Topology Design Research Articles

Topological Shape Optimization Design of the Whole Bead of 265/35R18 Steel-Belted Radial Tire

The tire bead, as the most important load-bearing component at the bead area, is closely related to the durability of the tire, but its structure is developing slowly. For this reason, the topological whole bead design was proposed, although it performs well, many defects existed due to the design based on traditional experience. Therefore, this paper studies the topology shape optimization algorithm, delves into the main criterion based on von Mises and the interlaminar shear stress, and provides guidance for the structurally optimal design of the 265/35R18 radial tire whole bead. The finite element simulation results show that the von Mises of the inner end of the chafer and the end of the carcass cord are reduced by 14.48% and 24.12%, respectively. The interlaminar shear stress decreased by 28.96% and 49.51%, respectively. The von Mises of chafer and carcass cord decreased by 13.17% to 40.36% and 7.71% to 20.51%, respectively. The optimization design is of great significance to further improve the safety performance of tires.

Design and Implementation of Active PFC Rectifier Topology for Avionic and Fleet Electrification

Design and Implementation of Active PFC Rectifier Topology for Avionic and Fleet Electrification

Magneto-Thermal Coupling Analysis of an Axially Split Phase Spherical Bearingless Flywheel Machine

The axially-split phase spherical bearingless flywheel machine (ASP-SBFM) operates mostly in fast charging and discharging conditions. The unique topology design and high power density of the ASP-SBFM can lead to complex machine losses and result in high-temperature rise. This article employs magneto-thermal coupling to perform an accurate analysis of the temperature field distribution of the ASP-SBFM. First, as the heat source for machine temperature rise, the ASP-SBFM losses are analyzed in detail. And the theoretical calculation results agree well with the FEA results. Then, the magneto-thermal coupling method is conducted to obtain the accurate temperature distribution of ASP-SBFM, where both natural cooling and high vacuum conditions are considered. The temperature distribution results can provide a reference for machine heat dissipation design, topology optimization, and machine body material selection.

Multifunctional mechanical metamaterials with tunable double-negative isotropic properties

This research was focused on innovative design of lattice metamaterials that can exhibit tunable double-negative mechanical properties and elastic isotropy simultaneously. A discrete topology optimization method using a multi-material ground structure was developed to create microlattices exhibiting both negative thermal expansion coefficient and negative Poisson’s ratio in a single integrated design, while maintaining elastic isotropy. First, the numerical homogenization method with beam elements was used to estimate the effective thermal and elastic properties of a microlattice. Second, the topological design, subject to required geometric constraints, was formulated as a mixed integer programming problem to discover a series of multi-material microlattices that present customized isotropic values of negative thermal expansion coefficient and negative Poisson’s ratio. Finally, several three-dimensional multi-material microstructures were produced by altering either the cross-sections or constituent materials of struts to demonstrate their tunable mechanical properties.

Development of a wireless sensor network simulator using energy-efficient traffic routing methods

This document represents possible algorithms and methods for the analysis, optimization, and control of wireless sensor networks. The main goal of the work is to find the optimal implementation of the particle swarm optimization method for solving the problem of improving the energy consumption of such networks. The result of the work is a software package for simulating WSN (Wireless sensor network) networks using all the methods of routing and optimization of WSN networks presented in the work. The usage of a combination of routing schemes and different systems of device state management raises the wireless sensor network lifetime and reduces the power consumption of the network. The developed and presented in the work network simulator allows any developer to design and test different network topologies with various network parameters. Such software will make it easy to design such networks both for large enterprises and independent developers.

Broadband vibration attenuation study and wave propagation analysis of extended arrow tetragonal lattice structure

In order to reduce vibration and noise with wide frequency, a new extended arrow tetragonal lattice topology is proposed. The band gap characteristics are discussed by combining the finite element method and Bloch’s theorem. The generation principle of band gap is explained by vibration mode analysis. By topological optimization of the structure, band gap has obvious optimization effect. The propagation characteristics of elastic waves with a specific frequency in the structure are studied from the point of view of energy. Finally, the band gap frequency range is compared with the transmission function, and the stress cloud diagram is analyzed. The research shows that the structure has good band gaps and can play a good role in vibration and noise reduction. Through the topological design of the structure, the band gap frequency range of the structure is optimized, which provides a new design idea for wide frequency vibration attenuation.

3D Printed Biomimetic Metamaterials with Graded Porosity and Tapering Topology for Improved Cell Seeding and Bone Regeneration.

