Structural Design Optimization Research Articles

Performance analysis of electrical signal output of multi-state flexoelectric structures with parameter uncertainties through quasi-Monte Carlo method

Flexoelectric effect is a more universal electromechanical coupling effect than piezoelectric effect. Flexoelectric beams as the main structural component of flexoelectric power signal output have broad application prospects in the next generation of micro–nano electromechanical systems. However, the electrical signal output of flexoelectric structures in macro-scale is far less than the output of the piezoelectric signal. Therefore, it is urgent to explore the influence of the parameter uncertainties on the electrical signal output of the flexoelectric structures, in order to improve the electrical signal output of flexoelectric materials with excellent design performance. Based on the quasi-static theory, the output voltage model and the output charge model of flexoelectric structures as well as the effective piezoelectric coefficient model are constructed. Then the influences of the flexoelectric parameters on the output voltage and the output charge are researched as well as the influence of the effective piezoelectric coefficient. Finally, the influences of uncertain parameters under different electrical states (e.g. the electrical open circuit and short circuit states) on the output performance of flexoelectric signal are studied by the quasi-Monte Carlo method, in order to further provide a reference for the reliability analysis and optimization design of the flexoelectric structures.

Dynamic response optimization of the multistage sandwich structures imperiled to explosive loading

Explosive attacks are increasing day by day in the present era, and the design optimization of protective structures without increasing their weight is mainly a critical task for vehicles. Assessment of the dynamic response of the structures under explosive loading through experimentation is costly, with many restrictions, and highly harmful for both people and the environment. Hence, the present study deals with an explicit numerical investigation of the protective sandwich structures’ blast performance. The influence of the number of stages of honeycomb on the sandwich structures’ blast mitigation capacity was evaluated with the effective utilization of face sheets’ material as their intermediate sheets while maintaining the total volumes as well as masses of the structure's constant. The explosive loads of 1 to 3 kg of trinitrotoluene were used for the stand-off distance of 100 mm. The rate-dependent Johnson-Cook plasticity model was implemented on the designed sandwich models to discover their damage behaviors. The sandwiches’ face deflection, energy absorption, kinetic energy variation, and crushing behaviors were considered to characterize their blast mitigation capacity. The obtained results showed that increasing the number of stages of core in the sandwich structure by using a fraction of the back face sheet materials for intermediate sheets significantly improved their blast performance without increasing their volume occupancies and masses. For the two-stage and three-stage sandwich designs, 50% and 20%, respectively, utilization of their back face material for their intermediate sheet was found to be optimal.

Structural analysis and optimal design of a spherical thin-walled stainless steel water tank without reinforced tie ribs

A spherical thin-walled stainless steel water tank without reinforced tie ribs has been designed to address the issues of easy fracture and corrosion of the ribs, difficulty in maintenance and cleaning, and short service life exposed during the use of thin-walled stainless steel water tanks with reinforced tie ribs. Firstly, an analytical model of a flat steel thin-walled water tank without reinforced tie ribs was established and subjected to static analysis under water pressure. The deformation and stress distribution patterns of the side molded plate of the flat box were obtained. Secondly, a spherical non ribbed thin-walled stainless steel water tank structure was designed with circular cross-section under different box bulge parameters, and its mechanical response characteristics under water pressure load were analyzed. A strengthening scheme was designed for the bottom box molded plate. Once again, optimize the combination design of the box scheme and the reinforcement scheme, and analyze their static, thermodynamic, and thermal solid coupling performance. Finally, the Latin Hypercube Sampling method was used to generate experimental design samples, and a response surface approximation model of a spherical thin-walled stainless steel water tank without reinforced tie ribs was constructed. The wall thickness of the box molded plate, skeleton, and reinforcement were used as design variables, and the maximum deformation and maximum equivalent stress were used as constraints. The lightweight design was carried out with the goal of minimizing mass. The research results indicate that the design program and parameter selection method for spherical thin-walled stainless steel water tanks without reinforced tie ribs proposed in the article are efficient and feasible, and can provide technical reference and theoretical support for the layout and overall optimization design of non ribbed thin-walled stainless steel water tank structures.

