novel models and improving accuracy, relatively limited attention has been paid to the modelling mechanism and relationships among diverse kinds of models. This paper aims to unify and reconstruct continuous-time grey models, highlighting the differences and similarities among different models. First, the unified form

This paper presents a novel hybrid numerical method combining the transfer matrix method for multibody systems with the finite element method and the Craig-Bampton reduction method. In the proposed method, the multibody system is divided into two types of subsystems, depending on the shape and stiffness of each component. All the subsystems are independently analyzed by the transfer matrix method for

In the present work, nonlinear dynamics of a simply-supported fluid-conveying composite pipe subjected to axial tension in sub- and super-critical regimes are investigated. The tension acting on the pipe is assumed to comprise an average component and a harmonically changing disturbance component. More specifically, the nonlinear equation of motion is derived based on the Euler-Bernoulli beam theory

This study addresses a healthcare facility location/network design problem considering equity and accessibility. Locating the healthcare facilities, planning the capacity of healthcare facilities, and designing the transfer network are the primary goals of the given problem. The presented model aims to minimize system costs, maximize accessibility, and minimize inequality among all demand nodes. A

This paper is concerned with influence of porosity and mechanical/electrical boundary conditions on buckling of moderately thick, porous sector and annular sector plates integrated with piezoelectric face sheets. Presence of both porous and piezoelectric elements in a configuration provides new opportunities for manipulating the buckling load broadly. To demonstrate these possibilities, across the

Accurate evaluation of preload in system with double-bolted connections is critical for the service performance of engineering structures or equipment. However, the theoretical framework for assessing preload is imperfect. An equivalent approach from the tightening process of double-bolted joints to second-order spectral problem of the energy-dependent potential is firstly established. This paper proposes

We introduce a new isometric strain model for the study of the dynamics of cloth garments in a moderate stress environment, such as robotic manipulation in the neighborhood of humans. This model treats textiles as surfaces that are inextensible, admitting only isometric motions. Inextensibility is derived in a continuous setting, prior to any discretization, which gives consistency with respect to

Free longitudinal vibrations of a viscoelastic growing rod in both lateral and axial directions are considered in terms of the classical model. Exact and approximate WKB solutions are obtained for the single-mode case for both undamped and damped vibrations of the rod. The coupled multi-mode system is investigated numerically. It is shown that because of the rod’s growth in the axial direction, the

A theoretical model is developed to investigate the influence of external mean flow on sound transmission loss (STL) through composite sandwich panels filled with porous materials. The equations of the motions for the composite laminate plates are established by adopting the first-order shear deformation theory. The porous materials in between the sandwich structures are characterized by an equivalent

In this paper, the hybrid active contour model driven by optimized local pre-fitting image (OLPFI) energy was proposed for fast image segmentation. Since the proposed model combines the local pre-fitted image (LPFI) function with region-based characteristic and the optimized edge indicator function with edge-based characteristic, the proposed model can not only correctly segment images with intensity

We study a two-level spare parts supply chain in which a manufacturer supplies a central warehouse (CW) with original equipment manufacturer (OEM) and replacement or pattern parts (PP). The CW, distantly located from the manufacturer, distributes both OEM parts and PP to a given number of depots facing stochastic demands. The demand for spare parts is intermittent, exhibiting an infrequent rate and

Prestressed piezoelectric energy harvesters (PEH) provide benefits referred to higher generation levels and scavenge energy from lower frequency sources. In the study of axially loaded beams subject to lateral base forces, it is common to assume that the axial displacement is of a lower order than the lateral one. When the beam is slender enough, it is well known from experimental and numerical results

To reflect the characteristics of soil more accurately, an improved two-parameter foundation-plate model is built. A vehicle-road coupled model is modeled as a 2-DOF vehicle moving along a plate with finite length and width on a cubic nonlinear foundation. The variation of depth of elastic layer is modeled using sine wave. The Galerkin truncation method is used to discretize the partial differential

