Structural Performance Research Articles

The synergistic effect of vertical structural parameters of vertical-type two-dimensional hole gas diamond MOSFETs on improving the overall performance of devices based on TCAD simulation

Vertical-type two-dimensional hole gas (2DHG) diamond metal-oxide-semiconductor field effect transistors (MOSFETs), featuring vertical geometry and typically p-channel, are poised for application in future logic technology, high-voltage and high-power miniaturization complementary circuits. P-channel achieving high breakdown voltage and low on-resistance can be realized through the use of p− drift layer, while a trench structure is shown to be beneficial for increasing the drain current density of vertical-type devices. However, the cumulative impact of these key parameters on the performance of vertical-type diamond MOSFETs remains unclear. In this paper, we explore the physical mechanism that how the key parameters design affects on off-state, breakdown and output characteristics has been simulated using Silvaco TCAD tools. We propose a vertical-type trench-gate 2DHG diamond MOSFET that is favorable for general integration applications and exhibits equivalent performance to the double-gate vertical structure without relying on a high concentration of nitrogen doped layer. This demonstrates that our work offers a universal approach for optimizing the comprehensive device performance in vertical-type structures, accounting for the effects of multiple parameters across all wide bandgap material-based FETs.

Interface modulation of AgBiO3 via BiOCl In situ growth: Simultaneously boosting O⁎ and OVs production

Photocatalytic activity of the composite photocatalyst AgBiO3/BiOCl was examined after the interface of AgBiO3 was modified by growing BiOCl in situ and building heterojunction towards increasing reactive oxygen species (O⁎) and oxygen vacancy (OVs) production. The degradation of rhodamine B (RhB) revealed that the photocatalytic performance of the heterojunction structure of AgBiO3/BiOCl-x (x=0.05, 0.2, 2, 5) was significantly improved over that of AgBiO3 monomer, with the degradation effect of AgBiO3/BiOCl-2 reaching 99.6% within 60minutes and no significant decrease in performance after reuse (93% degradation after four cycles). Similar experiments also used another contaminant, tetracycline hydrochloride (TC-HCl). Within 60minutes, under visible light irradiation, the degradation rate of TC was 89.1% and the degradation rate was 0.0367min-1. The effects of catalyst addition, varied starting concentrations, and pH on RhB degradation were also studied. Furthermore, the free radical scavenging studies and chemical characterizations revealed that the principal reactive radicals functioning in the reaction system were h+, 1O2 and ‧O2-. Based on the findings, a potential catalytic mechanism for the synergistic degradation of RhB via photo-driven and chemical oxidation of AgBiO3/BiOCl heterostructures was postulated.

Ce-doped LaMnO3-δ perovskite as an efficient ozonation catalyst for the degradation of high-concentration phenol wastewater

In this study, a series of La1−xCexMnO3-δ (x = 0, 0.1, 0.3, 0.5, 0.7, 0.9, 1.0) perovskites with different Ce doping ratios were synthesized by the citrate sol-gel method for catalytic ozonation degradation of phenol at high concentration. Among them, the La0.9Ce0.1MnO3-δ catalyst showed the best catalytic performance, increasing COD removal nearly three times compared with ozonation alone. The COD removal of the catalysts was 0.1 > 0.3 > 0 > 0.5 > 0.7 > 0.9 > 1.0, which corresponded to COD removal of 67.56%, 58.12%, 57.94%, 53.68%, 52.18%, 49.19%, and 39.24%, respectively. SEM, BET, and XRD characterized the structural performance of the catalysts. The two critical parameters of catalyst dosage and pH were also optimized. Simultaneous reproducibility experiments demonstrated the good reusability of the catalyst. In addition, the catalytic degradation mechanism was investigated by the qualitative and quantitative detection of free radicals, EPR, fluorescence detection, XPS and TPD/TPR tests, which indicated that the surface hydroxyl groups, oxygen vacancies, and Mn(Ⅲ)/Mn(Ⅳ) and Ce(Ⅲ)/Ce(Ⅳ) redox pairs on the surface of the catalysts were the potential active sites for the decomposition of ozone to ROSs. The doping of Ce can effectively increase the number of active sites and promote the electron cycling process, thus generating large amounts of •OH and O2-•, effectively mineralizing phenol.

