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Ultrathin devices are rapidly developing for skin‐compatible medical applications and wearable electronics. Powering skin‐interfaced electronics requires thin and lightweight energy storage devices, where solution‐processing enables scalable fabrication. To attain such devices, a sequential deposition is employed to achieve all spray‐coated symmetric microsupercapacitors (μSCs) on ultrathin parylene C substrates, where both electrode and gel electrolyte are based on the cheap and abundant biopolymer, cellulose. The optimized spraying procedure allows an overall device thickness of ≈11 µm to be obtained with a 40% active material volume fraction and a resulting volumetric capacitance of 7 F cm−3. Long‐term operation capability (90% of capacitance retention after 104 cycles) and mechanical robustness are achieved (1000 cycles, capacitance retention of 98%) under extreme bending (rolling) conditions. Finite element analysis is utilized to simulate stresses and strains in real‐sized μSCs under different bending conditions. Moreover, an organic electrochromic display is printed and powered with two serially connected μ‐SCs as an example of a wearable, skin‐integrated, fully organic electronic application. [ABSTRACT FROM AUTHOR]

Flexible sensors have versatile applications in a home environment to create better ambient intelligence, which still have high fabrication costs and disposable value. As a proof‐of‐concept example to resolve these problems, the graphite‐based sensors on a disposable paper cup by laser patterning to measure the water level and temperature are proposed. The optimal process parameters of graphitic film, sensing mechanisms, and the sensor performance are investigated in the experiments. Moreover, the paper cup with graphitic sensors is simulated by the finite element method to analyze the experimental results. This fast and low‐cost manufacturing method may open up avenues for the development of disposable flexible electronics in smart home necessities. [ABSTRACT FROM AUTHOR]

Paper has always been of great importance as a printing and packaging material. Due to its potential for recyclability and reusability, which result in a low environmental impact, it is expected that this importance will soar over the coming years. Nevertheless, even though paper has been in use for decades, many research questions are still open, especially in the field of mechanics. One of these questions is the appropriate size of a representative volume element (RVE) of the microstructure of paper. Therefore, a finite element network model of interconnected fibers was developed which represents the microstructure of paper. In order to create the network model realistically, geometry and material quantities were taken from experimental investigations. Additionally, single fibers and fiber bonds were investigated beforehand in order to incorporate their proper behavior into the network. Based on this, the networks were generated and subsequently loaded by applying mixed displacement and traction boundary conditions. The resulting effective stresses were compared to determine the necessary RVE size. Two approaches were considered for modeling the RVE: (i) one single "large" network, and (ii) a certain number of smaller networks whose average yielded a statistically representative effective response. As a result, the second approach turned out to be less computationally intensive due to smaller models and the possibility to run calculations simultaneously. Concluding, it was possible to determine the size of the RVE which will be used to investigate various individual microstructural effects on the macrostructure in the future. [ABSTRACT FROM AUTHOR]

In this contribution, the causes leading to the undesired unevenness on the exterior surface of a paper‐based sandwich structure during the manufacturing process are investigated. This provides insight into the manufacturing parameters that need to be adjusted to reduce this waviness. A finite element model of the pressing process is developed in the commercial software ABAQUS and then used to analyze the formation of the surface unevenness. The sandwich structure adopted in the model consists of a decorative layer, an intermediate layer, a corrugated core and a bottom layer. In particular, the core has a sinusoidal structure with various geometry parameters, which are adjusted in the model to investigate the effect on the waviness of the top surface. The results of the quasi‐static process simulation correlate well with the experimental results. A subsequent parameter study based on the design of experiments (DoE) shows the relationship between the material parameters of the intermediate/bottom layer and the resulting waviness. [ABSTRACT FROM AUTHOR]

Strain sensors which are embeded in AMOLED are introduced and studied in this paper. High accuray strain sensing are achieved, resolution of the sensors are about 0.05%. By combing the strain sensors in the panel, mechanical behaviors can be monitored and studied in real time. The snesors are used to conduct the foldable AMOLED mechanical and reliability study. Dynamic and static strains and related mechanism are introduced and discussed. Finite element simulation models considering the mechanical properties of materials including hyperelasticity, viscoelasticity and creep are established. Finally, the strain sensors and finite element anlysis are combined to study the mechanical response of AMOLED under dynamic folding, static folding, and different temperature and humidity environments. [ABSTRACT FROM AUTHOR]

A moisture-dependent and temperature-dependent constitutive model for paper materials was proposed and implemented into a finite element model of the paper hydroforming process. Experimental hydroforming was conducted at temperatures of 23°C and 110 °C and moisture contents of 6.9 and 10.6 (respectively corresponding to 50 and 80% relative humidity). The proposed model, which also included the effects of drying, captured the extent of forming of all experimental results within reasonable accuracy. For the moisture content and temperature conditions in this study, the phenomenon of drying was found to be the reason why the application of temperature had a much greater effect on the degree of forming than hydroforming at various moisture contents. A simulation-based parametric study was conducted in order to identify the importance of various process and material parameters. This parametric study confirmed many previous empirical findings and was capable of quantifying the extent to which these process and material parameters affect the three-dimensional formability of paper. The coefficient of friction was identified as one of the most important factors when determining the extent of forming. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: This paper investigates the skiving and cutting stock problem (SCSP) encountered in the paper and plastic film industries, in which a set of nonstandard reels generated from previous cutting processes are used to produce finished rolls through the skiving and cutting process. First, reels are skived together lengthwise to form a reel‐pyramid (a polygon), and then the reel‐pyramid is cut into finished rolls of small widths. Depending on if a reel can be divided lengthwise into subreels to form the reel‐pyramid, the problem can be classified into divisible SCSP (DSCSP) and indivisible SCSP (ISCSP). In this paper, two integer programming (IP) models are proposed for DSCSP and ISCSP, respectively. A sequential value correction procedure combined with the two IP models (SVCTIP) is developed to solve the two SCSPs. The effectiveness of the SVCTIP is demonstrated through extensive computational tests. [ABSTRACT FROM AUTHOR]

