Analysis Of Structural Behavior Research Articles

Enhanced ethylenediamine detection using WO3-BiVO4 nanoflakes heterostructure with exceptional adsorption capabilities: Experimental and theoretical studies.

The present work describes the synthesis of WO3-BiVO4- nanoflakes heterostructure (NFHs) by a single step hydrothermal method. The analysis of crystalline phases and structural behavior deduced the formation of good crystal quality WO3-BiVO4 NFHs. Under microscopic observation, the as-prepared WO3-BiVO4 displayed uniform and conspicuous nanoflakes like structures. The extensive density functional theory (DFT) was studied to examine the electronic and band structures of as-prepared WO3-BiVO4 NFHs in terms of formation energy, charge density, density of state (DOS) and band structures. The synthesized WO3-BiVO4 NFHs was used as sensing electrode towards the detection of ethylenediamine (EDA) chemical that displayed a good sensitivity of ~318.52 mA.mM-1cm-2, excellent dynamic range of 1 μM - 1 mM with detection limit (LOD) of ~94.51 nM and retention coefficient of ~0.9929. WO3-BiVO4 NFHs electrode possessed the good reproducibility, stability, and repeatability towards EDA chemical. To the best of our knowledge, for the first time, the fabricated chemical sensor fabricated with WO3-BiVO4 NFHs electrode could be promising electrode materials to identify dangerous chemicals at very low concentration in environment. Importantly, the fabricated chemical sensor can be effective for environmental monitoring.
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A systematic review of energy storing dynamic response foot for prosthetic rehabilitation.

The purpose of this paper is to undertake a systematic review on various mechanical design considerations, simulation and optimization techniques as well as the clinical applications of energy storing and return (ESAR) prosthetic feet used in amputee rehabilitation. Methodological databases including PubMed, EMBASE, and SCOPUS were searched till July 2022, and the retrieved records were evaluated for relevance. The design, mechanism, materials used, mechanical and simulation techniques and clinical applications of ESAR foot used in developed and developing nations were reviewed. 61 articles met the inclusion criteria out of total 577 studies. A wide variety of design matrices for energy- storing feet was found, but the clinical relevance of its design parameters is uncommon. Definitive factors on technical and clinical characteristics were derived and included in the summary tables. To modify existing foot failure mechanisms, material selection and multiple experiments must be improved. Gait analysis and International Organization for Standardization (ISO) mechanical testing standards of energy-storing feet were the methods for integrating clinical experimentation with numerical results. To meet technological requirements, various frameworks simulate finite element models of the energy-storing foot, whereas clinical investigations involving gait analysis require proper insight. Analysis of structural behavior under varying loads and its effect on studies of functional gait are limited. For optimal functional performance, durability and affordability, more research and technological advancements are required to characterize materials and standardize prosthetic foot protocols.

Developing lightweight steel profile and lattice polymeric core composite for structural use

Embracing modular construction, advanced materials, and digital technologies can drive innovation in the building industry, address global material consumption challenges, and foster a sustainable future. This paper presents the innovative concept of the lightweight hybrid lattice-filled profile (HLFP) for modular engineering, which combines a thin-walled steel tubular shell and additively manufactured lattice structure (AMLS) as a lightweight core. The AMLS achieves precise shape, internal structure, and stiffness, ensuring the decided structural performance with minimum materials. This study provides a theoretical model of HLFP, focusing on adhesively bonded AMLS. The experimental verification demonstrates that the adhesively bonded AMLS ensures an additional 130 % during the elastic stage and, even after partial debonding, maintains 50 % of the mechanical resistance compared to the theoretical sum of the HLFP components. Reducing the infill density does not severely affect the load-bearing capacity of the HLFP—a fourfold decrease of the ALMS density (from 10 % to 2.5 %) results in a 20 % decrease in the ultimate load. However, the sparse lattice structure alters the failure mechanism of ALMS, changing it from favorable ductile to dangerous brittle and determining the object for further optimization. The parametric study reveals the efficiency of the theoretical model for predicting the load-bearing capacity of HLFP. However, the finite element model developed in this study should be used for a more detailed analysis of the HLFP's structural behavior.

