Structural Performance Analysis Research Articles

Designing hard carbon microsphere structure via halogenation amination and oxidative polymerization reactions for sodium ion insertion mechanism investigation

Hard carbon as a negative electrode material for sodium-ion batteries (SIBs) has great commercial potential and has been widely studied. The sodium-ion intercalation in graphite domains and the filling of closed pores in the low voltage platform region still remain a subject of controversy. We have successfully constructed hard carbon materials with a pseudo-graphitic structure by using polymerizable p-phenylenediamine and dichloromethane as carbon sources. This was achieved by a halogenated amination reaction and oxidative polymerization. It was found that the capacity of hard carbon materials mainly originates from intercalation into graphite domains. The study found that the prepared hard carbon could store 339.33 mAh g−1 of sodium in a reversible way at a current density of 25 mA g−1, and it had an initial coulomb efficiency of 80.23%. It even maintained a reversible sodium storage capacity of 125.53 mAh g−1 at a high current density of 12.8 A g−1. Based on the analysis of hard carbon structure and electrochemical performance, it was shown that the materials conform with an “adsorption-intercalation” mechanism for sodium storage.

Structure optimization design and performance analysis of liquid cooling plate for power battery

The structural design of liquid cooling plates represents a significant area of research within battery thermal management systems. In this study, we aimed to analyze the cooling performance of topological structures based on theoretical calculation and simple structures based on design experience to achieve the best comprehensive performance and analyze their operating environment characteristics. The COMSOL Multiphysics software and topology optimization method were used to calculate the topology structure. To assess performance, the numerical computation method was employed to simulate and calculate the optimized structure, comparing its temperature, velocity, and pressure related parameters and changes. Moreover, the study analyzed the impact of inlet flow velocity, ambient temperature, and coolant temperature on heat dissipation performance. The results revealed a reduction of 0.31 % in the highest temperature and a 21.20 % decrease in pressure drop for the topology-based results compared to the post-processing results. However, the cooling performance advantage offered by the topology structure was not significant, the enhancement in cooling performance did not offset the increase in production cost. Furthermore, we found that variations in service conditions influence the heat dissipation performance of liquid cooling plates, requiring comprehensive consideration when selecting condition parameters.

Creep compliance of functionalized graphene-epoxy nanocomposites

Creep behavior is observed even at room temperature in polymers and polymer composites under constant stress. In the design of structural elements using these materials, the determination of creep compliance for structural strength and performance analysis is crucial in terms of reliability and usability. In this study, the creep compliance of pure epoxy and functionalized graphene-reinforced epoxy nanocomposites were experimentally investigated and compared at room temperature at constant stress levels of 50, 100, and 200 MPa representing the viscoelastic region, yielding region and viscoplastic region, respectively. To reveal the effect of temperature as well as stress level on this behavior, the creep compliance of epoxy and graphene-epoxy nanocomposites was investigated at 65°C in addition to room temperature after the pure graphene used as a reinforcement element was functionalized with Triton X-100, nanocomposite production was carried out. In 2h creep tests, it was observed that as the constant stress level increased, the creep compliance increased and the creep compliance of the nanocomposite was lower than that of the epoxy at all stress levels. The creep compliance of the epoxy was improved by 65% with the addition of functionalized graphene at room temperature and a stress level of 100 MPa. As the temperature increased, the creep compliance of both epoxy and functionalized graphene-epoxy nanocomposite increased due to molecular mobility and viscous flow. However, at high temperatures, the positive effect of functionalized graphene on the compliance of the epoxy is higher. At 65°C and a stress level of 100 MPa, the improvement rate of creep compliance is 78%. Functionalized graphene exhibited a more effective behavior on creep resistance at high temperatures. The obtained results showed that creep compliance was significantly affected by stress level and temperature.

