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The current study analyzes the potential of an environmentally benign integration of a parabolic trough solar collector (PTSC) with a heat-intensive multi-effect evaporator (MEE) used in pulp and paper industry. Actual plant data was used to simulate the MEE and estimate the steam economy (SE) and steam consumption (SC), which are used to judge the performance of PTSC-MEE system. Four distinct alternatives for the integration are investigated with Self-adaptive Differential Evolution (SaDE) utilized for optimization. Initially, a normal PTSC with four different model configurations of MEE, basic or with energy reduction schemes (ERSs) are tested and found that SE is slightly increased for each. Next, a geometrically optimized/combinatorial optimized PTSC with basic MEE is examined, a rise of ∼3.4% in SE is noted for both, with current integration outperforming one out of three ERSs. Subsequently, geometrical plus combinatorial optimized PTSC with basic MEE is inspected, increase in SE reached 7.59% and two of the three ERSs outperformed. Economic analysis is conducted to estimate the steam saving with different PTSC-MEE systems and corresponding payback periods. The possibility of decarbonization with the various integration possibilities is also explored by evaluating the fuel savings and related CO 2 savings. • Integration of PTSC with an MEE used in pulp and paper industry is investigated. • The fusion of PTSC with MEE is studied with various possibilities. • Self-adaptive Differential Evolution (SaDE) is used for various optimizations. • The steam savings and payback times are estimated for various PTSC-MEE systems. • Decarbonization is studied by analyzing fuel savings and CO 2 reductions. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive study on applying the two-scale asymptotic homogenization method to derive the effective properties of piezoelectric composite materials characterized by generalized periodicity in curvilinear coordinates. The methodology involves formulating the homogenization problem in a general curvilinear framework suitable for materials with complex geometric configurations. By systematically deriving the homogenized equations and effective coefficients, the paper provides a robust theoretical foundation for understanding the macroscopic behavior of piezoelectric composites under various loading conditions. The model's versatility is demonstrated through its application to specific curvilinear coordinate systems, including the helix coordinate system and cylindrical coordinates with wavy geometry. These examples highlight the potential of the proposed approach in analyzing and designing piezoelectric materials with intricate geometries. The state-of-the-art numerical homogenization methods have also validated the proposed homogenization method, ensuring its accuracy and robustness. [ABSTRACT FROM AUTHOR]

This paper focuses on the experimental and analytical behavior assessment of novel sandwich panels fabricated with recycled glass-fiber/polyester resin (GFRP) core and PVC face sheets. The originality of the present work is based on sustainable development and waste recovery to design lightweight and eco-friendly structures. In this respect, the panels cores were fabricated using fully recycling of fiber-glass waste issued form the boats building. Accordingly, a set of sandwich panels with various core configuration and fibers orientation were manufactured and tested up to failure under three-point bending to characterize flexural and shear properties. In addition, validated analytical equations were advocated to assess the bearing capacity of the studied panels. The obtained results in terms of mechanical, thermal and physical features are emphasized, discussed and confronted with a good agreement to literature ones. A principal component analysis was conducted to optimize the effect of the geometrical parameters on the panel failure mechanisms. As main outcomes, the work can provide environmental and economic solutions for the design of sandwich structures. • Lightweight and eco-friendly sandwich structures-based GFRP waste core were designed • Validated analytical equations were advocated to assess the bearing capacity of the studied panels under bending • A principal component analysis was conducted to optimize the geometric parameters of the panels • The paper results provide environmental and economic solutions for the design of sandwich structures [ABSTRACT FROM AUTHOR]

In this work, we present a comprehensive analytical model for the Spacer-Engineered Reconfigurable Silicon Nanowire Schottky Barrier Transistor (SE R–Si NW SBT) for biosensing applications. This device operates in both n-mode and p-mode configurations by incorporating dual gates located near the source and drain terminals. The electrostatic integrity of the device is enhanced by incorporating high-K spacers on both sides of the gate electrode, facilitating improved interaction between the gate and the Schottky barrier. The biomolecules present on the silicon dioxide layer within the underlap cavity at the channel center, significantly impact the electrostatic properties throughout the device channel, including channel surface potential, drain current, electric field, and threshold voltage. By utilizing the 2D Poisson equation, we effectively capture the behavior of these key electrostatic properties. The primary metrics for biomolecule detection in this device are the changes observed in the threshold voltage and drain current. Furthermore, the variations in threshold voltage are analyzed to evaluate the sensitivity of the proposed biosensor and compared with that of state-of-the-art FET-based biosensors. The reliability of our analytical approach is validated using a virtual model of the proposed biosensor and performing simulations using the Silvaco TCAD device simulation tool. Through a meticulous comparison of our analytical findings with the simulated results, we establish the accuracy and dependability of our model. • The paper introduces a novel physics-based analytical model for detecting charged and neutral biomolecules. • The model accurately estimates channel surface potential, drain current, electric field, and threshold voltage profiles. • The analytical model is calibrated with experimental results. • The paper benchmarks the performance of proposed biosensors against state-of-the-art FET-based biosensors. [ABSTRACT FROM AUTHOR]

The electrohydrodynamic (EHD) actuator system, which produces thrust by ionizing a gas and accelerating it, is a novel propulsion system for near space vehicles. In this paper, an analytical model for EHD actuators, called EHD-AM, has been presented to estimate the thrust produced by the actuators in a wire-to-cylinder configuration. Experimental data from six previous studies have been used to validate the model and the mean absolute percentage error (MAPE) between each configuration and EHD-AM has been calculated under different environmental conditions. Based on the evaluations, the MAPE between EHD-AM and the experimental results for different pressures and wire-to-airfoil structures is 7.18% and 6.16%, respectively. The MAPE between EHD-AM and the experimental data measured by particle image velocimetry (PIV) method and with conventional experimental setups is 10.59% and 6.76%, respectively. Based on the EHD-AM, at a constant voltage, the relation between thrust and pressure has a local minimum and a local maximum point in the range of 0.05–1 atm. From 0.05 atm to 0.5 atm, as the pressure increases, the thrust decreases and then increases. As the pressure increases from 0.5 to 1 atm, the thrust decreases. In addition, a higher voltage can result in a higher pressure at which thrust is maximized. Furthermore, the generated thrust is monotonically increasing as the voltage amplitude increases. By implementation of EHD-AM thrust scale in a simple numerical model, the thrust generated by the actuator has been computed and simulated numerically. Initially, the numerical model was verified using experimental results from a previous study. The MAPE between the numerical model and the EHD-AM is 24.08%. Finally, when the interelectrode gap, the collector radius and the emitter radius are relatively large, the thrust of the actuator is predicted by EHD-AM and compared with the numerical results. EHD-AM can be used in the design and optimization of EHD actuators, and also for controller design and related analyses in a control system. • In EHD actuator, the relation between the thrust and the pressure is determined. • The relationship between corona current and voltage has been considered based on the space-charge-limited current relations. • In high and low mobility of ions, the thrust is obtained as a function of voltage. • Analytical model for corona discharge-based EHD plasma actuator is obtained by incorporating environmental conditions. [ABSTRACT FROM AUTHOR]