In recent years, the development of high‐speed railways in China has been rapid. High‐speed railway bridges play an essential role whenever the railway intersects with existing facilities in three dimensions. With the increasing speed of high‐speed railways and increasingly complex geographical locations, the span of bridges is constantly increasing. Based on their advantages, steel structures in large‐span bridges are beginning to replace traditional concrete structures. Taking the steel cover beam technology applied in the Fuqiangbao Tremendous Bridge as a starting point, this paper uses Rhino parameterized modeling and Abaqus software to conduct finite element analysis on the stress of steel cover beams. It compares and analyzes stress under different conditions. The results show that the steel cover beam's most unfavorable and unstable position in this paper is at the support on the stress side. This provides a reference for monitoring the steel cover beam after its application in the Fuqiangbao Tremendous Bridge and technical accumulation for the application of steel cover beam technology. [ABSTRACT FROM AUTHOR]

The focus of this paper is on the solution of Maxwell's equations for time-harmonic fields on triangular, possibly non-orthogonal meshes. The method described was first introduced in References 1 and 2 for eigenvalue problems arising in the design of accelerator components and dielectric loaded waveguides. It is based on the well-known Finite Integration Technique (FIT) which is a proven consistent discretization method for the computation of electromagnetic fields. The FIT-discretization on non-orthogonal 2D grids has close relations to the Nédélec elements or edge elements in the Finite Element Method. Revisiting FIT on triangular grids this paper intends to stimulate thorough studies of the latter subject which is well worth further investigations. Copyright © 1999 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

For the simulation of acoustic-structure interaction problems, the coupled field equations must be solved. The structure is commonly discretized using finite elements, whereas for the acoustic field the boundary element method (BEM) is favorable. A mortar BEM-FEM coupling algorithm is developed that allows the combination of non-conforming meshes. The high flexibility for the choice of discretizations offers a high efficiency, since specialized shape functions and adaptive mesh refinement can be used in the subdomains. The mortar coupling algorithm yields a saddle point problem that is solved using a preconditioned inexact Uzawa algorithm. The iterative solver enables the use of the fast multipole BEM and thus coupled simulations on large boundary element models. [ABSTRACT FROM AUTHOR]

IMPACT OF THE PAPER This paper 1 addressed a very specific topic and by itself would not have had much impact in the intervening years. However, most of the paper's content was subsequently included in an extensive report on the Damage Tolerance (DT) properties of aluminium alloys. 2 This report enabled guidelines for flight simulation fatigue crack growth testing to be formulated. 3,4 [ABSTRACT FROM AUTHOR]

The numerical simulation of paperboard creasing and folding processes is of increasing importance for the design and production of safe and reliable packaging systems. The extreme material anisotropy and the complexity of these processes require however simulation capabilities which are seldom available in commercial codes. Several approaches have been proposed in the literature over the years, in most cases making use of non-linear material models developed ad hoc for this purpose. These models, some of which are very effective and accurate, are not in general available in commercial codes and are often based on the definition of a large number of parameters. In this paper, the possibility to obtain acceptable, first-hand simulation results using only features already available in a commercial code is investigated. An advanced continuum constitutive model, recently presented in the literature, has been used as a reference for tuning the model and for assessing its accuracy. It is shown how standard features, usually available in state-of-the-art commercial codes, can be employed to deal with the extreme material anisotropy, obtaining qualitatively good results in both the creasing and folding phases. The used standard model accounts for the extremely high anisotropy by means of embedded shell elements, playing the role of reinforcements in the fibre direction. The matrix is assumed to be isotropic and elastoplastic, with properties determined based on the behaviour in the thickness direction. The adopted plasticity model is a modified Drucker-Prager model with a cutoff on the tensile pressure side, available in the used commercial code. The procedure adopted for the identification of the small number of required material parameters is also discussed. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The main challenge faced by many mechanical engineering educators is the implementation of real solutions during their courses. One alternative can be a realistic case study, where the students can be engaged in the development and analysis process currently applied in the industry. This kind of teaching process not only can be used to improve the quality of teaching‐learning process but also the students can have opportunities to solve real engineering problem. Therefore, this paper reports a realistic case implemented in mechanical engineering courses given in bachelor's and master's degrees. The component under evaluation has been selected considering the student's interest, this criterion was also taken to involve several students into a real project process to their learning development. The same problem was solved during an academic semester, it was solved using different approaches and student's abilities. This procedure can be replicated for students and teachers by following steps. The first step in this process was to describe the theoretical basis for modal analysis to understand how it was structured a numerical finite element model. This model was then solved and simulated using Hypermesh, Optistruct, and HyperView software to obtain numerical modal parameters. On the other, hand, the experimental modal parameters were obtained using a three‐dimensional scanning vibrometer on 60 samples. It is well noted that the implementation of engineering software commonly used at the industry would increase students' confidence. This allows students to perform real problem‐solving activities to develop outcomes as establish goals, plan task, meet deadlines. These activities are extremely important to the actual automotive industry. Therefore, this paper shows an engineering solution process to provide a learning alternative to teach the modal finite method solutions correlation with experimental solutions. [ABSTRACT FROM AUTHOR]

A replaceable buckling‐restrained flange cover plate (BRFCP) was previously proposed to improve seismic performance of beam‐to‐column joints. Quasi‐static tests were conducted to investigate the seismic performance of beam‐to‐column joints using three different formats of restraint plates for BRFCP: no restraint plate, separated restraint plate, and integral restraint plate. The test results showed that both separated and integral restraint plates restrained the core plate buckling under compression and increased the beam‐to‐column joints load resistances. This paper first validates finite element models (FEMs) using test results. Then the validated FEMs are used to investigate influences from different BRFCP design parameters (such as core plate thickness, restraint plate thickness and length, restraining gap size, and restraint plate blot prestress force) to the beam‐to‐column joint load–drift hysteretic responses. Finally, the paper proposes a design range of each investigated design parameter and a BRFCP design procedure. [ABSTRACT FROM AUTHOR]

