Three-dimensional Frame Structure Research Articles

A three-dimensional rubber-steel phononic crystal for broad and low-frequency vibration attenuation

Elastic metamaterials and phononic crystals have the potential for vibration isolation applications due to wave band gaps where elastic waves cannot propagate. However, their real-life application may be compromised by the narrow band gaps of the former and the high frequencies of the latter. In the current study, we present a three-dimensional frame structure made of steel and rubber elements that presents a wide complete band bag at low frequency. The structure provides extreme vibration isolation because it combines band gaps with high impedance mismatch between steel and rubber damping. The manufacturing process of the proposed frame structure is widely used in mounting pads, and its cost is relatively low. It provides reasonable structural strength, which makes its application in real life possible. The dynamic behavior predicted with spectral and finite element models is validated with experimental results.

Synergistically Boosting Li Storage Performance of MnWO4 Nanorods Anode via Carbon Coating and Additives

Polyanionic structures, (MO4)n−, can be beneficial to the transport of lithium ions by virtue of the open three-dimensional frame structure. However, an unstable interface suppresses the life of the (MO4)n−-based anode. In this study, MnWO4@C nanorods with dense nanocavities have been synthesized through a hydrothermal route, followed by a chemical deposition method. As a result, the MnWO4@C anode exhibits better cycle and rate performance than MnWO4 as a Li-ion battery; the capacity is maintained at 718 mAh g−1 at 1000 mA g−1 after 400 cycles because the transport of lithium ions and the contribution of pseudo-capacitance are increased. Generally, benefiting from the carbon shell and electrolyte additive (e.g., FEC), the cycle performance of the MnWO4@C electrode is also effectively improved for lithium storage.

High-energy bimetallic substituted Na3V2(PO4)3 cathode for advanced sodium-ion batteries

NASICON-type cathodes have attracted great attention due to their open three-dimensional (3D) frame structure and excellent ion transport properties. Accordingly, how to improve the stability and energy density of materials is a hot topic of research. In this study, the significant effects of aluminum-zirconium bimetallic substitution on electrode kinetics and structural stability are reported. The designed Na2.9V1.8Al0.1Zr0.1(PO4)3 cathode exhibits a highly reversible capacity of 107 mAh g-1 at 1C and decent cyclic stability (75 mAh g-1 capacity after 2000 cycles at 20C). These excellent electrochemical properties can be attributed to expanding the lattice structure and activating part of V4+, which facilitates the migration of Na+ and increases the reversible capacity. The cyclic voltammetry, electrochemical impedance spectra and galvanostatic intermittent titration technique tests analyze the diffusion kinetics of sodium ions and confirm the desired sodium ion diffusion coefficients (DNa+). In situ X-ray diffraction reveals reversible structural changes during the electrochemical reaction, which confirms that the bimetallic doping strategy slows down material volume change. This work provides a new perspective for the construction of high-performance NASICON cathode materials.

Component tests and numerical simulations of 3D steel frame structures for progressive collapse

This paper presents a comprehensive study on three-dimensional steel frame structures subjected to progressive collapse, drawing insights from a full-scale steel frame substructure test. The investigation encompasses connection component tests and numerical simulations, focusing on extended end plate and double-angle cleat connections employed in the substructure test. The mechanical properties of the connection components were tested, forming a basis for defining component properties in subsequent connection models. Finite element (FE) models of the test substructure were developed, utilizing hybrid elements for the steel frame part, which include beam, connector, and spring elements based on the component method. To simulate reinforced concrete slabs, a combination of refined solid elements and simplified shell elements was employed. The former accurately captures detailed failure modes, while the latter efficiently simulates the collapse behavior of large-scale steel frame structures. Validation of the established models against test results encompassed load-displacement responses, internal forces in structural members, and failure modes. The validated FE models were then utilized to analyze and discuss the contributions of various structural components in resisting progressive collapse. Specific focus was placed on the development of load-resisting mechanisms in the floor slab and the influence of beam-column connection types on structural behavior. The paper explores the role of bracing systems in a building in resisting progressive collapse. Additionally, it evaluates the effectiveness of the restraint systems used in the test, shedding light on their ability to accurately reflect real restraint effects from the surrounding structure. The findings presented herein contribute valuable insights to the understanding of progressive collapse behavior in steel frame structures, with implications for robustness design of multi-story steel buildings.

