Hasil untuk "Materials of engineering and construction. Mechanics of materials"

Chunxiang Qian, Wenxiang Du, Yudong Xie et al.

With the growing demand for large-scale infrastructure development in China—such as deep-sea, deep-underground, and urban subsurface projects—combined with the widespread use of general-purpose raw materials, there is an urgent need for more precise crack control technologies in concrete. This need stems from the imperative to reduce unnecessary material consumption and environmental impact caused by excessive safety margins. To address this, a set of governing equations that account for the mutual feedback between temperature and humidity was first proposed. A non-constant form of the diffusion coefficient was introduced, alongside latent heat terms and unsteady-state heat source terms, to establish a hygrothermal coupling model. This model was further enhanced by incorporating the effects of creep relaxation, reinforcement constraint, structural restraint, and thermal conduction characteristics of formwork, thereby forming a comprehensive multi-field coupling evaluation framework that encompasses the temperature field, moisture content field, strain field, and cracking index field. Subsequently, the proposed theoretical framework was applied to representative engineering scenarios, including large-scale concrete foundation slabs, bridge bearing platforms, large-area long-span side walls and prefabricated tunnel segments. The accuracy and reliability of the model were validated through comparisons between simulation results and field-monitored data. The results demonstrate that this method effectively overcomes the technical limitations of traditional concrete crack prediction models, particularly those relying on constant parameter assumptions and decoupled field interactions. It offers a practical and robust approach for engineering applications, providing a novel perspective for precision crack control in concrete and contributing to the broader goals of sustainability and resource efficiency.

Hongyun Yang, J. Gao, Yongchao Ding et al.

Tamkin Karimi

Ultra-High Performance Concrete (UHPC) has emerged as a leading construction material across diverse engineering applications due to its exceptional mechanical properties and durability that exceed those of conventional concrete. This comprehensive review explores UHPC’s material composition, production additives, behavior in both fresh and hardened states, and environmental durability characteristics. The low water-to-cement ratio combined with a high binder content and the use of superplasticizers result in a densely compacted microstructure, substantially enhancing UHPC’s strength. Pozzolanic additives—including silica fume (SF), metakaolin (MK), fly ash (FA), and ground granulated blast furnace slag (GGBFS)—contribute to reduced cement consumption while improving long-term durability by enhancing permeability resistance, sulfate attack mitigation, and chloride ion durability. The integration of nanomaterials such as nano-silica (NS), carbon nanotubes (CNT), and graphene oxide (GO) increases the reactive surface area within the matrix, leading to a more uniform and denser microstructure. Fiber reinforcements—comprising steel, synthetic, glass, or hybrid fibers—impart ductility to UHPC, significantly boosting tensile and flexural strengths as well as energy absorption capacity, complementing its notable compressive strength. Fresh-state properties such as consistency, slump, and flowability are critical for manufacturability and application quality, with optimized mixtures delivering superior structural performance in terms of impact resistance, fatigue durability, and fracture mechanics. Additionally, UHPC demonstrates outstanding resistance to freeze-thaw cycles, sulfate and acid attacks, and chloride ingress, making it highly suitable for infrastructure exposed to aggressive environments. This review synthesizes the current understanding of UHPC’s technical advancements and multifaceted benefits, positioning it as a next-generation sustainable construction material that meets the demanding requirements of modern infrastructure.