Smart windows are attractive because of their numerous advantages such as elegance in construction design and energy conservation. Smart windows with variable transmission are especially desirable for obvious reasons. The simplest way to make a variable transmission smart window is to use two patterned polarizers, and control the transmission by changing the relative position of the two polarizers. We have demonstrated a high‐dichroic‐ratio polarizer by photoalignment and proposed a simple one‐step photo‐copy method to realize a continuous axis varying polarizer. The patterned polarizer shows high optical performance, and its thickness is as thin as 100 nm, which is favorable in practical window applications. [ABSTRACT FROM AUTHOR]

Planetary Threaded Roller Bearing (PTRB) is a new bearing suitable for the heavy load linear drive mechanism. The load is transferred internally through annular threads, affecting the bearing capacity of the thread's contact load distribution characteristics. The structure of PTRB is discretized to study the contact load distribution of PTRB. The axial stiffness of the thread's teeth, its axial stiffness, and the contact stiffness of contact points are calculated. Moreover, a 1D equivalent spring network model is proposed based on discretized structure and stiffness. The PTRB contact load calculation model is proposed using the direct stiffness method and a 1D equivalent spring network model. Finally, the accuracy of the model proposed in this paper for calculating the contact load distribution of threaded teeth is verified by comparing the results obtained from theoretical model calculations, finite element methods, and experiments. The theoretical model proposed in this paper can provide theoretical guidance for PTRB parameters. [ABSTRACT FROM AUTHOR]

The work is built on a previous research by Wiryana and Berg, in which wicking into four wet-formed paper stripes, consisting of cellulose fibers and four different percentages of the powdered carboxymethyl cellulose (CMC) superabsorbent, was studied experimentally. Because of the swelling of cellulose fibers and CMC powder on contact with water, the wicking was accompanied by a swelling of the matrix. A finite element/control volume (FE/CV)-based computer program is used for the first time to model the wicking in such swelling porous medium. The simulation used a novel form of continuity equation, which included the effects of liquid absorption and matrix swelling, in conjunction with the Darcy's law to model the single-phase flow behind a clearly defined liquid-front. A new method of estimating the time-varying permeability of the paper, based on the absorbed liquid-mass vs. time plots, is also proposed. Later, this time-dependent permeability is used in the numerical simulation to change the permeability in elements behind the moving liquid-front as a function of the time that the element has been wetted by the liquid, since the passage of the liquid-front. The numerical prediction of the wicking-front location as a function of time compares well with the reported experimental data. © 2011 American Institute of Chemical Engineers AIChE J, 58: 2536-2544, 2012 [ABSTRACT FROM AUTHOR]

2 Gupta P, Duarte CA, Dhankhar A. Accuracy and robustness of stress intensity factor extraction methods for the generalized/extended finite element method. Later in § 3.1, we refer to GDD-DCM as "the displacement correlation method of Gupta, Duarte, and Dhankhar", specifically acknowledging the contribution to the DCM family in Reference 2. At no point in Reference 1 do we make any statement about the convergence or lack thereof of the stress intensity factors computed with the DCM in combination with displacement fields computed with G/XFEM. [Extracted from the article]

Summary: H‐shaped circular arc is a relatively novel type of open‐web steel arch, and currently, no reports have been published concerning its in‐plane stability. In this paper, the elastic and elastic–plastic in‐plane stability of the H‐shaped hollow circular arch is studied by theoretical deduction combined with numerical simulation. First, the overall shear rigidity of the H‐shaped circular arch is calculated, and the elastic buckling load formula of the arch is proposed and verified considering double shear deformation under full‐span radial and uniform loading. The overall elastic buckling load deduced in this paper is reasonable according to the finite element analysis. The results indicate that the influence of shear deformation on the overall elastic buckling load of the arch decreases with the increase of the span length. The arch‐bearing capacity is the largest when the rise‐span ratio is 0.25. Second, the restriction conditions necessary for avoiding local buckling of the chordal web before integral buckling of the H‐shaped steel hollow circular arch are analyzed. Finally, the elastic–plastic failure mechanism of the H‐shaped arch under full‐span radial and uniform loading is examined, and the formula for determining the ultimate bearing capacity that is achievable before failure under full‐span radial and uniform loading is proposed. ANSYS analysis shows that under the radial uniform loading, the chordal bars will yield near 1/4L and 3/4L, and ultimately, the structural failure of the lower chord occurs in the vicinity of 1/4L. The formulas presented in this paper agree well with the results obtained from the finite element analysis and can be used as a reference for engineering applications. [ABSTRACT FROM AUTHOR]

This paper investigates the vibration characteristics, both linear and non‐linear, of beams made from functional gradient materials (FGMs) with layers of Terfenol‐D attached to the top and bottom surfaces. Given the porosities that can occur during the manufacture of FGMs, the study examines the vibrational behaviour of beams with porosities. Euler–Bernoulli beam theory and the von‐Kármán non‐linear deformation field are used to formulate a fundamental equation predicting the free dynamic vibration of Terfenol‐D FGM structures with porosities. To complete this analysis, the paper also presents the application of two advanced methods. The first method involves employing the generalised finite element method (GFEM) associated with the reduced quadrature finite element method (RQFEM). GFEM offers a versatile and powerful approach, while RQFEM provides a specific method for studying dynamic phenomena. The second method utilises a semi‐analytical approach, the variational iteration method (VIM), which examines and complements the first method. Furthermore, we have demonstrated substantial alignment between the proposed solution and the results of finite element analysis, as well as with the existing literature, underscoring the effectiveness and accuracy of our analytical approach. The study also explores the influences of material property distribution, thermal loading, and porosity volume fraction on the linear and non‐linear behaviour of Terfenol‐D FGM beams. This comprehensive exploration furnishes valuable information on the intricate interplay of factors affecting vibration dynamics and control mechanisms in these advanced composite structures, offering insightful perspectives into the potential application of Terfenol‐D FGM beams in various fields. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to carry out parameter design and dynamic stability verification experiment of controllable damping ferrofluid bearing. A new type of ferrofluid bearings is designed, and its internal magnetic fields are simulated by the finite element analysis software ANSYS. In this paper, the coefficient of magnetic leakage is taken as the optimization object, and the optimal parameters of ferrofluid bearings are updated. At the same time, the working principle of the ferrofluid bearings test platform is introduced, which includes a servomotor with a controller, an eddy displace sensor, an amplifier and a power supply. Finally, the dynamic stability of ferrofluid bearing is verified by experiments. The experimental results show that when the applied current is less than or equal to 0.08 A, the amplitude of the rotor supported by the ferrofluid bearing decreases with the applied current increment. Besides, the dynamic stability of the rotor is also related to the rotational speed. When the applied current is 0.08 A, the amplitude of the rotor supported by the ferrofluid bearing firstly increases and then decreases with the rotational speed increment. It is proved that the ferrofluid bearings have a strong function of the dynamic stability, which can suppress the vibration of the rotor, and have high accuracy of both position and rotation. [ABSTRACT FROM AUTHOR]