Optimal design of truss domes with frequency constraints using seven metaheuristic algorithms incorporating a comprehensive statistical assessment

In this article, seven recently developed metaheuristic algorithms are utilized for optimal design of dome-shaped trusses with natural frequency constraints. These algorithms are social network search, jellyfish search optimizer, equilibrium optimizer, teaching-learning-based optimization, grey wolf optimizer, colliding bodies optimization, and the improved grey wolf optimizer. This study focuses on the assessment and tuning of these algorithms to enhance both computational efficiency and solution quality. In particular, we introduce a hyperparameter tuning procedure that significantly improves the performance of the algorithms to make them more suitable for the solution of structural optimization problems. The performance of the selected algorithms is studied through five benchmark examples for design optimization of dome structures, from small-scale to large-scale cases, with frequency constraints. Many combination scenarios are studied for hyperparameter tuning of the algorithms in each design example in order to provide comprehensive statistical results determining the sufficient number of structural analyses as well as the number of particles to find an efficient condition of each algorithm. Indeed, this study also presents an insight into the efficient setting of hyperparameters for each algorithm, leading to a better solution with lower computational cost. Furthermore, the optimization results provide a comparison of the solutions obtained in the current and previous studies in order to demonstrate the suitability of the selected algorithms.

A novel subset assignment and matching method for DIC measurement of complex deformation in aircraft braking process

This paper proposes a measurement method related to the braking deformation of a complex motion. During the braking process, the deformation of the wheel includes large amounts of movement, vibration, warping, and distortion. A novel subset assignment and correlation method is proposed to measure the complex deformation. The proposed method can greatly improve the accuracy and stability of the calculation of complex deformations by simplifying the complex deformation into translational deformations in logarithmic coordinate system. According to the simulation and actual experiments, the proposed method can be utilized to measure the deformations of up to 100% tensile strain under complex deformation. According to the accuracy verification experiment, the error of the proposed method is less than 50 με. The results show that the proposed method can effectively carry out structural deformation measurement in the complex motion and deformation process. The proposed method has great significance for structural performance analysis and optimization design considering complex motion and deformation.

Failure analysis and numerical drive structure optimization design of Cr12Mo1V1 electrical connection die

A type of Cr12Mo1V1 electric connection die occured brittle fracture after 200 times of service, and its life was much lower than the design life of the die. In this paper, the 5M1E failure analysis method was adopted, combined with the characteristics of Cr12Mo1V1 cold-work die steel, scanning electron microscopy, direct reading spectrometer, Rockwell hardness tester, metallographic microscope and other means were used to analyze and test the macro fracture morphology, material composition, mechanical properties and microstructure of Cr12Mo1V1 electric connection die. The crimping process of the die was simulated by Deform software. The results show that the material composition is not up to standard, the strength is too low, the internal eutectic carbide is not uniform, the size of carbide exceeds the standard and so on are the root causes of the short life and brittle fracture of the die. In addition, the unreasonable designs of the crack slot and round hole of the die lead to excessive stress concentration in the crimping process of the die, which is too the main reason for the brittle fracture failure of the die. In view of the above factors, the paper puts forward some measures to prolong the life of the electric connection die from the aspects of raw materials, heat treatment, forging process and die structure design.

Numerical Analysis of Water–Sediment Flow Fields within the Intake Structure of Pumping Station under Different Hydraulic Conditions

The vortices, backflow, and siltation caused by sediment-laden flow are detrimental to the safe and efficient operation of pumping stations. To explore the effects of water–sediment two-phase flow on the velocity field, vorticity field, and sediment distribution within intake structures, field tests and numerical simulations were conducted in this study with consideration for the sediment concentration, flow rate, and start-up combination. We applied a non-contact laser scanner and ultrasonic Doppler velocimetry to obtain the field data and reverse modeling of the three-dimensional model of the intake structure under siltation. A multiphase flow model based on the Euler–Euler approach combined with the k-ε turbulence model was adopted for numerical simulation under 10 working conditions, and the reliability was verified with field data. The results indicate that sediment promotes the evolution of coaxial vortices into larger-scale spiral vortices along the water depth, and the process of sediment deposition is controlled by the range, intensity, and flow velocity of the backflow zone. Furthermore, the maximum volume fraction of the near-bottom sediment increased by 202.01% compared to the initial state. The increase in flow rate exacerbates the turbulence of the flow field. Although the increase in sediment concentration benefits the flow diffusion, it further promotes sediment deposition. This study provides a new idea for modeling complex surfaces and considers different operating conditions. It can serve as a scientific reference for the structural optimization and anti-siltation design of similar water-conservancy projects.