Development of Environmental Monitoring Sensor for Steel Corrosion in Concrete based on Micro-Electro-Mechanical Systems (MEMS)

Many bridges located near marine environments usually have high risk to lose their structural performance due to corrosion of reinforcing bars with chloride attack. While a huge amount of budget to maintain may be consumed for the structural maintenance methodologies, an efficient monitoring system for Reinforced Concrete (RC) structures in the corrosive environment is strongly demanded. Thus, structural health monitoring in real situations is significant for bridge asset management. The alternative way for preventing severe damage propagation is proactively monitoring the environmental condition containing chloride ion and its effect on the durability of concrete structures, for which numerous methods have been conventionally suggested such as dry gauze method to capture chlorides in air. In this study, Micro Energy Harvester (MEH) based on Micro-Electro-Mechanical Systems (MEMS) is technically applied to develop a sensor to identify the corrosion environment with chlorides in the exposure condition. MEMS is a rapidly evolving device, which enables to monitor the changes in natural frequency and amplitude at nodal locations of the targeting structure due to vibration-based electrostatic power generation induced by the corrosive environment. The purpose of this research is to develop a system for detecting the high corrosion-prone areas and finding the suitable metal sheet material for various chloride ion conditions, using the metal sheet as a cantilever structure for the MEMS device. 4 types of metal, aluminium, copper, iron and zinc are considered for the parametric experiments. Several scenarios are considered including chloride ion concentration, temperatures, and wet and dry conditions to compare the dominant frequency changes of each metal sheet and determine their sensitivity to corrosion environment. From the preliminary results, iron and zinc have a significant drop in frequency with the elapsed exposure period, which indicates that they are highly sensitive to the external chloride ion environment. These results offer an innovative and proactive approach to structural health monitoring for further developed applications. It enables prompt maintenance and early detection of potential issues for corrosion of steel bars in concrete, ensuring the longevity and safety of RC bridge structures.

Behavioural Study of Beam-Column Joint for Seismic Loading

Abstract: The seismic performance of Reinforced Concrete (RC) structures is a critical aspect of structural engineering, particularly in regions prone to seismic activity. This project presents a detailed study focusing on the behaviour of joints in RC structures following seismic events, utilizing the powerful computational tool ETABS. The primary objectives include understanding the response of joints under seismic loading, assessing their vulnerability, and proposing strategies for enhancing their seismic resilience. The study employs ETABS, a widely used software package for structural analysis and design, to simulate seismic actions on RC structures. Various types of joints, including beam-column joints and slab-column connections, are meticulously analysed under different seismic intensities and structural configurations. Through comprehensive analysis, the project aims to identify critical failure modes, such as shear failure, flexural failure, and joint sliding, and evaluate their impact on overall structural performance. Findings from this study contribute to the advancement of seismic design and retrofitting practices, offering insights into effective strategies for enhancing the seismic resistance of RC structures. The outcomes are valuable for engineers, researchers, and practitioners involved in earthquake engineering, providing essential knowledge for designing resilient structures capable of withstanding seismic hazards. This project underscores the importance of understanding joint behaviours in RC structures subjected to seismic loading, offering practical implications for improving structural safety and mitigating the impact of earthquakes on the built environment.

Evaluation of Mechanical Joint Structural Performance through Actual Performance Testing of PC Connections

Evaluation of Mechanical Joint Structural Performance through Actual Performance Testing of PC Connections

Integrated structural and energy building retrofit by reinforced concrete wall addition

In light of the paramount considerations of environmental sustainability and the protection of both life and property, a significant number of existing reinforced concrete (RC) buildings fall short of meeting contemporary standards in terms of their structural and energy performances. In response to these pressing concerns, there is an imperative need for comprehensive building retrofitting processes that integrate both structural and energy considerations. One such approach, the addition of RC walls, is commonly employed as a structural retrofitting technique. However, its potential to enhance overall building efficiency has been relatively underexplored in previous research. In this study, we focus on a representative RC building and utilize two key performance indices: structural residual life and energy consumption, to comprehensively evaluate the impact of RC wall retrofitting on both structural and energy performance. Our investigation considers retrofitting on both the exterior and interior sides of the building. It is observed that the structural performance exhibits notable improvement with the addition of RC walls on either side, and this improvement becomes even more pronounced when complemented by local retrofits to adjacent beams. While the RC walls added on the interior side have negligible impact on the building energy efficiency, those installed on the exterior side could obviously reduce the energy consumption of the HVAC system by 7.9%. Hence, the outcomes of this study indicate that employing the RC wall retrofitting on the exterior side of the existing building is an efficient way to reach structural and energy performance targets simultaneously.