Highlights This paper presents a comprehensive study on anisotropic heat transmission behaviors in quartz fiber fabrics. Considering the random distribution characteristic of fibers within the yarn, an innovative two‐scale finite element method (tFEM) is introduced, incorporating multiple micro‐scale fiber models (MMFM) based on scanning electron microscope (SEM) observations. MMFM are divided into 8 distinct models to capture intricate fiber arrangements. The macro‐scale fabric model is constructed based on the geometric structure analysis by Micro‐CT technology. Both micro‐ and macro‐scale models are assembled with the air matrix to form the two‐phase composite model. The Hot‐Disk thermal analysis instrument is applied to measure the anisotropic thermal conductivity (ATC). Numerical results from MMFM shows more excellent agreements with the experimental ones at 3D orthogonal directions of fabrics, i.e., the error rates of the thermal conductivity in the warp, weft and thickness directions between numerical and experimental methods are all less than 3%, which indicates the tFEM including MMFM in this paper is more accurate than the tFEM including OSMFM. In addition, the temperature distribution and heat transmission differences due to fiber arrangements are simulated and illustrated through the MMFM. Afterwards, temperature drop and isothermal characteristics are demonstrated in this study. Effects of fiber arrangements on steady heat transfer behaviors at micro‐scale are illustrated. Isothermal and temperature‐drop characteristics at micro‐ and macro‐scale are simulated and studied. The transverse isotropy of thermal conductivity at micro‐scale and the anisotropy of that at macro‐scale are revealed. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive analysis, electromagnetic evaluation, and prototyping of a novel motor structure called the sinusoidal rotor switched reluctance motor. In this innovative design, a significant departure from the conventional switched reluctance motor is observed, as modifications are made to the rotor with the goal of reduction torque ripple and radial force characteristics. Importantly, despite these advancements, the proposed motor retains the weight and volume characteristics of the traditional, type. The key attributes of these motors have been thoroughly assessed using the three‐dimensional finite element method, complemented by a sensitivity analysis aimed at identifying the most optimal configuration within the proposed design. The findings reveal that the suggested structure successfully achieves a notable reduction in torque ripple and radial force when compared to the traditional counterpart, albeit with an expected reduction in average torque. These features render the new topology particularly well‐suited for applications that prioritise noise and vibration reduction. Furthermore, the effectiveness of the proposed topology is corroborated through experimental tests, providing empirical evidence of its advantages and potential for practical applications. [ABSTRACT FROM AUTHOR]

This paper presents the development of an Air‐Cored Axial Flux Permanent Magnet Generator (ACAF PMG) integrated for direct battery charging scheme for urban and rural micro‐wind turbine applications rated at 1 kW. The proposed generator has a Single Stator Double Rotor configuration with a relatively short axial length. In this paper, the analytical model for generator sizing is presented and the main parameters are defined. Novel analytical model is presented to determine the required number of turns for each phase in order to produce a balanced voltage in the three phases. The generator is electromagnetically analyzed using Finite Element model and simulated using Matlab/Simulink to predict its performance under several operating conditions. The effect of retainment ring type on the generator performance is also demonstrated. The machine is harnessed to a battery bank via a three‐phase fully controlled converter using six bridge thyristors to regulate the output voltage delivered from the generator to the battery. Generator model and simulation results are validated via experimental tests. The preliminary experimental results showed a good match with the simulation results. Moreover, the proposed machine is compared favourably with other counter machines of similar configuration and power ratings in terms of machine size, power‐to‐weight ratio, and voltage regulation. This paper therefore demonstrates the concrete benefits of utilizing the axial flux PMG in scavenging energy to generate electrical power from micro wind turbines. [ABSTRACT FROM AUTHOR]

Sanding production of the underground gas storage (UGS) in the depleted reservoir will cause the decline of effective storage capacity, and the erosion of well string and auxiliary equipment, and other engineering problems. A deep understanding of the sanding production contributes to maintaining the injection and production capacity of gas storage and the long‐term safety of the UGS. In this paper, core samples of five main sedimentary microfacies were drilled from the UGS in middle China. The mechanical properties with different conditions of the moisture content in multi‐cycling injection–production process were tested. The critical drawdown pressure (CDP) calculation methods for the UGS were established based on the stress analysis near the wellbore and the Mogi–Coulomb criterion. Adopting the finite element method simulation on the geological model of the target UGS, the geo‐stress of the formation was calculated by inversed analysis and validated based on the Kaiser effect of rock. Then, the CDP of two target wells of the UGS were investigated. The effects of the water moisture and the cycling times of the injection–production process on the CDP were also analyzed. The geo‐stress distribution shows that the horizontal maximum principal stress ranges from 53 to 68 MPa, and the horizontal minimum principal stress is 46–58 MPa in the target reservoir section, and the vertical minimum principal stress is 69–77 MPa in the target reservoir. The calculated CDP changed with the types of the sedimentary microfacies in the range of [6.27, 8.77] MPa, in which the CDP of the mixed mud and sand flat sedimentary facies was the lowest. The weakness of the CDP with the increasing of the moisture content and the cycling times were analyzed quantitively. [ABSTRACT FROM AUTHOR]

