Topology Design Research Articles

Maximum power extraction of partially shaded solar photovoltaic array using reconfiguration method

ABSTRACT This article presents a reconfiguration strategy, named the Cheetah Optimization Algorithm (COA), for maximizing power generation in partially shaded solar photovoltaic (PSPV) arrays. The proposed method’s originality aims to mitigate the negative impacts of partial shading, improve the output power of the PV system, and prevent thermal failure of shaded solar panels. The strategy combines efficient maximum power point tracking techniques with suitable photovoltaic system design topologies. The COA is done on the MATLAB platform and is analyzed with the existing methods such as the Wild Horse Optimizer (WHO), Salp Swarm Algorithm and Heap-based Optimizer. The outcome shows the superior performance of the COA in achieving the extraction of maximum power compared to the other methods. Additionally, by comparing the two patterns of partial shading, it is shown that the COA extracts more power than the existing methods and gets to the global power value faster. The COA is compared with existing methods, including WHO, SSA, and HBO. In terms of accuracy, the proposed system achieves the highest value of 0.93, surpassing the accuracy of HBO, WHO, and SSA, which stand at 0.8, 0.9, and 0.9, respectively. The specificity, precision and recall are also reflect the superiority of the proposed system with the values of 0.87, 0.9, and 0.86, respectively, outperforming the existing algorithms in most categories.

Topology optimization method for transient heat conduction using the Lyapunov equation

This study presents a novel topology optimization approach for transient heat conduction during the transition period based on the Lyapunov equation. For the problem under consideration, traditional topology optimization methods face computational challenges due to the time dependence of the transient responses. To address this issue, this article introduces a new optimization formulation that contains a modified governing equation for transient heat conduction and a new objective function. The new formulation aims to simplify the evaluation of transient response performance by utilizing the Lyapunov equation, thereby avoiding time-consuming transient analysis during the optimization iteration process. Additionally, this study employs model reduction techniques to reduce the size of the analysis model and further enhance the efficiency of the optimization process. After comparing two classic methods, the Proper Orthogonal Decomposition (POD) method is selected for its higher efficiency. Numerical examples consider both heat conduction and temperature control problems, employing 2D and 3D models to validate the proposed method's effectiveness. The results of the point-to-point heat conduction example indicate that, compared to the conventional design, the optimized topology design obtained using the proposed method successfully reduce the heating time by approximately 35%. Furthermore, the optimized designs display clear distinguishing features from conventional designs, further emphasizing the significance of implementing transient heat conduction topology optimization.

Design, fabrication, and clinical characterization of additively manufactured tantalum hip joint prosthesis

Abstract The joint prosthesis plays a vital role in the outcome of total hip arthroplasty. The key factors that determine the performance of joint prostheses are the materials used and the structural design of the prosthesis. This study aimed to fabricate a porous tantalum (Ta) hip prosthesis using selective laser melting (SLM) technology. The feasibility of SLM Ta use in hip prosthesis was verified by studying its chemical composition, metallographic structure, and mechanical properties. In vitro experiments proved that SLM Ta exhibited better biological activities in promoting osteogenesis and inhibiting inflammation than SLM Ti6Al4V. Then, the topological optimization design of the femoral stem of the SLM Ta hip prosthesis was carried out by finite element simulation, and the fatigue performance of the optimized prosthesis was tested to verify the biomechanical safety of the prosthesis. A porous Ta acetabulum cup was also designed and fabricated using SLM. Its mechanical properties were then studied. Finally, clinical trials were conducted to verify the clinical efficacy of the SLM Ta hip prosthesis. The porous structure could reduce the weight of the prosthesis and stress shielding and avoid bone resorption around the prosthesis. In addition, anti-infection drugs can also be loaded into the pores for infection treatment. The acetabular cup can be custom-designed based on the severity of bone loss on the acetabular side, and the integrated acetabular cup can repair the acetabular bone defect while achieving the function of the acetabular cup.

