Structural Performance Research Articles

Partial Replacement of Coarse Aggregate with EPS Beads

The rising for natural aggregates in construction has caused resource exhaustion and environmental issues, prompting the search for sustainable options. This research explores the substitution of coarse aggregates with Expanded Polystyrene (EPS) beads in concrete, with the goal of tackling issues related to aggregate shortages and the management of EPS waste. EPS beads, recognized for their light weight, thermal insulation capabilities, and moisture resistance, provide possible advantages for the creation of lightweight and environmentally friendly concrete. The study assesses how different volumes of EPS beads as a replacement impact the physical and mechanical characteristics of concrete, such as density, workability, compressive strength, and durability. Experimental findings indicate that raising the EPS bead content decreases the self-weight of concrete and improves thermal insulation, although it negatively affects compressive strength. An optimal replacement ratio achieves a balance between structural performance and sustainability, rendering EPS-concrete appropriate for non-load-bearing structures, lightweight construction, and thermal insulation uses. The Compressive strength of 5%, 10% EPS based concretes compared to control concrete.This research shows the viability of utilizing EPS beads as a partial substitute for coarse aggregates, promoting sustainable construction methods and lessening environmental effects. The results offer important perspectives on the mix design and real-world uses of EPS-concrete, promoting its use as an eco-friendly option in the construction sector. KEYWORDS: Exhaustion, workability, expanded polystyrene, durability, thermal insulation.

Flexural Behavior and Failure Modes of Pultruded GFRP Tube Concrete-Filled Composite Beams: A Review of Experimental and Numerical Studies

Pultruded glass fiber-reinforced polymer (GFRP) materials are increasingly recognized in civil engineering for their exceptional properties, including a high strength-to-weight ratio, corrosion resistance, and ease of fabrication, making them ideal for composite structural applications. The use of concrete infill enhances the structural integrity of thin-walled GFRP sections and compensates for the low elastic modulus of hollow profiles. Despite the widespread adoption of concrete-filled pultruded GFRP tubes in composite beams, critical gaps remain in understanding their flexural behavior and failure mechanisms, particularly concerning design optimization and manufacturing strategies to mitigate failure modes. This paper provides a comprehensive review of experimental and numerical studies that investigate the impact of key parameters, such as concrete infill types, reinforcement strategies, bonding levels, and GFRP tube geometries, on the flexural performance and failure behavior of concrete-filled pultruded GFRP tubular members in composite beam applications. The analysis includes full-scale GFRP beam studies, offering a thorough comparison of documented flexural responses, failure modes, and structural performance outcomes. The findings are synthesized to highlight current trends, identify research gaps, and propose strategies to advance the understanding and application of these composite systems. The paper concludes with actionable recommendations for future research, emphasizing the development of innovative material combinations, optimization of structural designs, and refinement of numerical modeling techniques.

A Comparative Review of Dynamic Analysis Techniques for Elevated Water Tanks: Time History Method Versus Response Spectrum Method

This paper presents a comprehensive review of dynamic analysis techniques for elevated water tanks, with a specific focus on comparing the Time History Method (THM) and Response Spectrum Method (RSM). Drawing upon a wide range of literature sources, the review synthesizes existing research efforts dedicated to understanding structural behavior, seismic performance, bracing configurations, material considerations, and soil-structure interaction in the context of elevated water tanks. Despite the extensive body of literature in this field, a notable research gap exists in the systematic comparison of dynamic analysis techniques, particularly between THM and RSM. This paper highlights the need for a comparative review to evaluate the advantages, limitations, and applicability of THM and RSM for dynamic analysis of elevated water tanks, providing valuable guidance for engineers and researchers in selecting the most suitable method based on project requirements and constraints.

A shaking table study on seismic behavior of pier of bridge in sand

Dynamic Soil-Bridge interaction (DSBI) is an important seismic design for bridges. The behavior of pier under earthquake loading is an important factor affecting the performance of such structures. Two series of laboratory tests were conducted to measure the response of structure when subjected to dynamic loads the first test the model was made of Aluminium and the second just the piles were made with Steel. A small shaking table was manufactured. The measurements taken in these experiments are horizontal displacement and strain of superstructure, acceleration in three dimensions in soil, pile, cap and superstructure. The soil used is sand and the model pile group (5x4) used has a diameter of 1 cm. It was concluded that the acceleration amplitudes increase with frequency for both model Aluminium and steel and the reaction of superstructure on aluminium piles is more than the steel ones.