To solve the problems mechanically caused by parallel direct‐drive permanent magnet motors (DD‐PMSM). This paper proposes a concave‐core stator direct‐drive permanent magnet motor (CCSDD‐PMSM) structure. In this study, an auxiliary yoke structure is proposed to optimise the magnetic circuit and analyse the cogging torque to achieve the minimum detent force. Based on the unit motor and combined with the magnetomotive force to analyse the symmetry of different winding distributions, the stability characteristics of the motor are studied. The magnetic field distribution of the motor load air gap is calculated using the finite element method. The contribution of different spatial order harmonics to the motor output torque is calculated using the Maxwell tensor method. The torque calculation expression of the CCSDD‐PMSM is given. Finally, an experimental prototype is made to verify the accuracy of the analysis in this paper. [ABSTRACT FROM AUTHOR]

This paper proposes a hybrid data‐driven and physics‐based simulation technique for seismic response evaluation of steel Buckling‐Restrained Braced Frames (BRBFs) considering brace fracture. Buckling‐Restrained Brace (BRB) fracture is represented by cumulative plastic deformation capacity. A dataset, consisting of 95 past BRB laboratory tests and 120 simulated BRB responses generated using the finite element method, is first developed. An Artificial Neural Network‐based (ANN) predictive model is then trained using the training dataset to estimate the cumulative plastic deformation of BRBs. The prediction capability of the ANN‐based predictive model is validated using the training dataset and an existing regression‐based predictive model. In the second part of the paper, an hybrid simulation technique combining the data‐driven model and physics‐based numerical modeling is presented to conduct the nonlinear time history analysis, followed by 1) validation against a full‐scale BRBF testing and 2) demonstration of the proposed simulation technique using a six‐story BRBF. The results confirm that the proposed predictive model can predict the BRB fracture with sufficient accuracy. Furthermore, the hybrid data‐driven physics‐based simulation technique can be used as a powerful tool for dynamic analysis of BRBFs considering BRB fracture. [ABSTRACT FROM AUTHOR]

In this paper, the effects of Maxwell nanoliquid transmission with MWCNT nanotube are investigated over two circular wires with opposite currents and a stretching sheet. The innovation of this paper is the examination of MWCNT nanotube temperature and nanofluid velocity and also magnetic potential and magnetic effect in the three different places of two circular wires on the sheet. The finite element method is utilized for calculating differential equations. By increasing the distance from two wires on the stretching sheet, the amount of MWCNT nanotube temperature increased, and a large vortex forms at the bottom of the sheet. Overall, the MWCNT nanotube velocity around the two circular wires at the beginning of the sheet is 46.09% higher than the middle of the sheet and 20% higher than the end of the sheet, also the MWCNT nanotube magnetic potential around the two circular wires at the beginning of the sheet is 13.40% higher than the middle of the sheet and 23% higher than the end of the sheet. The second part of the essay relates to the using response surface methodology (RSM) method in the Design‐Expert software. Based on the results obtained from the MWCNT nanotube velocity graphs and the heat transfer cantors, and magnetism effects in the Design‐Expert software, the best optimization occurred for u = 0.07, T = 1.15, and H = 4.531. [ABSTRACT FROM AUTHOR]

Summary: The material point method is a versatile technique which can be used to solve various types of solid mechanics problems, especially those involving large deformations. However, the capability of the material point method to track a load‐displacement response can deteriorate once a limit point, such as snap‐through or snap‐back, in the response is encountered. One way of overcoming this is to use path following techniques, such as an arc‐length method. This technique is well established in finite element analysis but not within any material point method formulation. This paper provides for the first time an arc‐length controlled implicit, quasi‐static material point method. The modifications to the standard arc‐length scheme to allow for the stable execution of an arc‐length solver within the material point method are detailed. The capability of the material point‐based arc‐length method is demonstrated through a number of problems, which include linear elastic, non‐linear elastic, linear elastic‐perfectly plastic and linear elastic‐plastic softening material behaviour under large deformations. The techniques presented in this paper are essential for arc‐length techniques to be applied effectively to the material point method and the combination of these techniques makes the method suitable for new problems that cannot be solved with existing implicit material point approaches. [ABSTRACT FROM AUTHOR]

Flexible OLED displays have become a development trend. CPI film in a flexible panel can improve the bending performance of the panel. However, CPI film is prone to plastic deformation in the bending process, which will affect the reliability and service life of OLED panel. Finite element analysis is employed in this paper to analyze how CPI film affects the bending performance of a flexible OLED panel. The simulation results show that the optimization of the structure of water‐drop‐shaped bending can improve the plastic deformation of CPI film. The reasonable position of CPI film in the stacked structure can also improve its plastic deformation. The increase of the thickness of the OCA located below the CPI film can significantly reduce its plastic deformation. The analysis method used in this paper can help improve the bending performance of a flexible OLED panel. [ABSTRACT FROM AUTHOR]

The mechanical behaviour of adhesively bonded point‐fixings, in the scope of glazing systems, are usually investigated by non‐linear finite element analysis (FEA). The accuracy of the finite element model depends on the availability of suitable experimental data, used to calibrate the material models that describe the appropriate behaviour of the adhesive material. This paper presents and discusses the outputs of an experimental campaign focused on characterizing the mechanical properties on bulk material of the structural adhesive Sikasil® SG‐500, a bi‐component structural silicone. The results of the experimental campaign are used to calibrate material models for finite element analysis. The best‐performing hyperplastic material models for the state of stresses analysed in this paper, are selected and presented, intended to be used by designers and engineers. [ABSTRACT FROM AUTHOR]

Air‐cored axial‐flux permanent‐magnet synchronous generators (AFPMSGs) are potential candidates for gearless direct‐coupled wind turbines (DCWTs) owing to providing high efficiency and power density. The design of a DCWT generator is so complicated since the generator cost, dimension, and weight affected by gear elimination. Therefore, it is essential to find an optimal AFPMSG design at rated conditions. In this paper, an accurate procedure for the optimal design of an air‐cored AFPMSG applicable for DCWTs is proposed. The genetic algorithm (GA) is used for multi‐objective design optimization to reach the optimal configuration as well as system dimension in order to decrease the weight, increase the power density and enhance the effectiveness of the generator. To validate the efficiency of the suggested optimization proceducer, a 30 kW AFPMSG has been considered as a case study. The results of optimization have been investigated by finite element analysis (FEA). A prototype generator is also fabricated, and the test results are offered and compared with the numerical study. The outcomes show that there exists an acceptable agreement between FEA and experimental outcomes with the error percentage about of 1.35%. [ABSTRACT FROM AUTHOR]

