Optimum Design Research Articles

Friction and Wear Mathematical Modeling and Optimization Design of Surface Microstructure Parameters of Unfolding Wheel based on Experiment and Numerical Simulation

Objective: In order to improve the friction-increasing and wear-reducing performance of the unfolding wheel surface, the surface microstructure of the unfolding wheel used in the detection of 8 kinds of steel balls was optimized by parameter matching. Method: Firstly, based on Hertz's theory, the contact area between steel balls of different sizes and the unfolding wheel are analyzed. The wear depth model is established based on Archard adhesive wear model. Secondly, the appropriate microstructure parameters for friction and wear experiments were selected. The finite element analysis software is used to simulate the stress on the surface of the microstructure unfolding wheel and calculate the wear depth. According to the experimental results, the relationship between friction coefficient, wear depth and microstructure parameters is obtained by data fitting, and the objective function of optimization design is established. Finally, based on the genetic algorithm DNSGA-II and Python, the parameters are optimized, and the optimal solution is obtained by using the TOPSIS method. Results: The feasibility of the simulation method is verified by friction and wear experiments, and the correctness of the optimization method is verified. Some existing patents on friction and wear of microstructure surfaces are introduced, and the future development of this field is prospected Conclusion: The research shows that the optimal parameters matching of microstructure for steel ball diameters of Ф16.6688 mm~Ф22.2250 mm: the shape is rhombus; the area of a single pit is close to the contact area, which is 0.0319 mm2 ~ 0.0554 mm2; the pit depth is 145 μm~150 μm, and the surface density of microstructure is (5.4~5.6) /mm2.

Optimum Model-Based Design of Diagnostics Experiments (DOE) with Hybrid Pulse Power Characterization (HPPC) for Lithium-Ion Batteries

Diagnostics of lithium-ion batteries are frequently performed in battery management systems for optimized operation of lithium-ion batteries or for second-life usage. However, attempting to extract dominant degradation information requires long rest times between diagnostic pulses, which compete with the need for efficient diagnostics. Here, we design a set of efficient optimal hybrid pulse power characterization (HPPC) diagnostics using model-based design of experiment (DOE) methods, applying knowledge of degradation effects on pulse kinetics and cell properties. We validate that these protocols are effective through minimization of uncertainty, and robust with Markov Chain Monte Carlo (MCMC) simulations. Contrary to traditional HPPC diagnostics which use fixed pulse magnitudes at uniformly distributed state of charges (SOC), we find that well-designed HPPC protocols using our framework outperform traditional protocols in terms of minimizing both parametric uncertainties and diagnostic time. Trade-offs between minimizing parametric uncertainty and total diagnostic time can be made based on different diagnostics needs.

Investigation of Different Miniscrew Head Designs by Finite Element Analysis.

To determine the optimum miniscrew head design in orthodontic treatments for primary stability and compare stress distribution on a representative bone structure. Miniscrews with cross heads, mushroom-shaped heads, button heads, bracket heads, and through-hole heads were compared using finite element analysis. Miniscrews, whose three-dimensional drawings were completed using the SolidWorks computer-aided software package, were inserted in the bone block. Orthodontic force was applied to the head, and stress distributions, strains, and total deformations were investigated. The lowest von Mises stress of 5.67 MPa was obtained using the bracket head. On the other hand, the highest von Mises stress of 22.4 MPa was found with the button head. Through mesh convergence analysis, the most appropriate mesh size was determined to be 0.5 mm; approximately 230,000 elements were formed for each model. Because the need for low stress is substantial for the primary stability of the miniscrew, this study demonstrated that the bracket head miniscrew is the optimal head design. In addition, it is posited that the success rate of orthodontic anchorage treatments will increase when bracket head miniscrews are used.

Secure Short-Packet Communications via UAV-Enabled Mobile Relaying: Joint Resource Optimization and 3D Trajectory Design

Secure Short-Packet Communications via UAV-Enabled Mobile Relaying: Joint Resource Optimization and 3D Trajectory Design

Design for optimisation of drug administration

In the last few years, a new technology based on microneedles has been used for the delivery of drugs and vaccines. Microneedle patches ensure rapid, easy, and hygienic administration of drugs. This project was conceived to ensure the comfortable and safe transport as well as the sterile application of microneedles by users. Microneedles are particularly useful for diseases requiring daily medical care via distributed therapeutic treatments throughout the day. Microneedle Reminder is a wearable device for the wrist, containing nine ready-to-use patches.