• New analytical solutions for free vibration of edge-cracked thick plates are derived. • New free vibration results of edge-cracked thick plates are provided as benchmarks. • The present symplectic approach has the advantages of strictness and high accuracy. • The effects of crack length and crack location on vibration behaviors are revealed. Analytical modeling for cracked plates' free vibration is of great significance as a crack alters the properties of plate structures and thus greatly affects the mechanical behaviors of such key engineering components. This paper presents novel analytical solutions for the free vibration of thick rectangular plates with a crack normal to an edge, a kind of typical edge-cracked plates. To resolve the jump discontinuity caused by the edge crack, an original plate is decomposed into four elementary plates, whose free vibration problems are solved analytically via an unusual symplectic superposition method (SSM). The SSM is implemented in the Hamiltonian system-based symplectic space, where several mathematical treatments such as the variable separation and the symplectic eigenvector expansion are valid, rendering rigorous step-by-step derivations without pre-defining solution forms. By incorporating the solutions of the elementary plates, the eventual solutions of the edge-cracked thick plates are obtained. Such a symplectic framework provides a new route to solving various complicated plate problems that cannot be analytically handled previously. Comprehensive free vibration results such as natural frequencies and vibration modes of edge-cracked thick plates are presented. High accuracy and fast convergence of the framework are confirmed. The present analytical solutions are also utilized to study the effects of both the crack length and crack location on free vibration behaviors of edge-cracked thick plates. [ABSTRACT FROM AUTHOR]

Focusing on buckling problem under hydrostatic pressure of ring stiffened shells and shells with stiffened cutout fabricated by filament winding process, a new form of equilibrium equations is given in this paper based on high-order shear deformation theory (HSDT). A novel theoretical model is proposed based on Messager's model of geometrical imperfection. The model contains both ring stiffened shell model (RSSM) and stiffened shell with cutout model (SSCM). In this model, changes in the shells' thickness z ˜ k (x , y) , k = 1,2 , ... , n are described using a Fourier series representation, which is included in HSDT stiffness matrix A, B, D, E, F, H. To evaluate the critical buckling pressure p c r , the model is applied and compared with the conventional stiffened cylindrical shell (SCS) model. The results demonstrate a significant reduction in error, ranging from 71.08% to 81.22%, when using the proposed model for shells stiffened by a ring stiffener in the middle, as compared to the SCS model. This highlights the enhanced accuracy provided by the proposed model. The results indicate that small stiffened cutouts in thin shells and large stiffened cutouts in moderately thick shells have relatively small influence on the critical buckling pressure. Conversely, the presence of a ring stiffener in the middle has a more pronounced effect. • Theoretical model contains ring stiffened shell model (RSSM) and the stiffened shell with cutout model (SSCM) is proposed. • A new form of equilibrium equations is given in this paper based on the high-order shear deformation theory (HSDT). • The middle ring stiffener shows a great effect on the global buckling load, while the small cutout shows little. [ABSTRACT FROM AUTHOR]

Given the increasing penetration of converter-interfaced resources in power systems, properly estimating the short-circuit current (SCC) contribution in large networks has become a growing challenge and necessity to ensure the security and stability of the systems and assets. This paper presents two novel methods to estimate the SCC contribution of type IV wind turbines at both the transient and steady-state stages of unbalanced and balanced faults: (1) a machine learning-based method trained with electromagnetic transient (EMT) simulations and capable of estimating some of the initial peak and transient current magnitudes; (2) an analytical approach to estimate the steady-state SCC based on the voltage and grid code dependency of the converter during the fault. The methods are coupled into a single framework and compared to field-validated EMT models of a real turbine. The results show that the majority of the estimated currents in the transient stages present errors below 5%. In steady-state, the errors are not greater than 1.21%. Given the complexity of the problem, these margins may be deemed acceptable for short-circuit studies. [Display omitted] • Short-Circuit Current Contribution from IBRs is becoming increasingly important. • The novel framework has been verified against field-validated EMT Models. • For the steady-state stage, the power-flow-based algorithm shows high accuracy. • Due to the complexity of the transient stage, a Machine-Learning model is used. [ABSTRACT FROM AUTHOR]

This paper presents an in-depth study of electrostatic actuators based on flexible side-electrodes focusing on the available electrostatic force and the derived useful force. A design tool is proposed considering technological aspects as aspect ratio, insulating layer material and voltage level. A space discretized mechanical approach based on Euler-Bernoulli beam theory is developed to model the bending deflection of the flexible movable electrode and "zipping" contact. Analytical developments and simplifications are achieved, rapidly and efficiently implemented in a proposed algorithm. ANSYS® simulations validate the procedure for updating the contact zone through the updating of the electrostatic pressure distribution. Optimum movable electrode width and appropriate "opposable" stiffness for guiding system are discussed. A "residual air thickness" parameter is introduced to address imperfect contact between the electrodes. characterization studies various prototypes with different structural parameters as thickness (50 µm and 200 µm), gaps (5 µm and 15 µm) and material for insulating layers (silicon oxide and parylene C). The metrology campaign highlights the impact of aspect ratio and oxidation/deoxidation on electrode sidewall quality and hence mechanical performance. A comparison with well-known comb-drive shows higher electrostatic force for flexible side-electrode actuators. As an example, for a 10 µm stroke, the available electrostatic force for flexible electrodes with irregular sidewalls (residual air thickness 0.6 µm) is 2.2 times greater and rises to 7.3 times greater for perfect sidewalls (no residual air). [Display omitted] • An analytical model and its algorithm are proposed for flexible side-electrodes electrostatic actuators. • Useful force is maximized according to an optimum electrode width and an appropriate "opposable" guiding stiffness. • Experimental characterization is conducted on set-ups including different aspect ratio and insulating layer material. • A relationship between performances and imperfection of the contact is established through a "residual air thickness". [ABSTRACT FROM AUTHOR]

Abstract The objective of the current paper is to provide an accurate distributed parameter model for random vibration analysis of multi-floor buildings. The Hamilton's principle is employed to derive the equations governing the dynamic behavior of the system as well as the related kinematic and natural boundary conditions. The natural frequency and mode shapes of the developed model are then extracted analytically and validated using finite element simulations. It is also observed that the predictions of the proposed model for the natural frequencies of the system is far more accurate than those of that of the discrete model available in the literature. Using a single mode approximation in the Lagrange equation, the partial differential equations of the motion are reduced to a single ordinary differential equation. Assuming a band limited white noise for the acceleration of the support, the random response specifications (such as expected value, autocorrelation, spectral density and mean square) of the system is calculated by making use of the random vibration theory. The qualitative and quantitative nature of the response characteristic are also analyzed to reveal the effects of different design parameters on the system's response. The suggested modeling approach in this paper may be employed for prediction of the dynamic behavior of more complex structures to different types of deterministic or random excitations. Also the provided analytical method for the random response calculation of the system can be utilized to make more informed decisions in the design process. Highlights • Presenting a distributed parameter model for a multi-floor building. • Deriving exact natural frequencies and mode-shapes of the multi-floor building. • Analyzing random response of a building to a random earthquake excitation. [ABSTRACT FROM AUTHOR]