Numerous studies have shown that highly strain‐rate dependent behavior is present in the mechanical properties of Hydroxyl‐terminated polybutadiene(HTPB)propellants, and many experts and scholars have attempted to develop constitutive models to describe such rate‐dependent properties of propellants. From the linear viscoelastic model to the Zhu‐Wang‐Tang model, the strain‐rate dependent properties of viscoelastic materials have been described to some extent. But due to the highly nonlinear mechanical behavior exhibited in propellant materials, the nonlinear behavior of propellants at different strain rates is difficult to be captured in the above constitutive models which are all based on linear elasticity. Therefore, in this paper, a nonlinear viscoelastic constitutive model was proposed based on the parallel rheological framework, in which the hyperelastic and viscoelastic flow laws were embedded. Because of the excellent ability to capture the nonlinear behavior of the material, the parallel rheological framework was used to predict the mechanical response at six sets of experiments with different rates. Surprisingly, this constitutive structure model performed good prediction of the mechanical properties of the material by comparison between theoretical calculations and experimental data. The constitutive model was verified by finite element method with numerical simulation software, and the robustness of the constitutive model was checked by a new set of experimental data. A good foundation was established for the accurate description of the propellant constitutive model strain‐rate dependent characteristics by the results of this paper, which could provide a new method for the rapid prediction and evaluation of the propellant mechanical response. [ABSTRACT FROM AUTHOR]

This paper focuses on the Y type perfobond shear connectors of steel‐concrete composite beams with the aim to investigate the influence of the structural parameter of the connection to the resistance and ductility of the structures. The Y shaped shear connections are a new shape developed with the benefits of resisting a higher shear force by the transversal bars and a bigger area of the concrete dowels surrounded by the Y shaped plate. This type of shear connection has significant resistance against vertical separation. In this paper, an advanced finite element model for a push‐out test with a Y type perfobond shear connector has been developed and validated by the experimental test. The aim of this research is to investigate different parameters such as the concrete strength, perfobond yield stress, the existence of the transversal bars on the structural behavior. The results showed that the concrete strength has a major effect as using a higher concrete resistance gave a higher ultimate resistance with a higher ductility. The existence of the transverse bars shows a major effect on the ductility load level. On the contrary, the effect of changing the diameter of the bars on the ductility load level was slightly noticeable. While using deferent steel grades for the perfobond plate significantly affected the ultimate resistance, but not the ductility load level. In further studies more parameters will be checked, and a formula and a guideline could be developed for a design purpose. [ABSTRACT FROM AUTHOR]

Acknowledging the potential of system‐based design approaches, most international design standards for steel structures include preliminary versions of such alternative design methods. The Direct Design Method (DDM) is one of these approaches, which allows designing steel structures directly using advanced numerical analyses without requiring further member checks. This paper presents the DDM design (and verification) procedure and summarizes the key aspects of the advanced finite element model necessary for the determination of the system strength, with an emphasis on cold‐formed stainless steel portal frames. Through the design of two frames, the DDM design procedure is illustrated and the resulting cross‐sections are compared with those derived using the traditional two‐step design approach in the Eurocode and ASCE design frameworks. The results demonstrate that the DDM verification process is simpler and more direct, and that lighter structures are obtained when designing using the DDM for strength considerations. Finally, this paper also highlights that allowing larger deformations in the ultimate limit state design for the DDM does not have additional negative effects on the serviceability requirements if compared to the traditional two‐step design approach. [ABSTRACT FROM AUTHOR]

One of the benefits of using corrugated web girders is the increase of lateral‐torsional buckling resistance. Different approaches have been presented to obtain the value of the critical moment as a function of the cross‐section geometry. Previous research works consider that the increase in buckling resistance must be accredited to a higher warping constant. The paper presents a systematic finite element numerical analysis of girders with different corrugated web shapes. Bending with respect to the weak axis shows that corrugated web implies higher moment of inertia. Torsion analysis results clearly demonstrate that the increase of torsion resistance is mainly due to higher torsional constant. The paper compares the elastic critical moment values obtained by using finite element elastic buckling analysis with the values provided by theoretical expressions introducing equivalent section properties. Results show that the equivalent section properties approach provides values very close to those obtained using finite elements. Finally, the paper presents closed form expressions to directly compute approximate equivalent section properties of any girder with corrugated web, which compare very satisfactory with those values obtained with finite element buckling analysis. [ABSTRACT FROM AUTHOR]

The mismatching constraint effect on crack propagation through the heat‐affected zone (HAZ) in a welded joint is presented in this paper. It is shown that due to this effect, the fracture behavior of an overmatched welded joint depends on the mechanical properties and the size of the region of the crack tip location, as well as on the properties and the size of surrounding regions. The finite element analysis of high‐strength low‐alloyed (HSLA) steel welded joints with crack tips in the heat‐affected zone is performed based on previous experimental work. Two locations of the crack tip are analyzed: fine‐grained HAZ (FGHAZ) and coarse‐grained HAZ (CGHAZ). In both cases, after the initial propagation of the crack in FGHAZ or CGHAZ, its propagation is directed toward more ductile base metal, thus increasing the fracture resistance of a welded joint. Some new observations about the reasons for such behavior due to crack tip strain fields are presented as well. Highlights: The behavior of the crack with the tip located in fine‐grained heat‐affected zone (FGHAZ) is under the significant influence of adjacent coarse‐grained HAZ (CGHAZ) and WM.Strain at the crack tip in CGHAZ is absorbed by more ductile regions, causing more favorable stress conditions.In both cases, overmatching changed the crack propagating direction toward weaker and more ductile base metal (BM). [ABSTRACT FROM AUTHOR]