This paper presents a new contact boundary condition for finite volume simulations of frictional contact problems involving geometrical and material non-linearities. Deformation of bodies in contact is described by the updated Lagrangian form of the momentum equation which is discretised in space using the cell-centred finite volume method. The proposed contact boundary condition is based on the finite

It has been extensively studied to employ memristors to model the relationship between the electromagnetic field and the membrane potential, especially for the research of modeling and dynamical analyses of electrical activity using HR neurons with memristors. This paper proposes a novel 4D HR model with a threshold flux-controlled memristor (MHR), which describes the electromagnetic induction effect

The present article deals with the reflection and transmission of waves at an interface of piezoelectric (ALN & PZT-5T) half-spaces with microstructures. Unlike the classical piezoelectric material, in the considered media, five coupled waves (2 bulk and 3 surface) [namely the Quasi-longitudinal wave (QP), Quasi-transverse wave (QSV), Electric-acoustic wave (EA), P-type surface wave (SP) and S-type

Recently, the closed-loop supply chain (CLSC) and its application to various fields have been an area of great interest. Despite the importance of CLSC, there remains a paucity of evidence on agriculture in this area. In this work, a CLSC network for the avocado industry is firstly designed by developing a bi-objective model considering the costs of the avocado industry and the social factor of job

We present a new, efficient and robust method for computing scalar wave propagation for those cases in which Dirichlet boundary conditions play a key role. The algorithm is versatile and it allows to treat reflection, diffraction, waveguiding regime, scattering and free propagation. The analysis is based upon a representation for a slow neutron wavefunction in terms of the incoming wave and integrals

In this paper, the simplified electromagnetic force/torque model and coupled orbit-attitude dynamics modeling in spacecraft electromagnetic docking are investigated, and an improved sliding mode control scheme based on planned trajectory is proposed. In this scenario, the docking two spacecraft are equipped with four energized solenoids with iron cores fixed in the body frame, and small- angle hypothesis

The present study deals with the buckling and postbuckling performances of functionally graded graphene platelets reinforced composite (FG-GPLRC) plate under external electric field. The elastic and dielectric properties of GPLRC are evaluated by effective medium theory (EMT) while the Poisson's ratio is calculated by rule of mixture. The GPL distribution throughout the thickness of the structure is

In the present paper, an isogeometric analysis formulation along with the Nitsche technique is implemented based on the first order shear deformation plate theory to investigate the aero-thermo-elastic panel flutter behavior of a functionally graded (FG) plate containing cracks in the supersonic flow field. A FG material is considered with temperature-dependent mechanical properties distributed in

Allee effect plays important roles in social species’ survival, invasion and evolution. The dynamical characteristics of populations incorporating component Allee effect and infectious disease remain unclear. In this paper, we propose an eco-epidemiological model of prey and predator interactions with assumptions that (1) The predator has cooperative social behavior in hunting prey; (2) The predator

The current study aims to study the velocity profile of torsional surface waves in a three-layer model consisting of sand-dunes deposit sandwiched between the watery-porous layer and the orthotropic half-space. The top and the middle layers exhibit irregular interfaces employing various geometrical shapes such as parabolic, rectangular, and triangular notch. The main objective is to analyze the effect

Level ice acting on vertical structures can impose large loads and cause damage. Phenomenological models have been developed to simulate ice-structure interaction and predict ice loads, however due to oversimplification of ice properties and interaction mechanisms, existing models either cannot predict the interaction well or are applicable to limited situations, such as when ice is brittle. This paper

Production and operations management (POM) uses learning curve (LC) models to determine the length of training sessions for new workers and predicting future task performance. Empirically validated LC parameters provide managers with quantitative information on the effects of the presumed factors behind the learning process. Previous studies considered LC to compose of cognitive and motor curves. Another