A perfect ultra-wideband solar absorber with a multilayer stacked structure of Ti-SiO2-GaAs: structure and outstanding characteristics.

In this paper, we introduce an entirely new solar absorber design-a multi-layer periodic stacked structure. Through coupling effects, this design has perfect ultra-wideband absorption characteristics. The absorber structure is composed of four absorption units with varying cycle lengths, which are cyclically stacked on the surface of the refractory metal Cr. Each cycle encompasses three-layer nanosheets of Ti-SiO2-GaAs. We verify through finite difference time domain method (FDTD) simulations that the absorber achieves an absorption efficiency of 97.8% within the wavelength range of 280 nm to 3000 nm, with an average efficiency of 96.6% under the AM1.5 standard solar spectrum. The absorber can achieve such a remarkable absorption effect because of surface plasmon resonance (SPR) and Fabry-Pérot resonance effects. At 1500 K, this structure exhibits a thermal radiation efficiency of up to 97.83%. Furthermore, the design is not affected by polarization and it is less affected by the incident angle of the light source. These absorption spectra remain consistent regardless of whether it is in the TE or TM mode. Even when the angle of incidence is increased to 60 degrees, the absorption efficiency remains high. Its unique structure and excellent performance characteristics provide higher solar energy efficiency. These outstanding features enable solar absorbers to have broad application potential in improving solar energy efficiency.

Research on the Development of the Bike-Sharing Industry Based on the SCP Analysis Model: A Case Study of OFO

With the rise of the sharing economy, the bike-sharing industry initially experienced rapid growth as an effective solution to the urban "last mile" problem. The emergence of bike-sharing not only transformed people's travel habits but also attracted significant capital investment, driving the industry's swift expansion. However, as the market became saturated and competition intensified, the industry encountered an unprecedented downturn. This paper utilizes the SCP (Structure-Conduct-Performance) model to analyze the development trajectory and challenges of the bike-sharing industry from three perspectives: market structure, business conduct, and business performance. By selecting OFO bike-sharing as a case study, the research extracts common issues faced by the industry from the lessons of OFOs operational failures. These issues include not only the intensity of market competition but also improper capital management and deficiencies in corporate governance. Through this analysis, the paper aims to provide insights for future companies to better assess and manage potential risks, thereby achieving sustainable development.

Research on the influence of titanium addition on the structure and frictional performance of laser clad tin bronze coating

Cu has a high infrared light reflectivity, which leads to the easy formation of defects such as pores in copper alloys during the laser cladding process. The purpose of this research is to reduce the porosity of tin bronze coatings during laser cladding by adding titanium elements with high infrared absorption. The porosity of the coating was characterized using scanning electron microscopy, metallographic microscopy, energy-dispersive spectroscopy, and x-ray diffraction. The research results indicate that as the content of titanium element increases, the porosity within the coating first decreases and then increases. When the titanium addition was 2%, the minimum porosity of the coating was 0.034%. The microhardness of the samples was tested using a semiautomatic Vickers hardness tester, and the reciprocating dry friction performance at room temperature was tested using a UMT-3 friction tester. The incorporation of titanium significantly enhances the microhardness and frictional properties of the laser-clad tin bronze coating. Therefore, this study provides experimental data support for controlling the porosity and frictional properties of laser-clad tin bronze coatings through elemental composition.

Structural Performance of Circular Hollow Section Damper Under Loading in Circumferential Direction

Structural Performance of Circular Hollow Section Damper Under Loading in Circumferential Direction

Optimal Strategies for Filament Orientation in Non-Planar 3D Printing

The structural integrity and surface quality of parts produced using traditional fused deposition modeling depend on factors such as layer height, filament and build orientation, print speed, nozzle temperature, and, crucially for this study, both planar and non-planar slicing. Recent research on non-planar slicing techniques has shown significant improvements in surface smoothness and mechanical properties. Key approaches include non-planar slicing for 3-axis printers, adaptive slicing to optimize material placement in critical areas, and post-processing. However, current studies lack a comprehensive method for parameterizing filament direction across both planar and non-planar layers. This work presents an approach to generate optimal trajectories for planar and non-planar layers using contours derived from level set functions. The methodology demonstrates the advantages of non-planar printing, particularly with a filament orientation of 30° for inclined surfaces, ensuring better surface quality, uniformity, and structural integrity. This emphasizes the importance of trajectory planning and filament orientation in achieving high-quality prints on inclined geometries. This research highlights the necessity of a methodology that tailors filament paths based on the load-bearing requirements of each part, demonstrating its potential to enhance surface quality and structural performance, and further the advancement of the 3D printing industry.