A force-restricted inerter damper for enhancing the resilience of seismically isolated structures

An inerter is a mechanical device that generates a resisting force proportional to the relative acceleration between its two terminals. Several inerter-based dampers have been developed and studied to protect critical structures from the damaging effects of strong earthquake events. However, under high-frequency excitations, conventional inerter-based dampers may generate high resisting forces, which can result in excessive stresses in the supporting members and degrade the performance of the isolation systems. To overcome this issue, a novel force-restricted inerter damper (FRID) is proposed in this study for use in base-isolated structures. A simplified mechanical model of the proposed FRID was developed, which consists of a parallel layout of a viscous damping element and a nonlinear inerter element with a friction force restriction mechanism. The nonlinear hysteretic behavior of the FRID is discussed with an emphasis on the frequency dependence. Time- and frequency-domain methods were developed to evaluate the nonlinear dynamic response of the FRID-controlled structure. The performance of the FRID was investigated and compared with that of commonly used fluid viscous dampers (FVDs) and viscous mass dampers, when incorporated into base-isolated structures under short- and long-period ground motions. Parametric studies were conducted to investigate the influence of the FRID’s characteristic parameters on the seismic performance of controlled structures. The analysis demonstrated that the viscous mass damper and FRID provided superior control than the FVD on the displacement of a base-isolated structure, and the FRID is more effective than the viscous mass damper in reducing the control force and structural acceleration. This confirms that the proposed FRID is a promising, high-performance, and cost-effective device for enhancing the resilience of seismically isolated structures.

Theoretical modeling of a bottom-raised oscillating surge wave energy converter structural loadings and power performances

This study presents theoretical formulations to evaluate the fundamental parameters and performance characteristics of a bottom-raised oscillating surge wave energy converter (OSWEC) device. Employing a flat plate assumption and potential flow formulation in elliptical coordinates, closed-form equations for the added mass, radiation damping, and excitation forces/torques in the relevant pitch-pitch and surge-pitch directions of motion are developed and used to calculate the system's response amplitude operator and the forces and moments acting on the foundation. The model is benchmarked against numerical simulations using WAMIT and WEC-Sim, showcasing excellent agreement. The sensitivity of plate thickness on the analytical hydrodynamic solutions is investigated over several thickness-to-width ratios ranging from 1:80 to 1:10. The results show that as the thickness of the benchmark OSWEC increases, the deviation of the analytical hydrodynamic coefficients from the numerical solutions grows from 3 % to 25 %. Differences in the excitation forces and torques, however, are contained within 12 %. While the flat plate assumption is a limitation of the proposed analytical model, the error is within a reasonable margin for use in the design space exploration phase before a higher-fidelity (and thus more computationally expensive) model is employed. A parametric study demonstrates the ability of the analytical model to quickly sweep over a domain of OSWEC dimensions, illustrating the analytical model's utility in the early phases of design.

A Molecular Dynamics Study on the Defect Formation and Mechanical Behavior of Molybdenum Disulfide under Irradiation.

Due to its appealing characteristics, molybdenum disulfide (MoS2) presents a promising avenue for the exploration of lubrication protection materials in high-energy irradiation scenarios. Herein, we present a comprehensive investigation into the defect behavior of multilayer MoS2 under argon (Ar) atom irradiation leveraging molecular dynamics simulations. We have demonstrated the energy shifts and structural evolution in MoS2 upon irradiation, including the emergence of Frenkel defects and intricate defect clusters. The structural damage exhibits an initial increase followed by a subsequent decrease as the incident kinetic energy increases, ultimately peaking at 2.5 keV. Moreover, we investigated the effect of postannealing on defect recovery and conducted the uniaxial tensile and interlayer shearing simulation in order to provide valuable insights for the defect evolution and its impact on mechanical and tribological properties. Furthermore, we have proposed the optimal annealing temperature. The current study reveals the atomic mechanisms underlying irradiation-induced damage on the structural integrity and mechanical performance of MoS2, thereby providing crucial guidance for its vital application in nuclear reactors and aerospace industries.