As a non‐destructive inspection method, micro‐computed tomography has been employed for determining local properties of a cellulose‐based product, specifically pressboard. Furthermore, by utilizing the determined properties in a detailed numerical model, by means of a finite element analysis, we demonstrate a continuum anisotropic viscoelastic‐viscoplastic model. Through such a combination of non‐invasive experiments with accurate computations in mechanics, we attain a better understanding of materials and its structural integrity at a pre‐production stage increasing the success of the first prototype. In detail, this combination of micro‐computed tomography and finite element analysis improves accuracy in predicting materials response by taking into account the local material variations. Specifically, we have performed indentation tests and scanned the internal structure of the specimen for analysing the densification patterns within the material. Subsequently, we have used a developed material model for predicting the response of material to indentation. We have computed the indentation test itself by simulating the mechanical response of high‐density cellulose‐based materials. In the end, we have observed that pressboard, having initially a heterogeneous density distribution through the thickness, shows a shift in the densification to the more porous part after indentation. The densification maps of the simulated results are presented by comparing with the experimental results. A reasonable agreement is observed between the experimental and the simulated densifications patterns, which suggests that the proposed methodology can be used to predict densification also for other fibre‐based materials during manufacturing or in service loading. [ABSTRACT FROM AUTHOR]

A series of pull‐out tests were conducted on semi‐grouting sleeve and steel bar connections to investigate the mechanical behavior of the connectors. Taking the steel bar diameter, anchorage length, and grouting material strength as the parameters. The test results showed that when the anchorage length was small and the grouting material strength was low, sufficient anchorage strength cannot be provided, specimens were subjected to bond slip failure, which belongs to the brittle failure. When the anchorage strength between the steel bar and the grouting material was sufficient, the steel bar breaking occurred on the specimens, which belongs to the ductile failure. Then, the semi‐grouting sleeve and steel bar connection was modeled by finite element software, and the bond slip between the steel bar and grouting material was simulated by COMBIN39 element. The results indicated that the failure mode of the specimen obtained by finite element simulation was the same as the test result. The ultimate bearing capacity of the specimen was highly similar to the test result, which verified the feasibility of the modeling method in this paper. Next, the number of specimens and parameter levels were increased through finite element modeling, and the influences of steel bar diameter, anchorage strength, and grouting material strength on the ultimate bearing capacity of semi‐grouting sleeve and steel bar connections were analyzed. The results testified that the ultimate bearing capacity of the specimen increased with the increase of steel bar diameter. In a certain range, the ultimate bearing capacity of the specimen increased with the raising of anchorage length and grouting material strength. While the anchorage length increased, the ultimate bearing capacity of the specimen did not necessarily increase because of the uneven distribution of stress. The steel bar diameter had the most significant influence on the ultimate bearing capacity of the specimen, while the grouting material strength had the most negligible impact, that was, increasing the steel bar diameter is the most effective method to improve the ultimate bearing capacity of the specimen. Finally, according to the results of finite element analysis, the calculation method of ultimate bearing capacity with different failure modes was obtained, and it has been proved to be effective and accurate by the comparison of calculated results and test results. The results of this paper have great significance for improving the calculation theory and design method of relevant engineering. [ABSTRACT FROM AUTHOR]

During the multistage fracturing of shale gas horizontal wells, casing damage frequently occurs, making it essential to evaluate casing stress and deformation. This paper establishes a mathematical model of thermo‐hydro‐mechanical coupling and a finite element model of casing‐cement sheath‐formation (CCF). This paper examines the effects of temperature, casing thickness, nonuniform in situ stress, mechanical properties of cement sheath, and treating pressure on the stress and deformation of CCF. Finally, the study investigates the variation of local in situ stress at the heel and casing stress from toe to heel. The results show that the low temperature of CCF, high elastic modulus of cement sheath, small casing thickness, high treating pressure, and large nonuniform in situ stress can exacerbate casing stress. After pumping off, the local in situ stress and its nonuniformity near heel gradually increased, and the effective stress of casing increases compared with the pumping on the process. As the fracturing stages increase, the effective stress of casing at heel increases, and the casing at heel preferentially damages. The results provide a theoretical basis and guidance for maintaining wellbore integrity and preventing casing damage in the multistage fracturing of shale gas horizontal wells. [ABSTRACT FROM AUTHOR]

Toroidal inductors are widely used in power electronic systems. With the increasing switching frequency of power devices, the AC losses of high‐frequency inductor windings have become an issue that cannot be ignored in design. A method with low computational time cost and high accuracy is urgently needed by designers. This paper proposes a modified analytical method for winding loss calculation of toroidal inductors based on the one‐dimensional Dowell method and the two‐dimensional Ferreira method, and proposes a compensated analytical model considering the proximity effect of inter‐turn conductors of toroidal windings. The analytical method calculates the non‐linear porosity of toroidal windings, and can accurately solve the AC losses of toroidal inductors with arbitrary porosity winding encapsulation. The analytical results are in good agreement with the finite element method (FEM) and experimental data. The experimental measurement data verifies the validity of the proposed model within 1‐MHz frequency, the calculation error of the modified analytical method is less than 25%, and the calculation error of the compensated analytical model is reduced to 10%. [ABSTRACT FROM AUTHOR]

Summary: A fast and reliable interturn short circuit (ITSC) diagnosis system is necessary to secure safe operations of permanent magnet synchronous motor (PMSM) for its widespread applications in industrial automation and electric vehicles. This paper develops a simple online real‐time technique based on signal extraction to detect the ITSC fault in the PMSM. Some popular diagnosis methods involving machine learning or instantaneous power information may require large computing resources, data storage, or extra sensing devices for data collection. This makes it difficult to fulfill online and self‐detection of ITSC faults in motor drive systems. This paper makes use of the second‐order harmonic components in dq‐axis current for diagnosis when they occur due to ITSC faults. Through the developed amplitude‐tracking algorithm, the diagnosis can be implemented by using a common digital signal processor without complex algorithms and additional hardware or sensors. Therefore, it is suitable for low‐cost and remote applications where self‐detection is needed. The proposed method is validated by finite element analysis and measurements with a hardware‐in‐the‐loop toolkit. It is found that the method successfully detects a short circuit fault with only one out of 54 turns in one phase of the motor (1.9%). [ABSTRACT FROM AUTHOR]