Implementing the Link‐Cut Tree

ABSTRACTWe consider the challenge of implementing the link‐cut tree data structure. This data structure is well known and has had a wide impact on several theoretical results. However, there is a gap in mixed practical applications. We have recently used this data structure to generate uniform spanning trees and to compute a feedback vertex set. In this kind of application, the theoretical performance of the data structure is relevant but only when verified in practice. We thus present two implementations. One implementation is based on pointers and obtains good experimental performance for small problems. The other implementation is based on splay trees and provides amortized worst‐case guarantees. We use a simple API that allows us to explain the expected functionality. Moreover, it is designed to extract full functionality from the data structure while at the same time being as simple and compact as possible, in particular, it provides support for the cycle processing required by our applications. We give an experimental evaluation of both implementations. For completeness, we also review the theoretical analysis of this structure and obtain entropy and static finger bounds.

Impact of Microwave Pre-Curing on Pore Structure and Environmental Performance of Metakaolin- and Fly Ash-Based Geopolymers

Microwave technology in geopolymer synthesis offers a transformative, sustainable alternative to traditional methods, enhancing material properties and production efficiency. However, the effects of microwave-induced changes on pore structure and their relationship with mechanical strength and environmental performance, such as heavy metal leachability, are not fully understood. This study investigates the impact of microwave pre-curing on geopolymers, focusing on how microwave power and duration influence their pore structure and environmental performance. A total of 48 mixtures were prepared using sodium silicate and sodium hydroxide as alkali activators, with metakaolin and fly ash as raw materials. The modulus was adjusted to 1.5, and the liquid-to-solid ratio was set at 1.6 for metakaolin and 0.7 for fly ash. Microwave irradiation power settings of 100 W, 300 W, 440 W, 600 W, and 800 W were tested. The heating times ranged from 30 s to 90 s at intervals of 15 s. Our findings reveal that optimal microwave settings (100 watts for 45 s) can significantly enhance mechanical properties, with compressive strengths reaching 15.9 MPa for fly ash-based and 9.094 MPa for metakaolin-based geopolymers. However, excessive microwave energy leads to increased porosity, with adverse effects on structural integrity. Moreover, microwave pre-curing effectively reduces heavy metal leachability. Chromium (III) was used in leaching tests and it was demonstrated that ion concentrations as low as 0.097 mg/L enhance environmental safety. Advanced techniques like Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and X-ray CT were applied for the analysis of the atomic bonding, phases and pore structure of the studied geopolymers along with their ability to withstand compression (MPa). Chromium (III) was encapsulated and its leached concentration was measured by ICP-MS to evaluate the performance of the synthesized geopolymers. These results underscore the need for precise control over microwave irradiation parameters to maximize the benefits while mitigating negative impacts. This study provides valuable insights into the controlled use of microwave technology for geopolymer synthesis, recommending optimal irradiation conditions for improved performance and sustainability and advancing sustainable construction materials. The developed geopolymers show promise for applications in construction, waste stabilization, and heavy metal immobilization, contributing to more sustainable and environmentally friendly materials in these industries.

Practical Repair Cost Assessment of Steel Office Buildings with Diverse Beam-to-Column Connection Types in Japan

This study investigates the seismic performance of beam-to-column connections in Japanese steel office buildings and evaluates their impact on repair costs as part of practical seismic loss assessment. Repair cost analysis is conducted following FEMA P-58 guidelines, utilizing a probabilistic seismic performance approach. Additionally, this study incorporates the damage and loss of non-structural components, accounting for uncertainties arising from various factors. By applying story loss functions and the Capacity Spectrum Method within the assessment framework of this study, the applicability of these methods in Japanese design practices is validated. A numerical model of a typical steel building is established based on prior experimental data, and a series of numerical analyses are conducted to quantitatively assess variations in building response distribution and fragility resulting from different beam-to-column connection types. Analysis results indicate that, within the range up to maximum strength, differences in connection performance contribute more to variations in fragility than to building response. Component fragility is particularly influenced by connection type and dimensions that affect inter-story drift ratios. This approach highlights the potential cost differences driven by structural specifications and emphasizes the importance of connection-specific fragility in accurately estimating seismic repair costs in practical design. Furthermore, improvements in structural performance have limited effects in reducing non-structural damage, underscoring the necessity of directly enhancing non-structural component performance.