Practicability and environmental impact assessment of synthetic fibre reinforced polymer (SFRP) stirrups in reinforced concrete beams

In this study, the objective is to explore the practicability of incorporating synthetic fibre reinforced polymer (SFRP) stirrups into reinforced concrete beams. This investigation revolves around evaluating their effectiveness from two key perspectives: their structural performance and environmental impact. To accomplish this, four set of specimens were prepared, each integrating SFRP stirrups, and testing them under a rigorous three-point bending load test. The structural performance analysis entails a comprehensive examination on the critical design factors such as: the load-deflection relationship and the contribution these SFRP stirrups to improve the ductility performance, flexural stiffness, deformability factor, flexural toughness and energy absorption capacity. The findings of this study indicate that the SFRP stirrups exhibit commendable shear capacity, meeting the necessary requirements, and simultaneously demonstrate satisfactory ductility. It is determined, that the optimal design for these SFRP stirrups involves utilizing narrow and thin stirrups placed at relatively larger intervals. Furthermore, this research delves into assessing the environmental impact of incorporating SFRP stirrups. This assessment enables us to comprehensively evaluate the environmental implications of the entire life cycle of these stirrups in structural beam. Moreover, the analysis reveals that, SFRP stirrups yields lower environmental impacts compared to their steel counterparts, they still provide valuable insights into the overall sustainability considerations within the context of reinforced concrete structures.

Exploring the Potential of Metal-Organic Frameworks for Cryogenic Helium-Based Gas Gap Heat Switches via High-Throughput Computational Screening.

With the advantages of a long lifetime and high reliability, gas gap heat switches (GGHSs) are attractive in many thermal management applications, especially in space-borne cryogenic systems. The performance of a GGHS is significantly affected by the adsorption characteristics of the adsorbent in the sorption pump. Compared with the commonly used adsorbent in the GGHSs (activated carbon), metal-organic frameworks (MOFs) have larger surface areas, higher pore volumes, and exceptional tunability, which motivates this study to explore their potential for application in cryogenic GGHSs. To this end, two performance metrics, the required volume of adsorbent (vsor) and total input heat (qtot), were computed for about 6000 MOFs via molecular simulations and compared with those of activated carbon. It is found that over 2300 MOFs possess a smaller vsor than activated carbon, and the smallest vsor of MOFs is about 12.7% of that of activated carbon. vsor and qtot generally change in the same direction, which implies it is possible to reduce both parameters simultaneously by choosing a suitable MOF. Structure-performance analysis reveals that 1/vsor consistently increases first and then decreases with pore limiting diameter, largest cavity diameter, available pore volume, accessible surface area, helium void fraction, and bulk density. Descriptor ranges corresponding to high-performing MOFs were identified based on Precision-Recall analysis. Notably, Zr-containing MOFs are particularly likely to have smaller vsor values than activated carbon. It is anticipated that the promising MOFs identified by this study will motivate further experimental investigations, and the insights into structure-performance relationships can serve to guide the rational design of novel MOF candidates for GGHSs.

A novel subset assignment and matching method for DIC measurement of complex deformation in aircraft braking process

This paper proposes a measurement method related to the braking deformation of a complex motion. During the braking process, the deformation of the wheel includes large amounts of movement, vibration, warping, and distortion. A novel subset assignment and correlation method is proposed to measure the complex deformation. The proposed method can greatly improve the accuracy and stability of the calculation of complex deformations by simplifying the complex deformation into translational deformations in logarithmic coordinate system. According to the simulation and actual experiments, the proposed method can be utilized to measure the deformations of up to 100% tensile strain under complex deformation. According to the accuracy verification experiment, the error of the proposed method is less than 50 με. The results show that the proposed method can effectively carry out structural deformation measurement in the complex motion and deformation process. The proposed method has great significance for structural performance analysis and optimization design considering complex motion and deformation.

Hydraulic fracturing simulation of concrete dam integrating intelligent crack detection and refined modeling methods

Concrete dams are prone to cracks during construction and operation process. Cracks on the upstream surface may induce the risk of hydraulic fracturing, thereby significantly reducing the safety of dam structure. Nevertheless, image processing technology, non-destructive testing technology and structural performance analysis technology with cracks are in a relatively independent state, leading to difficulties in analysis of actual cracks combined with numerical simulations. This paper proposes a novel approach for combination of intelligent identification technology and refined finite element method (FEM) for modeling and simulating the hydraulic fracturing resistance of the actual crack in concrete dams. With image processing technology and non-destructive testing technology, direction and depth of actual cracks are identified and extracted, then the 3D geometric model of actual cracks is generated. The refined model with the identified actual crack is constructed by the node projection strategy. This approach is used to assess the hydraulic fracturing resistance of the concrete dam with actual cracks in the alpine region. The results demonstrate that the critical crack depth of hydraulic fracturing is 12.93 m, and the opening width is 1.01 mm, which is 2.53 times the limit value for Class D cracks in the code (DL/T5251–2010). The refined modelling method based on actual crack detected on site can accurately evaluate the crack state compared to the conservative code.

