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T-shaped reinforced concrete (T-RC) beams are widely used in high-rise buildings due to their advantages of reduced concrete usage, low sectional stress, and decreased weight of the structure. However, the calculation method of residual flexural stiffness of T-RC beams has limited existing research. To address this knowledge gap, a comprehensive experimental investigation was conducted, comprising fire tests, dynamic tests, and static load tests on 10 T-RC beams. The aim was to analyze the effects of fire time and load ratio on the residual flexural stiffness of composite beams. The experimental results showed that the residual flexural stiffness of T-RC beams decreased with increasing fire time and load ratio. However, the impact of fire time was more significant than the load ratio. A refined finite element model of T-RC beams under high temperature and after high temperature was established by modifying the frequency data of the dynamic test and considering the impact of cracks. The model accurately predicted the temperature field and deflection change of T-RC beams under fire. Furthermore, a method for calculating the residual flexural stiffness of T-RC beams considering the effect of fire was proposed and validated against the measured values. The proposed method demonstrated a low error rate of less than 10%. [ABSTRACT FROM AUTHOR]

Perforated cold-formed steel (PCFS) beams are increasingly used in constructional industry and become popular due to their advantages and economic benefit. Apart from the light weight, the openings in PCFS beams can also be used for services such as pipe utilities to release more building space. However, beams with web perforations may collapse as the result of web-distortional buckling or flange/web distortional buckling due to the web weakness caused by perforations. In this paper a study on the flange/web distortional buckling of PCFS beams is presented. An analytical solution to determine the critical stress of flange/web distortional buckling of PCFS beams is derived by using energy method. To demonstrate the analytical solution, finite element analysis is also carried out. The finite element analysis results show that the analytical solution provided can give good and reliable prediction for the flange/web distortional buckling of PCFS beams. [ABSTRACT FROM AUTHOR]

Macroporous characteristics have been shown to play a key role in the osteoinductivity of hydroxyapatite ceramics, but the physics underlying the new bone formation and distribution in such scaffolds still remain elusive. The work here has emphasized the osteoinductive capacity of porous hydroxyapatite scaffolds containing different macroporous sizes (200–400 μm, 1200–1500 μm) and geometries (star shape, spherical shape). The assumption is that both the size and shape of a macropore structure may affect the microfluidic pathways in the scaffolds, which results in the different bone formations and distribution. Herein, a mathematical model and an animal experiment were proposed to support this hypothesis. The results showed that the porous scaffolds with the spherical macropores and large pore sizes (1200–1500 μm) had higher new bone production and more uniform new bone distribution than others. A finite element analysis suggested that the macropore shape affected the distribution of the medium–high velocity flow field, while the macropore size effected microfluid speed and the value of the shear stress in the scaffolds. Additionally, the result of scaffolds implanted into the dorsal muscle having a higher new bone mass than the abdominal cavity suggested that the mechanical load of the host tissue could play a key role in the microfluidic pathway mechanism. All these findings suggested that the osteoinduction of these scaffolds depends on both the microfluid velocity and shear stress generated by the macropore size and shape. This study, therefore, provides new insights into the inherent osteoinductive mechanisms of bioceramics, and may offer clues toward a rational design of bioceramic scaffolds with improved osteoinductivity. [ABSTRACT FROM AUTHOR]

This paper proposes a multi-platform simulation method for the seismic performance assessment of masonry infilled reinforced concrete (RC) frames, especially for those that, due to inadequate reinforcing details, tend to undergo shear failure during an earthquake. The multi-platform method is based on a micro–macro modeling approach in which a detailed finite element model of the RC frame is incorporated with a strut model of the infill wall. It exploits the strut model to increase its computational efficiency and the finite element model based on the modified compression field theory to capture the nonlinear behaviour of the RC frame. The proposed method is validated against previously tested frames subjected to lateral loads, and its advantages over the conventional strut models are demonstrated through both quasi-static and dynamic analyses. [ABSTRACT FROM AUTHOR]