Unraveling the modified mechanism of ruthenium substitution on Na3V2(PO4)3 with superior rate capability and ultralong cyclic performance

Na3V2(PO4)3(NVP) is an ideal cathode material for sodium ion battery due to its stable three-dimensional frame structure and high operating voltage. However, the low intrinsic conductivity and serious structural collapse limit its further application. In this work, a simultaneous optimized Na3V1.96Ru0.04(PO4)3/C@CNTs cathode material is synthesized by a simple sol–gel method. Specifically, the ionic radius of Ru3+ is slightly larger than that of V3+ (0.68 Å vs 0.64 Å), which not only ensures the feasibility of Ru3+ replacing V3+ site, but also appropriately expands the migration channel of sodium ions in NVP and stabilizes the structure, effectively improving the diffusion efficiency of sodium ions. Moreover, CNTs construct a three-dimensional conductive network between the grains, reducing the impedance at the interface and effectively improving the electronic conductivity. Ex-situ XRD analysis at different SOC were performed to determine the change in the crystal structure of Ru3+doped Na3V2(PO4)3, and the refinement results simultaneously demonstrate the relatively low volume shrinkage value of less than 3 % during the de-intercalation process, further verifying the stabilized crystal construction after Ru3+ substitution. Furthermore, the ex-situ XRD/SEM/CV/EIS after cycling indicate the significantly improved kinetic characteristics and enhanced structural stability. Notably, the modified Na3V1.96Ru0.04(PO4)3/C@CNTs reveals superior rate capability and ultralong cyclic performance. It submits high capacities of 82.3/80.9 mAh g−1 at 80/120C and maintains 71.3/59.6 mAh g−1 after 14800/6250 cycles, indicating excellent retention ratios of 86.6 % and 73.6 %, respectively. This work provides a multi-modification strategy for the realization of high-performance cathode materials, which can be widely applied in the optimization of various materials.

Experimental Study on 3D RC Frame Structures with VE Energy Dissipation Braces Using STM32-Matlab-OpenSees Hybrid Test Platform

This study aims to reveal the control mechanism of viscoelastic (VE) energy dissipation braces with strong mechanical nonlinear characteristics on the seismic response of reinforced concrete (RC) frame structures. Firstly, a new STM32-Matlab-OpenSees joint hybrid test platform is developed by introducing OpenSees, which is convenient for structural modeling and fast for structural calculation. The overall architecture and operation of the hybrid test platform are comprehensively analyzed. Then, a series of simulated seismic hybrid tests on three-dimensional (3D) RC frame structures with VE energy dissipation braces under different seismic waves are successfully carried out. Lastly, the hybrid test results of this structure system at different working conditions are compared and analyzed comprehensively. The research results show that the developed platform breaks the boundary limitation that OpenSees relies on the framework software OpenFresco and can only be connected to specific control systems in the hybrid test. Thus, it greatly expands the application scope of flexible configuration controller and actuator categories for the hybrid test platform, and it also provides a good reference value for the establishment and implementation of similar hybrid test platforms. Under the action of various seismic waves, VE energy dissipation braces has good universality for the shock absorption of RC frame structures. The damping control effect and energy dissipation efficiency of VE energy dissipation braces are significantly different under various seismic waves. In the design of RC frame structures with VE energy dispersion braces, it is very necessary to conduct the seismic analysis of the structures under multiple ground motions with wide frequency domain. The additional position of VE energy dissipation braces should be an important analysis indicators in the optimization design of the structures.