Analysis of Structural Behavior in Elevated Tanks Through the Configuration of Viscous Fluid Dissipators

Analysis of Structural Behavior in Elevated Tanks Through the Configuration of Viscous Fluid Dissipators

Mechanical behavior analysis of sandwich composite structures with different core geometries under three-point bending

This study presents a comprehensive investigation into the mechanical behavior of sandwich composite structures featuring six distinct core geometries under three-point bending conditions. Through detailed finite element analysis (FEA), the research examines the performance characteristics of I-shaped, traditional honeycomb (NIDA), O-shaped, X-shaped, semi-circular, and modified core geometries. The analysis focused on stress distribution patterns, displacement responses, and overall structural integrity. Results demonstrate that the semi-circular core geometry exhibits superior mechanical properties, achieving an 84.66% improvement in positive stress resistance and 74.79% enhancement in negative stress resistance compared to the traditional honeycomb reference model. The study revealed consistent linear elastic behavior across all models within the tested displacement range, with the semi-circular configuration showing optimal stress distribution and minimal core deformation. Using aluminum for facings and core materials, the research evaluated mechanical responses through displacement-controlled loading conditions, measuring stress concentrations at critical points and analyzing deformation patterns. This research provides valuable insights into the relationship between core geometry and mechanical performance, offering practical implications for engineering applications requiring high strength-to-weight ratios and enhanced flexural resistance in modern structural design.

Analysis of Structural, Optical, Morphological and Magnetic Behaviour of Lead Nanoferrite by Two Different Methods

Sol gel and the hydrothermal approach are two distinct techniques that have been successfully used to synthesise lead nanoferrite (PbFe2O4). To determine which of the two approaches is superior, the features of the sample prepared by each have been examined. Vibration Sample Magnetometer (VSM), Fourier Transform Infrared Spectroscopy, UV-VIS Spectral investigations, Scanning Electron Microscopy (SEM), X-Ray Diffraction, and Size, Band Gap Energies, Morphology, and Magnetic Properties of Nanostructures were used to determine and compare its various aspects. The mean diameters of the synthesised lead ferrite nanocrystalline were found to be 33 nm for the sol gel method and 20 nm for the hydrothermal method, respectively, based on X-Ray Diffraction analysis using Debye-Scherer’s formula with the peak. FTIR spectra are used to analyse the vibration characteristics of nanomaterials. The optical characteristics of the synthesised nanomaterials, such as their Energy Band Gap, were determined using UV-VIS Spectral investigations. SEM is used for surface morphological investigations, allowing the structure of the synthesised nanomaterials to be studied. Using VSM, the magnetisation of the produced nanomaterials was examined, and the hysteresis loops were used to calculate the saturation magnetisation (Ms), coercivity (Hc), and retainivity (Mr).

The Structural Analysis of Fitness Center Participation Behavior Using Planned Behavior Theory

The Structural Analysis of Fitness Center Participation Behavior Using Planned Behavior Theory

Visualization of stepwise electrode decomposition in a nail penetrated commercial lithium-ion cell using low-temperature synchrotron X-ray computed tomography

The transition towards zero carbon emissions in power generation hinges on the integration of efficient electrical energy storage systems, with lithium-ion batteries (LIBs) positioned as a pivotal technology. While generally safe, deviations in their operational guidelines due to manufacturing defects or misuse can lead to critical safety concerns, notably thermal runaway (TR) events. Internal short circuits (ISCs) are primary initiators of TR within LIBs. For abuse testing, ISCs are often triggered by nail penetration. This study explores the morphological changes and mechanisms underlying ISC-induced TR in LIBs using operando synchrotron X-ray computed tomography (SXCT) at subzero temperatures. A novel cryogenic setup was developed to control a stepwise temperature increase in the damaged sample while monitoring electrochemical characteristics and simultaneously enabling acquisition of high-resolution SXCT images. The findings reveal that conducting nail penetration at minus 80 °C prevents immediate TR, enabling detailed analysis of subsequent structural and electrochemical behavior during controlled thawing. Thus, the initiation of TR processes at localized ISC sites has been observed, evidenced by voltage fluctuations and morphological changes, such as cathode material cracking and decomposition. These results underscore the importance of temperature control in mitigating TR risks and provide critical insights into the internal dynamics of LIBs under abusive conditions. The developed cryogenic SXCT methodology offers a powerful tool for non-destructive, high-resolution investigation of battery failure mechanisms, contributing to the enhancement of LIB safety.