In the field of external strengthening and repairing of existing reinforced concrete structures, steel reinforced polymers (SRP) systems have emerged as a competitive alternative to the use of the more common carbon and glass fiber reinforced polymer (FRP) composites. Experimental investigations have frequently shown the potentials of these innovative composite systems in improving the performance of deficient structural members. At the same time, additional studies are needed to expand the existing knowledge and either to provide design recommendations or to develop specific guidelines. The paper fills some of the foregoing knowledge gaps by presenting an analytical investigation on the bond behaviour between SRP and concrete in which closed-form solutions are derived to predict the entire debonding propagation process. In particular, accurate and simplified local shear stress-slip (τ-s) laws are employed in the proposed modelling from which different expressions for the interfacial shear stress distribution, the axial stress profile and the concrete-SRP relative displacement (slip) are developed and commented in the paper; analytical estimates of the SRP effective bonded length are provided as well as relationships for calculating the maximum axial stress (or peak force) at SRP laminate debonding. The analytical procedure was, firstly, applied to simulate some single-lap shear tests performed in a previous experimental program with the purpose to investigate the influence on the debonding propagation process of the following main parameters: a) concrete strength, b) concrete surface finish and c) steel tape density. Then, the comparisons between the numerical simulations and the experimental results available for some bond tests have allowed for verifying the accuracy of the proposed modelling. [ABSTRACT FROM AUTHOR]

• Design, modelling and prototype of the novel Axial Active Magnetic Bearing. • Validated analytical model is convergent with experiments and numerical simulation. • Schwarz-Christoffel transformation is utilized in study of the actuator end effect. • Three-dimensional complex permeance function represents the stator pole pieces. • Computational time of analytical model is significantly shorter then numerical one. The article presents a novel design of the axial active magnetic bearing with six poles. An analytical magnetic bearing model was developed to provide the axial magnetic induction distribution in 3D. The model utilizes magnetic vector potential formulation and Schwarz-Christoffel mapping. The paper covers in-depth deliberations on the end effect influence and the conjugate complex permeance function. Numerical model and simulations were provided in 3D mode with support of COMSOL Multiphysics software. The six pole axial active magnetic bearing was manufactured and investigated experimentally. Identification of the magnetic field distribution was carried out with a single axis magnetic induction sensor using custom automatic field scanner. High convergence of the modeling results and experimental research was demonstrated. The main advantage of the proposed analytical method is significantly shorter computation time compared to the numerical one that is useful from the modeling and controller study point of view. The configuration, modeling, simulation and experimental investigation results are well illustrated for the better overview. [ABSTRACT FROM AUTHOR]

The paper focuses on thermal torsional post buckling of functionally graded carbon nanotube reinforced composite cylindrical shells with sur-bonding piezoelectric layers and embedded in an elastic medium. The distribution of reinforcements through the thickness of the shells is considered to be uniform and functionally graded. The basic equations using geometrically nonlinearity in von Karman-Donnell sense within the classical thin shell theory are established. The torsional post-buckling behavior of the piezoelectric functionally graded carbon nanotubes reinforced composite (FG-CNTRC) shells is analyzed with using the Airy's stress function and the Galerkin's method, in which a three-term approximate solution of the deflection of the shell is assumed. Effects of thermal environment, CNT volume fraction, piezoelectric layers (the thickness and the constant voltage), distribution type of the reinforcement, dimensional parameters and Winkler and Pasternak foundation are investigated in this paper. Numerical and graphical results show that the carbon nanotube volume fraction and the piezoelectric layers as well as the elastic foundation and the thermal loads have significantly influenced on the torsional postbuckling behavior of nanocomposite shells. [ABSTRACT FROM AUTHOR]

Although TiB reinforced titanium matrix (TiB-Ti) composites exhibit superior wear resistance and strength, they still demonstrate severe problems resulted from lowered toughness and ductility, as compared with titanium and its alloys. To reduce these problems, this paper tailors a three-dimensional quasi-continuous network (3DQCN) microstructure within TiB-Ti composites by in-situ laser deposition-additive manufacturing process. Results show that the laser power has great impacts on the formation of 3DQCN microstructure and the 3DQCN microstructure is beneficial to both strengthening and toughening effects on TiB-Ti composites. To have a quantitative understanding of strengthening effects, this paper, for the first time, has modeled the yield strength of TiB-Ti composites with 3DQCN microstructure. [ABSTRACT FROM AUTHOR]

Progressive collapse can be triggered by impact loading from vehicles or other objects and propagated by impact loading from falling debris. Therefore, the correct modeling of impact loading is necessary to assess the resistance of a structure against progressive collapse. As the number of timber buildings increases, the importance of adequate considerations of impact loading is growing. Previous research on impact loading of wood or timber was carried out on small clearwood specimens or on single boards. However, modern timber buildings use advanced wood-based composites, such as glued laminated timber and laminated veneer lumber. The characteristics of these materials are widely different from clearwood and single boards. In this paper, energy-based equations are derived for the peak impact force and the dynamic strength increase factor. These are quantified by pendulum impact hammer tests on 95 full-size glued laminated timber beams. The results are applied in a calculation example to demonstrate their potential use in practice. • Energy-based models for impact loading of timber beams are presented. • Results from 95 impact tests on full-size timber beams are discussed. • High-speed imagery reveals the impact process and five distinct failure modes. • The energy-release properties of timber beams are found to be strength class independent. • The dynamic increase or load duration factor is found for impact loading of timber beams. [ABSTRACT FROM AUTHOR]

• The creep in compaction was correlated with the recovery in the relaxation phase. • A unified viscoelastic-plastic model with one set of parameters was proposed. • Elevated temperature and in-plane tension intensify creep/recovery behavior. • Model captured temp. and time-related creep/recovery considering in-plane strain. In the manufacturing process of fiber-reinforced composite materials, the preforming of dry fiber fabrics is typically carried out under specific out-of-plane pressure, in-plane tension, and at designated temperatures. The fabric exhibits significant time and temperature-dependent permanent deformation as well as creep/recovery behavior. Gaining a better understanding of these phenomena and harnessing predictive capabilities will be instrumental in achieving more precise control over fiber volume fraction and material composition. In this paper, creep/recovery experiments and cyclic loading-unloading tests were conducted on CF3031 dry fiber preforms under various in-plane tensions and temperatures, measuring in-plane strains using Fiber Bragg Grating (FBG) sensors. Based on this data, a modified Burgers viscoelastic-plastic model has been proposed to describe the time-dependent creep/recovery behavior of dry fiber fabric preforming under the coupled effects of in-plane tension, out-of-plane pressure, and temperature variations. This model employs a single set of equations and parameters to represent the complete creep/recovery process of the material. The experimental results align well with the predicted outcomes across different compression scenarios. [ABSTRACT FROM AUTHOR]

In this paper, the temperature-dependent gate-induced drain leakage (GIDL) current model is proposed with the help of a lateral electric field (E L) across the inner and outer gate interfaces of the junctionless double-gate-all-around (JL-DGAA) field-effect transistor (FET). The E L at the interface is obtained from the surface potential equation after solving the 3D Poisson equation with appropriate boundary conditions. The derived model is validated using the well-calibrated TCAD simulator platform with experimental data. A higher GIDL current at the outer gate-channel interface is observed compared to the inner gate-channel interface in the OFF-state conditions due to the high E L between the channel and drain, which is reported for the first time here. The effect of temperature (from 200 K to 500 K) on the GIDL current is also observed, which increases linearly with increasing temperature. Further, the impact of induced mechanical stress (MS) is investigated on the GIDL current, where the GIDL current increases exponentially with increasing induced MS due to effective mass and band gap reduction. Finally, the dynamic performance is investigated in terms of the gate delay time as a function of channel length and temperature. The gate delay diminishes with decreasing channel length and increasing temperature, which shows the switching speed and ability of the device. [ABSTRACT FROM AUTHOR]