A homogenization approach is one of effective strategies to solve multiscale elliptic problems approximately. The finite element heterogeneous multiscale method (FEHMM) which is based on the finite element makes possible to simulate such process numerically. In this paper we introduce a FEHMM scheme for multiscale elliptic problems based on nonconforming elements. In particular we use the noconforming element with the periodic boundary condition introduced in the companion paper. Theoretical analysis derives a priori error estimates in the standard Sobolev norms. Several numerical results which confirm our analysis are provided. [ABSTRACT FROM AUTHOR]

This paper presents the mixed mode I/II stress intensity factors (SIFs) of slanted cracks/notches under tension loading. A two‐dimensional finite element analysis (FEA) was employed using the ABAQUS program. Based on the literature survey, there is a lack of solutions for SIFs of slanted cracks in plane stress plates. The strain energy approach (SEA) was adopted to analyze the notched cases. Mode I and II SIFs are derived via the SEA method from the strain energy computed using the FEA technique. The results show excellent agreement with other researchers' work. The key contribution of the present paper is the presentation of the effect of the crack/notch length to plate width ratio on the mode I and II SIFs of a slant‐edge‐cracked/notched plate under different boundary conditions. Sets of new data of mode I and II SIFs are provided herein in tabular and graphical formats. Highlights: Stress intensity factors (SIFs) of single edge‐cracked/notched plates under mode I/II loading computed.Parametric and comparative analysis of SIFs of pinned/clamped boundary conditions (BCs).SIFs derived from finite element analysis (FEA) computed elemental energies by strain energy approach.Effects of pinned and clamped BCs on mode I/II SIFs of cracked/notched plates shown. [ABSTRACT FROM AUTHOR]

Structural damage identification technology based on modal parameters is an extremely effective monitoring method. Because of the structural characteristics of the conductor, with its small diameter and long span, it is not easy to obtain the modal parameters by manual excitation. Here, a method for structural health monitoring of the conductor under wind load excitation is proposed. Firstly, the natural frequency change law of the conductor after broken strand damage is obtained by analyzing the conductor modal parameters calculation formula and IEEE standards. Then, the vibration characteristics are calculated by vibration experiments and finite element methods. Finally, through the broken strand experiment, this paper demonstrates how to determine the damage degree of the conductor using the modal parameters. And it is applied to online monitoring in the field. The results show that this method is convenient, fast, and accurate. [ABSTRACT FROM AUTHOR]

In curved liquid crystal display, the glass substrate is in the state of bending, and the bending stress is generated inside the glass. Under the effect of stress photoelastic effect, the display will produce light leakage, which is called stress‐Mura. Based on the theory of stress photoelasticity and the finite element analysis of panel forming, this paper deduces the light leakage intensity of curved LCD (liquid crystal display) by using the Jones matrix, and puts forward a scheme to improve the design of curved curvature of LCD, which is verified by experiments. [ABSTRACT FROM AUTHOR]

Harmonic magnetic gears (HMGs) have the advantage of lubrication‐free, high speed ratio and high torque density, which make it an attractive solution for safety critical applications. Due to eccentricity caused by machining and assembly, HMG suffers from dynamic eccentricity (DE) in operation, however, its effect on HMG performance is still unknown. Transmission characteristic of HMG under DE is studied. First, a magnetic equivalent circuit (MEC) model of HMG is proposed to build the magnetic coupling torque analytically, and the geometry of air gap is analysed parametrically to derive its equivalent reluctances. Flux density and coupling torque can be acquired by solving MEC equations. The accuracy of the MEC model is verified by finite element method. To study the transmission characteristic, an electromechanical coupling simulation framework for HMG is constructed, motion trajectories of rotors are investigated in case of DE, the output torque in locked‐rotor condition and speed response in continuous operation can be derived by simulation. It is found that torque ripples that have the same frequency with input rotor are induced by DE; the results are then verified in the experiment. This paper provides a theoretical guidance for the design and condition monitoring of HMG. [ABSTRACT FROM AUTHOR]

This paper introduces a technique aimed at improving the performance of an interior permanent magnet synchronous machine (IPMSM) by reducing torque ripple and radial force harmonics. Unlike conventional IPMSMs, the proposed method employs a variable airgap length that is defined by a mathematical function. Two distinct rotor shapes are investigated to determine the most efficient design. Finite Element Analysis is employed to assess both the electromagnetic and mechanical attributes of the proposed motors. It compares the results for three operating points of the shaped motor with those of a conventional one. The investigation delves into the influence of rotor geometry on key output parameters, including Back Electromotive Force (back‐EMF) harmonics, average torque, cogging torque, torque ripple, efficiency, power factor, and radial force harmonics. The findings indicate that optimising rotor shape can significantly enhance IPMSM performance by reducing torque ripples and radial force harmonics, while simultaneously increasing average torque and efficiency at different operating points. [ABSTRACT FROM AUTHOR]

In this paper, counter rotating dual rotor wound field flux switching wind power generator is revisited to study the generating characteristics of the AC output power curves based on finite element analysis (FEA) and experimental study. Analysis are performed under dynamic conditions, such as variable resistance, field excitation and speed. Also, electromagnetic performance is studied under variation of the field and armature currents. Analysis reveals that outer port machines with higher power capability and better electromagnetic performance compared to the inner port counterparts, although with higher fluctuations exhibited on the torque profiles of the former due to higher slotting effects. From the power generation characteristics curves, it is clear that the developed wind generator is able to produce reliable performance over a wide operating range. The accuracy of the FEA predicted results are validated, experimentally. The cover image is based on the Research Article Generating characteristics and experimentation of counter rotating dual rotor wound field flux switching wind generator by Wasiq Ullah et al., https://doi.org/10.1049/elp2.12374. [ABSTRACT FROM AUTHOR]

In this paper, we consider an explicit fully‐discrete approximation of the Cahn–Hilliard–Cook (CHC) equation with additive noise, performed by a standard finite element method in space and a kind of nonlinearity‐tamed Euler scheme in time. The main result in this paper establishes strong convergence rates of the proposed scheme. The key ingredient in the proof of our main result is to employ uniform moment bounds for the numerical approximations. To the best of our knowledge, the main contribution of this work is the first result in the literature which establishes strong convergence for an explicit fully‐discrete finite element approximation of the CHC equation. Finally, numerical results are finally reported to confirm the previous theoretical findings. [ABSTRACT FROM AUTHOR]