Regulating the Intralayer Cation Disorder in Layered Lithium-Rich Cathodes to Improve Cycle Performance.

The Li/Mn ordered structure of lithium-rich (LR) cathodes leads to the heterogeneous Li2MnO3 and LiTMO2 components, readily triggering structural degeneration and performance degradation in long-term cycling. However, the lack of guiding principles for promoting cation disorder within the transition metal (TM) layers has posed a persistent challenge in designing homogeneous layered LR cathodes. Herein, the (Li + Mn)TM content in the TM layer as a criterion for the design of cation-disordered layered LR cathodes is proposed. The intralayer cation disorder can be achieved by tuning the (Li + Mn)TM content less than 0.5 combined with incorporating the solute ions with suitable ionic radii. For a multicomponent LR nickel cobalt manganese (LRNCM) oxides system, multiscale structural analyses reveal that cation-disordered layered Li1.1(Ni0.6Co0.1Mn0.3)0.9O2 (LR613) exhibits enhanced compositional homogeneity and higher R m symmetry. The developed LR613 cathode undergoes a solid-solution reaction during Li+ deintercalation and mitigates voltage decay during cycling. It is elucidated that intralayer cation disorder effectively alleviates microstrain within the cathode structure and enhances overall structural stability. This comprehensive understanding of the composition-structure-electrochemical behavior relationship inspires the development of durable cation-disordered layered LR cathodes through composition tuning.

Experimentation Evaluation of Dynamics of Steel Wire Rope

Wire ropes represent a distinct category of ropes synthesized through the intertwining or braiding of individual steel wires. This unique construction confers notable attributes such as strength, flexibility, and durability to the resultant rope. The pervasive wire ropes across diverse industries underscores their capacity to adeptly manage substantial loads and endure adverse environmental conditions finding its application in mechanical, civil, mining, and marine engineering. This paper presents usage of image processing method to detect the deflection of a steel wire rope. The system comprises of dividing the wire rope into different sections, spatial referencing, frame separation, color-based detection, morphological operations, data collection and visualization. The steel wire rope deflection program will allow designers to conveniently process the transverse deflection trajectories of a steel wire rope in real time. One may further introduce any control actions when the deflection distance reaches a threshold value. The image-based algorithm enabled a robust detection of the deformed shape as a function of time, thus obtaining its dynamic trajectories. The deflection shapes and trajectories are compared with numerical predictions made using Cosserat Rod theory, which considers the geometric nonlinearities introduced due to large deflection. The numerical solution gave a rough estimate of the static deformation state of the wire, which agrees with the experimental results. This study will be useful for Structural Health Monitoring, Safety Assurance, Fatigue Analysis and Performance optimization. Moreover, the Continuum Mechanics employs Cosserat rod theory to model continuum robots which will provide enhanced computational efficiency and better dynamic simulation capabilities[18]. The deflection shapes and trajectories are compared with analytical predictions made using Cosserat Rod theory, which considers the geometric nonlinearities introduced due to large deflection.

Torsional Behavior Enhancement of Asymmetric-Plan Building Structures Using Optimum Tuned Mass Damper Inerter

ABSTRACT Torsional irregularity can significantly affect the seismic performance of structures, potentially resulting in structural failure. This paper aims to mitigate the substantial levels of torsional displacements experienced in torsionally coupled shear building structures subjected to bi-directional earthquakes by optimizing a passive control device, namely, a double-tuned mass damper inerter. Particle Swarm Optimization is employed to minimize two discrete objective functions to select the optimal placement and design parameters of Tuned mass damper inerters installed in asymmetric-plan building structures with different levels of torsional irregularity. The results demonstrate that this approach is highly effective for regulating structural behavior during seismic events.