This paper deals with the vibration and buckling behaviour of orthotropic double -layered graphene sheets with various boundary conditions in a hygrothermal environment. Two graphene sheets are coupled by an elastic media and also limited to the external Pasternak elastic foundations. The governing equations of motion and equilibrium are derived using Hamilton's principle and then solved using Galerkin's method. The general equations for transverse vibration and buckling of orthotropic double-layered graphene sheets subjected to in-plane edge hygrothemal loadings are formulated on the basis of Eringen's differential nonlocal elastic law and the new first order shear deformation theory. The accuracy of the present solutions is demonstrated by comparison with solutions available in the literature. Numerical results are presented to show variations of the frequency and critical buckling load corresponding to various values of the nonlocal parameter, temperature rise, moisture rise, elastic foundation parameter, and aspect ratio. Also, seven different boundary conditions are discussed in the paper. [ABSTRACT FROM AUTHOR]

Multiwall plates consist of parallel thin-walled plates connected by a given number of vertical ribs to yield a light and yet a high strength structure. Unlike composite and sandwich plates, the multiwall plate does not have cross-section material continuity and therefore cannot be analyzed in terms of stress distribution in a simple way. The first order shear deformation theory (FSDT) model is used to obtain a homogeneous plate. Innovative analytic and finite element models were developed to obtain the elastic equivalent constants of the plate. A good matching was obtained between the analytic model results and the numerical ones. It turned out that the analytical approach cannot yield all the elastic equivalent constants, therefore an experimental approach was developed and implemented to obtain all the equivalent elastic constants of a typical multiwall plate. Those results were in good matching with the numerical finite element ones. The structural response to loading for the orthotropic equivalent plate can be easily calculated either analytically, numerically or experimentally. • A homogenization of multiwall plates yielding an orthotropic solid plate with equivalent properties was validated numerically, analytically and experimentally. The authors believe that this was done for the first time for such type of plates. • The output of the present paper is that calculating by FEA the deflection of a rectangular homogenized plate reduces drastically the computation time as compared with the full original plate. This should be hold as the second highlight. • It turned out that a multiwall plate structure has a relatively low transverse shear rigidity in y direction. Therefore, shear deformations must be considered in the design process. Also, the plate's twist rigidity is reduced due to this low rigidity. This conclusion should be considered as the third highlight of the present paper. • It seems than in a multiwall rectangular plate, the Poisson's effect induces a stress in the ribs under y direction tension and bending. This is different from a solid plate, where Poisson's strains are stress less. This interesting conclusion would be the 4th highlight. [ABSTRACT FROM AUTHOR]

• An analytical solution is proposed for a pin fin heat/mass exchanger sorber bed. • Graphite flake additives in CaCl 2 -silica gel composite sorbents. • ANOVA is utilized to understand the contribution of each parameter on performance. • Parametric study is carried out to examine the effect of key design parameters. • Transient measurement using gravimetric large temperature jump test bed. This paper proposes a novel closed-form analytical model to predict the sorption performance of a pin fin heat/mass exchanger (PF-HMX) prototype, using the Eigenfunction expansion method to solve the governing energy equation. The proposed transient 2-D solution includes all salient thermophysical and sorption properties, sorbent geometry, operating conditions, and the thermal contact resistance at the interface between the sorber bed heat exchanger and sorption composite. An analysis of variance (ANOVA) method is utilized to understand the percentage contribution of each parameter on specific cooling power (SCP) and coefficient of performance (COP). It is shown that the amount of graphite flake, sorbent thickness, and fin radius on one hand and cycle time and graphite flake content on the other have the highest level of contribution to the COP and SCP, respectively. Moreover, a parametric study found that HMX geometry, sorbent properties, and cycle time counteract effects on COP and SCP, which should be optimized simultaneously to build an optimal design. The analytical model was validated successfully using the sorption data from a custom-built gravimetric large temperature jump (G-LTJ) testbed. The experimental results show that the present PF-HMX design with a relatively low mass ratio (MR) can achieve an SCP of 1160 W kg−1 and a COP of 0.68 which are higher than the previously published results in the literature. [ABSTRACT FROM AUTHOR]

The paper presents one of the initial steps in the evaluation process towards possible implementation of an innovative taxiway intersection design at Munich Airport apron. A roundabout is proposed as a potential solution for the 12-line intersection area expected at redesigned Apron 3. Although it is a common solution used in road transport for complex intersections, the roundabout has never previously been used for airport surface operations nor has its possible use been considered or analyzed. The paper presents preliminary design and operations concepts of the apron roundabout, followed by its capacity evaluation under Munich Airport operating conditions. The aim was to analyze whether a roundabout is suitable to replace a conventional intersection, in terms of capacity. [ABSTRACT FROM AUTHOR]

This paper deals with the lateral–torsional buckling of elastoplastic steel beams under pure bending considering various cross-section geometries. Critical buckling moment expressions for elastic beams are well documented. In contrast, less attention has been devoted to the lateral–torsional buckling phenomenon in elastoplastic regime. When considering short beams (with sufficiently low slenderness), plastic zones will develop before buckling occurs. The problem being faced here is however much more complex than the classical problem of an elastoplastic beam subjected to an axial compressive force. Under such loading, plasticity occurs instantaneously and evolves uniformly over the cross-section and along the beam length whereas, in the other case, plasticity will spread gradually and the plastic zones will change with the loading. The main objective of the present paper is to develop original analytical solutions for the elastoplastic lateral–torsional buckling of perfectly straight beams. A general formulation based on a previously developed 3D plastic bifurcation theory is first proposed and then applied to the cases of two specific cross-section geometries, namely rectangular and I profiles. For the sake of simplicity, transverse shear strains are neglected in the analysis. The von Mises yield criterion with a linear isotropic hardening is adopted. In the case of a rectangular cross-section, closed-form solutions are obtained for the elastoplastic critical buckling moment, which is shown to depend on the geometric and material parameters of the beam, including the yield stress. For validation purposes, all the analytical solutions are compared against the results of numerical computations performed with an in-house program based on a shell finite element formulation. Analytical and numerical results are in very good accordance, making the analytical method presented here an efficient and precise tool to analyze the elastoplastic lateral–torsional buckling phenomenon. [ABSTRACT FROM AUTHOR]

Transverse beam vibrations can be controlled by bonding resistively shunted piezoelectrics to the beam's surface. The piezoelectrics convert a part of the system's mechanical energy into electrical energy, which is dissipated by the shunted resistance. An analytical model is presented in this paper to represent the resistively shunted piezoelectric beam. A single expression for the system response, encompassing both the mechanical and electrical aspects, is derived. The aptness of the presented model in describing the system is evident from the discussions of the shortcomings of the two most employed models found in literature. In deriving the optimal resistor from the magnitude plot of the FRF, the previous works ignore the inherent damping of the structure in their analytical models. In this paper, the optimal resistance is derived from the analytical model which includes the inherent damping of the structure. A modification was done to the presented analytical model to include the design of the metallic electrodes covering the piezoceramics. Experimental results from literature were used to validate the presented model, and it was found that the presented analytical model offered closer predictions than the model given in the literature. Furthermore, results from the experiments conducted on a cantilever piezoelectric beam were used to validate the modified analytical model. [ABSTRACT FROM AUTHOR]