The first engineering application of 10MN CFRP cables in cable-stayed bridge in China

Existing engineering applications typically involve carbon fiber reinforced polymers (CFRP) cables with relatively small ultimate tensile forces (less than 10MN). This study presents the engineering application of China's first thousand-ton-grade CFRP cable-stayed bridge. The optimal steel and CFRP hybrid cable system was determined through a comparative analysis of structural behavior and life cycle cost. Thereafter, the CFRP cable, consisting of 121 strands of φ7 CFRP tendons, along with its anchoring system, was designed and manufactured with a theoretical ultimate tensile strength of 10,710 kN (Pb). Subsequently, the mechanical properties of 7–121 CFRP cable were investigated and experimentally verified. The tensile test revealed a satisfied ultimate tensile bearing capacity of 10,805 kN. Furthermore, after two million fatigue cycles, the CFRP cables retained approximately 90 % of their theoretical ultimate force, highlighting their excellent fatigue resistance. Besides, no damage occurred with a maintained tension force of 0.45 Pb at a temperature of 150 °C for a duration of at least 30 min, meeting the requirements of specification. Moreover, the key procedures of CFRP cable installation were also claimed. This study aims to further promote the application and development of CFRP cables in larger span and even super-long span bridges.

A numerical algorithm for damage progression of reinforced concrete bridge piers during air temperature and solar radiation cycles

Reinforced concrete (RC) solid piers are unavoidably affected by air temperature changes and solar radiation during service life. Nevertheless, the deterioration of pier concrete with increased exposure age remains unclear. A novel thermal-mechanical numerical algorithm (finite element model) for characterizing the deterioration characteristics of RC structures under cyclic environmental loads has been suggested. The deterioration of RC pier concrete after 100 years of air temperature and solar radiation cycles is simulated. The numerical results demonstrate that tensile damage of pier concrete during air temperature and solar radiation cycles increases continuously with exposure age. After one year of exposure, the tensile damage value of pier surface concrete increased to 0.201 and further increased to 0.286 and 0.357 as the exposure age grew to 10 and 100 years. Pier concrete tensile damage can be mitigated by using surface short-wave absorption-reducing methods, controlling the thermal properties of concrete, and raising the concrete peak tensile strain. The proposed finite element framework and numerical solutions enable a viable simulation-based method for the analysis of bridge structural long-term deterioration behavior and design of the bridge engineering.

Distributed fiber optic sensing (DFOS) as a part of diagnostics and monitoring of prestressed structures

Distributed Fiber Optic Sensing (DFOS) is a measurement technology that has experienced dynamic development in recent years and is increasingly used in various industries, including construction. By embedding sensors during the manufacturing stage of prestressed concrete elements, significant insights can be gained into their behavior during concrete pouring, prestressing, curing, and under rheological influences. DFOS sensors allow for the analysis of structural behavior under load and changes occurring over time with a level of accuracy previously unattainable with conventional methods. The paper presents research results on the implementation of this technology in pre-tensioned and post-tensioned elements. The main objective of the research was to verify the feasibility of using DFOS sensors to identify damages (e.g., cracks and simulated voids in cable ducts) and monitor the state of deformations and displacements in prestressed concrete elements.

Viscoelastic modeling and creep behavior analysis of composite bistable column-shell structures based on model validation technology

Anti-symmetric composite bistable structures have both efficient storage capacity and high mechanical properties, gaining widespread attention in engineering fields. In this paper, the effect of the viscoelastic behavior on the second stable-state curvature of the composite bistable column-shell structure is investigated. First, a method to determine viscoelastic parameters is proposed by model validation technology. Digital image correlation (DIC) technology is adopted to test the creep behavior of bistable composite structures and provide effective experimental data for model validation. Finally, the viscoelastic parameter identification results are used to establish a finite element model of the composite bistable structure for studying the creep behavior of the structure. Several simulation and experiment examples show that the theoretical and finite element model of the composite bistable column-shell structure established by the proposed method can accurately obtain the structural creep behavior.