Topology Design and Graph Embedding for Decentralized Federated Learning

Topology Design and Graph Embedding for Decentralized Federated Learning

Hybrid topology and circuit design of power converter based on Si and SiC

Hybrid topology and circuit design of power converter based on Si and SiC

Design and optimization of high torque density flux modulated multi-winding permanent magnet machines for electric vehicles

In order to achieve high-quality energy conversion operation in electric vehicles, the optimization design of drive motors has been considered as one of the most crucial research areas. For enhancing torque density without deteriorating power factor, a spoke-type flux modulated multi-winding permanent magnet machine is proposed and optimized, where the highly efficient utilization of harmonic flux is realized according to the contribution of windings with various pole pairs. Firstly, the operating principles and the initial design of topology are investigated. Then, the improved non-dominated sorting genetic algorithm is adopted for multi-objective optimization. To enhance the efficiency and accuracy of the optimization, the weight coefficients of the multi-objectives are established through a gray correlation strategy, while the design parameters are stratified based on a comprehensive sensitivity degree analysis. In addition, the comparative analysis of machines before and after optimization are carried out. Finally, the correctness of the theoretical analysis and the effectiveness of the proposed optimization are verified by a prototype machine. It shows that high torque density without deteriorating power factor is achieved on the proposed machines.

PV-Based Design and Evaluation of Power Electronic Topologies for EV Applications

PV-Based Design and Evaluation of Power Electronic Topologies for EV Applications

Implementation of DOS Attack Using NS2

This paper presents a comprehensive study on the implementation of a Denial of Service (DOS) attack using NS2, a widely-used network simulator. The project involves the installation and configuration of NS2 and NAM on Ubuntu, the design of a realistic network topology, and the generation of TCP and UDP traffic to simulate a DOS attack. By evaluating the impact of the attack on network performance metrics such as throughput and latency, this study aims to enhance understanding of DOS attacks in simulated environments and propose effective mitigation strategies. The findings contribute to the field of network security by providing insights into the behavior of DOS attacks and highlighting the importance of proactive defense mechanisms.

Reliability-Based Topology Optimization with a Proportional Topology for Reliability

This research proposes an efficient technique for reliability-based topology optimization (RBTO), which deals with uncertainty and employs proportional topology optimization (PTO) to achieve the optimal reliability structure. The recent technique, called proportional topology optimization for reliability (PTOr), uses Latin hypercube sampling (LHS) for uncertainty quantification. The difficulty of the double-loop nested problem in uncertainty quantification (UQ) with LHS can be alleviated by the power of PTO, enabling RBTO to be performed easily. The rigorous advantage of PTOr is its ability to accomplish topology optimization (TO) without gradient information, making it faster than TO with evolutionary algorithms. Particularly, for reliability-based topology design, evolutionary techniques often fail to achieve satisfactory results compared to gradient-based techniques. Unlike recent PTOr advancement, which enhances the RBTO performance, this achievement was previously unattainable. Test problems, including an aircraft pylon, reveal its performances. Furthermore, the proposed efficient framework facilitates easy integration with other uncertainty quantification techniques, increasing its performance in uncertainty quantification. Lastly, this research provides computer programs for the newcomer studying cutting-edge knowledge in engineering design, including UQ, TO, and RBTO, in a simple manner.

Stiffening patterns for freeform composite shell structures

This paper investigates innovative approaches for enhancing the structural integrity of form-found shell structures with a focus on rib-based reinforcements. It discusses the significance of ribs in enhancing stability and addressing the sensitivity of form-found structures to various loads. Traditional methods such as increasing shell thickness or introducing supports often compromise efficiency and aesthetics. A more intelligent approach involves reinforcing the shell with ribs and advanced materials. Diverse rib patterns are presented, including geometric, biomimetic, and topological optimization-inspired designs, each adhering to a 50 % volume constraint, when compared to the original shell. Physical testing and numerical simulations demonstrate that these rib patterns significantly increase stiffness and buckling resistance. The findings presented in the paper suggest that combining form-finding methodologies with well-designed rib patterns can create sustainable and resilient structures, contributing to a reduction in both the consumption of materials and the environmental impact of these structures.