Optimum design of a novel Ku-band rasorber for RADAR warfare systems using ML neural network

The design, fabrication, and testing of a conformal Frequency Selective Rasorber (FSR) operating at A-T-A mode is designed for RADAR warfare systems. In the design of a miniaturized single-layer FSR element, multiple parameters influencing the absorption and transmission characteristics need to be optimized. This simulation using conventional methods consumes more simulation time. Thus, the geometrical parameters are optimized and predicted using supervised machine learning (ML) techniques to expedite the process. The multiple output regression neural network (MORNN) is used to generate multiple input and output features from the dataset. The ML algorithm is trained using the datasets generated from the electromagnetic solver using which a scalable FSR is synthesized. The reflection coefficient, (|S11|), and transmission coefficient (|S21|) are used as input data, and the dimension of the FSR unit cell for the user input frequency requirements are derived as output data. The extracted dimensions of the FSR offered a small mean square error (MSE) of 0.02 between the desired and observed results. The designed FSR offers absorption at 11.5 GHz and 18.9 GHz while the transmission window extends from 15.02 GHz to 16.09 GHz. The neural network results are endorsed using the EM simulation tool and validated by experimental measurements.

Investigate the optimum design of atomizing nozzles for coal dust suppression by using multifactor level response surface methodology

Mechanized coal extraction generates substantial dust, adversely affecting the physical and mental wellbeing of underground workers and degrading the operational environment. To address the limitations of traditional spray systems, which often suffer from poor atomization effects and limited ability to withstand wind interference, the innovative vortex atomizing nozzle has been developed specifically for dust suppression. This advanced solution was rigorously tested through detailed numerical simulations and comprehensive experimental investigations. These studies focused on examining the impact of critical parameters, including the velocity at the airflow director's exit, the angle of the exit hole, and its radius, on the efficacy of dust suppression. Findings highlighted the paramount importance of the airflow director's exit velocity in enhancing dust removal, with the exit hole's radius having the least impact. Optimal conditions for dust suppression were identified as an airflow director exit velocity of 20 m/s, an angle of 60°, and a radius of 0.6 mm. Field validations under these optimum parameters demonstrated unparalleled dust control efficiency, achieving a reduction in coal dust concentration exceeding 90 %. This apparatus offers a highly effective, user-friendly solution for comprehensive coal dust management across various mine locations.

Research of hydrodynamic processes in the flow part of a low-flow thermopressor

This research explores the hydrodynamic processes within the flow section of a low-flow thermopressor as a jet-type heat exchanger that utilizes the instantaneous evaporation of highly dispersed liquid in accelerated superheated gas flow resulting in reducing gas temperature with minimum resistance losses in contrast to conventional surface heat exchanger. The efficiency of thermopressor, as a contact heat exchanger, is highly dependent on the design of the flow section and the water injection nozzle. Geometric characteristics perform a crucial role in shaping gas-dynamic processes along the length of the thermopressor's flow section, influenced by resistance losses and local resistance in the tapering and expanding channel segments. Therefore, the optimum thermopressor design has to ensure minimize pressure losses. Using Computational Fluid Dynamics (CFD), the prototype thermopressor models were simulated and the results were compared with experimental data. The empirical equations for local resistance coefficients of thermopressor diffuser and confuser were received to evaluate the impact of various design parameters. The obtained local resistance coefficients for the confuser ranged from 0.02 to 0.08 and for the diffuser – from 0.08 to 0.32. The practical recommendations on geometric and operating parameters and characteristics for enhancing the efficiency of hydrodynamic processes in thermopressor flow part were given.