• Analytical modeling of Love waves propagation in viscoelastic waveg-uide loaded with complex fluids is proposed. • Complex dispersion equation is established in order to quantitatively analyze the Love wave behavior. • Complex dispersion equation reveals a very good agreement with those in the literature in some particular cases. • Obtained results are fundamental and can be very useful in the design and optimization of Love wave fluid sensors. Love waves propagation in a viscoelastic waveguide loaded on its surface with viscoelastic fluids of finite thickness is investigated in this paper. The Maxwell and Kelvin-Voigt constitutive equations are employed in order to describe the fluid viscoelasticity. By solving the equations of motion in the different media (viscoelastic fluid, viscoelastic waveguide and elastic substrate) and imposing the suitable boundary conditions, an accurate and simple generalized complex dispersion equation is established for Love waves. Subsequently, a comparison is made with the published complex dispersion equations in the literature in some particular cases, and a very good agreement is showed. A detailed study was conducted by varying key parameters such as operating frequency, waveguide thickness and fluid thickness. The waveguide surface was subjected to various glycerol concentrations, with a wide range of dynamic viscosity, representing both Newtonian and viscoelastic behaviors. Theoretical analysis shows that to reasonably predict the characteristics responses of Love waves, the Maxwell fluid is more appropriate for low glycerol concentration and, the Kelvin-Voigt fluid is more suitable for high glycerol concentration and at high frequency. Results also evaluated the influence of layer thickness on the dispersion curves. The obtained results can be very useful in the design and optimization of Love wave fluid sensors. [ABSTRACT FROM AUTHOR]

The concrete-cored cement mixing (CCM) pile composite foundation is a practical technology for soft soil ground treatment. This paper proposed a theoretical analysis model for the CCM pile composite foundation under embankment in undrained condition which comprehensively considered the interaction between the various components of the CCM pile composite foundation. The working behavior and influencing factors of CCM pile composite foundation under the embankment was also investigated based on the proposed analysis model. The research results showed that: the embankment load was transferred from the outer soil column to the inner soil column. The formation of soil arch effect promoted the concrete core pile to undertake the majority of embankment load, which improved the working behavior of the CCM pile composite foundation under flexible foundation. There was a neutral plane at a certain depth below the ground surface, and the pile shaft above the neutral plane was under negative skin friction, moreover, the vertical stresses of the concrete core pile, cement mixing pile and the soil around the pile all reached the maximum value at the neutral plane. [ABSTRACT FROM AUTHOR]

This research article focuses on using a junctionless-based dielectric modulated vertical Tunnel FET (VTFET-DM-JL) as a biosensor. The objective is to detect biomolecules without the need for labeling, using electrical signals by modulating the dielectric constant. The JLFET, which is a device without any doping gradient or junction, serves as the structural foundation for this research. To understand the behavior of the structure, a potential model is created in this research which involves solving the Poisson equations (PE) under various boundary conditions. In addition, the incorporation of a high- K gate oxide improves the reliability of the device, particularly in terms of low power consumption. The paper explores the impact of dielectric constant values ranges from 1 to 12 by calculating figure of merit (FOM) values, including linearity, sensitivity, and noise assessment. As an example, Gelatin with a dielectric constant value of 12 exhibits a drain current sensitivity of 6.7 × 108, which is 9 % higher than apomyoglobin (κ = 8.1), 12 % higher than Bacteriophage-T7 (κ = 6.4), and 46 % higher than APTES (κ = 3.57) sensitivity, at a cavity length of 30 nm. Additionally, various FOMs, including linearity, sensitivity, and noise characteristics, are computed for the device across the dielectric constant range of 1–12. The simulated results obtained using the widely available Silvaco TCAD tool is compared with the modeled outcomes. A comprehensive assessment of the FOM standards establishes the promising nature of the proposed VTFET-DM-JL structure in terms of linearity and sensitivity. • In this manuscript, the sensitivity, linearity, and noise evaluation attributes of the VTFET-DM-JL biosensor is explained in detail. • The VTFET-DM-JL device exhibits a comprehensive surface potential model, incorporating five separate regions, as its distinguishing feature. The regions included the depleted regions for the source and drain, along with depleted sections within the channel at the source and drain sides, as well as channel transport regions. • This novel model is specifically developed for low voltage applications. The analytical model utilizes a parabolic approximation to solve both the one-dimensional (1-D) and two-dimensional (2-D) Poisson's equations. It improves the effect of band bending and enables smoother electrons tunneling paths, thereby enhancing device performance. • The accuracy of the potential model is evaluated by comparing it with simulated results. The observation reveals a strong agreement between both sets of results, demonstrating the reliability of the potential model proposed in this study. [ABSTRACT FROM AUTHOR]

This paper investigates the problem of the mechanical behavior of an interfacially cracked layered beam with possible bending-extension coupling (BEC) and residual hygrothermal stresses (RHTS), as well as shear deformations and crack-root rotations. The paper presents a mechanical model of a beam that results by assembling two sublaminates by a semi-rigid interface. The beam is clamped at its one end and interfacially cracked and generally loaded at the other. First, the mathematical problem is formulated and analytically solved in terms of the internal forces, strains, displacements, and interfacial stresses. Novel closed-form expressions are derived regarding these quantities and thoroughly reported in tables. The proposed expressions stand out for their generality; they apply to beams with arbitrary layers of random thicknesses and materials and consider general loading, BEC, and RHTS. Next, we highlight some specific cases by appropriately reducing the general expressions. As an example, we investigate the mechanical responses of composite laminates with possible BEC and RHTS using the double cantilever beam configuration. Lastly, the paper discusses new ways to deepen our knowledge of additional aspects of the fracture response of interfacially cracked beams with BEC and RHTS. • Analytical modeling of a generally laminated beam with an interfacial crack. • Extraction of a closed-form solution in the form of practical formulae. • Consideration of the effects of BEC, RHTS, shear deformations, and crack-tip rotations. • Discussion of interesting specific cases and identification of possible future extensions. [ABSTRACT FROM AUTHOR]

The structural performance of thin walled multi-cell multi-tapered (discrete variation of tapered angles at any point along the beam length) composite beams subjected to constrained torsional loading is examined in this paper. A simplified analytical procedure for determining the constrained torsional response of a particular class of thin walled multi-cell multi-tapered composite beams is explained in some detail. The constrained condition analyzed is that of the cantilevered multi-cell multi-tapered beam with torque applied at the free end of the beam. In order to avoid the elastic couplings between bending, torsion and axial effects in the beams, laminates are layed-up symmetrically about their own mid-planes in such a manner that they possess in-plane orthotropy. The analysis approach essentially makes use of the existing theories of torsion appropriate to non-isotropic nature of composite constructions. The details of the finite element analysis are also included in the paper. The comparisons between the theory and finite element results are shown to give close agreement. [ABSTRACT FROM AUTHOR]

