Structural Design Research Articles

The effect of surface profile and groove bottom profile on steady-state performance of dry gas seals

Purpose The purpose of this paper is to improve the film stiffness of a dry gas seal (DGS) through the proper design of 3D macroscopic surface structures based on numerical study. Design/methodology/approach A novel generalized three-dimensional (3D) geometric model is proposed to characterize macroscopic surface structures of a DGS, including grooves, waviness, radial taper and step. The mathematical model is established to simulate film pressure distribution. The effect of the surface profile and groove bottom profile on the steady-state performance of DGSs at different working conditions is investigated. Findings The unidirectional groove surface has the largest film stiffness at different speed conditions and the largest opening force at medium and high speed, whereas the annular groove has the largest opening force at static pressure. For obtaining the maximum film stiffness, unidirectional combined variable depth groove surface when ns = 0.4 and k = 0.5 outperforms the other unidirectional groove surfaces, whereas circumferential waviness when ns = 1 and k = 1 is the best choice among annular groove surfaces. Originality/value This study proposes a novel generalized 3D geometric model to characterize macroscopic surface structures of a DGS. The optimal groove bottom profile for different surface profiles of DGS is presented.

Anti-Seismic Performance Research of Complicated Nodes Involved in Ultra-Limited Steel Structures Subjected to Rare Occurrence Earthquakes

This study focuses on the seismic performance of complicated nodes in the ultra-limited steel structure under rare occurrence earthquakes. The Xi’an Urban Exhibition Center (Chang’an Cloud) is chosen as the engineering background, and the ANSYS (18.0) analysis software is employed. Based on the overall importance and the extent of post-damage impacts, the critical nodes are selected for structural design. The research aims to develop simplified and reliable structural forms that can withstand the most adverse conditions at both the overall nodes and local component levels. Stress distribution under the most unfavorable scenarios is calculated to achieve the seismic design objectives of the overall structure. The research results indicate that localized stress concentration areas can reach or exceed the yield strength of the steel, which enters the plastic phase. The Von Mises stresses in the remaining nodes are lower than the yield strength of the steel. The overall performance is excellent without significant plastic deformation. Thus, the design requirements for non-yielding performance under rare seismic events are met. The conclusions can provide reliable references for the critical structural techniques and seismic design of complicated nodes.

Optimization of Separation Parameters for a Pneumatic Separation Device for Plastic Evidence at Explosion Sites

AbstractExtracting and recovering plastic evidence at explosion sites is important for police investigations. Pneumatic separation is an efficient recovery method that is simple and environmentally friendly. To improve the accuracy of material separation, it is necessary to fully understand the influence of internal flow fields and structural design when using a material evidence classification device at explosion sites. In this study, a combination of a simulation and experiments is used. The results from the simulation are used to design a pneumatic separation device that is applied to explosive separation experiments. The grade and recovery rate of the plastic materials are excellent, which confirms the suitability of the device to classify plastic evidence at explosion sites.

Force Feedback Method for Statically Indeterminate Steel Structure Construction Based on Staged Temperature Measurement

Structural design usually adopts uniform temperature action. However, during the actual construction of the structure, the temperature field acting on the structure is inhomogeneous. Therefore, the simulation of the construction of statically indeterminate steel structures considering only the uniform temperature field cannot truly reflect the temperature action after structural molding and the evolution of the stress performance of the temporary stress system of structural construction. This paper proposes a force feedback method for the construction of statically indeterminate steel structures based on staged temperature measurements. In this method, the construction sequence and the measured temperature are taken into account, and the structural response under the action of temperature is obtained by using the first processing method in the matrix displacement method and the deformation coordination formula to obtain the deformation and stress values of the structure. The application results show that the structural forces calculated by the method proposed in this paper are closer to the measured data in the field, and the error is reduced by 10~40%. This paper provides a reference for the calculation of construction forces in statically indeterminate steel structures considering the effect of temperature inhomogeneity and provides a basis for construction safety assessment and schedule management.