Multi-Objective Optimization in Support of Life-Cycle Cost-Performance-Based Design of Reinforced Concrete Structures

Surveys on the optimum seismic design of structures reveal that many investigations focus on minimizing initial costs while satisfying performance constraints. Although reducing initial costs while complying with earthquake design codes significantly ensures occupant safety, it may still cause considerable economic losses and fatalities. Therefore, calculating potential earthquake damages over the structure’s lifetime is essential from an optimal Life-Cycle Cost (LCC) design perspective. LCC analysis evaluates economic feasibility, including construction, operation, occupancy, maintenance, and end-of-life costs. The population-based, meta-heuristic Ideal Gas Molecular Movement (IGMM) algorithm has proven effective in solving highly nonlinear mono- and multi-objective engineering problems. This paper investigates the LCC-based mono- and multi-objective optimum design of a 3D four-story concrete building structure using the Endurance Time (ET) method, which is employed for its efficiency in estimating structural responses under varying seismic hazard levels. The novelty of this work lies in integrating the ET method with the IGMM algorithm to comprehensively address both economic and performance criteria in seismic design. The results indicate that the proposed technique significantly reduces minor injury costs, rental costs, and income costs by 22%, 16%, and 16%, respectively, achieving a total reduction of 10% in all structural Life-Cycle Costs, which is considered significant.

Numerical study of electrode permeability influence on planar SOFC performance

A solid oxide fuel cell (SOFC) is a clean and very efficient electrochemical conversion device, which generates electricity directly from fuel electrochemical oxidation. In this paper, a three dimensional numerical model has been developed in order to analyse the role of some thermophysical and morphological parameters on the performance of the SOFC cell. In particular, we studied the effect of the variation of permeability of the electrodes: fuel distribution, ionic and electric current density, pressure and diffusion flux are analyzed and compared. The volume fraction of the ionic and electronic phase in the electrodes is studied using a parametric study. It was shown that the current density enhanced by decreasing the permeability, up to a defined value, and it diminished with very small permeability. A remarkable influence of pressure and diffusion of species on the performance of the cell, with the variation of permeability, has been recognized. Varying the permeability in the active layer of electrodes has a large impact on the current density, connected to the volume fraction of ionic phase. This study permits to comprehend the relationship between the performance and microstructure of SOFCs. Meanwhile, it furnishes theoretical guidance for an optimum design of the electrode permeability.

Integrated Design Optimization Process for Building Projects

In this study, a cost-design optimization is conducted for a reinforced concrete structure with irregular voids and inclined axes, which is a real-world application. Data transfers are performed on a 3D model to achieve the optimization. Data exchange is managed automatically by the created software program. As an application example, a hospital building with 10 beds is considered. Optimum design and minimum cost values are obtained for optimization processes using the Rao algorithms. The construction cost values are compared both among algorithms and with actual cost values, indicating a successful optimization process. The software program developed in this study accelerates the processes in optimization operations, thereby contributing to the realization of automatic data transfers.

Design and comparison of particle swarm optimization tuned Kalman filter based linear quadratic Gaussian controller and linear quadratic regulator for surface to air missile guidance system

AbstractThe study of missile guidance systems is a well‐known nonlinear control engineering area of research. To enhance the control performance of a missle guidance system, several technologies have been proposed in existing works. To resolve the weighting matrix selection issue of a linear quadratic Gaussian (LQG) controller for the surface‐to‐air missile guidance control system, this study utilizes the particle swarm optimization (PSO) technique. Selecting the best state (Q) and input (R) weighting matrices is a significant difficulty in the design of the LQG controller for real‐time applications since it affects the controller's performance and optimality. The weighting matrices are often chosen by a trial‐and‐error method that not only complicates the design but also does not yield optimal outcomes. Therefore, in this paper, a PSO method is developed and used in the design of the linear quadratic regulator (LQR) and LQG controllers for the surface‐to‐air missile control system to choose the elements of the Q and R matrices in the best possible way. Finally, a comparative analysis between the designed controllers was presented. The results shows that a good performance was achieved by using the proposed PSO‐tuned design process. The LQG and LQR are designed by manually adjusting the weighting matrices and utilizing an intelligent procedure, PSO algorithm which achieved optimal results. Further results indicate that the designed controllers, the PSO tuned LQR and LQG achieved a better performance over the manually adjusted LQR and LQG controllers.