W-HYDRA: a new experimental platform for the Water-Cooled Lead Lithium Breeding Blanket

Abstract In the framework of the activities coordinated by the EUROfusion consortium, the Water thermal-HYDRAulic (W-HYDRA) experimental platform is being built at the ENEA Brasimone Research Centre in order to support the development of the Water-Cooled Lead Lithium (WCLL) Breeding Blanket (BB). In particular, this infrastructure will make possible the installation and testing of prototypical mock-ups under relevant working conditions, such as the First Wall (FW), the manifold and the Steam Generator (SG). Moreover, it will represent an integral test facility for the investigation of phenomena characteristic of WCLL BB concept, such as the PbLi/water interaction. Finally, the collection of data coming from the different planned experimental campaigns will allow to qualify and validate numerical models and codes currently adopted for the design of components, as well as for the modelling of complex phenomena typical of the WCLL BB.
In order to come to a definitive design of the different facilities constituting the experimental platform, several design analyses assessing the thermal, hydraulic and structural performances of the different facilities and components are necessary. The paper reports a highlight of the W-HYDRA platform with a general description of the facilities. Some of the most relevant design studies carried out so far are reported as well, highlighting their impact on the evolution of the design.

Assimilation of PSO and SVR into an improved ARIMA model for monthly precipitation forecasting

Precipitation due to its complex nature requires a comprehensive model for forecasting purposes and the efficiency of improved ARIMA (IARIMA) forecasts has been proved relative to the conventional models. This study used two procedures in the structure of IARIMA to obtain accurate monthly precipitation forecasts in four stations located in northern Iran; Bandar Anzali, Rasht, Ramsar, and Babolsar. The first procedure applied support vector regression (SVR) for modeling the statistical characteristics and monthly precipitation of each class, IARIMA-SVR, which improved the evaluation metrics so that the decrease of Theil's coefficient and average relative variance in all stations was 21.14% and 17.06%, respectively. Two approaches are defined in the second procedure which includes a forecast combination (C) scheme, IARIMA-C-particle swarm optimization (PSO), and artificial intelligence technique. Generally, most of the time, IARIMA-C-PSO relative to the other approach, exhibited acceptable results and the accuracy improvement was greater than zero at all stations. Comparing the two procedures, it is found that the capability of IARIMA-C-PSO is higher concerning the IARIMA-SVR, so the decrease in the normalized mean squared error value from IARIMA to IARIMA-SVR and IARIMA-C-PSO is 36.72% and 39.92%, respectively for all stations. The residual predictive deviation (RPD) of IARIMA-C-PSO for all stations is greater than 2, which indicates the high performance of the model. With a comprehensive investigation, the performance of Bandar Anzali station is better than the other stations. By developing an improved ARIMA model, one can achieve a high performance in structure identifying and forecasting of monthly time series which is one of the issues of interest and importance.

Integrated lightweight optimization design of wall thickness, material, and performance of automobile body side structure

Integrated lightweight optimization design of wall thickness, material, and performance of automobile body side structure

Preparation, Characterization, and High-Temperature Anti-Seizing Application of CrAlN-Based Gradient Multilayer Coatings

High-temperature fasteners are metal parts of gas turbines and steam turbines, which work at high temperatures and under stress for a long time. However, the frequent seizures of fasteners bring great trouble to the normal maintenance of power plants. In this paper, three kinds of dense and controllable CrAlN-based gradient multilayer coatings were prepared on the samples and screws by arc ion plating (AIP) technology. The morphology, composition, structure, nano hardness, adhesion, residual stress, and room temperature tribological performance of the coating were investigated. To evaluate the high-temperature, anti-seizing performance, coated screws were heated to 700 °C for 140 h with a torque of 20 N·m. The results indicate that the CrN/CrAlN multilayer coating shows better comprehensive properties. The characterization of coated screws proved that the coating structures obtained on the screws were similar to the flat samples. However, the as-prepared coating on the screws showed different thickness variation rules, which was related to the clamping method, deposition distance, and screw shape. After a simulation service, the thread of the screw remained intact with similar structure and thinner thickness. The above results indicate that the high-temperature seize prevention of fasteners can be successfully achieved by preparing a CrAlN-based multilayer coating, which is suitable for fasteners with service temperatures below 700 °C.