Dynamics analysis of rotor in disc centrifuge for separation of bioengineering

In order to reveal the influence of gyroscope effect and structure parameters on the modal frequency and critical speed of the rotor system in disc centrifuge for separation of bioengineering. Based on the rotor rigid body dynamics, the fixed-point gyroscope motion of the rotating spindle of the disc centrifuge was analyzed. Establishing a finite element dynamic model for the rotor system of a disc centrifuge, taking into account the gyroscopic moment caused by the rotational inertia of the rotor disk and the elastic support of the bearings. We calculated the gyroscopic moment and the analytical expression of critical speed. Analyzing the quantitative relationship between the gyroscope effect, bearing support stiffness, drum material density and the critical speed of the rotor system. The results show that the calculated value of finite element is close to the measured value. The influence of gyroscopic force on the vibration characteristics of rotor system for dish centrifuge cannot be ignored. The critical speeds of the rotor system increase with the increase of elastic support stiffness, while the first critical speed decreases with the increase of drum density, but the second critical speed increases with the increase of drum density. These studies provide a theoretical reference for the dynamic response, structural design and dynamic balance of disc centrifuge.

3D simulation of Polar Bear Fur's thermal Insulation

Abstract Biomimicry, emulating nature's time-tested strategies, has emerged as a powerful tool for solving complex engineering challenges. Over millions of years of evolution, organisms have developed highly efficient systems for survival in extreme environments, offering solutions that often surpass human-made technologies. Scientists can create materials that mimic nature's exceptional efficiency in regulating heat transfer by studying natural systems, such as polar bears fur or other organism's structures adapted to harsh climates. 
With its specialised multi-layered structure and optical properties, the polar bear's fur is an excellent model for managing heat retention. This study examines its insulating qualities using a comprehensive 3D simulation to understand how the structure regulates body heat. We use MATLAB to simulate radiative heat transfer between individual hair fibers while considering optical characteristics such as transmittance, absorption, and reflectivity. The results reveal that even in freezing temperatures (-40°C), the unique structure of polar bear hair considerably reduces radiative heat loss, keeping interior temperatures over 37°C. Additionally, according to our simulations, multi-layer hair arrangements increase thermal efficiency by up to 16°C, indicating conceivable uses for bio-inspired insulation materials. These results have consequences for ecological sustainability, the development of thermal insulation technology, and the design of energy-efficient materials and structures.

The Impact of Heave Motion on Gap Resonance in Floating Structures: A Numerical Investigation

The phenomenon of gap resonance has increasingly captured the attention of researchers due to its significant impact on offshore and coastal structures. Despite extensive studies, the effect of the heave motion of floating structures on gap resonance has lacked thorough investigation. This paper addresses this gap by using a two-dimensional numerical wave tank in OpenFOAM (version v1812) to compare both fixed-box and floating-box systems. Our findings reveal that the inclusion of the heave motions of structures shifts the resonance frequency to higher values (larger kh) and significantly reduces wave amplification compared with fixed-box systems. Furthermore, while gap resonance can induce extreme wave forces, its impact on the rear box in floating-box systems is minimal. These results underscore the necessity of considering the motion of floating structures in gap resonance studies to enhance the stability and design of offshore and coastal structures, a factor that has been insufficiently addressed in previous research.

Fusion Modes and Number of Fused Rings: Their Impact on Acceptor-Donor-Acceptor Nonfullerene Acceptors in Organic Solar Cells.

The power conversion efficiency (PCE) of organic solar cells (OSCs) devices has surpassed 19% owing to the blooming of fused-ring nonfullerene acceptors (NFAs), especially for acceptor-donor-acceptor (A-D-A) type NFAs. However, the structural effect of the angular/linear fusion mode and number of fused rings for A-D-A type NFAs on the photovoltaic performance in OSCs devices remains unclear. Herein, the A-D-A type NFAs (F-0Cl, IDIC8-H, and ITIC) have been selected to obtain the intrinsic role of structural design strategies including the angular/linear fusion mode and the number of fused rings. The results indicate that compared to the linear fusion mode in ITIC, the angular fusion mode in F-0Cl effectively diminishes electronic vibrational coupling within the low-frequency range, leading to lower charge reorganization during the exciton diffusion process. Meanwhile, it facilitates the generation of multiple charge transfer mechanisms at the donor/acceptor (D/A) interface and increases the rates of hole transfer. On the other hand, the decreased number of fused rings of NFAs could inhibit the exciton decay and charge recombination but increase the rates of exciton diffusion and exciton dissociation for individual NFAs and the rates of electron separation for D/A interface. This work provides theoretical insights into structural design strategies, such as linear/angular fusion, and the number of fused rings of NFA, which presents a promising outlook for further enhancing PCE of high-performance A-D-A type NFAs.