B. Tiss, D. Martínez-Martínez, C. Mansilla et al.

YANG Hongwei, WANG Haifeng, YANG Jun, PU Renbin, YANG Can, JIN Chen

In order to enhance the long-term protective performance of water-based epoxy coatings，benzotriazole (BTAH) corrosion inhibitor was incorporated into hollow cerium oxide (CeO2) nanocontainers，resulting in the preparation of BTAH＠CeO2-doped epoxy coatings.The surface morphology，chemical composition and corrosion resistance of the epoxy/BTAH＠CeO2 composite coating were characterized using scanning electron microscopy (SEM)，X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS).The results showed that the loading amount of BTAH inhibitor in the CeO2 nanocontainers was 24.7%.The BTAH inhibitor was able to be rapidly released from the CeO2 nanocontainers，with a release amount reaching 92.6%after 8 h.The BTAH＠CeO2 particles were uniformly dispersed in the water-based epoxy resin and effectively filled the microscopic voids inside the coating.Electrochemical impedance testing results after corrosion in a 3.5%NaCl solution for 1 h indicated that the coating resistance of the epoxy/BTAH＠CeO2 composite coating was 16.7 times higher than that of pure epoxy coatings.After immersion in a 3.5%(mass fraction) NaCl solution for 30 d，the polarization resistance loss rate of the epoxy/BTAH＠CeO2 composite coating was only 10.6%compared to 1 h of immersion，demonstrating excellent long-term protective performance.

YUE Yan, LI Yu, ZHOU Xianxian et al.

[Purposes] Because of the high charging overpotential and lagging electrochemical reaction kinetics caused by the low electronic conductivity of Li2O2 in Li-O2 batteries, it is important to develop cathode catalysts with high activity. [Methods] By coating nitrogen-doped molybdenum disulfide ultra-thin nanosheets on the surface of nitrogen-doped carbon nanotubes, the N-MoS2/N-CNTs composite was prepared through hydrothermal method combined with ammonia annealing method. The morphology, surface element state, and Li-O2 battery electrochemical performance of N-MoS2/N-CNTs were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and electrochemical tests. [Results] The cathode obtains high initial charge/discharge capacity (7909/10015 mAh g-1), low charging overpotential, and high catalytic activity. Moreover, the performance of Li-O2 battery is further improved at large O2 mass transfer area. According to electrochemical reaction engineering, it is proposed that the possible initial discharge reaction interface is electrode/Li2O2 interface, and the charging reaction interface is electrode/electrolyte/Li2O2 interface. Three overpotential theories are used to explain the capacity and rate performance improvement mechanism of N-MoS2/N-CNTs cathode Li-O2 batteries, which is the decrease of electrochemical reaction overpotential (ηR) providing more space for the increase of concentration overpotential (ηC).

Li Zhou, Qing Liu, Zehui Fang et al.

The single-function agents with wide-spectrum activity which tend to disturb the ecological balance of oral cavity cannot satisfy dental treatment need. A multi-functional agent with specifically targeted killing property and in situ remineralization is warranted for caries management. A novel multi-functional agent (8DSS-C8-P-113) consisting of three domains, i.e., a non-specific antimicrobial peptide (AMP) (P-113), a competence stimulating peptide (C8), and an enhancing remineralization domain (8DSS), is fabricated and evaluated in this study. The findings demonstrates that 2 μM mL−1 of 8DSS-C8-P-113 eliminates planktonic Streptococcus mutans (S. mutans) without disrupting the oral normal flora. At a concentration of 8 μM mL−1, it exhibits the ability to prevent S. mutans' adhesion. Furthermore, 8DSS-C8-P-113 self-assembles a hydrogel state at the higher concentration of 16 μM mL−1. This hydrogel self-adheres on the tooth surface, resisting acid attack, eradicating S. mutans’ biofilm, and inducing mineralization in order to facilitate the repair of demineralized dental hard tissue. Its significant effectiveness in reducing the severity of dental caries is also demonstrated in vivo in a rat model. This study suggests that the multi-functional bioactive AMP 8DSS-C8-P-113 is a promising agent to specifically target pathogen, prevent tooth demineralization, and effectively induce in situ bio-mimic remineralization for the management of dental caries.