Although solving the dynamic response of layered media has always been a major concern in the engineering field, the problem of interlayer contact of layered media has seldom been addressed in the related studies. Thus, this paper proposes an algorithm to analyze the dynamic displacement and stress responses of two-dimensional layered media with imperfect interfaces between layers at an arbitrary point

To address the low computational efficiency and accuracy for reliability optimization of flexible mechanisms, the mean-probability decomposition-coordination-based extreme support vector machine regression (MPDC-ESVR) method based on the dynamics and uncertainty is proposed. Firstly, a dynamical model is built to calculate the maximum deformation. Then, the ESVR is used as a surrogate model to study

We present a mathematical model to study the steady-state performance of a membrane-less reversible redox flow battery formed by two immiscible electrolytes that spontaneously form a liquid-liquid system separated by a well defined interface. The model assumes a two-dimensional battery with two coflowing electrolytes and flat electrodes at the channel walls. In this configuration, the analysis of the

In many microsystem applications, a nanometric surface quality is crucial to the performance of a device. Soft abrasive flow machining (SAFM) is capable of finishing surfaces at very fine scale with complex geometries since, unlike traditional flow machining processes, abrasive grains are carried by a very low viscosity fluid. Several empirical studies have been done to ensure final high quality surfaces

In this paper, to characterize the limited availability of medical resources, we incorporate a saturated treatment rate into a network-based susceptible-infected-susceptible (SIS) epidemic model with time delay and nonlinear incidence rate. Analytical study shows the boundedness of solutions, the basic reproduction number R0 and equilibrium points of the proposed system. For any infection delay, we

The present paper is concerned with nonlinear vibration of a simply supported functionally graded graphene reinforced composite (GRC) cylindrical panel subjected to the transverse excitation. Functionally graded structure is proposed to distribute more graphene platelets (GPLs) to the most needed layer for the optimal performance. The modified Halpin-Tsai model and the rule of mixture are carried out

This paper strives to derive the analytical solutions for the dynamic analysis of stepped multi-span rotor system, where the rotating shaft's internal damping effect is also considered. Specifically, the steady-state whirl analysis and free vibration analysis is given herein. For the steady-state whirl analysis, firstly, the stepped shaft is spilt to several uniform segments and their governing equations

Cavity shedding mechanisms, such as those due to re-entrant jets (RJ) and condensation shocks (CS), are important but challenging topics in cavitating flows. This study investigates unsteady cavity shedding around a NACA66 hydrofoil using a self-defined compressible cavitation solver based on OpenFOAM with a dynamic cubic nonlinear subgrid-scale model. The predictions give satisfactory agreement with

Understanding drug release from pharmaceutical granules is vital to the development of targeted release profiles. A model describing diffusion and solubility-limited drug dissolution and release from a porous spherical granule of drug and excipient is considered. Radially varying porosity and initial concentration profiles which can arise in pharmaceutical granules are incorporated. A range of boundary-value

Composite insulators are widely used in high-voltage line transmission and electrical equipment due to their excellent water resistance. They are exposed to the natural environment for a long time, and they suffer from weathering corrosion of various factors and external uncertain shocks, which together lead to failure. According to the failure mechanism of composite insulators, a reliability model

To guarantee the best driving experience and status of the driver, further improve the driving safety of human–machine co-driving vehicles, reduce the conflict between the driver and controller, and weaken the impact of the driver's uncertain behaviours, a human–machine co-driving system with a dynamic weight allocation model is designed. First, a human–machine co-driving system is built with a fixed

This paper presents the derivation of the Clausius-Duhem inequality for quasi-1D transient flows of compressible fluids in radially deformable pipes of varying cross-section area. To do so, a decomposition of the normal stress in spherical and deviatoric components was considered, so that the power expended to radially deform the fluid could be properly accounted for in the first law of thermodynamics