Biomimetic metallic biomaterials prepared for bone scaffolds have drawn more and more attention in recent years. However, the topological design of scaffolds is critical to cater to multi-physical requirements for efficient cell seeding and bone regeneration, yet remains a big scientific challenge owing to the coupling of mechanical and mass-transport properties in conventional scaffolds that lead to poor control towards favorable modulus and permeability combinations. Herein, inspired by the microstructure of natural sea urchin spines, biomimetic scaffolds constructed by pentamode metamaterials (PMs) with hierarchical structural tunability were additively manufactured via selective laser melting. The mechanical and mass-transport properties of scaffolds could be simultaneously tuned by the graded porosity (B/T ratio) and the tapering level (D/d ratio). Compared with traditional metallic biomaterials, our biomimetic PM scaffolds possess graded pore distribution, suitable strength, and significant improvements to cell seeding efficiency, permeability, and impact-tolerant capacity, and they also promote in vivo osteogenesis, indicating promising application for cell proliferation and bone regeneration using a structural innovation.

Composite power supply topology design with energy-controlled distribution switches

An electric car’s battery is equivalent to a fuel vehicle’s engine, without a battery, it is equal to an empty shell. The single energy supply of the battery is difficult to meet the long-term endurance requirements of electric vehicles. Combined with the existing traditional composite power structure, the advantages and disadvantages of the existing traditional composite power supply structure are analyzed. A composite power supply structure combining a supercapacitor and power battery is proposed. The supercapacitor is responsible for the peak high power output, and the power battery is responsible for smooth power output. Simulation results show that the new composite power supply has noticeable improvements compared to traditional structures regarding energy loss and power distribution.

Modelling of Bi-Directional Buck-Boost Converter for Electric Vehicle

Abstract: The rapid growth of electric vehicles (EVs) has necessitated the development of efficient and versatile energy storage systems. In this study, we present the modelling and implementation of a switching bi-directional buck-boost converter based on electric vehicle hybrid energy storage. The proposed converter offers a flexible and reliable solution for managing energy flow between different storage elements in an EV, such as batteries and ultra-capacitors. First, a comprehensive mathematical model of the converter is developed, taking into account the dynamic behaviour of the energy storage components. This model enables us to analyse and optimize the converter's performance in terms of efficiency, voltage regulation, and power delivery capabilities. Furthermore, simulation studies are conducted to validate the accuracy of the model and assess the converter's performance under various operating conditions. Based on the modelling and simulation results, a practical implementation of the converter is carried out using high-quality electronic components. The design considerations, including component selection, circuit layout, and control strategy, are discussed in detail. The implemented converter is then evaluated experimentally to validate its performance and verify the effectiveness of the proposed modelling approach. The results demonstrate that the switching bidirectional buck-boost converter effectively manages the energy flow between the different storage elements in the hybrid energy storage system. It achieves high conversion efficiency, voltage regulation, and power transfer capabilities, enhancing the overall performance and range of electric vehicles. The developed model and implementation provide valuable insights for the design and optimization of similar converter topologies for electric vehicle applications. Overall, this study contributes to the advancement of energy storage systems in electric vehicles, facilitating the adoption of sustainable and efficient transportation solutions in the future

Design and Analysis of a Novel Multi-Level Inverter Topology Using DC Sources

Design and Analysis of a Novel Multi-Level Inverter Topology Using DC Sources

SIGNAL PROPAGATION

<p style="text-align: justify;">One of the participants that affects the loss of signal quality is propagation. In addition to it, we also have connection attenuation, latency, topology and network design. The quality of the digital signal transmitted from the transmitting to the receiving radio-relay device depends on the influence of environmental effects on the propagation of electromagnetic waves. Signal propagation is defined as path loss when the transmitter and receiver are directly facing each other, and in the event that there are no obstacles present in free space, there is still some signal attenuation. This is decisive for designing communication systems so that they can work despite the problems they may encounter. As the application of local wireless networks grows, so does the need for quality assessment of signal propagation in buildings. The Fresnel zone represents the air space between two transmitters through which radio waves propagate. It has an unlimited number of such zones, but the first three zones are important for signal quality and strength. Most often, only the first zone is counted because it occupies the largest volume and the quality and strength of the signal mostly depends on it. Within these environments, it is extremely important to take into account the types of obstacles and the type of room in which the signal is propagated. As part of this work, there is an overview of the most important propagation models and a review of them.</p>

Manajemen Penjadwalan Waktu Blokir Akses Internet pada Mikrotik RouterOS

Restricting internet access at certain hours allows for more efficient allocation of network resources and bandwidth. This limitation ensures that internet usage is not excessive, preventing the network from slowing down or being burdened by unproductive activities during critical hours. The research methodology employed involves the analysis of hardware and software requirements, network topology design, and network configuration. The research findings demonstrate the effectiveness of limiting internet access at specific times, supporting remote learning, and enhancing internet usage efficiency. System testing was conducted on Windows 10 and Debian 10, demonstrating the successful implementation of the scheduled blocking system. Although successful in simulation, this study has the potential to provide further benefits in real-world network environments.