Toward enhanced mechanical rigidity: additive manufacturing of auxetic tubes with PU core and comparative analysis of unique structural behaviors

Toward enhanced mechanical rigidity: additive manufacturing of auxetic tubes with PU core and comparative analysis of unique structural behaviors

Incomplete dissolved behavior and mechanical analysis of SnAgCu-SnBi composite solder structures for high-reliable package-on-package techniques

Due to the development of advanced packaging technology such as Package on Package (POP), traditional Sn-Ag-Cu (SAC) solder can no longer meet the demand. Utilizing the differences in temperature and performance of various solder materials to create composite structures for soldering is an effective method to achieve PoP interconnection. In this research, the microstructure of the interface between SAC305 and liquid in the incomplete dissolved solider ball was observed, and the grain orientation after solidification was analyzed. In addition, the effect of SnBi ratios on the microstructure and mechanical properties of SAC305-SnBi composite solder balls, and the fracture mechanism was analyzed according to the fracture morphology. The results show that according to Electron Backscatter Diffraction (EBSD) analysis, the grain size of Sn-Ag-Cu-Bi is small, and the orientation tends to be the same. With the rise in SnBi content, the eutectic structure in the solder ball exhibited a progressive increase and the IMC at the interface gradually changed from uneven rod-like structure to more uniform scallop-like structure. When the weight fraction of SnBi is 66.7%, the shear strength researches a maximum value of 62.2 MPa. As the SnBi content increases, there is an observable shift in the fracture location from the IMC to the solder.

Similitude laws for dynamic response of beam-plate coupled structure

The beam-plate coupled structure is a typical structure in spacecraft solar wings, and the prediction of its mechanical environment is crucial for overall design, structure and mechanism subsystem design. However, it is usually difficult to perform ground simulation tests on spacecraft solar wings with full-size structure. Therefore, a scaled model is established based on similarity theory to forecast the dynamic response of the full-size structure. In this article, finite element (FE) and hybrid finite element-statistical energy analysis (FE-SEA) models of the beam-plate coupled structure are established according to the band division principle. Finite element model allows for detailed analysis of structural behaviour, while hybrid models incorporate statistical energy analysis to account for high-frequency dynamics. By integrating these approaches, a comprehensive understanding of the coupled structure’s response can be achieved, facilitating efficient design and optimisation processes. The scaling laws of the dynamic response are obtained by combining the dimensional analysis and equation analysis methods, respectively. The scaled models are designed for verification, and the natural characteristics and vibration responses predicted by the scaled models are basically consistent with those of the prototype. The findings indicate that the prediction accuracy derived from the FE-SEA model is higher, which provides a novel approach for the dynamic similarity of complicated structures such as the solar wings of spacecraft.

Comprehensive sensitivity analysis of repeated eigenvalues and eigenvectors for structures with viscoelastic elements

The paper discusses systems with viscoelastic elements that exhibit repeated eigenvalues in the eigenvalue problem. The mechanical behavior of viscoelastic elements can be described using classical rheological models as well as models that involve fractional derivatives. Formulas have been derived to calculate first- and second-order sensitivities of repeated eigenvalues and their corresponding eigenvectors. A specific case was also examined, where the first derivatives of eigenvalues are repeated. Calculating derivatives of eigenvectors associated with repeated eigenvalues is complex because they are not unique. To compute their derivatives, it is necessary to identify appropriate adjacent eigenvectors to ensure stable control of eigenvector changes. The derivatives of eigenvectors are obtained by dividing them into particular and homogeneous solutions. Additionally, in the paper, a special factor in the coefficient matrix has been introduced to reduce its condition number. The provided examples validate the correctness of the derived formulas and offer a more detailed analysis of structural behavior for structures with viscoelastic elements when altering a single design parameter or simultaneously changing multiple parameters.

Increased stability of short femoral stem through customized distribution of coefficient of friction in porous coating

Stress shielding and aseptic loosening are complications of short stem total hip arthroplasty, which may lead to hardware failure. Stems with increased porosity toward the distal end were discovered to be effective in reducing stress shielding, however, there is a lack of research on optimized porous distribution in stem’s coating. This study aimed to optimize the distribution of the coefficient of friction of a metaphyseal femoral stem, aiming for reducing stress shielding in the proximal area. A finite element analysis model of an implanted, titanium alloy short-tapered wedge stem featuring a porous coating made of titanium was designed to simulate a static structural analysis of the femoral stem's behavior under axial loading in Analysis System Mechanical Software. For computational feasibility, 500 combinations of coefficients of friction were randomly sampled. Increased strains in proximal femur were found in 8.4% of the models, which had decreased coefficients of friction in middle medial areas of porous coating and increased in lateral proximal and lateral and medial distal areas. This study reported the importance of the interface between bone and middle medial and distal lateral areas of the porous coating in influencing the biomechanical behavior of the proximal femur, and potentially reducing stress shielding.