The generalized Cattaneo model describes the heat conduction system in the perspective of time-nonlocality. This paper proposes an accurate and robust meshless technique for approximating the solution of the time fractional Cattaneo model applied to the heat flow in a porous medium. The fractional derivative is formulated in the Caputo sense with order 1<α<2. First, a finite difference technique of

Financial market is a complex system full of unknown and indeterminacy. It is well known that uncertainty and randomness are two basic types of indeterminacy. Hence, the complexity of real financial markets may lead to various types of security returns. They are usually assumed as random variables when there are enough historical data. If there is a lack of available data, they can be considered as

This study considers an item that can be operated over an indefinitely long run operation cycle n (n = 1, 2, 3, …), where each operation period causes a random amount of damage to the item, where the damage is accumulated over time, and where the item fails when the cumulated damage/wear exceeds a failure level ξ0. For such an item, a warranty policy in a discrete-time form is considered. It is suggested

Most of the existing energy harvesters are based on vibration amplification, which inevitably causes large disturbing force transmitted to the base. In this paper, a novel energy harvesting device is proposed based on vibration localization, through which the force transmitted to the base can be significantly reduced, thereby achieving simultaneous energy harvesting and vibration isolation. The proposed

This work considers the application of the air entrainment model developed in [P. Lopes et al. Int. J. Nonlin. Sci. Num., vol. 18, pp. 559-574, 2017] to simulation of flows in stepped spillways. Four Froude numbers are considered for the flow, with parameters selected to match available experimental data. An extensive simulation campaign led to the identification of several deficiencies in the model

The study analyzes the dynamic interaction of proximate masses using a new form of semi-analytical results for the moving mass problem developed by the author. This paper presents the results for a particular case of two moving masses of equal value acted upon by constant forces of equal values. The interaction level was demonstrated to be substantially high, making it impossible to superimpose the

Image segmentation aims to extract the target objects or to identify the corresponding boundaries. For corrupted images due to occlusions, obscurities or noises, to get an accurate segmentation result is very difficult. To overcome this issue, the prior information is often introduced and particularly, the convex prior attracts more and more attentions recently. In this paper, we propose a topology-

The present paper investigates the scattering phenomenon of horizontally polarized Shear wave on an irregular surface of the piezomagnetic stratum lying over a piezomagnetic substrate. The expressions of frequency relation and group velocity of scattered Shear wave on the considered piezomagnetic stratum-substrate structure are deduced for magnetically open and magnetically short cases by inducing

In this study, a new approach is presented to determine the stress and displacement field of a shallow buried circular tunnel subject to gravity and arbitrary lateral stress based on the complex variable method. The soil mass and lining are conformally mapped onto two ring regions. A more effective method than the power series method is used to solve the undetermined coefficients of complex potential

For nonlinear discrete-time systems where measurements can be randomly delayed by multiple sampling periods, measurements are dependent conditioned on the state trajectory, and the dependence becomes more complicated with the increase of step of random delay. A particle filtering for this system is developed, which is novel in that the likelihood is computed allowing multi step of delay and dependence

In this paper, a novel concept of optimal space-filling identifiable design is proposed in the framework of symmetrical global sensitivity analysis for exploring complex black-box models. The initial identifiable design is first generated algorithmically. Then based on two commonly used measures of space filling, the ϕq and L2-discrepancy criterions, two optimal space-filling identifiable designs are

This paper is to explore the dynamical analysis and active control synthesis for improving seaport operations through system optimization. First, the multi-dimensional system of the fractional Lotka-Volterra model is utilized to investigate its underlying dynamics of port competition and cooperation for container throughput. The nonlinear dynamical behaviors are intensely examined by using eigenvalue

In this paper, a novel discrete differential geometry-based numerical procedure for buckling and vibration analyses of rectangular plates with non-uniform thickness is developed. In the proposed approach a plate is discretized using a finite number of rigid bars, lumped masses, and elastic rotational springs to simulate both bending and shear deformation responses, allowing the analysis of thick plates