Structural Design Optimization Research Articles

Using In situ Transmission Electron Microscopy to Study Strong Metal‐Support Interactions in Heterogeneous Catalysis

AbstractPrecisely controlling the microstructure of supported metal catalysts and regulating metal‐support interactions at the atomic level are essential for achieving highly efficient heterogeneous catalysts. Strong metal‐support interaction (SMSI) not only stabilizes metal nanoparticles and improves their resistance to sintering but also modulates the electrical interaction between metal species and the support, optimizing the catalytic activity and selectivity. Therefore, understating the formation mechanism of SMSI and its dynamic evolution during the chemical reaction at the atomic scale is crucial for guiding the structural design and performance optimization of supported metal catalysts. Recent advancements in in situ transmission electron microscopy (TEM) have shed new light on these complex phenomena, providing deeper insights into the SMSI dynamics. Here, the research progress of in situ TEM investigation on SMSI in heterogeneous catalysis is systematically reviewed, focusing on the formation dynamics, structural evolution during the catalytic reactions, and regulation methods of SMSI. The significant advantages of in situ TEM technologies for SMSI research are also highlighted. Moreover, the challenges and probable development paths of in situ TEM studies on the SMSI are also provided.

Design and optimization of pore structure in three-dimensional micro-nano hierarchical SnOx supercapacitor electrodes for enhanced ion diffusion

This paper introduced a novel continuous electrochemical synthesis strategy to address the challenges of slow ion/electron transport rates and low electrode reaction efficiency in Sn-based electrode materials. This approach leveraged the induction and confinement of bubble templates to assist atoms deposition, generating micron-sized tin skeletons. Subsequently, these skeletons were transformed into a secondary nanoporous structure through dissolution-deposition etching effects. From liquid-phase ions to metal skeletons to porous oxides, the sequential material transformations realized the innovative design of three-dimensional (3D) hierarchical structures. This strategy ingeniously exploited the diffusion advantages of the electrolyte in the micro-nano hierarchical structure to achieve the diffusion enhancement of ions, thus solving the “dead surface” problem in the energy storage process. This study revealed the thermodynamic and kinetic feasibility of the constructed 3D micro-nano hierarchical structure through electrochemical evaluations and theoretical calculations, and elucidated the constitutive relationship in which the electrochemical performance of the electrode materials was enhanced with decreasing pore size. In addition, design optimization of pore structures and modelling exploration of pore size limit values were conducted based on density functional theory (DFT) simulations. These simulations demonstrated the advantages of hierarchical structures with controllable pore sizes in facilitating electrolyte ion diffusion, predicting an optimal pore size of 55 μm for 3D hierarchical porous SnOx electrodes. The integration of this innovative structural design with simulation insights offered significant implications for enhancing the sluggish electrode reaction kinetics of metal oxide electrode materials, advancing the controllable fabrication of high-performance energy storage devices.

The thermal-mechanical deformations of CO2 mixture gases dry gas seal based on two-way thermal-fluid-solid coupling model

PurposeThis study aims to investigate the influence mechanism of thermal-mechanical deformations on the CO2 mixture gases dry gas seal (DGS) flow field and compare the deformation characteristics and sealing performance between two-way and one-way thermal-fluid-solid coupling models.Design/methodology/approachThe authors established a two-way thermal-fluid-solid coupling model by using gas film thickness as the transfer parameter between the fluid and solid domain, and the model was solved using the finite difference method and finite element method. The thermal-mechanical deformations of the sealing rings, the influence of face deformation on the flow field and sealing performance were obtained.FindingsThermal-mechanical deformations cause a convergent gap between the two sealing end faces, resulting in an increase in the gas film thickness, but a decrease in the gas film temperature and sealing ring temperature. The axial relative deformations of rotating and stationary ring end faces caused by mechanical and thermal loads in the two-way coupling model are less than those in the one-way coupling (OWC) model, and the gas film thickness and leakage rate are larger than those in the OWC model, whereas the gas film stiffness is the opposite.Originality/valueThis paper provides a theoretical support and reference for the operational stability and structural optimization design of CO2 mixture gases DGS under high-pressure and high-speed operation conditions.