Cycle Tests and Structure Repair of Bridge Pier Models

This research was conducted in anticipation of the risk of fatal damage to the structure due to the earthquake. In this study, experiments were carried out on the test object in the form of a bridge pillar model, which consisted of 2 test steps. The cyclic test is in the form of a pier bridge model and is continued in step 2 in the form of repairs with grouting and carbon wrapping materials as well as conducting another cyclic test to evaluate the performance of the repair materials used. This study uses the pier model, which consists of two test objects, namely a column with dimensions of 0.25x0.25x1.68 meters and a column cap of 1.20x0.55x0.36 meters. This test provides a constant axial load of 0.2 fc’.Ag and a cyclic lateral load. Phase 1 testing was carried out until the drift ratio was 3.5%. The achieved lateral peak strength is 8,606 tonf with a drift ratio of 2.20%. Lateral strength experienced a decrease in peak lateral strength of 86.93%. The damage is dominated by shear cracks which are characterized by the number of cracks with a diagonal pattern. Structural performance analysis was carried out according to ACI 374.1-05. The results of the theoretical analysis of the peak strength of the pier model were 15.2144 tonnes in the tensile direction, while the experimental ones were 8.606 in the pushing direction and -7.812 in the pulling direction.

Multi-objective structure optimization and performance analysis of catalytic micro-reactor channel designed by an improved topology optimization model

Previous micro-reactor channel studies mainly focus on the limited design space or structure layout, rarely exploits design forms in which the procedural topology structure evolves freely. Therefore, a multi-objective topology optimization model are proposed for the inverse free evolution of micro-reactor channels, which can synergistically balance the effects among three objectives of reaction rate, flow loss and heat transfer to achieve optimal comprehensive performance. The topology optimization problem is formulated based on the material density-based design variable. The fluid dynamics response of design variables at each optimization iteration is updated by solving multi-physics governing equations, objective functions and variable constraints. Adjoint-based sensitivity analysis and GCMMA algorithm are used to obtain the gradient information of objective functions and update design variables, respectively. Additionally, the strict volume constraints and proposed pseudo-design-domain concept are introduced into the multi-objective function. In numerical examples, the influence of different Re conditions and different multi-objective weight-ratios on optimal designs is investigated, and their regular evolution mechanisms and the trade-off between performance optimization and structure evolution are analyzed. Then, the optimization principles for topology structure and performance parameters under the control of multi-objective functions are revealed. Finally, the comprehensive performance of micro-reactors under topology optimization method is compared with that of traditional micro-reactors to demonstrate the effectiveness of the improved method and reveal the physical mechanisms of multi-objective performance enhancement. The comparison results show that topology optimization designs can achieve 86.1% growth in reaction rate and 47.1% reduction in flow loss, and comprehensive performance coefficients have also been significantly optimized.

Study on the impact of soil environment organic substances on the ageing of urban PE gas pipes in service