The intermittent heating is considered to be able to achieve a high energy saving rate compared with the continuous heating. This paper builds a two-stage lumped parameter model to study the thermal dynamic process of the intermittent heating. Meanwhile, the on-site measurement was carried out on a residence in Cambridgeshire to verify the correctness of the model. On-site measurement validates the model we build and shows that the intermittent heating system we measured is able to provide comfort indoor thermal environment. However, the associated energy saving rate is only about 5% compared with the continuous heating system, which is not significant. Both the model and the on-site measurement show that the temperature change of the indoor air after the heating was recovered follows the exponent law and accordingly the thermal dynamic process of intermittent heating can be characterized by the thermal time constant. The thermal time constant is found to be a key index of intermittent heating. Low thermal capacity and high heat transfer coefficient lead to a small thermal time constant. The intermittent heating system with small thermal constant time is able to elevate indoor temperature quickly and has large energy saving potential. The thermal time constant of the intermittent heating system we surveyed has been calculated. Lastly, suggestions for improving the energy saving rate of intermittent heating systems have been provided in this paper. [ABSTRACT FROM AUTHOR]

The structural behaviour of eccentrically loaded reinforced concrete columns with rectangular cross sections strengthened with a cement based composite materials wrapping system, is analysed in the paper, both experimentally and analytically. The main issues focussed in the paper were: i) the effectiveness of the cement based wrapping systems to improve the strength of the reinforced concrete columns, ii) the influence of the load eccentricity and the reinforcement ratio on the structural response of wrapped columns, iii) the prediction, by an analytical procedure, of the structural behaviour of wrapped columns. A total of 8 reinforced concrete columns with end corbels, wrapped with fabric meshes of PBO (short of Polypara-phenylene-benzo-bisthiazole) fibers embedded into a cement based matrix (PBO-FRCM system), were tested varying both the reinforcement ratio, ρ f , and the eccentricity-to-section height ratio ( e/h ). The influence of mechanical and geometrical parameters on the structural response of wrapped columns was analysed in terms of failure modes, strength and ductility. To predict the structural response of wrapped columns, a non linear second-order analysis that takes into account the changes in geometry caused by lateral deformations is, also, developed. Theoretical results were compared with experimental ones to validate the effectiveness of the proposed procedure. [ABSTRACT FROM AUTHOR]

Switching transients and earth fault in a wind farm collection grid are two transient phenomena which can lead to resonant overvoltages at the LV terminal of the wind turbine transformers as well as inside HV and LV windings. The aim of this paper is to analyze the potential of the resonant overvoltage for various winding designs; disc, layer and pancake. In this way, the least vulnerable winding design can be recommended. For this aim, a 500 kVA transformer test object with the three aforementioned winding types has been designed and manufactured. Similar geometrical characteristics are used for all the three windings. By measuring the frequency response, the resonant frequencies can be found and the amplitude of the transferred voltage at these frequencies can be compared. The windings are also modeled in this paper in detail based on analytical functions. This RLC ladder model is verified by the measurements. The measurements and modeling results show that all winding designs have a resonant frequency around 800 kHz for the transferred voltage to LV terminal. Disc winding shows the lowest amplitude of the transferred overvoltages (6 p.u.). The layer winding, also has a resonance at 1.6 MHz with an even higher transferred overvoltage (80 p.u.). The frequency response of the pancake winding has characteristics of both disc and layer windings. In spite of having the lowest transferred overvoltage peak, the disc winding has many additional resonant frequencies in the range of 100 kHz-1 MHz. This could excite resonances in other parts of the winding. Consequently, pancake winding designs might be the most promising to minimize resonance situations. [ABSTRACT FROM AUTHOR]

Cross-spring pivots have been widely employed over the last decades in a broad variety of precision engineering applications due to the high motion repeatability achieved thanks to the absence of stick slip and clearance. In this paper, the non-linear effect of the anticlastic curvature of the leaf-springs is considered for the accurate analytical modeling of the elasto-kinematic behavior of cross-spring pivots. Finite element analyses (FEA), based on a non-linear thin-shell model, are carried out in order to compare them with the analytical results for the main performance parameters of this type of device, i.e. center-shift, rotational stiffness and stress in the leaf-springs. Furthermore, an experimental setup is built to assess the applicability limits of both models. Finally, remarkable performance aspects of cross-spring pivots are discussed aiming for design improvements. [ABSTRACT FROM AUTHOR]

• A novel concrete cover delamination model is proposed. • Flat concrete surface and non-uniform distribution of rust are duly accounted for. • The interaction between neighboring corroded rebars is considered. • Bulging deformation of cover surface and volume of rust can be predicted manually. Cover delamination failure caused by the corrosion of closely spaced rebars is commonly found in deteriorated reinforced concrete (RC) structures. However, analytical studies carried out on this failure mode of RC structures are rare. In response, this paper proposes a novel analytical model for cover delamination which takes into account the interaction between the neighboring corroded rebars, non-uniform distribution of rust around the steel/concrete interface, and boundary conditions of the concrete surface. This simple model enables manual prediction of the bulging deformation of the cover surface and the maximum thickness of rust. The predicted results are then verified with numerically derived results from a nonlinear finite element analysis. Finally, the effects of the rebar spacing, tensile strength of concrete and cover thickness on the bulging of the concrete cover surface and the maximum thickness of rust are studied with the verified analytical model. [ABSTRACT FROM AUTHOR]

• A simple linear elastodynamic model of a shielded longitudinal gradient coil (GC) is introduced. • The model is used to investigate the frequency response of a typical whole-body GC cylinder. • The frequency response is governed by the Fourier decomposition of the spatial current density. • The widths of all structural resonances are decreased when shielding currents are present. • Numerical results are consistent with available in-situ experimental data and numerical models. The reduction of gradient coil (GC) vibration continues to be a challenging problem in the optimization of magnetic resonance imaging systems. A key deficiency for passive reduction strategies is that, under realistic thick-shell conditions, there are no existing mathematical models that can provide reliable theoretical predictions about the parametrical behaviors of the vibration response. In this paper, we introduce a simple linear elastodynamic model of a shielded longitudinal GC that can serve as a baseline theoretical model for studying the steady-state linear vibration response of an undamped GC cylinder under the condition that only the Z-coil windings are excited by Lorentz forces. The exact three-dimensional theory of linear elasticity is used to formulate the model, and hence, there are no built-in geometrical constraints. An exact closed-form solution for the steady-state displacement field of the GC cylinder is given, and the solution is then used to numerically investigate the frequency response of a typical whole-body GC cylinder. A core prediction of the model is that the frequency response is essentially governed by the Fourier decomposition of a dimensionless "profile function" that specifies how the current density varies along the GC cylinder axis. An interesting corollary is that generally the same set of resonant modes are excited independent of how the currents are spatially distributed. The model also predicts that the widths of all resonances are substantially decreased when shielding currents are present. Numerical results obtained using generic profile functions are found to be remarkably consistent with available in-situ experimental data and existing numerical models. The model is therefore well-suited for parametric studies of the steady-state linear vibration response assuming that Z-coil windings are excited exclusively. [ABSTRACT FROM AUTHOR]