This paper presents the development, implementation and application of an integrated simulation method for non‐linear soil‐structure interaction (SSI) analysis of nuclear structures. The integrated simulation method allows decomposition of the soil‐structure system into three subsystems: the superstructure, the soil‐foundation interface, and the soil domain. Each decomposed subsystem can be modelled independently using a proper finite element analysis program to accurately represent its non‐linear behaviour as per the current guideline for non‐linear SSI analysis of nuclear structures. The integrated simulation method is applicable to both static and dynamic analysis cases. The method was applied to the detailed SSI analysis of a realistic nuclear containment structure. The analysis was benefited by using different analysis tools for the three subsystems to capture both material and geometrical nonlinearities such as sliding and gapping at the soil‐foundation interface. The integrated model was compared with the model based on the fixed‐base assumption. Different results address the importance of non‐linear SSI analysis for seismic performance assessment of nuclear structures. [ABSTRACT FROM AUTHOR]

The longitudinal end effect of the double-sided permanent magnet linear synchronous motor (DS-PMLSM) causes a large end force. To overcome this drawback, this paper proposes a novel DS-PMLSM structure, in which the upper or lower primary component is shifted by a certain distance. First, the end-force model of the DS-PMLSM is established, based on which, the influences of the staggered structure on the fundamental and higher order end-force components are analyzed. Following this, the DS-PMLSMs with different slot–pole combinations are divided into four categories, and the design principles of possible winding arrangements are discussed. Furthermore, the staggered structures are applied to four slot–pole combinations, namely 21-, 15-, 20-, and 16-pole/18-slot. The back electromotive forces, detent forces, thrusts, and normal forces of the four combinations are analyzed and compared through the finite-element method. The electromagnetic and output characteristics of the novel DS-PMLSM are also compared with the traditional DS-PMLSM prototype to verify the effect of the proposed structure on suppressing the end force. [ABSTRACT FROM AUTHOR]

Thermally conductive materials are crucial for stable operation of integrated circuits, and there is high interest in improving the thermal conductivity of MXene. This study develops a facile method to enhance the chelating and reducing abilities of MXene towards metal ions by coating a thin layer of polydopamine onto the MXene surface, followed by decoration of silver nanoparticles on the nanosheet surface through in-situ reduction. Naturally abundant nanocellulose fibers were used as the matrix, and continuous thermal pathways were constructed between the fibers by vacuum filtration of the prepared nanofillers. The essential role of AgNPs in providing efficient thermal conductive networks was analyzed using the finite element analysis software. The prepared composite films exhibited an in-plane thermal conductivity up to 7.31 W/m K and demonstrated superior temperature control in heat dissipation tests. At a filler mass fraction of 30 wt%, the average electromagnetic shielding effectiveness of the film with a thickness of 0.17 mm was measured to be 25.8 dB in the X-band, which exceeds the target value for commercial applications. The outstanding performance of the composite paper has demonstrated the great potential of silver-decorated MXene for widespread application in fields such as electronic devices, aerospace, and aviation. [Display omitted] [ABSTRACT FROM AUTHOR]

Traditionally, straggering the primaries of the double-sided permanent magnet linear synchronous motor (DS-PMLSM) is beneficial in helping to reduce the detent force caused by the longitudinal end effect, but leading to a reduction of the average thrust. To overcome this disadvantage, this paper provides a novel DS-PMLSM, which adopts the structure of staggering two primaries and rearranging windings. First, the characteristics of the voltage and detent force are analyzed theoretically and verified by finite element (FEM) simulations. The inductance, thrust, and normal forces are then compared with the traditional DS-PMLSM. Furthermore, the geometrical parameters are optimized to improve the thrust. Finally, one DS-PMLSM prototype is tested. The detent force and back electromotive force tested results verify the effectiveness of the topology proposed in this research. [ABSTRACT FROM AUTHOR]

This paper investigates a modular slotless tubular permanent magnet linear synchronous motor, which includes several sectional motors by setting flux barriers and rearranging windings. It focuses on the design method of the different combinations with small detent force. The detent force models of the sectional and whole modular motor are established analytically in terms of a Fourier expansion and verified by a prototype. Then the design principles of the sectional motors are analyzed. On the basis of the models, the schemes whose flux barriers’ widths equal to one-third of the pole pitch are selected, followed by the comparison of two kinds of different sectional combinations. Their detent-force characteristics are then described in detail. The conclusions about the different combinations are drawn. [ABSTRACT FROM AUTHOR]