Porous freestanding FeCoMnNiSe2 medium-entropy bifunctional electrocatalyst for oxygen and hydrogen evolution reactions in alkaline medium

Efficient bifunctional electrocatalysts towards oxygen and hydrogen evolution reactions (OER/HER) in water splitting is highly desirable for fuel cells and sustainable energy storage. Herein, one novel three-dimensional medium-entropy freestanding flower-like OER/HER bifunctional FeCoMnNi diselenide (FeCoMnNiSe2) electrocatalyst is fabricated by a facile hydrothermal and selenizing method. Benefiting from three-dimensional porous frame structure, lattice distortion and synergy effects, the as-prepared FeCoMnNiSe2 presents superior OER/HER bifunctional electrocatalytic activities with the quite low overpotentials of 223.1 mV for OER and 142.2 mV for HER at 100 mA cm−2 in 1.0 M KOH. More impressively, when employed for water splitting in a full cell, this bifunctional FeCoMnNiSe2 only requires ca. 1.42 V to drive the current densities of 100 mA cm−2 and displays outstanding stability for more than 60 h in 1.0 M KOH at 10, 50, 80 and 100 mA cm−2, surpassing almost all of reported advanced non-noble metal-containing OER/HER bifunctional electrocatalysts, and showing a promising potential application for industrial-scale water splitting.

Magnetic/conductive biochar frames derived from Fe3O4-coated loofah sponges for green electromagnetic interference shielding application

Several biochar frame electromagnetic interference shielding composites have been developed; however, integrating high shielding effectiveness (SE) and low reflection coefficient ([Formula: see text]) into biochar frames with excellent electrical conductivity have proven to be a great challenge. Herein, because of the abundant groups on the surface of the intricate fibers of the loofah sponge, it absorbed many iron ions, which can form a Fe3O4 coating when they react with hydroxyl groups. After carbonization, the Fe3O4 coating still tightly held the carbonized fibers in a porous structure, forming a biochar frame with consecutive magnetic/conductive interfaces. Furthermore, the incorporation of a Fe3O4 coating did not negatively affect the electrical conductivity of the composites obtained ([Formula: see text]21 S/m) but instead endowed the composites with good magnetic properties. The resultant composites had an SE, specific SE, [Formula: see text] and green index ([Formula: see text]) of 47.2 dB, 363 dB/cm, 0.089, and 10.2, respectively, which were better than those of previously reported biochar-based shielding materials. The synergistic effect of the three-dimensional carbon frame, magnetic coating, and porous structure is responsible for excellent green shielding abilities.

Research on a hierarchical feature-based contour extraction method for spatial complex truss-like structures in aerial images

Spatial truss-like structures are three-dimensional frame structures consisting of a series of linear members and nodes, which are widely used in the power engineering. UAVs and various land-air robots are widely used in power inspection to reduce the reliance on manual labor. Extracting the contours of such objects (represented in the form of points and line segments) in aerial images will further improve the efficiency of power inspections. Because existing methods struggle to deal with the complex background interference in aerial images, an innovative contour extraction method based on hierarchical features is proposed in this paper, which uses two artificial neural networks to extract image-wise features and patch-wise features respectively and link them with patch division. The IoU of the method can reach 83.4%, which is improved by 5.4% and 50.8% compared to the lightweight semantic segmentation network and HED-based method, respectively. Meanwhile the Polygons and line segments measurement (PoLis) outperforms the other four types of methods compared with it by at least 39.1%, which overcomes the drawbacks of the other methods that have poor contour extraction ability in complex backgrounds and aerial images with numerous feature. Meanwhile, the running time of this method is 85 ms. The proposed method overcomes the shortcomings of existing contour extraction methods, improves the effect of contour extraction in complex backgrounds in power inspection scenarios, facilitating the improvement of the intelligence level of inspection robots, which in turn promotes the automation level in power engineering.