PurposeThe service environment of urban polyethylene (PE) pipes has a crucial influence on their long-term safety and performance. Based on the application and structural performance analysis of PE pipe failure cases, this study aims to investigate the impact of organic substances in the soil on the aging behavior of PE pipes by designing organic solutions with different concentrations, which are based on the composition of organic substances in the soil environment, and periodic immersion tests.Design/methodology/approachSoil samples in the vicinity of the failed pipes were analyzed by gas chromatography-mass spectrometry, sensitive organic substances were screened and soaking solutions of different concentrations were designed. After the soaking test, the PE pipe samples were analyzed using differential scanning calorimetry, Fourier-transform infrared spectroscopy and other testing methods.FindingsThe performance difference between the outer surface and the middle of the cross section of PE pipes highlights the influence of the soil service environment on their aging. Different organic solutions can have varying impacts on the aging behavior of PE pipes when immersed. For instance, when exposed to amine organic solutions, PE pipes may have an increased weight and decreased material yield strength, although there is no reduction in their thermal or oxygen stability. On the contrary, when subjected to ether organic solutions, the surface of PE pipe specimens may be affected, leading to a reduction in material fracture elongation and a decrease in their thermal and oxygen stability. Furthermore, immersion in either amine or ether organic solutions may result in the production of hydroxyl and other aging groups on the surface of the material.Originality/valueUnderstanding the potential impact of organic substances in the soil environment on the aging of PE pipe ensures the long-term performance and safety of urban PE pipe. This research approach will provide valuable insights into improving the durability and reliability of urban PE pipes in soil environments.

Comparative analysis of structure performance of PDC cutter tooth surface and interface matching pair

Comparative analysis of structure performance of PDC cutter tooth surface and interface matching pair

Gasoline Engine Inlet Structure Design and Performance Analysis

By creating a three-dimensional model of the intake pipeline, using AVL software to mesh and virtual simulation experiments, using the control variable method, changing the temperature conditions and pressure conditions one by one to observe the flow of the air pipe and the cylinder, and observing the numerical changes of the flow direction coefficient and tumbling flow ratio, the best solution was found. Through the virtual simulation experiment of the 3D model, the influence of external factors such as temperature and pressure on the air flow in the cylinder is obtained. The relationship between the characteristic parameters of the air intake tract was found through AVL numerical simulation, and the established three-dimensional model could accurately obtain the data after testing, which provided theoretical proof for the subsequent optimization scheme. The experimental results show that the tumbling flow ratio is increased as much as possible without changing the flow coefficient and the fuel economy of the engine is improved. But it also affects the flow coefficient, making it go down. Temperature has little effect on the flow in the cylinder. The flow velocity in the cylinder changes significantly under different pressures, and the area of the vortex area increases.

Analysis on the Dynamic Behavior of Space Shafting under Combined Load

The space shafting is the core component of the momentum exchange attitude control actuator for spacecraft.The dynamic behavior of space shafting has an important impact on the performance of the actuators. Based on the dynamic theory of rolling bearing, this paper presents a dynamic analysis model of space shafting for the interaction between bearing balls and oil-containing nonmetallic cage under combined loads. Also, the accuracy of the analysis model was verified through a high-speed camera system to conduct a cage speed test. In addition, the dynamic behavior of balls and cage under combined loads and the interaction between them is also analysed. The results show that the axial displacements of balls fluctuate periodically under combined loads, and the rotation speeds of balls and cage are easily affected by the load, presenting as the oscillation of speed. Also, the force between balls and cage increases as the load increases. The dynamic behavior of balls and cage could be effectively improved by avoiding excessive torque loads and limiting the axial preload to 40 N. The wear failure caused by unstable operation of bearings cannot be ignored. This model is more practical in completing simulation analysis of different operating conditions and structural parameters of the shafting system. It provides a theoretical reference for the structural design and performance analysis of space shafting.

Insight into melting point differences of dinitroimidazoles and dinitropyrazoles from the perspective of intermolecular interactions.

Dinitroimidazole (DNI) and dinitropyrazole (DNP), along with their congeners, possess similar molecular structures but exhibit distinct melting points. To analyse and elucidate the fundamental reasons for property differences from the perspective of intermolecular interactions, we proposed a simplified approach named binding energy in clusters (BEC) in computing weak interactions within complex crystal systems. Based on the results of the symmetry-adapted perturbation theory (SAPT) calculations, an approximate estimation of the melting point range can be derived by taking into account the cumulative effect (energy of electrostatic, dispersion and induction terms) and repulsive effect (energy of exchange term) values. We have also proposed a formula for calculating the specific melting point, which indicates that stronger intermolecular interactions have a major impact on the melting point, while the distribution of weak interactions also affects the melting point. This work would provide an effective reference for molecular design and structure-performance analysis.