Review on structural optimization techniques for additively manufactured implantable medical devices

Recent developments in additive manufacturing (AM) have led to significant opportunities in the design and fabrication of implantable medical devices due to the advantages that AM offers compared to conventional manufacturing, such as high customizability, the ability to fabricate highly complex shapes, good dimensional accuracy, a clean build environment, and reduced material usage. The study of structural design optimization (SDO) involves techniques such as Topology Optimization (TO), Shape Optimization (SHO), and Size Optimization (SO) that determine specific parameters to achieve the best measurable performance in a defined design space under a given set of loads and constraints. Integration of SDO techniques with AM leads to utmost benefits in designing and fabricating optimized implantable medical devices with enhanced functional performance. Research and development of various lattice structures represents a powerful method for unleashing the full potential of additive manufacturing (AM) technologies in creating medical implants with improved surface roughness, biocompatibility, and mechanical properties. Furthermore, the integration of artificial intelligence (AI) and machine learning (ML) in structural optimization has expanded opportunities to improve device performance, adaptability, and durability. The review is meticulously divided into two main sections, reflecting the predictability of the implant’s internal structure: (a) unpredictable interior topology, which explores topology-based optimization techniques, and (b) predictable inner topology, concentrating on lattice structures. The analysis of the reviewed literature highlights a common focus on addressing issues such as stress shielding, osseointegration enhancement, customization to individual needs, programmable functionalities, and weight reduction in implant designs. It emphasizes significant advances in reducing stress shielding effects, promoting osseointegration, and facilitating personalized implant creation. The review provides a detailed classification of optimization methods, with each approach scrutinized for its unique contribution to overcoming specific challenges in medical implant design, thus leading to more advanced, effective, and patient-oriented implantable devices.

Structural Optimization and Control System Design for a Rake Dryer

Structural Optimization and Control System Design for a Rake Dryer

Acoustic wave devices based on piezoelectric/ferroelectric thin films for high-frequency communication systems and sensing applications

Surface acoustic wave (SAW) and bulk acoustic wave (BAW) based radio-frequency (RF) filters dominate in handsets markets mainly because they have miniature size so multiple filters can be used but take up very small board area. Besides, due to their inherent advantages, such as low insertion loss, relatively high resonant frequency, and miniature size, their application in the physical and biochemical sensing fields has also gradually expanded. The successful implementation requires specific knowledge of acoustic wave properties, the working mechanisms, material properties, and device design. So, in this review, we survey the SAW and BAW filter technology by discussing the working principles and the comparison between the operation frequency band allocations. In addition, the approaches to enhance the performance including the selection of single crystal/ferroelectric materials for BAW and the structure design optimization for SAW are introduced with discussions for further improvement. Then, flexible SAW and BAW devices are also presented and their new application opportunities in the fields of skin-like electronics and wearable health monitoring devices can be foreseen. Finally, the potential challenges of high frequency, wide bandwidth, miniaturization, and compatibility with the integrated circuits (IC) manufacturing process are overviewed as well.

Multi-physical Field Analysis Method for Enclosed Isolated Phase Busbar of Hydropower Station

In this paper, geometrical modelling and finite element multi-physical field analysis method are carried out for the actual layout of the enclosed isolated phase busbar (EIPB) of a hydropower station, for the horizontal and vertical connection parts that can hardly be considered in the analytical calculation process. The finite element model is able to accurately represent the main structure of the EIPB by reasonably simplifying some of the components. Meanwhile, the finite element model incorporates the coupling of magnetic field and transient structural field, allowing for analysis of the magnetic field distribution, stress-strain distribution, modal analysis, and harmonic response of each component of the EIPB. It is capable of analyzing the vibration response of the complex horizontal-vertical structure EIPB under different excitations. This method can overcome the limitations of analytical calculation methods in calculating complex structure EIPBs. It can also provide valuable guidance for the structural optimization design of future EIPBs.

Design and Study of Machine Tools for the Fly-Cutting of Ceramic-Copper Substrates.

Ceramic-copper substrates, as high-power, load-bearing components, are widely used in new energy vehicles, electric locomotives, high-energy lasers, integrated circuits, and other fields. The service length will depend on the substrate's copper-coated surface quality, which frequently achieved by utilising an abrasive strip polishing procedure on the substrate's copper-coated surface. Precision diamond fly-cutting processing machine tools were made because of the low processing accuracy and inability to match the production line's efficiency. An analysis of the fly-cutting machining principle and the structural makeup of the ceramic-copper substrate is the first step in creating a roughness prediction model based on a tool tip trajectory. This model demonstrates that a shift in the tool tip trajectory due to spindle runout error directly impacts the machined surface's roughness. The device's structural optimisation design is derived from the above analyses and implemented using finite element software. Modal and harmonic response analysis validated the machine's gantry symmetrical structural layout, a parametric variable optimisation design optimised the machine tool's overall dimensions, and simulation validated the fly-cutterring's constituent parts. Enhancing the machine tool's stability and motion accuracy requires using the LK-G5000 laser sensor to measure the guideway's straightness. The result verified the machine tool's design index, with the Z- and Y-axes' straightness being better than 2.42 μm/800 mm and 2.32 μm/200 mm, respectively. Ultimately, the device's machining accuracy was confirmed. Experiments with flying-cut machining on a 190 × 140 mm ceramic-copper substrate yielded a roughness of Sa9.058 nm. According to the experimental results, the developed machine tool can fulfil the design specifications.