A. L. Chernyaev, Kirill V. Marfin

Girder-slab structures are widely used in industrial buildings, bridge decks, complex combined engineering structures and other objects of construction and mechanical engineering. An important task in their design is to find the most economical structural solution with the least amount of material while ensuring the necessary strength and rigidity. Therefore, the development of methods and algorithms for searching of the most rational and optimal design solutions is of great significance. The authors offer a technique of variant design of girder-slab structures with various cell shapes: rectangular, triangular, rhombic, trapezoidal and other, when analyzing vibrations. The technique is based on the principles of physicomechanical analogies and geometrical methods of structural mechanics. For a numerical example, a cantilever girder-slab structure on trapezoidal base is studied. The bars are of typical sections, the flooring is smooth steel. It is shown that cell geometry affects flexural vibrations of the girder-slab structure and material consumption.

Li Li, Ayaka Fuchigami

A graphic animation tool has been developed and refined to enhance learners' ability to conceptualize and understand complex structural mechanics concepts, particularly those that are challenging to visualize. This tool enables users to observe real-time changes in deflection curves, stress diagrams, and stress distribution diagrams for statically determinate beams under various loading conditions. Users can interactively modify parameters such as beam types, load types, load magnitudes and positions, cross-sectional dimensions, and material properties, allowing them to explore the resulting effects. To evaluate the tool's effectiveness, four questionnaire-based surveys were conducted to assess improvements in learners' comprehension of beam deflections and to track their level of certainty over time. The results demonstrated that most students found the tool beneficial for enhancing their understanding. Furthermore, repeated use of the tool significantly reduced error rates in exams on beam deformations, underscoring the value of visual representation in facilitating the comprehension of complex mechanical phenomena.

Mamahonov Azam, Sultanov Davronbek

The article presents a detailed study of the physical and mechanical properties of natural mountain rocks that are commonly used by the local population as construction materials in the mountainous areas of Chartak District, located in the Namangan Region. The research was conducted to determine the suitability of these rock types for various construction and infrastructure purposes, especially in regions where natural resources are directly used from the surrounding environment. As part of the study, several critical parameters were analyzed through laboratory testing. The compressive strength of the examined rock samples was found to range between 66 and 78 MPa, which indicates a relatively high ability to withstand axial loads. This makes the rocks well-suited for use in load-bearing walls and foundations. In addition to compressive strength, the flexural strength of the rocks was assessed. The values ranged from 5.63 to 13.07 MPa, reflecting the materials’ capacity to resist bending forces, which is crucial in structural components subject to stress and vibration. These values suggest that the rocks exhibit sufficient resistance to flexural deformation, which further supports their application in various building elements. Another significant aspect evaluated was the abrasion resistance, represented by the index И₁, which ranged from 11.6% to 11.8%. This relatively low abrasion loss indicates that the rocks possess good wear resistance, making them particularly effective for use in areas exposed to friction and mechanical wear, such as pavements and road surfaces. Furthermore, when the obtained values were compared to relevant construction and materials standards, it was determined that these rocks meet the necessary requirements for use in the construction of highways, pedestrian walkways, and structures subjected to high loads. Their strength, durability, and resistance to external influences make them a viable option for sustainable and long-term use in civil engineering projects. Overall, the findings of this research provide valuable insight into the engineering characteristics of locally available rock materials and support their broader application in infrastructure development, especially in rural and mountainous regions where access to industrial materials may be limited.

Deepak Kumar Mishra, Sushant Kumar, Suresh Chandra et al.