Mechanical structure design and performance analysis of heat storage working medium for heat insulation layer

In order to solve the problems of low temperature inside the greenhouse caused by continuous haze weather or cloudy, rainy, and snowy weather, as well as the large heat dissipation capacity and insufficient cross time heat storage of existing solar greenhouses, by optimizing the design of the external insulation materials and structure of the heat storage water tank and studying the combination of heat storage working fluids, the greenhouse heat storage device has achieved cross time heat storage and segmented slow release heat release. The experiment shows that the combined heat insulation effect of heat insulation coating + aerogel + rubber and plastic insulation cotton is better, its 24-hour heat dissipation is reduced by 0.367 MJ compared to a single insulation material. The heat preservation material of the tank is 80~120 mm, and the cylinder heat storage tank is 6~10 m3 and 1:1. Which cannot only ensure a low effective heat dissipation rate, but also control engineering. The results show that the composite phase change material can increase the heat storage capacity, optimize the exothermic process, and achieve the gradual release of heat.

Analysis of Structural, Photoluminescence, and Colorimetric Performance of Gd-Incorporated BNT Ceramic.

Structural, optical, photoluminescence and colorimetric analyses of Gd (1-5mol %) doped BNT ceramics synthesized by the solid-state reaction technique are reported. Structural analyses of all the samples are done by the X-ray diffraction method. It is shown that the samples have rhombohedral crystal structures with an R3C space group. The energy band gap of all the phosphors is computed from the UV-visible absorbance spectra. Photoluminescence behaviors are analyzed from the excitation along with the emission spectra of the prepared materials. The critical quenching concentration with the critical energy transfer distance is observed owing to the dipole-dipole interactions between the materials. Colorimetric analyses are carried out with the help of CIE chromaticity. Moreover, the color purity, correlated color temperature, color rendering index, and luminous efficiency of radiation values are evaluated by using the chromaticity coordinates.

Exploring the Electrochemical Properties of Ultrathin LiMn1.5Ni0.5O4 Films at High and Low Current Rates for Lithium-Ion Micro Battery Applications

The development in the miniaturized - smart electric and electronic gadgets with the advancement in technologies has dramatically enhanced the demand for cobalt free-high energy density batteries. Among various choice of high-performance cathode materials Ni substituted LiMn2O4 spinel of composition LiMn1.5Ni0.5O4 (LMNO) has proved to be one of the solutions to yield a high-performance high-energy density battery which can operate at a higher potential window. Ultra - thin films of LMNO fabricated by Pulsed laser deposition method at 600 °C substrate temperature using 2000 pulses. LMNO films fabricated on SrTiO3 (STO) and stainless steel (SS) substrates are employed for a detailed structural and electrochemical performance analysis. Disordered phase corresponding to fd3m space group of LMNO thin film exhibits better electrochemical performance compared to the ordered phase. Phase formation of LMNO thin films are studied employing X-ray diffraction and Raman spectroscopy methods. The morphology obtained for the film of thickness 41.63 nm identified from the scanning electron microscopy (SEM) images clearly reveals the effect of growth conditions such as substrate temperature and base pressure on the growth behavior of these films. Since the electrochemical data obtained for the films are area limited, the capacity of the ultra-thin film is significantly low and can be ameliorate by controlling the area. Kinetic study of LMNO film reveals that the lithium diffusion during the charge storage mechanism resembles to a diffusion-limited process similar to a faradic process. The cycling stability and rate capability at different current densities of LMNO thin film electrodes are further investigated. Charge discharge profile for both higher (25, 50, 75, 100 and 125 mA) and lower (5, 10, 15, 20, and 25 mA) current densities are obtained and subjected for 500 cycles. The thin film electrode shows a stable profile for 500 cycles. Areal discharge capacity of 1.3 μAh/cm2 is observed at a higher current density while at lower current density an areal discharge capacity obtained is 2.13 μAh/cm2 with a coulombic efficiency of around 80% and 96% respectively. Electrochemical impedance spectroscopy studies carried out on LMNO films before and after cycle shows a strong contribution of charge-transfer resistance along with film resistance and solution resistance and the equivalent circuit model for the same is evolved. Present studies indicates that LMNO ultra-thin films can be employed as a cathode layer for fabricating the all-solid thin film micro-batteries for energy applications. Figure 1