Effective Mechanical Properties of an Innovative Module-Free Li-Ion Battery Pack Integrated with Honeycomb Cells and Optimum Design for Enhanced Crash Energy Absorption

Effective Mechanical Properties of an Innovative Module-Free Li-Ion Battery Pack Integrated with Honeycomb Cells and Optimum Design for Enhanced Crash Energy Absorption

A novel semi-analytical pseudo-steady state finite-conductivity model for optimum horizontal-well completion design

This paper introduces a new technique to determine the optimum horizontal-well completion design in terms of the optimum horizontal-well length, the minimum wellbore/reservoir pressure drop, and the maximum wellbore/reservoir productivity index (PI) at pseudo-steady state (PSS). Frictional-wellbore pressure losses (FWPL) are accounted for based on a new general semi-analytical PSS finite-conductivity model (FCM) for a horizontal well under a rectangular bounded reservoir producing at a constant rate. The PSS FCM is coupling a PSS infinite-conductivity model (ICM) with a frictional-wellbore model (FWM) by using their correct-discretization resolution of the wellbore (CDRW), which has never been achieved before. The new FWM is developed in a general form to be coupled easily with any general ICM and can be applied at any time of the well production life. Two field examples are presented to show the effect of different reservoir, well, and fluid properties on horizontal-well performance.The new technique is based on the optimization of dimensionless well length (LD) between the two systems (i.e., ICM and FWM) of the FCM because LD is directly proportional to the PI of the first system and inversely proportional to the PI of the second system. Therefore, there is always a minimum point on the wellbore/reservoir pressure drop curve corresponds to a maximum point on the wellbore/reservoir PI curve.Results show that: 1. LD has the key role in the wellbore/reservoir coupling model.2. FWPL is crucial if both well production rate (qw) and horizontal permeability (kh) are high, where a notable drop in FCM PSS PI occurs, recommending shortening to the horizontal-well length.3. FWPL is insignificant if qw is low and oil viscosity (μo) is high, where no decrease in FCM PSS PI occurs, recommending lengthening to the horizontal-well length.4. Wellbore segment length (ΔL) of the FWM must be small, ΔL = 0.25 ft in this study. If it is not enough small, a critical overestimation may be occurred in the optimum horizontal-well length and the maximum PSS PI of the horizontal-well completion design.

Influence of PCHE size and types on thermodynamic and economic performance of supercritical carbon dioxide Brayton cycle for small modular reactors and its optimization

The supercritical CO2 Brayton cycle is a potential technology in small modular reactors (SMRs), and the overall system efficiency can be significantly improved by optimizing the PCHE design parameters. This study develops a thermodynamic-economic analysis model for a supercritical CO2 simple Brayton cycle cooled SMR, with consideration of the detailed parameters of PCHEs. The impact of the length, channel number and channel type for the recuperator and the precooler on system thermal efficiency and levelized cost of electricity (LCOE) are analyzed. A dual-objective optimization study is conducted at the system level to identify the optimal design of size parameters and types for the heat exchangers. The results indicate that the influence of PCHE size parameters variations on system performance varies across different channel types. Additionally, the selection of the recommended recuperator type is influenced by the recuperator inlet Reynolds number. At the optimum design, the recommended channel type for recuperator and precooler are both S-shaped, resulting in a system efficiency of 39.12% and LCOE of 0.0456 $/kWe. The findings are valuable for enhancing energy utilization and reducing the power generation cost of SMRs.