Unique electromagnetic wave absorber for three-dimensional framework engineering with copious heterostructures

In order to obtain high-performance electromagnetic wave absorbers, the adjustment of structure and components is essential. Based on the above requirements, this system forms a three-dimensional frame structure consisting of MXene and transition metal oxides (TMOs) through efficient electrostatic self-assembly. This three-dimensional network structure has rich heterojunction structures, which can cause a large amount of interface polarization and conduction losses in incident electromagnetic waves. Hollow structures cause multiple reflections and scattering of electromagnetic waves, which is also an important reason for further increasing electromagnetic wave losses. When the doping ratio is 1:1, the system has the best impedance matching, the maximum effective absorption bandwidth (EABmax) can reach 5.12 GHz at 1.7 mm, and the minimum reflection loss (RLmin) is -50.30 dB at 1.8 mm. This provides a reference for the subsequent formation of 2D-MXene materials into 3D materials.

Hg3(SeO3)2(SO4): A UV Nonlinear Optical Mercury Selenite Sulfate Constructed by Neat [Hg6O8(SeO3)4]∞ Layers and SO4 Tetrahedra.

A novel mercury selenite sulfate named Hg3(SeO3)2(SO4) has been successfully synthesized under a mild hydrothermal method. Hg3(SeO3)2(SO4) crystallizes in a monoclinic space group P21 and features a unique three-dimensional (3D) frame structure formed by [Hg6O8(SeO3)4]∞ layers and SO4 tetrahedra, which enables it to exhibit a comprehensive performance of a moderate second-harmonic generation (SHG) response of approximately 1.3 times that of baseline KH2PO4 (KDP), a moderate birefringence (0.118@546 nm), and a wide band gap (4.70 eV), which indicates that it has potential for application as an ultraviolet (UV) nonlinear optical material. Detailed theoretical calculations show that the Hg2+-based polyhedra with large polarizability and deformability and the SeO3 groups with stereochemically active lone pair (SCALP) electrons are the main contributors to moderate optical properties.

Development of rocking constraint device with vertical damping capacity for three-dimensional base-isolated frame structures

Development of rocking constraint device with vertical damping capacity for three-dimensional base-isolated frame structures

Shape stabilized three-dimensional porous SiC-based phase change materials for thermal management of electronic components

As electronic components get smaller and more powerful, effective thermal management is needed to address the problem of more heat accumulation due to increased power density. Phase change materials (PCM) have shown great potential in thermal management within confined spaces, but the low thermal conductivity of PCM, and low enthalpy and electrical resistance of composite PCM (CPCM) significantly limit its application in electronic systems. Herein, porous silicon carbide felt (SiC) with stable shape was prepared by using commercial carbon fiber felt (CF) as carbon source. CPCM was prepared by using a multi-layer porous network structure composed of silicon carbide nanowires and silicon carbide fibers as a three-dimensional frame structure to seal paraffin (PA), which improved the thermal conductivity and electrical resistivity of the PCM. The PA/S1 based on porous SiC skeleton has high thermal conductivity (0.794 W·(m·K)−1), high enthalpy (231.4 J·g−1), high energy storage efficiency (89.81%) and high electrical resistivity (2.05 × 106 Ω·cm), as well as good shape stability and acceptable thermal performance. As a kind of thermal management material, CPCM shows excellent heat storage performance and temperature resistance effect, which enlarges the time of the heating element in reaching its peak temperature by five times. Therefore, the CPCM has enormous potential in thermal management of electronic products.

Research on Improved MOF Materials Modified by Functional Groups for Purification of Water.

With the rapid development of urbanization and industrialization, water contamination has gradually become a big problem. Relevant studies show that adsorption is an efficient strategy to treat pollutants in water. MOFs are a class of porous materials with a three-dimensional frame structure shaped by the self-assembly of metal centers and organic ligands. Because of its unique performance advantages, it has become a promising adsorbent. At present, single MOFs cannot meet the needs, but the introduction of familiar functional groups on MOFs can promote the adsorption performance of MOFs on the target. In this review, the main advantages, adsorption mechanism, and specific applications of various functional MOF adsorbents for pollutants in water are reviewed. At the end of the article, we summarize and discuss the future development direction.