Graphene oxide nanoparticles synthesized from waste tires: A multi-faceted analysis of structure, morphology and antibacterial behavior

In recent years, the sustainable utilization of waste materials has become a significant research area due to environmental concerns and resource scarcity. Graphene oxide nanoparticles (GONPs) are regarded as one of the most important materials due to their capacity to serve as a potentially scalable precursor to graphene and, more recently, as the most promising substance in biomedical research. This study successfully explores the synthesis of GONPs using recovered carbon black (rCB) derived from waste tires. The structural, morphological and antibacterial properties of the synthesised GONPs in this study were highlighted. The intensity ratio (ID/IG) from Raman spectroscopy analysis, obtained at 0.82, with FTIR spectral results shows the functional groups of hydroxyl, carboxyl and epoxy, similar to GO synthesised from pure graphite. TEM analysis showed that the surface morphology of the GONPs contains nanoparticles with a size of 44.95 nm. Despite using waste material, GONPs exhibited potential antibacterial activity towards the gram-positive and gram-negative bacteria tested in this study. The data presented here are novel and show the possibility of GONP synthesis from waste tires as a future cost-effective antibacterial agent.

Research on Modal Behavior of Large Francis Turbine Runner

The water-added-mass can affect the modal behavior of the Francis turbine runner largely. The sealing rings in the band-chamber and the crown-chamber outside of the runner are utilized to prevent leakage of water around the Francis turbine. The sealing rings and the chambers filled with water can also affect the modal behavior of the turbine. When the turbine runner operates in the power plant at various operating conditions, the seal clearances of the band-chamber and the crown-chamber filled with water may change the modal behavior of the large Francis turbine runner. Firstly, the 3D geometrical structure of the studied large-scale Francis turbine runner was constructed, and then the CAD model was meshed to establish the finite-element model for numerical analysis. Next, the modal shapes and the natural-frequencies of runners in the air were calculated, which is the traditional method used for the structural modal behavior analysis of the turbine runners. Finally, this paper investigates the modal behavior of a large-scale Francis runner prototype with the combined effects of sealing rings and water added-mass by direct water-structure coupled analysis via the finite element method (FEM) to obtain more realistic results. The results reveal that the effects of water-added-mass and sealing rings cause a significant decrease in the natural-frequency of the large Francis turbine runner, which may lead to an increase in the amplitude of vibrations and even cracks. Technical suggestions are proposed to improve the monitoring and maintenance in the power stations to maintain the safe and efficient operation of the large Francis turbine units.

Homogenization of rammed earth walls under changing environmental conditions

Construction with rammed earth walls is a technique used for the construction of structures that has been increasing and by its nature requires in-depth knowledge due to the exposure of its materials (soil) to environmental factors, such as precipitation and solar radiation. This causes its structural elements to experience humidity fluctuations that affect the soil that constitutes them, resulting in a structure built with a material with heterogeneous properties, a fact that makes it difficult to understand its behaviour. The use of simulations in numerical models has helped to understand the internal dynamics of these elements. However, these procedures can present challenges in model construction and can also be computationally expensive, depending on the complexity of the model. In this context, the present research focuses on examining the behaviour of rammed earth walls against seismic action, when despite being made up of a single material, its composition is considered heterogeneous due to the humidity variations inherent to its exposure. Next, these models were subjected to a homogenization process of its properties using the Hashin and Shtrikman homogenization bounding theory. The objective is to find equivalent properties that facilitate the analysis of structural behaviour, assuming the homogeneity of the material. This homogenization process was extended to all parameters defined within the Pressure Independent Multi-yield material model employed in OpenSees, encompassing shear modulus, bulk modulus and density. As a result, applying Hashin and Shtrikman's upper bound to homogenize rammed earth walls produces remarkably similar results to those obtained using simulations of heterogeneous walls. This research provides valuable insights to understand rammed earth wall homogenization techniques and their behaviour, with important implications for their design and analysis.