The increasing demand for sustainable construction materials has motivated the exploration of agro-residue–based polymer composites as an alternative to conventional synthetic materials. This study investigates the mechanical behaviour and environmental durability of agro-residue fiber–reinforced epoxy composites as sustainable alternatives for grain storage structures. Eleven composite formulations were fabricated using paddy straw, bagasse, mustard stalk, and wood sawdust as reinforcements with epoxy resin, silica filler, and hardener (HY-951) at varying residue-to-epoxy ratios (RERs). Mechanical testing—including tensile, compressive, flexural strength, toughness, and Brinell hardness—was performed according to ASTM standards, with the paddy straw–bagasse hybrid showing optimal performance (tensile strength: 40.5 MPa, compressive strength: 42.8 MPa, flexural strength: 52.3 MPa). Statistical analysis revealed a strong linear correlation (R2 = 0.98) between RER and density, validating formulation stability. Durability assessments under moisture, UV, and microbial exposure indicated uncoated composites degraded within 2.5–3 years due to hydrolytic, photochemical, and fungal activity. To extend service life, protective strategies—UV-stable polyurethane coatings, silane-based hydrophobic barriers, and antifungal additives (ZnO nanoparticles, quaternary ammonium compounds)—were employed, and accelerated testing confirmed resistance improvements projecting 7–10 years of durability. These findings provide a mechanics-based understanding of reinforcement effects and protective treatments on structural performance, demonstrating that agro-residue composites not only enable value-added waste utilization but also offer eco-efficient, durable materials aligned with sustainable polymer development and materials science goals.

L. Goruleva, I. I. Obabkov, E. Prosviryakov

The flow of viscous incompressible fluids in engineering devices, in technological and natural processes is characterized by the stratification of hydrodynamic fields. Conventionally, the stratification of the velocity field and the pressure field is studied for isothermal flows. If fluid motion occurs in a thermal field, temperature is an important characteristic of an incompressible fluid. Convective fluid flow has a very complex topological structure of hydrodynamic fields due to the temperature dependence of density. As is known, in the description of convection in the Boussinesq approximation, the dependence of density on the spatial coordinate and time is ignored in the continuity equation, which is then transformed into the incompressibility equation. Field and experimental observations of fluid flow allow us to identify flow regions with discrete density distribution along one of the coordinates. Such fluids are referred to as stratified fluids in the scientific literature. Their mathematical description is significantly complicated since it is necessary to solve the Oberbeck–Boussinesq equations for each layer and join the analytical or numerical solutions between the layers and the boundaries. For applied studies of convective flows, the Stokes approximation for the total derivative of a vector or scalar function is often introduced. The paper considers the construction of exact Lin–Sidorov–Aristov solutions for describing slow (creeping) flows of a non-uniformly heated stratified fluid. In this case, hydrodynamic fields are described by special polynomials with functional arbitrariness. It is shown how the calculations of unknown coefficients can be automated to form hydrodynamic fields (velocities and temperatures). For steady-state Stokes-type flows, an exact solution of the Oberbeck–Boussinesq system is written out explicitly (by means of formulas).

V. Babeshko

In this work, for the first time, an exact solution of the static contact problem of the action of a rigid wedge-shaped die occupying the first quadrant on a layer of composite material having arbitrary anisotropy is constructed using the block element method. Unlike numerous, mostly unsuccessful attempts to solve this and similar problems by analytical or numerical methods, which allowed us to identify only partial properties of the solution to this problem, the block element method made it possible to reveal a richer set of properties of its solutions. The solution is obtained in both coordinate and Fourier transforms. This makes it especially convenient to further study it by numerical analysis using standard computer programs. They will allow us to identify certain properties of composites as structural materials dictated by different types of anisotropies. It is shown that the obtained solution exactly satis es the two-dimensional Wiener-Hopf equation for an arbitrary right-hand side. A number of previously unknown properties of the solution have been revealed. In particular, the obtained representation of the solution of the contact problem in a wedge gave it a general appearance. In comparison with strip stamps, it contains an additively additional term describing the concentration of contact stresses at the angular point, that is, at the top of the stamp. The calculation of the indicator of the peculiarity of the concentration of contact stresses at this point is close to the values performed by numerical methods in a number of works. The paper shows that the zone near the top of the stamp has superior malleability when the stamp is inserted into the medium, compared with remote zones. This corresponds to the estimates obtained by the example of the introduction of strip stamps narrowing in width into the layer. In the zone considered away from the top of the stamp, the exact solution turns into a solution for the case of a semi-infinite stamp. The developed method is applicable to composites of arbitrary anisotropies arising in linearly elastic materials and crystals of any cross-sections that allow the construction of the Green function, and hence the two-dimensional Wiener-Hopf integral equations. The establishment of a general type of solution to the considered contact problem opens up the possibility of studying the precursors of increased seismicity in mountainous areas, as well as improving numerical methods to obtain more accurate solutions to complicated contact problems in engineering practice.