Summary: This study evaluates capabilities of the VecTor4 computer program to assess the seismic performance of a concrete containment structure subjected to both design‐basis and beyond design‐basis earthquakes. Based on a detailed nonlinear finite element model of the nuclear power plant containment structure, the seismic performance in terms of stress and strain distributions, cracks, yielding of reinforcement bars and tendons, as well as overall failure mechanism, is thoroughly reviewed. In addition, the post‐seismic performance of the containment structure subjected to a subsequent pressure increase is also investigated. Consideration is also given to the time‐dependent parameters of creep, shrinkage, and relaxation of prestressing tendons. It is found that the time‐dependent parameters and earthquake have a non‐negligible impact on pressure‐induced structural performance but that this impact can be predicted for a given earthquake. The proposed method is useful for assessing the progressive failure behaviour of containment structure under chain events. [ABSTRACT FROM AUTHOR]

The application and demand of titanium alloys has been steadily increasing in aviation due to the excellent high-temperature performance. Powder metallurgy (PM) technology has been widely applied in the production of titanium alloy but with more disadvantages. The application of the cross-wedge rolling (CWR) process to manufacture powder sintering titanium alloy has received the least attention but is most significant. This paper presents a numerical and experimental study on the CWR of sintering TC4 alloy blade preforms. The deformation behavior of sintering TC4 alloy was investigated, and a constitutive equation at peak stress was developed and implemented into a finite element (FE) model, by which we analyzed the effect of tool parameters, forming quality, and forming mechanism in the CWR process. We also investigated the effect of the deformation temperature and area reduction on forming quality with CWR experiments. The results show that the deformation behavior of sintering TC4 alloy is sensitive to temperature and strain rate, and the constitutive equation is capable of predicting the flow stress for the CWR process. Among the tool parameters, area reduction is the most significant factor and showed the best performance at less than 65.9%. An applicable range of process parameters for the CWR of sintering TC4 alloy was obtained. After rolling, the relative density improves from 86.21 to 98.2%, and the mechanical properties of the workpiece are significantly enhanced, especially for elongation. Compared with 45# steel, the temperature difference in the radial direction (Δ T) of TC4 alloy is much larger due to a lower thermal conductivity. However, the rolling force and torque of TC4 alloy needed in the CWR process are only half as much as those of 45#. [ABSTRACT FROM AUTHOR]

Because of the need for lightweight design, the application of hollow shaft parts rapidly increases. The mandrel plays an important role in the process of forming hollow shafts using cross wedge rolling (CWR). This paper presents the experimental and numerical analysis on the effect of the mandrel diameter on non-circularity in CWR for the hollow shafts with mandrel. A thermomechanical finite element (FE) model was developed to simulate the CWR process of hollow shaft. The experiments and numerical analysis suggest that the diameter of mandrel has a great effect on the non-circularity of hollow shafts. During the CWR process, because of the effect of the mandrel, the workpiece is compressed in radial direction and extended along the circumferential direction, which lead to the increase of the non-circularity. With increasing diameters, the workpieces show larger non-circularity. The non-circularity slowly increases when mandrel diameter is small. However, when the mandrel diameter exceeds a certain value, the non-circularity increases rapidly. Besides, the non-circularity of the inner hole is larger than that of the outer circle. According to the strain curves during the forming process, it can be found that circumferential compressive strain plays an important role in the rounding forming stage. Larger compressive strains decrease the non-circularity of the rolled pieces. [ABSTRACT FROM AUTHOR]

Ti-6Al-4V alloy is an ideal material for gas turbine blades with high strength and low density. The application of the cross-wedge rolling (CWR) process for manufacturing Ti-6Al-4V alloy blade preforms has great innovative potential. In this study, isothermal hot compression tests with strain rates between 0.01 and 10 s and deformation temperatures between 850 and 1050 °C were carried out. The constitutive equation was established and implemented into a 3D finite element (FE) model to analyze the formability of the CWR of Ti-6Al-4V alloy. Furthermore, CWR experiments were developed to verify the dependability of the FE simulation results and to investigate the influence of the process parameters on the formability of Ti-6Al-4V. The comprehensive results of the FE simulation and CWR experiments show that both the tool parameters and rolling temperature significantly affect the formability of the Ti-6Al-4V alloy. When the forming angle was 30° or 35°, the stretching angle was less than 7°, the area reduction was less than 72.4%, and the rolling temperature was 950 °C, The surface quality during the CWR process can be significantly improved. [ABSTRACT FROM AUTHOR]