Evaluating Sisal Fiber-Reinforced Gypsum Composites for Water Absorption and Mechanical Performance

There has been a great research interest for investigation of new construction materials which can reduce environmental impact and cost, with improved structural performance. Recently, sisal fiber is being used as a reinforcement material in the development of reinforced composites. Here, sisal fiber-gypsum reinforced composites were prepared using the hand lay-up method followed by the compression technique. The effects of weight percentage (Wt. %) of the sisal fiber reinforcement on the mechanical properties of the developed sisal fiber-gypsum composites were investigated experimentally by varying the Wt. % as 5, 10, and 15%. The mechanical properties were tested as per the ASTM standards. The results revealed that the long unidirectional sisal fiber-gypsum composites exhibited higher impact and hardness strengths with lower water absorption behaviour than the short-chopped sisal fiber-gypsum composites. In addition, the impact strength increased with increase in Wt. % for both short-chopped and long unidirectional sisal fiber reinforcement. While the hardness strength decreased with increase in Wt. % for both short-chopped and long unidirectional sisal fiber. The experimental investigation has established sisal fiber as an important reinforcement material for improving the performance of the neat gypsum in a wide range of architectural applications such as ceilings, decorative partitions, and light covers.

Prediction of compressive strength of cross‐shaped stub CFSTs under axial loading: Numerical and analytical study

AbstractSpecial‐shaped concrete‐filled steel tubes (CFSTs) have been used in modern structures like high‐rise commercial and residential buildings due to their superior structural performance compared to steel and reinforced concrete members. Various shapes of special‐shaped CFSTs might be necessary to meet architectural and aesthetic needs. Cross‐shaped CFSTs could be used where two orthogonal walls cross in high‐rise buildings. However, at present, the research on the compressive performance of cross‐shaped CFSTs is limited, consequently, the unavailability of design guidelines and design‐oriented strength prediction models. Therefore, in this study, a finite element (FE) model of cross‐shaped CFSTs was developed following the past experimental data, and the model's accuracy was verified by the failure modes and load–strain curves of specimens. Sensitivity analysis was performed for some parameters of the concrete damaged plasticity model besides imperfections and residual stress. The parametric analysis was conducted considering various study parameters such as the width‐to‐thickness ratio, width‐to‐depth ratio, and steel and concrete strengths. The compressive strength of cross‐shaped CFSTs was predicted by different design codes and available design formulas, which gave unsatisfactory results necessitating the development of new strength prediction models. Finally, a new design formula was developed by performing a linear regression of FE and test results. The proposed formula predicted the strength of cross‐shaped CFSTs with great accuracy and can be used for design purposes.

Influence of Rebar Anchorage in the Structural Performance of Reinforced Concrete Members

Influence of Rebar Anchorage in the Structural Performance of Reinforced Concrete Members

Experimental study on the flexural behaviour of lap-spliced rapid hardening concrete beams

Rapid-hardening concrete (RHC) has recently garnered significant attention because of its potential to expedite construction schedules and enhance structural performance. However, the flexural behaviour of lap-spliced RHC beams requires further investigation to provide valuable insights into the performance of this innovative construction material and splice technique. This study examined the flexural behavior of 22 lap-spliced RHC beams with varying lap splice lengths and compared them with four normal-strength concrete (NSC) beams. The key parameters investigated included lap splice length, concrete type, concrete cover, bar diameter, and splice end shape. The flexural performance of the beams was evaluated by analysing the load-deflection response, crack patterns, reinforcement strain distribution, and failure modes. Rapid-hardening concrete beams were tested three days after casting, whereas normal-strength concrete beams were tested 28 days later. The results of the study revealed that lap-spliced RHC beams exhibited increased ductility and load capacity by an average of 76 % and 32 %, respectively. In addition, the lap splice length in RHC beams could be reduced by up to 30 %.

Effects of Seawater on Mechanical Performance of Composite Sandwich Structures: A Machine Learning Framework

Effects of Seawater on Mechanical Performance of Composite Sandwich Structures: A Machine Learning Framework

The Accurate Synthesis of a Multiscale Metallic Interface on Graphdiyne.

The accurate construction of composite material systems containing graphdiyne (GDY) and other metallic materials has promoted the formation of innovative structures and practical applications in the fields of energy, catalysis, optoelectronics, and biomedicine. To fulfill the practical requirements, the precise formation of multiscale interfaces over a wide range, from single atoms to nanostructures, plays an important role in the optimization of the structural design and properties. The intrinsic correlations between the structure, synthesis process, characteristic properties, and device performance are systematically investigated. This review outlines the current research achievements regarding the controlled formation of multiscale metallic interfaces on GDY. Synthetic strategies for interface regulation, as well as the correlation between the structure and performance, are presented. Furthermore, innovative research ideas for the design and synthesis of functional metal-based materials loaded onto GDY-based substances are also provided, demonstrating the promising application potential of GDY-based materials.