Wentao Li, Yizhe Chen, Jiangjie Qiu et al.

Data scarcity and the high cost of annotation have long been persistent challenges in the field of materials science. Inspired by its potential in other fields like computer vision, we propose the MatWheel framework, which train the material property prediction model using the synthetic data generated by the conditional generative model. We explore two scenarios: fully-supervised and semi-supervised learning. Using CGCNN for property prediction and Con-CDVAE as the conditional generative model, experiments on two data-scarce material property datasets from Matminer database are conducted. Results show that synthetic data has potential in extreme data-scarce scenarios, achieving performance close to or exceeding that of real samples in all two tasks. We also find that pseudo-labels have little impact on generated data quality. Future work will integrate advanced models and optimize generation conditions to boost the effectiveness of the materials data flywheel.

A. Kalgutkar, Sauvik Banerjee

Abstract Stiffeners are frequently utilized in many engineering projects because they boost strength while adding only a small amount of weight to the overall structure. The environments that the stiffened composite constructions are typically exposed to are harsh, which can result in damage like interlayer delamination and debond at the plate-stiffener interface, which can cause catastrophic failure. As a result, it is necessary to examine these structures’ dynamic behavior in addition to their stability performance. The current study attempts to investigate the free vibration response of stiffened composite plates with plate-stiffener interfacial debonding under hygrothermal circumstances using a robust finite element (FE) model. The skin and stiffener flange are simulated in the current work using a 9-noded heterosis element to prevent the shear-locking issue. Additionally, to considerably enhance computational performance, the stiffener web is formulated as a 3-noded isoparametric beam element with the torsion correction factor. Additionally, a dummy node is created to represent the debond, and a fictitious spring is added to stop the nodes from interpenetrating one another. Three schemes of hygrothermally stable laminates (θ/(90- θ))s, (22.5/−67.5)s and (77.5/−12.5)s are considered to identify the stiffened plate configuration with improved free vibration characteristics. Further, extensive parametric analyses are conducted on the obtained stiffened plate with improved performance in a hygrothermal environment by considering debond at the skin-stiffener interface. The vibrational behavior of the debonded plate is shown to be significantly more affected by moisture than by temperature. Additionally, the debond has a more obvious impact on the vibration characteristics in the plate with a centrally attached stiffener than in the plate with an eccentricity attached stiffener. As a result, the established FE formulation is anticipated to be trustworthy and computationally effective while effectively analyzing the debonded stiffened panel’s free vibration behavior in a hygrothermal environment. HIGHLIGHTS Developed a simplified finite element model to incorporate the interfacial debonding between the plate and stiffener. The current model reduces the computational cost by partially modeling the T-stiffener with the beam element. Investigates free vibration behavior of hygrothermally stable stiffened composite panels in hygrothermal conditions. Extreme environmental conditions significantly reduce the panel’s natural frequency. Large stiffener depth debonded panel’s frequency drops considerably at higher moisture concentration. Graphical Abstract

Qiwen Wang, Qiang Sheng, Wei Liu et al.