Plasma‐assisted fabrication of multiscale materials for electrochemical energy conversion and storage

AbstractPlasma, the fourth state of matter, is characterized by the presence of charged particles, including ions and electrons. It has been shown to induce unique physical and chemical reactions. Recently, there have been increased applications of plasma technology in the field of multiscale functional materials' preparation, with a number of interesting results. This review will begin by introducing the basic knowledge of plasma, including the definition, typical parameters, and classification of plasma setups. Following this, we will provide a comprehensive review and summary of the applications (phase conversion, doping, deposition, etching, exfoliation, and surface treatment) of plasma in common energy conversion and storage systems, such as electrocatalytic conversion of small molecules, batteries, fuel cells, and supercapacitors. This article summarizes the structure–performance relationships of electrochemical energy conversion and storage materials (ECSMs) that have been prepared or modified by plasma. It also provides an overview of the challenges and perspectives of plasma technology, which could lead to a new approach for designing and modifying electrode materials in ECSMs.

Terminal Effects of Fulleropyrrolidine Electron Transport Materials for Efficient Perovskite Solar Cells

AbstractFullerene (C60) and its derivatives are the most prevalent and efficient electron transport materials (ETMs) for state‐of‐the‐art perovskite solar cells (PSCs). Benefiting from the high performance, simple synthesis, and easy availability of raw materials, fulleropyrrolidine derivatives (FDs) are potential next‐generation ETM alternatives to currently used fullerene materials. However, the power conversion efficiency (PCE) of FDs still lags far behind that of methanofullerene derivatives such as [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM). Moreover, the underlying mechanism remains unclear. In this work, six FD ETMs are designed and synthesized, i.e., CN‐TPAX (X = H, Me, OMe, Cl, Br, I), for p‐i‐n PSCs, and obtained a champion PCE of over 25% for the CN‐TPACl ETM, outperforming all reported FDs until now. Subsequently, their performance is systematically characterized in terms of molecular characteristics, including single‐crystal structure, electronic properties, film formability/morphology, and electron dynamics, which helped reveal the terminal effects of FD ETMs on the molecular characteristics and photovoltaic performance of PSCs. This approach clarified the structure–performance relationships between the FDs and the resulting devices, highlighting the importance of the terminal design of fullerene ETMs for high‐performance PSCs.

Vulnerability assessment of major urban tunnel subjected to fire induced by traffic incidents - a case study

As a type of critical transportation infrastructures, safety of major tunnels in urban transportation corridors has become unprecedentedly crucial. In various fire incidents with high temperature environment, the ceiling and wall of a tunnel would risk spalling, strength reduction, and even structural failure. In addition to risks of structural damage, high temperature and thick smoke in fire incidents will increase the risk of severe injury and even death due to burning, lack of oxygen, inhaling smoke and reduced visibility for people inside the tunnel. Limited mobility of evacuees would delay the evacuation process by endangering the safety of both evacuees and first responders. A comprehensive simulation-based case study is conducted to look into the fire and smoke simulation as well as potential threats to structural integrity and human health caused by fire in typical traffic incidents of three types of vehicles. Fire and smoke simulation are conducted using the Fire Dynamics Simulator (FDS), followed by the thermal and structural analyses with ANSYS. The comprehensive parametric study provides insights in terms of the impacts of different parameters including various typical traffic fire incidents on the structural performance and potential threats to evacuees.

A Research on The Economic Consequences of The Implementation of Dual-Class Share (DCS) Structure: A Case Study Based on Kuaishou Technology

Following the abolition of the dual-class share structure in 1989, the Hong Kong Exchanges and Clearing Limited re-launched the "Weighted Voting Right" mechanism. In February 2021, Kuaishou Technology listed in Hong Kong with a dual-class share structure, which has been regarded as the initial public offering of “the first stock of short video” drew the attention of many investors. Particularly, numerous international scholars have examined the performance of the dual-class share structure. This paper examines the economic consequences of the three dimensions based on the IPO of Kuaishou Technology. Taken together, by adopting a dual-class share structure, managers are more likely to face lower unsystematic risk and firms are less likely to face acquisition risks, as well as higher innovation performance and thus greater growth potential with a particular emphasis on operation capacity and profitability, even if the performance is not obvious in the short term. The contribution of this paper is to provide practical experiences for other Internet companies with the aim of promoting dual-class share structure and corporate sustainability.

Discovering the Impact of Printing Parameters on the Crashworthiness Performance of 3D-Printed Cellular Structures

Discovering the Impact of Printing Parameters on the Crashworthiness Performance of 3D-Printed Cellular Structures