Topology optimization for magnetic circuits with continuous adjoint method in 3D

PurposeThe purpose of this paper is to present a new approach to optimizing the design of 3D magnetic circuits. This approach is based on topology optimization, where derivative calculations are performed using the continuous adjoint method. Thus, the continuous adjoint method for magnetostatics has to be developed in 3D and has to be combined with penalization, filtering and homotopy approaches to provide an efficient optimization code.Design/methodology/approachTo provide this new topology optimization code, this study starts from 2D magnetostatic results to perform the sensitivity analysis, and this approach is extended to 3D. From this sensitivity analysis, the continuous adjoint method is derived to compute the gradient of an objective function of a 3D topological optimization design problem. From this result, this design problem is discretized and can then be solved by finite element software. Thus, by adding the solid isotropic material with penalization (SIMP) penalization approach and developing a homotopy-based optimization algorithm, an interesting means for designing 3D magnetic circuits is provided.FindingsIn this paper, the 3D continuous adjoint method for magnetostatic problems involving an objective least-squares function is presented. Based on 2D results, new theoretical results for developing sensitivity analysis in 3D taking into account different parameters including the ferromagnetic material, the current density and the magnetization are provided. Then, by discretizing, filtering and penalizing using SIMP approaches, a topology optimization code has been derived to address only the ferromagnetic material parameters. Based on this efficient gradient computation method, a homotopy-based optimization algorithm for solving large-scale 3D design problems is developed.Originality/valueIn this paper, an approach based on topology optimization to solve 3D magnetostatic design problems when an objective least-squares function is involved is proposed. This approach is based on the continuous adjoint method derived for 3D magnetostatic design problems. The effectiveness of this topology optimization code is demonstrated by solving the design of a 3D magnetic circuit with up to 100,000 design variables.

Two-layer Lagrange-based relay network topology and trajectory design for solar system explorations

Two-layer Lagrange-based relay network topology and trajectory design for solar system explorations

Topology Design of Compliant Mechanism Design With Multiple Component Modeling Connected by Various Joints

Abstract This study presents a novel framework for the optimal design of compliant mechanisms, specifically addressing the structural drawbacks of conventional single-point or de facto hinges. The hinges often lead to structural instability and stress concentration while deriving maximum motion. To overcome these issues, we introduce a new method that can design stable and elastic domains connected by either revolute or prismatic joints. The new method, called sequential analysis based on the reaction force, can successfully eliminate weak hinge points while optimizing joint locations. The efficiency of developed methodology is validated through several numerical examples, yielding compliant mechanisms with suppressed hinges.

Trade-off topology design for hierarchical network based on job characteristics

Trade-off topology design for hierarchical network based on job characteristics

Multifidelity topology design of a maritime survey operation with UUVs

Multifidelity topology design of a maritime survey operation with UUVs

Topological isomerism design of Demulsifiers: A fusion of molecular dynamics simulation and experiment

Demulsifiers are crucial for enhancing crude oil extraction and transportation efficiency by facilitating the separation of oil–water emulsions. However, research conducted on the design and synthesis of demulsifiers based on the results of molecular dynamics simulation remains scarce. Herein, we designed eight block polyethers, and explored their interfacial behaviors at the oil–water interface via molecular dynamics simulation. Correspondingly, eight block polyether demulsifiers were synthesized, and their interface properties were tested. The simulation results were consistent with the experimental results, indicating that the energy of simulation systems could be efficiently reduced by designed molecules, and that the prepared demulsifiers with the same structure could achieve effective demulsification correspondingly. Based on the simulation and experimental results, a “hand-shaped” demulsification mechanism model was proposed. The demulsifiers with hydrophobic “palm” and hydrophilic “fingers” demonstrated a more efficient performance in demulsification. The hydrophobic “palm” was stable in the continuous oil phase, and the hydrophilic “fingers” could attract dispersed water droplets to aggregate, facilitating demulsification. The study also finds that longer hydrophilic “fingers” exert stronger molecular force. Combining molecular dynamics simulation and experiment significantly accelerates the development of new demulsifiers, highlighting the utility of this approach in the research on demulsifiers.

Topological and multi-objective optimization of single-phase heat transfer and energy efficiency using manifold micro-channels for high-power electrics cooling