Preparation of Hexagonal Boron Nitride-Containing Foam with Improved Thermal Conductivity of Epoxy Resins

With the continuous development of electrical and electronic devices, the thermal conductivity of dielectric polymer composites within devices is becoming increasingly important. However, improving the thermal conductivity usually requires the incorporation of a large amount of filler in polymer material, which undoubtedly increases the production cost while destroying the processability and the dielectric properties of the material. In this work, an efficient heat transfer network was constructed inside the resin matrix to overcome this drawback. Using the opposite surface potentials of hexagonal boron nitride (h-BN) and polyethyleneimine (PEI) in solvent, h-BN was anchored on the surface of melamine foam (MF) by an electrostatic self-assembly technique to construct a thermal conductive skeleton with a three-dimensional open pore structure, and the corresponding epoxy (EP) composite was prepared by vacuum-assisted impregnation. This EP–MF@BN composite showed a significant increase in the heat arrival rate at an extremely low filler loading. At a h-BN loading of 2.1 wt %, the thermal conductivity of the composite reached 0.433 W/(m·K), which was 147% higher than that of the pure resin matrix. This is mainly attributed to the unique three-dimensional open-hole structure of the MF foam, which formed a three-dimensional frame structure with extremely low thermal resistance after anchoring by h-BN, thus providing a great degree of weakening of the scattering behavior during phonon transport. In addition, the transport behavior of carriers inside the composite under strong electric field conditions was analyzed in the current study. This strategy of constructing an efficient heat transfer network inside the polymer matrix provides an idea and method for the preparation of composites in the field of electrical insulation.

МЕТОДИЧЕСКИЕ АСПЕКТЫ ПРИМЕНЕНИЯ ЧИСЛЕННОГО ПРОЧНОСТНОГО АНАЛИЗА СИЛОВОГО КАРКАСА КВАДРОЦИКЛА

The design of an ATV structure is a complex engineering task, where the development of a load-bearing frame is one of the priorities, which requires a systematic methodology. Purely analytical approaches to calculations, the results of which can be used in the development of a threedimensional tubular frame structure, are now becoming a thing of the past, since the assumptions used in analytical methods give a significant calculation error, which makes it possible to obtain only a very approximate picture of the distribution of stresses and resulting deformations of the structure. It is also necessary to take into account that modern design technologies provide for the simultaneous use of various profiles of not only round, but also more complex sections, which should provide the necessary functionality of different sections of the frame (while providing a sufficiently large number of structural requirements for it), but significantly complicates the calculation procedures. With such input data, preliminary virtual electronic simulation of real products in combination with subsequent numerical engineering analysis is optimal and allows taking into account various design and technological nuances. Such software systems as CATIA related to PLM-systems (PLM – English product lifecycle management system) make it possible to perform both product modeling and, in fact, a series of numerical experiments within a single interactive environment. In the conditions of real design at the production facilities, such works are methodologically undeveloped and innovative. The purpose of the article is to consider approaches to optimizing the design of the power frame of an ATV using software computer engineering analysis tools and a previously created electronic geometric model of an ATV. In particular, the issues of preparing a model for subsequent finite element partitioning, evaluating the results of a numerical study in relation to evaluating the performance of the designed power frame of an ATV under the conditions of using the component base of previously developed power frames of motorcycles and buggies are touched upon.

Parametric analyses of dynamic interaction between three-dimensional soil and frame structure group under earthquake loadings

Parametric analyses of dynamic interaction between three-dimensional soil and frame structure group under earthquake loadings

Design of Economical and Achievable Aluminum Carbon Composite Aerogel for Efficient Thermal Protection of Aerospace.