The mechanical performance of the steel reinforced reactive powder concrete (SRRPC) structural components significantly depends on the steel-concrete interfacial bond behavior. This paper presents an experimental and analytical investigation on the bond-slip behavior between the reactive power concrete and the H-shaped steel. A total of 11 specimens, considering the cover thickness, embedded length, stirrup ratio and bonding part (whole section, flange and web), were tested through the push-out configurations. Results showed that the cover thickness has the most significant impact on the interfacial properties. Moreover, the SRRPC exhibited the highest residual bond strength compared with the other steel reinforced concretes. The five-stage model and the modified tri-linear model were proposed to describe the average bond stress-slip relationship. It was found that the five-stage model had an excellent accuracy while the modified tri-linear model can reasonably predict the average bond stress-slip relationship. Finally, a comprehensive analytical model was developed to investigate the local longitudinal strain of the shape, bond stress and relative slip. • Cover thickness had the most significant impact on the interfacial properties. • Bond strength of steel-reinforced concrete highly depended on the concrete types. • Steel-reinforced reactive powder concrete exhibited great residual bond strength. • An interface analytical model was successfully developed. [ABSTRACT FROM AUTHOR]

• This paper presents an analytical model for amorphous-IGZO thin film transistors based on device physics with an additional contact voltage parameter which enhance its scope to short channel devices • The Physical parameters are extracted by employing least square (LSQ) curve-fit function and the average error between measured data and model output is found to be <3% • The proposed model is able to accurately reproduce the measured characteristics for both long and short channel TFTs with channel length ranging from 20 μm down to 2 μm with a single set of physical parameters. This paper presents an analytical model for amorphous In-Ga-Zn-O thin film transistors based on device physics. The proposed model comprises physical parameters including subgap density-of-states (DOS) and is useful for fabrication process optimization. In addition to delocalized free band states, the model accounts for deep and tail trap states and is valid for complete region of operation. Physical parameters are extracted by employing least square (LSQ) curve-fit function and the model is validated by comparing model outcome with measured characteristics of the device. The proposed model is able to predict the I-V characteristics of the long channel devices to good accuracy. Further, this model is enhanced to predict the behavior of the short channel devices by taking contact voltage drop into account. The model accurately reproduces the measured response of long and short channel oxide TFTs with channel length ranging from 20 μm down to 2 μm with channel width fixed to 20 μm. The average error between measured data and model outcome is found to be < 3 %. The proposed model is useful to design oxide TFT based circuits with different channel lengths using a single set of physical parameters through circuit simulator. [ABSTRACT FROM AUTHOR]

This paper develops an analytical model of temperature in Laser Powder Bed Fusion (LPBF) considering the geometrical effect of the build part, which is reflected by the part size and shape. The model is established based on the moving point heat source under a semi-infinite medium. A modified coefficient is utilized to calibrate the temperature along the build direction. The heat sink is adopted to consider the heat loss at the edge of the build part, and the superposition method is applied to calculate the multi-tracks effect of the laser beam. The material thermal properties are dependent on the temperature, and an iteration method is utilized to obtain the dynamic stable melt pool during the process. To validate the proposed model, the experimental data in the published paper are compared with the model predictions. Good agreement is found about the melt pool size. Based on the verified model, a sensitivity analysis of temperature with respect to the laser process parameters, the material properties, and the geometry of the build part is discussed. Both the depth and width of the melt pool have a negative relationship with the size of the part within the explored range. It is also shown that the size of the melt pool has a negative correlation with the length of the previous track, which is determined by the shape of the build part. [ABSTRACT FROM AUTHOR]

• Analytical modeling of oscillatory heat transfer in sorber beds considering TCR. • Closed-form relationships for heat flux and temperature in sorbent and HEX. • Evaluation of sorber bed performance in terms of different performance indices. • Remarkable enhancement of performance and heat flux by improving α sorb and TCR. This paper outlines a novel closed-form analytical model that considers the thermal contact resistance (TCR) at the interface between the sorbent layer and heat exchanger (HEX). Governing energy equations with oscillatory boundary conditions are solved using an orthogonal expansion technique and closed-form relationships are reported to calculate the temperature distribution and heat flux inside the sorbent coating and HEX. In addition, a new gravimetric large pressure jump (GLAP) test bed is designed to measure the uptake of sorption material. The performance of sorber beds are evaluated in terms of specific cooling power, heat flux at HEX base and sorbent temperature standard deviation. It is found that the sorbent thermal diffusivity and TCR at the interface between the sorption coating and HEX are the key parameters that determine the thermal performance of a sorption cooling system (SCS). [ABSTRACT FROM AUTHOR]

In the present, based on geometrical nonlinearity in von Karman sense and classical thin shell theory (CLT), the vibrational analyses of conveying-fluid functionally graded carbon nanotube reinforced composite (FG-CNTRC) cylindrical shells with piezoelectric layers in thermal environment are taken into account by an analytical approach. The uniform and functionally graded CNTs are used to reinforce through the thickness of the shell. The fluid flow in the shell is mentioned as non-viscous, incompressible, isentropic and irrotational. Furthermore, piezoelectric layers are bonded onto the outer surface of the cylindrical shell to act as an actuator. The equations of motion are derived by using the CLT, von Karman nonlinearity theory, the fluid velocity potential and then solved by Galerkin's technique. Moreover, the fourth-order Runge-Kutta method is used to resolve the differential equations. The fundamental frequencies, responses of nonlinear vibration as time histories and bifurcation diagram are studied in this paper. Furthermore, the effects of CNT volume fraction, piezoelectric actuator, thermal environment, geometrical parameters, elastic medium and the fluid flow velocity are carefully analyzed. The obtained results that are validated with those of other studies can be used as benchmark solutions for an analytical approach serving in further research. [ABSTRACT FROM AUTHOR]

Highlights • Bio-resourced composite is efficient for strengthening and repairing concretes. • Bio-resourced and carbon-epoxy composites efficiency is comparable for containment. • Bio-resourced composites are less efficient for repairing than carbon-epoxy ones. Abstract Carbon fiber reinforced polymer CFRP has been attracting to repair concrete structures in the last 40 years due to its high mechanical performances and low weight. However using CFRP is still an expensive option and does not match with sustainable development. This paper aims to compare both effects of CFRP and flax fiber reinforced polymer FFRP on repairing by confining mechanically damaged cylindrical concrete specimens under compression. External use of flax fiber is investigated experimentally and analytically in order to check how far it can replace CFRP to repair concrete structures. For this purpose, two compressive damage levels are applied to cylindrical concrete specimens before confining them with three different types of composites. Results showed that using two layers of FFRP composites for repairing damaged concrete lead to slightly lower performances than those when using CFRP ones. FFRP composites allowed not only enhancing properties of damaged concrete strength by 150%, but also giving a great ductility to confined concrete specimens. [ABSTRACT FROM AUTHOR]

Abstract This paper presents an experimental study carried out on the structural performance of shear-critical reinforced concrete (RC) deep beams internally reinforced with two different stirrups configurations; i.e. aligned and unaligned with the fabric-reinforced cementitious matrix (FRCM) strips. The test matrix involved two unstrengthened (reference) beams and twelve strengthened deep beams tested under three-point bending. Three test variables were investigated: (a) the configuration of the internal transverse reinforcement (ITR), (b) the type of FRCM fabric (carbon, glass, and polyparaphenylene benzobisoxazole, PBO), and (c) the strengthening technique (externally bonded, EB, and near-surface embedded, NSE). Experimental results demonstrated an effective application of the FRCM in improving the load capacities (P max) of deep beams; however, its performance depends on the test variables. The NSE-FRCM provided an inherent anchorage that prevented the premature debonding of the FRCM composite, which was a standard failure mode in the externally bonded FRCM strengthened beams. Finally, a simple strut and tie model (STM) is used to predict the load capacities of the deep beams strengthened with different FRCM systems and resulted in a satisfactory prediction with an average P th /P ex ratio of 1.11 and a standard deviation of 5.7%. [ABSTRACT FROM AUTHOR]