Numerical study of steady-state dynamic characteristic of non-pneumatic tire with local structural damage

Non-pneumatic tires (NPTs) fundamentally avoid the risk of tire blowout of traditional pneumatic tires, but the overall and key component performance inevitably degrades due to factors such as high temperature, variable load, variable working conditions and impact in its service process. Once this leads to failure, it will significantly impact on vehicle safety. To this end, this paper studied the influence of local structural damage on the dynamic response of NPTs, which lays the foundation for realizing health monitoring of intelligent non-pneumatic tires (INPTs). Firstly, a three-dimensional nonlinear finite element model of NPTs was established, and the failure locations of NPTs were determined by fracture mechanics and maximum strain energy density; Secondly, the influence of structural damage on the static and dynamic performance of NPTs was analyzed; Finally, the sensitivity of the acceleration signal and sensor position of the tire inner liner to the local structural damage was studied. The research results show that structural damage will cause the stress of the spokes and shear layer to increase, and as the number of broken spokes increases, the shear layer will bear a larger load. Compared with the circumferential and lateral acceleration, the radial acceleration has the highest sensitivity to the damage of NPTs. The sensor closest to the damage location is the most sensitive to the damage. The research results provide a reference for the structural optimization design and health monitoring of INPTs.

Artificial neural network infused quasi oppositional learning partial reinforcement algorithm for structural design optimization of vehicle suspension components

Abstract This paper introduces and investigates an enhanced Partial Reinforcement Optimization Algorithm (E-PROA), a novel evolutionary algorithm inspired by partial reinforcement theory to efficiently solve complex engineering optimization problems. The proposed algorithm combines the Partial Reinforcement Optimization Algorithm (PROA) with a quasi-oppositional learning approach to improve the performance of the pure PROA. The E-PROA was applied to five distinct engineering design components: speed reducer design, step-cone pulley weight optimization, economic optimization of cantilever beams, coupling with bolted rim optimization, and vehicle suspension arm optimization problems. An artificial neural network as a metamodeling approach is used to obtain equations for shape optimization. Comparative analyses with other benchmark algorithms, such as the ship rescue optimization algorithm, mountain gazelle optimizer, and cheetah optimization algorithm, demonstrated the superior performance of E-PROA in terms of convergence rate, solution quality, and computational efficiency. The results indicate that E-PROA holds excellent promise as a technique for addressing complex engineering optimization problems.

Bending stiffness analysis of regular polyhedron sandwich structures

Abstract As a new type of sandwich structure, regular polyhedron sandwich structure has excellent structure performances such as high bending resistance and energy-absorbing features. However, the current design process of regular polyhedron sandwich structures often ignores the influence of unit-cell parameters on structural bending stiffness. Based on origami geometry, this study analyzes the geometric characteristics of polyhedron unit-cell structures. A simulation model was established to analyze the bending performance of regular polyhedron sandwich structures. The influence of the number of polyhedron surfaces and similarity transformation parameters on bending stiffness was analyzed by finite element software. Through finite simulation analysis, the influence graph of bending performance in the impact of various parameters was obtained. This analysis provides valuable insights for the optimization design of regular polyhedron sandwich structures.

Structural Design and Mechanical Properties Optimization of a Balanced Fiber-Reinforced Rubber Hose

This paper focuses on the optimal design of the structure of a balanced fiber-reinforced rubber hose (RH). A multi-spherical RH is proposed. Based on the grid method, the structure optimization design of single-spherical and multi-spherical RHs is performed. According to the constraints, the optimization results of the structural parameters of the RH are solved. Then, combined with the deformation characteristics of the conical RH, the cone-spherical RH is improved based on the spherical RH. The mechanical equilibrium angle and deformation expressions of the cone-spherical RH are deduced. The mechanical model of the balance performance, stiffness, and burst pressure for the cone-spherical RH is constructed. The structural optimization design of double-spherical and double cone-spherical RHs is performed to further reduce the stiffness of the RH based on the multi-spherical RH. Eventually, the correctness of the theoretical model and its optimization results is verified through experiments. The results of this research can provide reference data for future studies in related fields.

Supercontinuum generation in Ga‐Sb‐S chalcogenide‐based PCF using optofluidic approach

AbstractWe report the design and theoretical study of a Ga‐Sb‐S chalcogenide glass‐based photonic crystal fiber (PCF) structure for mid‐infrared supercontinuum generation. The proposed design is engineered by adjusting the diameter of air holes in the cladding region and pitch, giving us control over the dispersion characteristics of the fiber. The optimized structure design offers the Zero Dispersion Wavelength of 5.2 μm. When pumped with 50 fs secant hyperbolic pulses of peak power 4.9 kW, for a fiber of length 8 mm at pump wavelength of 5 μm, the proposed structure design produces an ultra‐broadband supercontinuum spectrum spanning 1.5–14 μm. Proposed PCF design should be helpful in, biomedical imaging, supercontinuum sources, biosesning, and optical coherence tomography.