Structure optimization design of extracorporeal circulation blood transport pump

Structure optimization design of extracorporeal circulation blood transport pump

Design optimization of irregularity RC structure based on ANN-PSO

Seismic design principles advocate for simple and regular structures to minimize earthquake damage. However, this frequently does not lead to unique and aesthetically pleasing designs, leading some engineers to select irregular structures despite the potential risks. The primary aim of this investigation is to achieve the optimal design of torsional irregularity coefficients for planar irregular reinforced concrete (RC) frames under static and dynamic loads, utilizing a 3D 6-layer model. Structural ground vibration analysis was conducted using the ETABS software. By imposing limits on the torsional irregularity coefficients for each layer of the frame layout, we subsequently applied the combination of artificial neural networks (ANN) with the particle swarm optimization (PSO) algorithm, namely ANN-PSO, to address the size distribution issue across the structure. The design variables included the dimensions of the columns located in each layer of the layout. The results demonstrate that the ANN-PSO algorithm optimizes the cross-sectional area of columns with significant variations. The coefficients of the torsion inequality rule in the optimized solution closely approach the minimum values. The dimensions and orientations of the optimized columns slightly differ from the pre-optimized scheme. In the optimized scheme, the coefficients of the torsional irregularity in the Y-direction meet the requirements, preventing any torsional irregularities from occurring. The research presented an effective method, including an innovative combination of ANN-PSO and the finite element method (FEM), for designing RC structures. The findings of the research provided a practical solution to fulfill torsional regularity criteria, indicating the proposed approach is an effective method for the economical and safe design of RC structures in earthquake-prone areas. The outcomes of the present study highlighted the innovative framework to achieve optimal and safe designs for irregular RC structures while minimizing torsional damage during earthquakes.

Topology optimization design of recoverable bistable structures for energy absorption with embedded shape memory alloys

In this work, multistable mechanical metamaterials with recoverable capabilities are designed for high energy absorption and resistance to repetitive impacts. Based on the known curved beam with energy dissipation characteristics, the shape memory alloys (SMAs) curved beam is added and optimized to achieve recoverability of the bi-layer beam structure. To simultaneously achieve bistable characteristics and recoverability in the designed metamaterial, the optimization model is formulated to maximize the energy absorption capacity of the structure while constraining the peak and valley forces. To solve this complex and highly nonlinear topological optimization problem with stringent constraints, the topological design of the SMAs layer is represented using a limited number of design variables along with the material-field series expansion strategy, and the optimization problem is subsequently solved using a non-gradient-based optimization algorithm. Finite element simulation results demonstrated that the optimized design possesses a substantial capacity for energy absorption. Additionally, the design structure can recover to its initial state from buckling induced by the initial load by regulating the external temperature. Different multistable metamaterials, including those designed to prevent repetitive impacts, have been further developed based on the designed recoverable high-energy-absorbing bistable unit cells, utilizing combinations of varying energy absorption capacities.

Structural design optimization through finite element analysis of additive manufactured bioresorbable polymeric stents

Coronary stents help to treat coronary artery disease. Polymeric-based stents are considered the next generation of these medical devices since the materials are more compatible with human cells. Developing a polymeric bioresorbable stent with a different and optimized design can improve the mechanical performance of polymeric additively manufactured coronary stents. In this study, two different polymers were processed by additive manufacturing, and their mechanical properties were analyzed: poly(lactic acid) (PLA) and poly(ε-caprolactone) (PCL). Five different designs (A, B, C, D, and E) were then conceptualized with three different thicknesses. Finite element analysis (FEA) of a stent implantation process, using the mechanical properties of the additively manufactured materials, was used to evaluate the influence of the design, after the stent expansion, on the radial recoil ratio (RRR) and foreshortening. The in-silico results demonstrated that reducing strut thickness originates more plastic deformation, which reduces the RRR and increases the absolute value of foreshortening. PLA-based stents presented less RRR but, simultaneously, more risk of fracture. In the case of PCL-based devices, only designs A, B, and C presented acceptable recoil ratios. Design A is the chosen design as it reduces the RRR for lower thicknesses without risk of fracture during the stent deployment.