Passive Isolator Design and Vibration Damping of EO/IR Gimbal Used in UAVs

One of the most critical factors affecting the quality of the images captured by the surveillance systems used in the unmanned aerial vehicles is the vibrations transmitted from the aircraft to the gimbal. The gimbal used in unmanned aerial vehicles is essential equipment, holding the camera steadily and accurately and pointing it in the desired direction. Within the scope of this article, a passive vibration isolation system design has been made for the two-axis electro-optical gimbal used in the mini unmanned aerial vehicle. By choosing the spring-damper system among different methods, the design that isolates the harmonic vibration from the platform on a single axis has been made using the analytical method. The analytical method was used to create a design that isolates the harmonic vibration from the platform along a single axis. In addition, the part named 'Pan Yoke', which contains this damper system, was designed with a computer-aided design program, and natural frequency values were checked with Ansys modal analysis. The frequency of the vibration transmitted from the air vehicle to the gimbal and the natural frequency of the designed part have been determined to be close to each other, at around 200 Hz. The natural frequency values of this part were optimised with various design changes and topology optimisations to prevent the part from resonating.

Weighted topology optimization of back-up supporting structures of antennas

In a working environment, the supporting structure usually suffers from asymmetric exterior loads with some finite elevation angles, leading to an asymmetric and irregular structure when applying traditional topology methods. To solve this problem, in this article, a weighted topology optimization method based on a shape feature function is presented, with an innovative concept of shape feature control function, which is employed to reshape the stiffness distribution and make the optimized structure symmetric for the manufacturing process. Topology optimization is also performed under fixed connection constraints. By introducing both the shape control and electromagnetic characteristics functions into the topological design domain, a relatively symmetric and regular topology structure is obtained through the weighted topology optimization method under the asymmetric exterior loads, which benefits the following detailed design and manufacturing process for reflector antennas. Numerical simulation demonstrates the effectiveness and advantages of the proposed method.

Topological design of open-cell microstructure with optimal effective thermal conductivity

The highly thermal conductive porous structure has many application scenarios, such as the skeletons embedded with phase change material. The additive manufacture technique combined with topology optimization motivates the design of microstructure of lattice material. A topology optimization framework based on isotropic material with penalization and finite element is developed. Aiming at extremely high thermal conductivity, the optimal lattices have closed pores. The conductivity is close to the theoretical Hashin-Strikman bound. In order to achieve the goal of open-cell lattice for heat and mass transport, a multi-objective function based on thermal conductivity and mass diffusivity is proposed. Optimization results reveal that various microstructure has optimal effective properties which are close to theoretical cross-property bound. In addition, the lattice materials are fabricated using selective laser melting. The experimental thermal conductivity results are in good agreement with the numerical simulation, with an error of less than 8%. The ability to fabricate the microstructure accurately provides an opportunity to use these lattice materials. This work provides a basis for designing lattice material, with better application in skeleton embedded with PCM, lattice channel, lattice heat sink, etc.

On‐Chip Electrically Driven Tunable Meta‐Lens for Dynamic Focusing and Beam Steering

AbstractThe on‐chip meta‐lenses consisting of subwavelength slot arrays with lateral gradients have shown great potential for parallel signal processing and optical computing. The dynamic tuning mechanisms which are necessary steps toward exploiting the applications of the on‐chip meta‐system have been rarely mentioned yet. Here, a free‐form functional microheater via topology design is proposed to manipulate the refractive index distribution, allowing for flexible optical wavefront shaping. For a proof‐of‐concept, wide range of dynamic focusing and beam steering are demonstrated via a tunable meta‐lens on silicon photonic platform. The continuous scanning of the focused beam is experimentally achieved with a maximum travel range of 100 µm in the longitudinal direction (≈95 nm mW−1) and 25 µm in the lateral direction (≈20 nm mW−1). The thermal‐optic tuning elements can response the electrical control within ≈41.2 µs. A waveguide array at the focal plane is used to characterize the device. The on‐chip loss of the tunable meta‐lens is measured to be <1 dB including the coupling loss from slab to single‐mode waveguide. The proposed tunable meta‐lenses are fabricated via a standard silicon photonic process and allow for arbitrarily two dimensional (2D) beam steering. It offers great versatility for on‐chip meta‐systems with a wider scope of functionalities and applications.