Analysis on Flexural Performance of Prestressed Steel-Reinforced UHPC Beams

The flexural performance of prestressed steel-reinforced ultra-high-performance concrete (UHPC) beams was investigated through finite element (FE) modeling and nonlinear numerical analysis. Two FE models were established for prestressed steel-reinforced concrete beams and prestressed UHPC beams, respectively, and the accuracy was validated by comparing with the experimental results. On this basis, a comprehensive analysis of load–deflection behavior, load–strain relationships, and failure modes was conducted under varying parameters, including reinforcement ratio, prestress level, steel web thickness, and steel flange thickness. The results indicate that an increase in reinforcement ratio from 1.17% to 1.90% enhanced the ultimate load by 12.05%, while increasing the prestress level from 0.61 to 0.76 improved the cracking load by 114.88% and the ultimate load by 53.73%. Moreover, the beams exhibited superior ductility and cracking resistance compared to conventional concrete structures. A formula for predicting the flexural capacity of prestressed steel-reinforced UHPC beams was derived, showing an average error of less than 3% when compared with FE simulations. This formula provides a reliable basis for the structural design and optimization of high-performance composite beams in engineering practice.

Predicting the glass transition temperature of polymer based on generative adversarial networks and automated machine learning

AbstractSolution styrene‐butadiene rubber (SSBR) finds wide applications in high performance tire design and various other fields. This study aims to create a quantitative structure–property relationship (QSPR) model linking SSBR's glass transition temperature (Tg) to its structural properties. A dataset of 68 sets of data from published literature was compiled to develop a predictive machine learning model for SSBR's structural design and synthesis using small sample sizes. To tackle small sample sizes, a framework combining generative adversarial networks (GAN) and the Tree‐based Pipeline Optimization Tool (TPOT) is proposed. GAN is first used to generate additional samples that mirror the original dataset's distribution, expanding the dataset. The TPOT is then applied to automatically find the best model and parameter combinations, creating an optimal predictive model for the mixed dataset. Experimental results show that using GAN to enlarge the dataset and TPOT regression models significantly enhances model performance, increasing the R2 value from 0.745 to 0.985 and decreasing the RMSE from 7.676 to 1.569. The proposed GAN–TPOT framework demonstrates the potential of combining generative models with automated machine learning to improve materials science research. This combination accelerates research and development processes, enhances prediction and design accuracy, and introduces new perspectives and possibilities for the field.

Sandwich Structure Bending Analysis Using Finite Element Analysis

The research conducted1 using ANSYS software focuses1 on analyzing the flexural behavior of sandwich composite1 materials widely utilized in various industrial applications. The finite element method (FEM) employed facilitates a detailed understanding of the material's response to external forces. This study involves developing a model of the sandwich1 structure, accounting for its multiple layers1 and the specific properties of the 1materials used. Numerical analysis is performed to evaluate the structural response under defined loads and boundary conditions, enabling precise1 assessment of deformations, stresses, and layer-specific behavior. The findings1 obtained from the ANSYS1 simulations provide valuable insights1 for the design and optimization of sandwich composite1 structures, contributing to improved performance and 1durability in industrial1 applications.

Sandwich Structure Bending Analysis Using Finite Element Analysis

The research conducted1 using ANSYS software focuses1 on analyzing the flexural behavior of sandwich composite1 materials widely utilized in various industrial applications. The finite element method (FEM) employed facilitates a detailed understanding of the material's response to external forces. This study involves developing a model of the sandwich1 structure, accounting for its multiple layers1 and the specific properties of the 1materials used. Numerical analysis is performed to evaluate the structural response under defined loads and boundary conditions, enabling precise1 assessment of deformations, stresses, and layer-specific behavior. The findings1 obtained from the ANSYS1 simulations provide valuable insights1 for the design and optimization of sandwich composite1 structures, contributing to improved performance and 1durability in industrial1 applications.