The objective of this study is to investigate the long-term performance of a typical CANDU® 1 ®Registered trademark of Atomic Energy of Canada Ltd. (AECL) used under exclusive license by Candu Energy Inc., a Member of the SNC-Lavalin Group. 1 containment structure. A three-dimensional nonlinear finite element model was built to realistically evaluate the performance of the structure under service load as well as a hypothetical beyond-design level internal pressure. Consideration is given to the time-dependent effects, such as shrinkage, creep, and relaxation of prestressing tendons, over a 60-year timeframe. In addition, the sensitivity of the response of the containment structure against support condition, internal temperature profile and temporary construction openings was also investigated. The accuracy of the numerical model was validated against structural measurements made during a routine leak rate test. The analysis results show that the containment structure would develop a ductile mechanism if the internal pressure significantly exceeded the design pressure. The pressure-deformation relationship of the structure is sensitive to the considered time-dependent parameters. [ABSTRACT FROM AUTHOR]

In this work, a terahertz (THz) fiber directional coupler with a symmetric dual-suspended core structure has been proposed for realizing low loss and polarization-insensitive coupling length in the THz frequency region. The fiber core of the directional coupler consists of two round solid dielectric rods supported by two intersecting thin dielectric layers. Numerical simulations performed using the full-vector finite element method show that a short polarization-independent coupling length can be obtained by adjusting the geometric parameters of the fiber. Moreover, a low-loss THz fiber directional coupling performance can also be achieved at a central frequency of 1.00-THz and approximately 0.16 THz of bandwidth. For example, a coupler with a length of 0.421 cm has a transmission loss of 0.30 dB and 0.26 dB for the x- and y-polarization modes, respectively. • The fiber core consists of two dielectric rods supported by dielectric layers. • The length of the coupler can be tuned to shorter lengths. • The coupling length is made polarization-independent. • The loss of the device is reduced effectively. [ABSTRACT FROM AUTHOR]

We explore the features of the U A ( 1 ) and chiral symmetry breaking of the Nambu–Jona-Lasinio model without the Kobayashi–Maskawa–'t Hooft determinant term in the presence of a parallel electromagnetic field. We show that the electromagnetic chiral anomaly can induce both finite neutral pion condensate and isospin-singlet pseudo-scalar η condensate and thus modifies the chiral symmetry breaking pattern. In order to characterize the strength of the U A ( 1 ) symmetry breaking, we evaluate the susceptibility associated with the U A ( 1 ) charge. The result shows that the susceptibility contributed from the chiral anomaly is consistent with the behavior of the corresponding η condensate. The spectra of the mesonic excitations are also studied. [ABSTRACT FROM AUTHOR]

• A multi-platform simulation method was proposed to assess the performance of reinforced concrete structures under impact loading; • Integration of the VecTor2 program with LS-DYNA to take advantage of the Modified Compression Field Theory for impact-induced shear damage; • Development of a coupling method to satisfy the compatibility at the interface between the LS-DYNA model and the VecTor2 model; • Verification of the proposed method through examples for general dynamic analysis as well as vehicle/ship head-on collisions; • The advantages of the multi-platform method over the conventional standalone simulation method as demonstrated through a vehicle-bridge collision problem. This study presents a multi-platform simulation method for performance assessment of reinforced concrete (RC) structures subjected to impact loading. The method is demonstrated through the integration of two finite element analysis packages, LS-DYNA and VecTor2, to take advantage of the explicit integration scheme and various contact types in LS-DYNA for impact analysis and the Modified Compression Field Theory (MCFT) in VecTor2 for reliable modelling of concrete structures, especially for shear-related failure. The communication between the two programs is enabled through a standardized communication protocol which allows data exchange during the simulation in a seamless manner. When applying this method to vehicle/ship collision analysis, one major challenge is the modelling of the impact interface between the three-dimensional LS-DYNA model and the two-dimensional VecTor2 model. Therefore, a coupling method for models with different dimensions is proposed and also justified through a few verification examples. The method is also applied to a vehicle-bridge head-on collision problem and it is found that the conventional modelling method based on a single LS-DYNA model could overestimate the crashworthiness of the RC structures. [ABSTRACT FROM AUTHOR]