Abstract In many cases, existing reinforced concrete (RC) columns have been designed according to old seismic recommendations and present inefficient seismic behavior. Moreover, they usually have prior damages due to moderate earthquake excitations. Therefore, it is necessary these columns to be retrofitted. Many researches concern the seismic strengthening of RC columns with fiber reinforced polymers (FRP) and models have been proposed for calculating shear strength (V R) and ultimate chord rotation capacities (θ u). This paper focuses on columns with lap-spliced bars, with or without previous damages, externally confined with FRPs. The accuracy of KANEPE and EC8.3 equations for estimating V R and θ u is investigated as well as reasonable modifications are proposed to improve the accuracy of predictions. [ABSTRACT FROM AUTHOR]

Abstract The response behavior of shear critical reinforced concrete beams was large investigated, and many studies were presented in literature. However, several issues, like the strain level of FRP at the shear failure, and the interaction between internal and external reinforcement, remain not completely understood. This paper presents an analytical model for the response behavior of reinforced concrete beams strengthened in shear with FRP. The proposed procedure has been based on the Modified Compression Field Theory and can reproduce the whole load-displacement curve. The stress and strain fields have been rigorously calculated for each load step. The effective failure strain of FRP reinforcement has been investigated by applying two different approaches. The reduction of the stirrups stress level in the presence of the external composite reinforcement has been alternately both neglected and taken into account, thus to obtain a comparison of the numerical predictions. The accuracy of the proposed model has been assessed using a database of 71 specimens reinforced with FRP. The results have showed that the proposed model has yielded accurate results and the influence of key parameters on the predictions has been highlighted. Furthermore, a simplified formulation for the evaluation of the shear strength has been derived. [ABSTRACT FROM AUTHOR]

Abstract Epilepsy is a prevalent neurological disorder with symptoms characterized by abnormal discharge in the brain. According to the classification of the International League Against Epilepsy (ILAE) Commission, temporal lobe epilepsy is the most common type of epilepsy accounting for the most cases of the disorder observed in patients. Electroencephalography (EEG) is the most common diagnostic tool for Epilepsy, by which abnormal electrical activity of the brain can be clearly seen. This paper uses chaos theory and proposes a new analytical mass model for temporal lobe Epilepsy. Chaotic behavior of the model indicates normal model, while its periodic behavior indicate epileptic mode of the brain. The proposed model includes a number of parameters for which a full bifurcation analysis is conducted. This fully characterizes different regimes of the model and allows studying how one can control the parameters to switch between different modes. The proposed model enables to effectively use advance chaos-based mathematical tools to get further insights on the underlying mechanisms of epilepsy. [ABSTRACT FROM AUTHOR]

The manufacturing of ribbed aluminum structural parts presents several difficulties due to the appearance of geometrical distortions after machining. The presence of residual stresses on the aluminum blanks before machining is reported to be the main source of distortions for aluminum alloys. The variability of these stresses and the inability to measure them in every aluminum blank is the main limitation on the optimization of the machining processes of these parts. In this paper, a layer-removal based residual stress characterization method is proposed for its application in manufacturing environment. This method enables the identification of the bulk stresses on the machining blank and still allow the final machining of the component, making possible the definition of an optimized machining process that would yield a minimum component distortion. [ABSTRACT FROM AUTHOR]

Abstract The fracture toughness of particulate-reinforced ultra-high-temperature-ceramics changes but does not decrease by a constant gradient with the increase of temperature. The change in microstructure and the occurrence of brittle-ductile transition affect the fracture toughness of materials at high temperature. In this paper, a novel temperature dependent fracture toughness model for the particulate-reinforced ultra-high-temperature-ceramics was developed based on the Griffith energy theories and the concept of the maximum storage of energy associated with fracture. The effect of change in microstructure was considered by introducing a non-dimensional value, the ratio of critical flaw sizes of materials at room temperature and high temperature. The effect of plastic power was included in the model. It should be noted that the model has no any fitting parameter and which only needs some basic material parameters such as Young's modulus and specific heat capacity. The predictions of the fracture toughness of the composites in argon or air agreed well with the experimental measurements. [ABSTRACT FROM AUTHOR]

Highlights • Analytical model of sandwich and I-beams is formulated, with consideration of the shear effect. • The model is based on linear and nonlinear hypothesis of deformation. • It is assumed that planar cross-section of a beam is no longer planar in bent beams. • Bending under three-point bending and uniformly distributed load problems are analytically analyzed. • The analytical results are compared each with other. Abstract The paper is devoted to simply supported sandwich beams and I-beams of symmetrical structure. Two types of loads are taken into account: three-point bending and uniformly distributed load. Moreover, two models of deformation of planar cross sections of these beams are also considered: zig-zag theory – classical "broken line" hypothesis and nonlinear theory – "polynomial" hypothesis. Based on the principle of stationary total potential energy the differential equations of equilibrium are obtained. The system of the equations is analytically solved for two types of loads and the deflections of the beams are calculated for exemplary beams with consideration of the shear effect. The results of the two models of deformation of planar cross sections are compared and specified in Tables. Graphical abstract Scheme of the simply supported beams with the two types of loads. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Analytical model for designing flexural strengthening of timber beams with FRPs. • Definition of an amplification factor (β) for the plastic compressive stress area. • Use of natural FRPs as greener and suitable alternative to classic FRPs. • Calibration and validation of the model on the flexural behavior of timber beams. Abstract Wood has always been considered as a valuable material for construction works. Nonetheless, over time timber structural components may need to be strengthened with other materials such as steel or, more recently, Fiber Reinforced Polymer (FRP) composites. This research paper concerns an analytical investigation based on the results of an experimental campaign carried out at the University of Padova (Italy) on full-scale timber beams flexure-strengthened by carbon and natural flax fibers. The theoretical work was carried out by means of a MATLAB code to develop an analytical model based on beam theories. This was then followed by calibration of the model with pilot tests and comparison of the results with those from other tests. During calibration, an equation for amplification coefficient of the plastic compressive stress block was developed. The analytical model and its related equations, including the amplification coefficient, can be used to model other timber beams by changing the significant mechanical parameters, boundary and loading patterns, providing a general procedure for designing flexure intervention on existing timber beams. [ABSTRACT FROM AUTHOR]

Abstract This paper proposed a micromechanical model to describe water-induced interfacial failure of natural plant fiber reinforced composites. The model was built with the consideration of fiber swelling, thick-wall cylinder deformation and analysis of shear-lag effect. Debonding tests and scanning electron microscope tests of ramie fiber/polypropylene micro-composites conditioned in environments with different water content were done to verify the model. The results showed that in the environment with 65% relative humidity (RH), the water-induced interfacial shear stress was predicted to be 1.51 MPa, much lower than the interfacial shear strength (IFSS) of dry micro-composites (19.67 MPa) and the interface was not damaged. In liquid water, a water-induced interfacial shear stress of 20.02 MPa was predicted, larger than 19.67 MPa and the interfacial adhesion was damaged solely by water absorption. At 90% RH, however, the predicted water-induced interfacial shear stress was only 5.32 MPa but premature debonding already occurred, which could be due to the matrix creep creating radial debonding. [ABSTRACT FROM AUTHOR]