To achieve energy-efficient cooling of high-power electrics, present work demonstrates combined methods using topological design and multi-objective optimization to reconstruct manifold micro-channels (MMC). The micro-channel domain is first topologized by density-based method under pressure drop and energy dissipation constraints. The multi-objective optimization is subsequently applied to optimize structure and operating parameters of reconstructed MMC using kriging model and genetic algorithm. The simulation results show that favorable thermal performance is obtained in the topological MMC with branch-channels, pin fins and root-channels, increasing average heat transfer coefficient by 19.4 % compared to conventional MMC. For the optimal flow rate, the lowest total thermal resistance (Rtotal) of 0.17 KW−1 is obtained for the optimized-topological MMC at a pumping power (Pp) of 9.53 mW, meanwhile the maximum temperature-rise is decreased by 15.2K. Furthermore, an extensive benchmark of different single-phase micro-fluidic cooling technologies is performed. For an extremely low Rtotal of 0.2 KW−1, present optimized-topological MMC only requires Pp of 3 mW, which is 11.7 times, 26.7 times and 70 times lower than that of conventional MMC, pin-fin and strip-fin micro-fluidic systems. This superior hydro-thermal performance successfully manages the heat flux of 100 W/cm2 to 400 W/cm2 with cooling coefficient of 104 to 107, significantly outperforming other micro-fluidic cooling technologies.

Topologically optimized flexible tricolor-shape micro-fibre arrayed film and three-dimensional tube display concurrent magnetism, luminescence and conductive aeolotropy

From the perspective of topology design, innovative devise concepts and manufacturing technologies are of great significance for manufacturing high-performance multifunctional composites. Herein, a one-dimensional tricolor-shape micro-fibre was innovatively devised and constructed via a triaxial parallel electro-spinning. As a study case and application, the unique structured [CoFe2O4/polymethylmethacrylate (PMMA)]//[polyaniline (PANI)/PMMA]//[Eu(TTA)3phen/PMMA] magnetic-conductive-luminescent multi-functionalized tricolor-shape micro-fibre arrayed film (marked as MTMAF) were fabricated by orientational arrangement of the tricolor-shape micro-fibres. Meanwhile, magnetic-conductive-luminescent multi-functional quasi tricolor-shape micro-fibre arrayed film (marked as MQMAF) and magnetic-conductive-luminescent multi-functional tricolor-shape nano-strip arrayed film (marked as MTNAF) were also fabricated by alteration of the proportions of solvents. It is further found that MTMAF has better performances than those of MTNAF and MQMAF. The tricolor-shape micro-fibre achieves the partitioning of three separate functional partitions on the microscopic-level through the elaborate topology devise and an electrospinning technology. More importantly, since magnetic, conductive, and luminescent fillings are limited in their subareas, adverse interactions among them can be effectively avoided, resulting in superior poly-functional performances. Since the intense conductive aeolotropism and multifunctionality, MTMAF can be employed as a stable micro-circuit interconnection, offering a foundation for practical applications. Red luminescence can be used to supervise whether MTMAF properly works or not in darkness. Three-dimensional tubes are constructed via crimping the MTMAF in two various modes. The high integration of zero-dimensional nanoparticles, one-dimensional micro-construction blocks, two-dimensional films and three-dimensional tubes is achieved in one material. The construction of three-dimensional tubes achieves the transformation of materials from two-dimension to three-dimension. Furthermore, a universal technique to manufacture micro-fibre/nano-strip with three micro-subareas has been established for constructing multi-functional composites, other functional fillings also can be introduced into the tricolor-shape micro-fibre/nano-strip to achieve different multi-function.

Additive manufacturing of metallic metamaterials with enhanced mechanical properties enabled by microstructural and structural design

The emergence of additive manufacturing (AM) facilitates the fabrication of lightweight mechanical metamaterials characterized by intricate geometrical features. Here, we focus on the contributions of microstructural and structural design to the significant performance enhancement of metamaterials. Cubic plate-lattices featuring spherical holes were produced using laser powder bed fusion. Different from commonly used optimization of AM parameters to change the thermal histories and the resulting properties, we employ a simple strategy inspired by the crystallographic and AM features—tilting the build orientation. Compared to the normal build orientation, the tilted build orientation converts the printed microstructure of the plate-lattices from (100)-dominated to (111)- and (101)-dominated crystallographic texture and significantly refines the grain size, leading to remarkable 30% and 10% increases in the compressive strength and strain of the printed plate-lattices, respectively. For further tailoring the performance of metamaterials, we integrate a wavy plate topology design to improve the isotropy of properties and increase the impact attenuation. Our work paves the way to optimize additively manufactured metamaterials by combining microstructural and structural designs.

Design and reliability analysis of converter topology for Micro Grid system through optimal switching control

Design and reliability analysis of converter topology for Micro Grid system through optimal switching control