Insulation materials play an extremely important role in the thermal protection of aerospace vehicles. Here, aluminum carbon aerogels (AlCAs) are designed for the thermal protection of aerospace. Taking AlCA with a carbonization temperature of 800 °C (AlCA–800) as an example, scanning electron microscopy (SEM) images show an integrated three-dimensional porous frame structure in AlCA–800. In addition, the thermogravimetric test (TGA) reveals that the weight loss of AlCA–800 is only ca. 10%, confirming its desirable thermal stability. Moreover, the thermal conductivity of AlCA–800 ranges from 0.018 W m−1 K−1 to 0.041 W m−1 K−1, revealing an enormous potential for heat insulation applications. In addition, ANSYS numerical simulations are carried out on a composite structure to forecast the thermal protection ability of AlCA–800 acting as a thermal protection layer. The results uncover that the thermal protective performance of the AlCA–800 layer is outstanding, causing a 1185 K temperature drop of the structure surface that is exposed to a heat environment for ten minutes. Briefly, this work unveils a rational fabrication of the aluminum carbon composite aerogel and paves a new way for the efficient thermal protection materials of aerospace via the simple and economical design of the aluminum carbon aerogels under the guidance of ANSYS numerical simulation.

Investigation on the progressive collapse resistance of three-dimensional concrete frame structures reinforced by steel-FRP composite bar

Compared with conventional steel bars, steel-FRP (fiber reinforced polymer) composite bars (SFCBs) have distinctive post-yield stiffness, and the high efficiency of SFCBs in enhancing the progressive collapse resistance of concrete frames has been confirmed by recent quasi-static experimental studies on SFCB beam–column subassemblages. However, the realistic progressive collapse of structures is a dynamic process, and the three-dimensional (3D) effects are essentially important for determining the collapse response. In this study, numerical models are built to explore the progressive collapse behavior of 3D frame structures reinforced by SFCBs. The static and dynamic capacities of five SFCB frames and one reinforced concrete (RC) frame are compared under different column–removal cases. Results show that by virtue of the post-yield stiffness, the static load factors of SFCB frames are much larger than those of RC frames at the same deformation, proving that SFCB frames have better robustness against collapse failure than RC frames. After the dynamic removal of columns, all RC frames are subjected to progressive collapse failure, while SFCB frames can successfully complete the dynamic load redistributions and quickly reach a steady state. Further, the dynamic increase factor (DIF) of SFCB frames is proposed based on the ratio of maximum dynamic flexural responses to static flexural responses of beam joint sections under the same gravity loads (1.2 times dead load plus 0.5 times live load), and the conservative DIFs of 1.55 and 1.3 are recommended for a corner column–removal case and the other single column–removal cases, respectively. Finally, parametric analyses are conducted to reveal the effect of beam longitudinal reinforcement ratio, beam span-to-depth ratio, and dynamic duration for the column removal on the progressive collapse resistance of SFCB frames. The results lay a foundation for the progressive collapse design of 3D SFCB frame structures.

Incorporating Near-Pseudocapacitance Insertion Ni/Co-Based Hexacyanoferrate and Low-Cost Metallic Zn for Aqueous K-Ion Batteries.

The limited availability of cathode materials with high specific capacity and significant cycling stability for aqueous K-ion batteries (AKIBs) hinder their further development owing to the large radius of K+ (1.38 Å). Prussian blue and its analogs with a three-dimensional frame structure possessing special energy storage mechanism are promising candidates as cathode materials for AKIBs. In this study, K0.2 Ni0.68 Co0.77 Fe(CN)6 ⋅ 1.8H2 O (KNCHCF) was prepared as a cathode material for AKIBs. Both the electrochemical activity of Co ions and the near-pseudocapacitance intercalation of KNCHCF enhance K+ storage. Therefore, KNCHCF exhibits a superior capacity maintenance rate of 86 % after 1000 cycles at a high current density of 3.0 A g-1 . The storage mechanism of K+ in AKIBs was revealed through ex situ X-ray diffraction, ex situ Fourier transform infrared spectroscopy, and ex situ X-ray photoelectron spectroscopy measurements. Moreover, the assembled K-Zn hybrid battery showed good cycling stability with 93.1 % capacity maintenance at 0.1 A g-1 after 50 cycles and a high energy density of 96.81 W h kg-1 . Hence, KNCHCF may be a potential material for the development of AKIBs.