Experimental and simulation study on mechanical properties of ZK60 magnesium alloy after accumulative roll bonding

Abstract The mechanical properties of two- and four-layered wrought ZK60 Mg alloy sheets after two passes of accumulative roll bonding (ARB) with different reduction were studied and the microstructure were analyzed. The four-layered ZK60 sheets after ARB with 50% reduction demonstrate better strength-ductility combinations with yield strength of 223 MPa, ultimate tensile strength of 327 MPa, and total elongation of 23.7%, compared with the initial ZK60 of 222 MPa, 291 MPa and 10.0%, respectively. The average grain size of four-layered ARB ZK60 sheet is reduced from 21.8 μm of the initial sample to 4.4 μm. Using a micromechanical finite element model, the strain hardening behavior of ZK60 sheet was successfully predicted. The predictions were in good agreement with the experimental results. The simulation results reveals that the high performance of ZK60 sheets may be contributed by the lamella structure formed by the fine and coarse grains, which can avoid the local stress concentration and inhibit initiation and propagation of the microcracks. These findings provide a theoretical basis for the structural optimization design of ZK60 Mg alloys.

A Novel Lifetime Estimation Method and Structural Optimization Design for Film Capacitors in EVs Considering Material Aging and Power Losses

A Novel Lifetime Estimation Method and Structural Optimization Design for Film Capacitors in EVs Considering Material Aging and Power Losses

Optimization of the annulus space structure for hydrocyclone separation of rubber particles based on NSGA-II and GMDH

Rubber particles produced during industrial rubber manufacturing pose significant health and environmental risks. Due to their small size, these particles are difficult to efficiently separate and recover. Previous studies have shown that increasing the annular gap can reduce the circulation of small particles within the hydrocyclone. However, the optimal design of the annular gap structure has not been thoroughly investigated. This paper focuses on the structural optimization of the annular space, dividing it into three parts: annular width (w), insertion depth (L), and diameter (Dh). Single-factor analysis reveals that an increase in annular width lowers the internal pressure field; an increase in annular insertion depth causes vortex movement downward, reducing the separation zone; and an increase in annular diameter generates vortices within the annular gap. Multi-factor analysis using GMDH and NSGA-II shows that the GMDH model has excellent predictive capability, with R2 values of 94.23 % for separation efficiency and 92.77 % for pressure drop. The optimal structure obtained from NSGA-II is the C-type hydrocyclone (Dh: 7.45, L: 7.2, w: 3.96), with separation efficiency and pressure drop of 85.72 % and 0.1649 MPa, respectively. The optimized hydrocyclone shows improvements of 4.46 % in separation efficiency and 8.89 % in pressure drop compared to the non-optimized performance. This study applies genetic algorithms to the structural optimization of the annular gap, providing theoretical insights into the design of hydrocyclone annular gap structures.

Electromagnetic Fields Calculation and Optimization of Structural Parameters for Axial and Radial Helical Air-Core Inductors

To improve the current density distribution and electromagnetic performance of air-core inductors, a structural optimization method combining back-propagation(BP) neural network and genetic algorithm(GA) is proposed for the study of axial and radial spiral multi-winding inductors. The Monte Carlo method was used to extract the structural size samples of the inductors, and the training dataset was obtained through the finite element calculation of electromagnetic fields. Based on BP neural networks, nonlinear mapping models between the inductance value, volumetric inductance density, current distribution non-uniformity coefficient, and inductor structural parameters were constructed. A sensitivity analysis of the inductor inductance value affected by the structural parameters was conducted using the Sobol index calculation. Using the current distribution non-uniformity coefficient as the fitness function and the volumetric inductance density as the constraint condition, a genetic algorithm was applied to globally optimize the structural parameters of the inductor. The optimization results were verified through a finite element comparison. The results show that, under the requirement of satisfying the volumetric inductance density, the current distribution non-uniformity coefficient of the Axial Helical Inductor (AHI)-type inductor was reduced by 4.57% compared with the best sample in the sampling, while that of the Radial Helical Inductor (RHI)-type inductor was reduced by 5.33%, demonstrating the practicality of the BP-GA joint algorithm in the structural optimization design of inductors.