USE OF GEO-INFORMATION SYSTEMS FOR GROUNDWATER MONITORING

Abstract . The article is devoted to the study of the possibilities of using geographic information systems (GIS) for monitoring the state of groundwater, which is important for ensuring environmental safety and sustainable management of water resources. Groundwater is an important source of fresh water for the population, industry and agriculture, but it is vulnerable to various pollutions caused by both natural and anthropogenic factors. Therefore, the implementation of reliable monitoring systems that allow timely detection, assessment and forecasting of changes in water quality is necessary to prevent the deterioration of the ecological situation and prevent the spread of pollution. Geographic information systems (GIS ) offer significant opportunities for the collection and integration of large volumes of spatial data, including satellite images, remote sensing results, automated sensor data, and field observations. GIS allow creating multi-layered maps reflecting the ecological state of underground aquifers, modeling pollution processes and predicting their possible impact on nearby ecosystems and water sources. Thanks to the use of GIS, it is possible to combine data from different sources in a single interactive system, which simplifies analysis and provides the ability to quickly respond to any detected deviations. The article examines in detail the key methods used within GIS for groundwater monitoring, including satellite sounding to analyze changes in the earth's surface, spectral indices to assess the state of vegetation and soil salinity, and radar methods to determine soil electrical conductivity. Particular attention is paid to the application of three-dimensional modeling, which allows visualization of the spread of pollution in underground aquifers, which facilitates decision-making regarding the optimal location of monitoring stations and the design of protective structures. In combination with automated sensors recording water parameters in real time, GIS provides continuous monitoring of the physico-chemical indicators of groundwater and allows for prompt assessment of their condition. The article also analyzes the possibilities of using predictive modeling in GIS to assess the further spread of pollution and develop environmental risk management measures. It is described how mathematical models in GIS can help predict the impact of anthropogenic and natural factors on groundwater, which ensures the development of scientifically based solutions to reduce pollution and maintain water quality at a safe level. The implementation of GIS in groundwater monitoring is an important step towards increasing the efficiency of water resources management, ensuring their protection from pollution and preserving the ecological stability of the regions.

Unified Elasto-Plastic Solution for High-Speed Railway Tunnel in Cold Regions Considering Dual Transverse Isotropic Model of Frozen Rock Mass

Frost damage is one of the main influencing factors for the deterioration of support structures in cold-region tunnels. A new dual transverse isotropic model of frozen rock mass is first proposed based on parameter strain and elastic modulus to serve as the theoretical basis for tunnel operation safety in cold regions. Subsequently, a unified elasto-plastic solution for high-speed railway tunnels in cold regions is derived based on the new dual transverse isotropic model, and the accuracy of the analytical solution is verified by comparisons with existing models and experimental results. Finally, the effect of the model parameters on stress and displacement is explored. The results reveal a significant negative correlation between the plastic radius of the frozen rock mass zone and the pressure acting on the inner surface of the support structure, the influence coefficient of intermediate principal stress, radial-gradient influence coefficient of the frozen rock mass, and anisotropic frost heave coefficient of the frozen rock mass, as well as between the frost-heaving force and the influence coefficient of intermediate principal stress parameter. However, the frost-heaving force is positively correlated with the pressure acting on the inner surface of the support structure, the radial gradient influence coefficient of the frozen rock mass, and the anisotropic frost heave coefficients of the frozen rock mass. Therefore, the pressure acting on the inner surface of the support structure, the radial gradient influence co-efficient of the frozen rock mass, and the anisotropic frost heave coefficients of frozen rock mass should be reasonably considered, but the strength theory of the surrounding rock should be strongly considered in the design of tunnel structures in cold regions.

Multiconnected Beam Gradient Seismic Metamaterials for Broadband Rayleigh Wave Attenuation

Local resonance metamaterials have addressed the limitations of Bragg scattering‐type periodic structures in low‐frequency applications, providing a new path for the development of new seismic systems. However, achieving broadband attenuation of low‐frequency seismic waves within a compact structural design remains challenging. This article presents a novel local resonance seismic metamaterial (SM) with an ultra‐low frequency broad bandgap. It consists of an external steel frame, peripheral steel connecting beams, bottom rubber cushions, and a central steel resonator. By combining dispersion analysis and acoustic cone methods to calculate its bandgap, the attenuation range of the SM is clarified, and the influence of structural parameter changes on the upper and lower limits of bandgap is discussed. The results demonstrate that the attenuation domain can be further broadened through parameter gradient design, and frequency domain analysis confirms that the proposed gradient local resonance SM can achieve broadband seismic wave attenuation from 1.0611 to 10.895 Hz. Finally, time‐domain analysis elucidates the dynamic response of the SM, further validating the study's effectiveness. The SM proposed herein has practical and economic applications in surface vibration isolation, effectively protecting large infrastructure and civil engineering structures.