Topological approach for optimizing the compressive properties of the square lattice-structured recycled walnut shell Poly Lactic Acid composite

In the polymer additive manufacturing process, lightweight biopolymeric components are developed by introducing lattice structures and reinforcing neat polymeric matrices with various types of organic fillers. The present work concentrates on the extrusion of Walnut Shell/PLA (WSP) composite filament and utilizing it for the fabrication of lattice-structured composite materials. The topology-based factors of the unit cell and studying the impact of topology-based factors on the compressive strength and compressive strength/density property of the developed lattice-structured composites. The topology-based factors such as cell size, skewing angle, wall thickness, and cell orientation of the unit cell were varied to develop a lightweight component with better compressive strength. The results highlighted that the lattice-structured WSP biopolymeric composites attained a higher compressive strength due to a lower cell size of 1.5 mm, a higher skewing angle of 20°, a higher wall thickness of 0.88 mm, a cell orientation of 90°. The major percentage contribution among the various topological design factors for obtaining higher compressive strength will be cell size of 44.60% and skewing angle of 25.27%. The regression study results show that, the R-square value of the lattice-structured WSP biopolymeric composites concerning compressive strength will be 90.11 and compressive strength/density will be 94.07. Fractured composites depicted that, the mode of fracture is majorly influenced by cell size and skewing angle. Developed WSP lattice-structured composite is more appropriate for low-strength applications such as household applications such as shelves coverages, windows, photo frames, and racks.

Influence of Manufacturing Process Modularity on Lead Time Performances and Complexity

In principle, modular or integral character of manufacturing lines depends on the topological designs of products and determined operation tasks. On the other hand, in specific situations there is an articulated need for modular design in smart manufacturing systems since modular layouts are a crucial step towards agile production via smart manufacturing. The aim of this paper is to explore how the modular layout relates to manufacturing lead time (MLT) and to operational complexity of smart manufacturing systems. For this purpose, topologically different models of alternative process layouts were simulated and tested, while MLT values were obtained using Tecnomatix Plant Simulation. The obtained positive findings of this research could be useful not only in selection of the most suitable process design from the alternative ones, but especially in deepening the knowledge and bettering understanding of the concept of optimal network modularity.

An integrated method of topological optimization and path design for 3D concrete printing

As an advanced construction technology, 3D concrete printing (3DCP) has the advantage of high manufacturing freedom for various freeform structures. The digital design of 3D printing using topology optimization contributes to obtaining the maximum performance potential from manufactured structures. However, most digitally designed structures obtained by topology optimization cannot be directly manufactured using 3DCP owing to various manufacturing constraints that have not yet been considered in the design process. This paper presents an integrated design method for 3DCP by incorporating extrusion-based manufacturing characteristics into the topology optimization algorithm. Topological optimization is based on the solid isotropic material with penalization (SIMP) method owing to its ease of adaptation to multiple constraints. During the optimization iteration, the manufacturing characteristics of nozzle size and path continuity are considered as the design requirements of 3D printed structures to achieve high-quality manufacturing by using intermittent interruption of topology optimization to modify the design variables. Meanwhile, the anisotropic behaviors of material constraints and the volume and Tsai-Wu criterion of design constraints are introduced to obtain the desired mechanical performance with lightweight designs. Moreover, the number of closed regions and overhang angle controls are incorporated to ensure the global path continuity and stable stacking of optimized 3D structures. A concrete arch structure is 3D printed to validate the proposed integrated method, and the removal of breakpoints and short paths and complete filling rate are demonstrated. The integrated method facilitates the engineering application of 3DCP in a high-efficiency and high-quality manner.

Memetic evolutionary algorithms to design optical networks with a local search that improves diversity

The last few years have seen an increasing demand for high-capacity Internet services, and this need has intensified in the years 2020 and 2021. In 2020 and 2021, Internet usage grew by 50% in several European countries, mainly due to home office, video streaming, hybrid teaching, and others. High-capacity optical networks usually meet this growing demand for Internet services. Thus, investigations that can improve the quality of optical networks are highly relevant in the current context. One of the research problems in this area is related to the physical topology design (PTD) of optical networks, which is classified as NP-hard. Several studies on PTD consider the application of meta-heuristics that obtain suboptimal solutions in a time compatible with engineering applications. However, meta-heuristics and local search techniques have been combined in several other optimization problems, which is not typical for the PTD problem. This paper proposes a solution to the PTD problem that combines a known multipurpose optimization algorithm, the NSGA-III, with operators considering the domain-specific knowledge of the problem to provide superior-quality networks. According to our results, the new proposal presents quality up to 8% higher than previous proposals concerning the hypervolume metrics (HV), maintaining a similar computational cost.