Abstract In order to improve the efficiency and stability of automobile hood doors under axial loading circumstances, this research investigates the reinforcing of these doors using graphene oxide powders (GOP). This work is separated into two different parts. In the first part, using the mathematical modeling, the results of the presented applicable structure are obtained. After that using the datasets of the mathematical modeling section, the results of deep neural networks (DNN) are trained, tested, and validated. The work focuses on double-curved panels’ linear strain fields, which are an essential part of vehicle construction. We solve the governing equations and boundary conditions for the reinforced automobile hood doors by using Navier’s solutions. GOP greatly enhances the mechanical characteristics by offering better load-carrying capability and deformation resistance. Our results show that DNNs can reliably and effectively forecast the performance of GOP-reinforced structures, providing a useful tool for improving automobile hood door designs. Enhanced automobile safety and durability are made possible by the combination of cutting-edge computational methodologies and novel materials, which also meet the increasing need for high-performance car components. This work highlights the revolutionary power of both technologies on contemporary vehicle design and manufacture, underscoring the mutually beneficial relationship between nanomaterial reinforcement and machine learning in the advancement of automotive engineering.

D. Rebot, S. Shcherbovskykh, Tetyana Stefanovych et al.

A mathematical model was developed to examine the influence of vibration on printed circuit boards utilized in machine control components. Nonlinear mechanics and Ateb functions were employed in the construction of the model. The study examined the impact of amplitude of oscillation and the elastic characteristics of the board's plate material on the change in oscillation frequency of the board. The findings of this study can inform further research on the reliability of printed electronic boards and their use in diverse operational modes and conditions.

Krishna Chapagain, Hemchandra Chaulagain

Most of the building stock in Nepal is based on masonry construction, which includes monumental, administrative, and residential structures. These structures are vulnerable during earthquakes, as evidenced by the massive structural damage, loss of human life, and property damage due to a lack of proper assessment and appropriate strengthening measures. An analysis of the seismic vulnerability of existing old Newari brick masonry buildings in the Pokhara Valley is presented. These buildings were built using indigenous knowledge and technology. The investigation is based on analytical studies, with some material properties obtained from field tests. Proper modeling of a masonry structure is crucial for reliable seismic resistance and structural design. However, modeling a real masonry structure is a challenging and computationally demanding task due to its complicated framework, requiring in-depth knowledge, realistic material properties, and relevant information. The aim of this research is to assess the seismic performance of old Newari masonry buildings using stress level and fragility curves. The research issues are addressed analytically through linear time history analysis using the finite element program-based software Sap 2000 v20. In dynamic analysis, numerical building models were subjected to three synthetic earthquakes. The performance status of the building based on various stress levels is evaluated, and weak regions are identified. The fragility curve of the structure is assessed, considering the ground motion parameters in the locality. The fragility function is plotted with the probability of failure at an interval of 0.10 g. The results of the analysis highlight that the studied structure is vulnerable compared to the codal provisions and standard recommendations.

Praja Dilla Atos, Romli Romli, Nanda Yusril Mahendra et al.

This research focuses on the finite element analysis for the design of reinforcement towers under dynamic load conditions. The reinforcement tower is a crucial part of the retrieval system that supports the system’s optimal function. This study identifies critical areas and plans reinforcement design steps on the construction of the retrieval tower. Stress analysis helps determine reinforcement design steps based on established standards and analytical approaches. The finite element method is used to analyze the design of the retrieval tower. The model is meshed into small triangular parts to find solutions in the form of finite element analysis of reinforcement tower design under dynamic load conditions. The results of finite element computation show normal stress fluctuations and increased displacement over time, indicating material deformation. This analysis is essential for understanding material behavior and designing systems that can effectively withstand dynamic loads.

Seung Ju Kim, Hyeon-Ji Lee, Chul-Ho Lee et al.

Abstract Neuromorphic hardware enables energy-efficient computing, which is essential for a sustainable system. Recently, significant progress has been reported in neuromorphic hardware based on two-dimensional materials. However, traditional planar-integrated architectures still suffer from high energy consumption. This review systematically explores recent advances in the three-dimensional integration of two-dimensional material-based neuromorphic hardware to address these challenges. The materials, process, device physics, array, and integration levels are discussed, highlighting challenges and perspectives.