Repair of Pier Bridge Model Post-Earthquake

This study concentrates on the bridge pier model which was damaged by the earthquake and repaired using grouting and carbon wrapping materials. This research consists of a one pier bridge model with two steps of testing, namely step 1 in the form of a cyclic test of the pier bridge model which will be followed by step 2 in the form of structural repairs with grouting and carbon wrapping materials and retesting. to evaluate the performance of the structural repair technology used. This research will show the cyclic test results using the repair material applied to the same sbr latex concrete material test object. The test object used is a pier bridge model with dimensions of 0.25×0.25×1.68 meters. The material specifications used are concrete f'c 30, fy 400 MPa deformed longitudinal reinforcement and stirrups fy 240 MPa. The test was carried out with a constant axial load of 0.2.f'c.Ag and a cyclic lateral load. Structural performance analysis was carried out according to ACI 374.1-05. Step 1 cyclic test was carried out until the drift ratio was 3.5%. The lateral peak strength achieved was 8.606 tonf with indications of shear damage indicated by the number of cracks in the web area. The second step of the cyclic test was carried out to a drift ratio of 6.25% with a lateral peak strength of 8.640 tonf with indications of flexural damage. Cyclic test results show that repair with a grouting material and carbon wrap can restore peak strength, deformation capacity, and stiffness degradation.

Effects of module-to-module connection rotational stiffness on the structural performance of high-rise steel modular buildings

With advantages including high productivity and sustainability, modular construction has attracted increasing interest in building project developments. As modular buildings are stepping higher, the modular systems should be better designed to ensure structural safety. In such systems, different types of connections, such as module-to-module (M2M) connections, play an important role in the loading transfer. However, the investigation into the rotational stiffness of the M2M connection was still insufficient in the literature. This paper aims to examine the effects of M2M connection rotational stiffness on the structural performance of high-rise steel modular buildings. A theoretical analysis was conducted on a hypothetic three-storey three-span steel frame to simplistically demonstrate the significant effect of connection rotational stiffness on the internal force distribution of modular buildings. To assess the applicability of preliminary findings in real-life high-rise steel modular buildings, validated numerical models were employed to determine the rotational stiffness of a newly proposed innovative and practical M2M connection. Subsequently, structural models of a 40-storey steel modular building with different M2M connection rotational stiffness values were established to conduct comprehensive investigations. The analysis results indicated that the rotational stiffness of M2M connections plays a critical role in determining the behaviours of critical structural members. The findings provide important references for the design of M2M connection stiffness and structural performance analysis of high-rise steel modular buildings.

Novel YAGG: Cr garnet phosphor ceramic with broadband near infrared (NIR) emission and luminescence thermal stability for plant growth

In recent years, NIR (Near-Infrared) phosphor-converted LEDs (pc-LEDs) have played an indispensable role in the field of plant lighting. This study presents the development of a novel garnet-based phosphor ceramic, YAGG:0.035Cr3+, obtained through a high-temperature solid-state method. Through optical and structural performance analysis, it was found that the sample can be effectively excited by a commercial 450 nm blue LED, emitting near-infrared light in the range of 650–850 nm. This emission spectrum overlaps with approximately 74% of PFR spectrum absorbed by plant growth, and it achieves QY of around 40%. Notably, this ceramic demonstrates excellent thermal luminescence properties, maintaining approximately 96% of its integrated emission intensity at 423 K compared to room temperature. To explain this outstanding thermal performance, we analyzed that the gradual substitution of the 4T2 level for the 2E level leads to the dominance of the 4T2-4A2 transition process in PL. Furthermore, the YAGG:0.035Cr3+ phosphor ceramic was packaged with a 450 nm LED, and the emitted light intensity exhibited a linear relationship with the driving current. Even under high-power driving conditions of 1000 mA, the luminescence did not reach saturation. These results effectively demonstrate the potential application of YAGG:0.035Cr3+ phosphor ceramic in the field of plant lighting.