Static and Dynamic Analysis of Coupled Vibration of Suspension Bridge Structure Under Earthquake Action

This article investigates the coupled vibration problem of suspension bridge structures under earthquake action, and conducts static and dynamic analysis using computer algorithms. In terms of static analysis, complex structures are divided into many small elements, and the stress and deformation of each element are calculated through finite element analysis, thereby obtaining the static characteristics of the entire structure. In terms of dynamic analysis, the seismic response analysis method based on time history considers seismic action as a time-varying external excitation, and calculates and simulates the dynamic response of the suspension bridge structure. In order to achieve efficient and accurate calculations, this article also adopts optimization algorithms and numerical calculation methods. Through a comprehensive study of statics and dynamics analysis, the key characteristics and regularities of coupled vibration of suspension bridge structures under earthquake action have been obtained. These research results not only provide important theoretical guidance and technical support for related engineering practices, but also provide useful references and inspirations for dynamic analysis and optimization design of similar structures. Meanwhile, using computer algorithms and simulation software for static and dynamic analysis can significantly reduce analysis costs and time, improve analysis accuracy and efficiency, and have broad application prospects.

Structural design and multi-objective optimization of a novel asymmetric magnetorheological damper

The MRD with continuously adjustable damping, small compression, and large extension for asymmetric output may improve all-terrain vehicle impact resistance and vibration reduction performance in a variety of conditions. A novel conical flow channel asymmetric MRD (CFC-MRD) is proposed to solve the structure complexity stroke sacrifice, and lack of failure protection concerns in currently studied asymmetric MRD structures. In the design, the non-parallel plate magnetic circuit characteristics of CFC-MRD are investigated, including theoretical analysis and finite element modeling, and the correctness of the model is proved by testing. Considerations in multi-objective optimization include special performance imposing extra restrictions, and making the work more complicated and prone to local optima. To address this, the Nelder–Mead approach is utilized, which decreases the complexity of the optimization model while simultaneously managing performance conflicts. And a collaborative optimization strategy employing Comsol and Matlab tools is applied to improve optimization efficiency. The greatest difference between theoretical optimized values and real values is less than 6.77% in the experiments, showing the efficiency of the CFC-MRD structure design and optimization process.

A review of fracture propagation in concrete: fundamentals, experimental techniques, modelling and applications

A comprehensive overview of fracture propagation in concrete, covering various aspects ranging from fundamentals to applications and future directions, is presented. The introduction presents an overview of fracture propagation in concrete, emphasising its importance in understanding the behaviour of concrete structures. The fundamentals of fracture propagation are then explored, including concrete as a composite material, crack initiation and propagation mechanisms, types of fractures and the factors that influence fracture propagation. Next, experimental techniques for studying fracture propagation are discussed, encompassing both destructive and non-destructive testing methods, such as acoustic emission, ultrasonic testing, digital image correlation and advanced imaging techniques like X-ray computed tomography and scanning electron microscopy. Modelling approaches, including continuum damage mechanics, the finite-element method, the discrete-element method, the lattice discrete particle model and hybrid models, for simulating and predicting fracture propagation behaviour are then reviewed. The applications of fracture propagation in concrete are highlighted, including structural health monitoring, design optimisation, failure analysis and repair and rehabilitation strategies. Research opportunities for further improvement are addressed. This article should serve as a valuable resource for researchers, engineers and professionals in the field, providing a comprehensive understanding of fracture propagation in concrete and guiding future research endeavours.

A computational tool for the design of rigid origami structures based on a lumped damage model

As it is well known, origami structures have broad application prospects in aerospace, medical, architectural, robotics, material science, and other engineering fields. However, the comprehension and modeling of the collapse process of this kind of structure are still in the process of development. This paper investigates one specific failure mode: ultra-low cycle fatigue under large displacements. Origami structures are represented as sets of elastic panels with small strains connected by inelastic (plastic-damaged) hinge lines with large rotations. A novel experimental study of the behavior of the Waterbomb origami structure subjected to cyclic loadings with constant amplitudes is first presented. Then, a new model of damage evolution for origami structures is proposed. Finally, parametric studies are described on the influence of several design parameters (initial folding height, number of sides of regular polygons, and length ratio) on structural collapse. The computational tools proposed in this paper can then be used for the optimum design of origami structures and the structural assessment during the two phases of loading: first, the deployment stage, and then service loads on the unfolded solid.