Design optimization method of pipeline parameter based on improved artificial neural network

The rationality of pipeline design is directly related to its energy efficiency, reliability, and safety. Pipeline vibration may lead to negative effects such as mechanical loss and fatigue damage. Therefore, this study utilizes pipeline optimization design to mitigate these effects. Recently, neural networks have been widely used in structure design optimization. In the study, a backpropagation neural network (BP) combined with a variant slime mould algorithm (SMA) is utilized to solve the pipeline structure design optimization problem. Pipeline transport plays a crucial role in the efficient movement of various commodities, including but not limited to gas, oil, water, and other liquid substances. The interaction between liquid and pipeline can cause pipeline vibration and even damage. Therefore, based on the simulation model considering FSI (fluid-structure interaction), machine learning methods such as BP can predict vibration characteristics of fluid-conveying pipelines. However, existing research has shown that BP has insufficient parsing ability in structure mechanics problems, especially in solving the overall characteristics of complex structures (such as maximum structural strain). This study proposes an Arithmetic-based slime mould algorithm (ACSMA) with an adaptive decision strategy and a chaotic mapping strategy. A hybrid algorithm named ACSMA-BP is presented to promote the model's prediction ability. At last, to verify the effectiveness of the proposed pipeline structure design optimization approach, the ACSMA-BP model is utilized to complete a structure design optimization case for a simulated pipeline. The numerical results indicate that compared with AOA, CWOA, ESSAWOA, NGS_WOA, and RSA, the ACSMA has the best optimization ability.

Research on the influence of unsteady cavitation on the dynamics structures of a twisted hydrofoil based on variational mode decomposition method

Cavitation will produce complex dynamic effects on hydrofoil structures. In this paper, the effects of unsteady cavitation conditions on the dynamics of twisted hydrofoil structures are studied by using variational mode decomposition (VMD) and pearson correlation coefficient (PCC), etc. The research results indicate that there is a certain synergy between the flow field pressure pulsation signal and the structural field stress-strain signal in the frequency distribution of the hydrofoil under cavitation conditions. The second-order center frequency of ΔP1 and the first-order center frequency of ΔP7 are close to the second-order center frequency of the stress-strain signal of the hydrofoil (1202.4Hz). Unsteady cavitation can lead to the increase of the high effective force region of the hydrofoil, especially the high effective force region connecting the leading edge and the root, which is the reason for the degradation of the hydrofoil performance. Cavitation increases the natural frequency of the hydrofoil, but has no obvious effect on the natural mode of the hydrofoil. The research results of this study reveal the effect of unsteady cavitation on the dynamics of hydrofoil structure, and provide important theoretical support for the optimization design and performance improvement of hydrofoil structure.

Historical evolution of structural optimization techniques for steel skeletal structures including industrial design applications

This study covers the review of algorithms developed for the optimum design of steel skeletal structures from the first article published in 1960 until to date. The paper initially describes the mathematical formulation of a simple truss structural design problem. The early optimum design algorithms that were based on mathematical programming techniques where the design variables are assumed to be continuous are reviewed. The optimum design of steel framed structures necessitates the selection of steel profiles from the standard list of discrete steel sections and requires the satisfaction of design code provisions. Both mathematical programming and optimality criteria techniques need more capability to produce solution to this type of optimum design problems. Soft computing techniques emerged recently provide solution directly without needing any approximation. These techniques are classified and reviewed and their use in obtaining the optimum solution of actual industrial steel design applications is given.

Mechanical Response and Anti-Reflective Crack Design in New Asphalt Overlays on Existing Asphalt Overlaying Composite Portland Cement Pavement

A detection and evaluation system containing a two-level index of structural integrity and bearing capacity was constructed based on ground-penetrating radar (GPR) and a falling weight deflector (FWD). This system was constructed to solve problems with the detection, evaluation, and structural and material design of asphalt rehabilitation for the prevention and control of asphalt reflection cracks in asphalt overlaying composite Portland cement pavement. Based on the detected data from the GPR and FWD, the reasonable and recommended thickness range of the stress-absorbing layer was determined by the finite element method, and the optimization design of an anti-reflective crack structure is proposed. Furthermore, a material design and engineering application of the stress-absorbing layer was carried out. The results show that an additional 10 cm layer of repaved asphalt can reduce temperature stress by 64.1%, reduce fatigue stress by 29.3% at the cement slab bottom, and extend the service life by 23.1 years. The reasonable thickness of the stress-absorbing layer ranges from 1.6 cm to 2.0 cm, and the recommended structural combination design is a 4 cm SMA-13 upper layer, a 4 cm AC-16 lower layer, and a 2 cm stress-absorbing layer overlaying existing asphalt overlay. The impact toughness of the designed stress-absorbing layer is 1.05 times and 1.44 times that of the other stress-absorbing layer and the AC-16 asphalt mixture, respectively, which have been successfully used for more than 5 years. The recommended design rehabilitation has good engineering application. The uniformity of the stress-absorbing layer can reach 63%, and an anti-reflective crack effect is expected. The results of this study provide design methodology and experience for composite pavement repaving.