Recent Developments in Electrospun Nanofiber-Based Triboelectric Nanogenerators: Materials, Structure, and Applications

Triboelectric nanogenerators (TENGs) have garnered significant attention due to their high energy conversion efficiency and extensive application potential in energy harvesting and self-powered devices. Recent advancements in electrospun nanofibers, attributed to their outstanding mechanical properties and tailored surface characteristics, have meant that they can be used as a critical material for enhancing TENGs performance. This review provides a comprehensive overview of the developments in electrospun nanofiber-based TENGs. It begins with an exploration of the fundamental principles behind electrospinning and triboelectricity, followed by a detailed examination of the application and performance of various polymer materials, including poly (vinylidene fluoride) (PVDF), polyamide (PA), thermoplastic polyurethane (TPU), polyacrylonitrile (PAN), and other significant polymers. Furthermore, this review analyzes the influence of diverse structural designs—such as fiber architectures, bionic configurations, and multilayer structures—on the performance of TENGs. Applications across self-powered devices, environmental energy harvesting, and wearable technologies are discussed. The review concludes by highlighting current challenges and outlining future research directions, offering valuable insights for researchers and engineers in the field.

Switchable Pancharatnam-Berry Phases in Heterogeneously Integrated THz Metasurfaces.

The Pancharatnam-Berry (PB) phase has revolutionized the design of metasurfaces, offering a straightforward and robust method for controlling wavefronts of electromagnetic waves. However, traditional metasurfaces have fixed PB phases determined by the orientation of their individual elements. In this study, an innovative structural design and integration scheme is proposed that utilizes vanadium dioxide, a phase-change material, to achieve thermally controlled dynamic PB phase control within the metasurface. By leveraging the material's properties, this can dynamically alter the optical orientation of individual elements of the metasurface and achieve temperature-dependent local phase modulation based on the geometric phase principle. This approach, combined with advanced fabrication processing technology, paves the way for next-generation dynamic devices with customizable functions.

The Structural Design and Analysis of the Multi Nozzle Relay Air-Jet Inserting System by Profile Reed Guiding for 3D Weaving Machine

Introduction: Based on the literature, this article designs a parameterized simulation model of a multi-layer jet weft insertion system by profiles reed guidance for a 3D loom on the PTC Creo9.0 platform, including the main supersonic nozzle, supersonic auxiliary nozzle (relay nozzle), and multi-slot profiles reed components. Method: Based on the existing basic theory, experimental results, and empirical data of turbulent jet, the parameters of the multi-layer jet weft insertion system, as well as the structural parameters and the relative positions of the main, auxiliary nozzle and profile reed components, such as the center distance of each layer's main nozzle, auxiliary nozzle spacing, auxiliary nozzle installation angle, spray direction angle, and spray angle, have been determined preliminarily. Result: Further, the basic flow field parameters, such as the supply pressure of the main and auxiliary nozzles and the shape of multi-layer profile reeds, have been determined optimally on the Virtual Prototype Collaborative Simulation Platform (PTC Creo9.0/ANSYS Workbench/Fluent 2024R1), and the rationality of the structural design also been verified; on the premise of ensuring that the airflow velocity of each layer's profiles groove meets the requirements of weft insertion, the design and simulation calculation is repeatedly modified, and the optimal structural design parameters of the multi-layer weft insertion system and nozzle is finally determined. Conclusion: To explore the feasibility of multi-layer jet weft insertion, the design of threedimensional multi-layer jet weft insertion looms has laid a theoretical foundation, laying a good foundation for the emergence and industrial manufacturing of three-dimensional multi-layer jet weft insertion looms, and providing an important reference for the innovative design of threedimensional multi-layer water jet weft insertion looms.

Diels-Alder reaction in hydrogel synthesis: Mechanisms and functional aspects.

The Diels-Alder reaction, a classical (4+2) cycloaddition process, holds significant standing within the realms of organic synthesis and polymer chemistry, frequently employed in areas such as pharmaceutical production and material science. Recently, hydrogels constructed via Diels-Alder reactions have garnered considerable attention from researchers. This review aims to summarize the advancements in utilizing the Diels-Alder reaction for hydrogel synthesis, exploring its impact on structural design, functionalization, and application domains. Initially, the fundamental principles of the Diels-Alder reaction are introduced alongside an examination of its benefits and characteristics in hydrogel fabrication. Subsequently, applications of Diels-Alder-generated hydrogels in biomedicine, smart responsive materials, drug delivery systems, among other fields, are comprehensively reviewed. Challenges and limitations encountered during hydrogel synthesis using this reaction are also discussed. Finally, prospective research directions and future prospects of Diels-Alder reactions in hydrogel synthesis are contemplated.

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

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