A structural mechanics analysis on a Type IV hydrogen storage tank during refueling and discharging

High-pressure hydrogen gas, as a power generation fuel widely used in transportation, has significantly contributed to the development of hydrogen fuel cell electric vehicles. However, obvious temperature rise and drop during fast refueling and discharging cause serious safety risk to the structural stability of on-board hydrogen storage tank. The American Society of Automotive Engineers SAE J2601 and the international standard ISO 15869 strictly stipulate that the operation temperature range of hydrogen storage tank varies from −40 °C to 85 °C. In this study, a finite element mechanics model was constructed using ACP and Static Mechanical software to better understand the deformation, stress, strain, and failure modes experienced by a Type IV tank during charging and discharging. Detailed parameters such as ply angle, ply thickness, mesh generation, and boundary conditions, were extensively elucidated. The results indicate that the high temperature and pressure generated during fast fueling of the storage tanks are less likely to cause yield failure of the inner, outer layers and plug, but the stress concentration caused by low temperature and high pressure may lead to the fracture rupture of internal polyethylene materials. Aluminum alloy plug, serving as sealing devices for the tank, are most susceptible to yielding failure under coupled conditions. The mechanical load reaching the yield stress of the plug is approximately 85 MPa with the nominal working temperature of 85 °C. Additionally, the maximum stress on the outer layer can be reduced by adjusting the circumferential layer direction from 90° to 70° or by optimizing the orientation of the maximum stress layer increasing it by 110°. The present study can offer new insights into the dynamic loading behavior of the Type IV tanks during fast charging and discharging, and may provide technical references for optimization design of the tank structures.

Sustainable and cost-effective optimal design of steel structures by minimizing cutting trim losses

Since the beginning of the structural optimization field, the optimal design was characterized by the least-weight configuration. In this sense, all the researchers agreed on adopting the minimum-weight optimization statement as the most promising approach to achieve an optimized employment of material. However, especially for steel structures, this approach completely fails the primary goal of encouraging standardization of pieces during the production phase. Except for rare cases, increasing diversity among structural elements leads to a dramatic increase in the financial cost as well as the environmental impact of the structure because of the material waste generated during the cutting procedure.In this paper, a real-coded Genetic Algorithm has been adopted and the well-known one-dimensional Bin Packing Problem has been implemented within the structural optimization process. The Objective Function formulation lies in a marked change of the paradigm in which the target function is represented by the amount of steel required by the factory instead of the structural cost (e.g. weight). The proposed approach is tested on different steel structures moving from 2D truss beams to 3D domes. Addressing the optimal stock of existing elements leads to a significant waste reduction of 40% in almost all the investigated case studies.

Structural design optimization of cast glass artwork via a digital design solution

Structural design optimization of cast glass artwork via a digital design solution

Low-frequency broadband acoustic metamaterial absorber based on nested resonator and synergistic coupled weak resonances

Utilizing absorbers with sub-wavelength thickness for low-frequency broadband noise control is a challenging problem, and rapid on-demand design of structures based on target noise frequency has received continuous attention. In this work, nested cavities are introduced into the typical neck-embedded Helmholtz resonator (NEHR) to obtain the nested neck-embedded Helmholtz resonator (NNEHR), which exhibits better cavity partitioning volume fraction and covers wider sound absorption band. Both theoretical analysis and simulations demonstrate that NNEHR possesses superior acoustic properties: generating an additional absorption peak, lowering the position of the first absorption peak by 11 %, and increasing the absorption coefficient by 4.7 %. Instantaneous velocity fields and thermal-viscous energy dissipation density illustrate that the efficient sound absorption of NNEHR originates from resonant dissipation in the neck and surrounding areas. Furthermore, by combining the theoretical model with genetic algorithms, three sets of NNEHR metasurfaces are optimized. The optimized structures achieve average absorption coefficients of 0.831, 0.913, and 0.885 in the range of 250–550 Hz, 400–1000 Hz, and 500–2000 Hz, with a thickness of only 50 mm, reflecting sub-wavelength, low-frequency broadband sound absorption characteristics. The excellent absorption stems from synergistic coupled weak resonances and higher-order absorption peaks of constituent units, and the overdamping characteristic ensures the realization of the optimal structure with minimal thickness. The contribution of weak resonant units to the total sound absorption performance can be measured by the surface admittance normalized by the total incident area, and the essence of the coupling effect is the strong interaction between units with adjacent absorbing frequencies. The proposed structure exhibits good sound absorption performance and great adjustability, while the genetic algorithm optimization based on the theoretical model demonstrates high efficiency and robustness, providing a methodology for the design and on-demand optimization of low-frequency broadband structures.