Optimization of column-in-column system based on non-conventional TMD concept

Previous studies showed that the non-conventional tuned mass damper (TMD) with large mass ratio outperforms the traditional one in respect to the structural vibration control efficiency and robustness. The authors recently proposed a novel control system based on the non-conventional TMD concept, namely the column-in-column (CIC) system, which was composed of a primary column, a secondary column and a series of interconnected springs/dashpots. In this novel system, the secondary column connected to the primary one with springs/dashpots could act as a large TMD to attenuate adverse vibration of the primary structure, and its control effectiveness was preliminarily verified through numerical investigations. However, the control robustness was found not sufficient based on the existing optimal formulae in the literature for CIC optimization. This paper presents a new design method for optimizing the CIC system for better harnessing its control effectiveness and robustness in reducing structural response. The CIC system consists of two columns with distributed mass and uniform flexural rigidity, connected by springs along the column height. The effective modal mass and modal stiffness of a specific vibration mode of the system can be straightforwardly calculated by using the Euler-Bernoulli beam theory. Considering the fundamental vibration mode of the system as the target response mode for vibration control, the multiple degree-of-freedom (DOF) CIC is simplified into a two DOF with three springs (2DOF3S) structural model, the design parameters, i.e., the optimal tuning frequency ratio and damping ratio of this system are derived to minimize the displacement response of the primary structure. To demonstrate the proposed design method, the effectiveness and robustness of the CIC system in controlling seismic induced structural vibrations are assessed in both the frequency and time domains. Results show that the derived optimum formulae are applicable for optimizing the TMD system with consideration of the distributed mass and deformation of the mass damper, i.e., a column in this study. The optimized CIC system has good control robustness even if the CIC is mistuned with its design parameters deviate from the optimal values by ±50 %. The conventional TMD system with lumped mass as the mass damper is a special case of the proposed CIC system. The optimized CIC system has favorable control efficiency in mitigating the seismic responses of structures with reduction ratios averagely varying within the range of 15 % ∼ 55 % with a probability of 92.67 %. It is concluded that the proposed method is reliable and can be used for the optimum design and control of the CIC system.

Optimum core structural design of the polymer optical waveguides as edge couplers for co-packaging

We simulate the optical properties of polymer optical waveguides with different refractive index profiles in their cores as coupling components (edge couplers) between single-mode fiber and SiOx waveguides. In this paper, we focus on the single-mode operation of graded-index (GI) core polymer waveguides, for which we previously demonstrated low propagation loss under multimode operation. We design the optimum core structure (size and index contrast) for different refractive index profiles, and then demonstrate the unique optical properties of GI waveguides contributing to the low optical loss compared to the step-index counterparts, in particular, mode field diameter variation and taper angle tolerance.

Reliability of Students’ Teaching Practice Scores Using Generalizability Theory

Purpose: The aim was to demonstrate the potency of using Generalisability Theory (GT) over Classical Test Theory (CTT) in reliability estimation. The objectives are to find the major source of error in the Intern Teaching Evaluation Form (ITEF) scores and to identify the optimum number of occasions of rating of teaching practice that would give the most reliable scores. Design/ Methodology/ Approach: A random effects one-facet fully crossed design in which intern (p) was fully crossed with occasion (o) was adopted for the study. In all, 9,082 bachelor’s degree teaching practice triplicate scores for three academic years from 2015/2016 to 2017/2018 were analysed in this study. A univariate generalisability analysis with EduG was performed to analyse data. Findings: The finding for relative interpretation, the scores were strongly reliable. For absolute interpretation, the scores were moderate to strongly dependable. The major source of error in the ITEF scores was the p x o interaction combined with unidentified sources. Research Limitation/Implications: A firm conclusion on one major source of error being a single facet in the ITEF scores could not be made. Practical Implication: The level of reliability and the optimum scoring design of the ITEF established by this study will aid in selecting the ITEF by teacher training institutions in Ghana for evaluation of teaching practice to train pre-service teachers for effective curriculum implementation to achieve national educational aims. Social Implication: Reliable evaluation data can inform policy decisions related to teacher certification, professional development, and educational standards. Policymakers can use this data to develop evidence-based policies that support teacher quality and student achievement. Originality/ Value: It has unearthed the psychometric properties and the ideal scoring design of the ITEF which were hitherto unknown.

Numerical optimization of hydrothermal and thermodynamical performance for metal foam multi-jet impingement cooling

A novel porous multi-jet impingement cooling technology since the current conventional cooling technologies are insufficient for thermal engineering devices. This innovative numerical study explores the effect of various metal foam sizes (h/H), jet numbers (n) and wavy jet target plates (C) on the hydrothermal performance and thermodynamical performance at varying Reynolds numbers (Re). The novel results of multi-objective optimum design are a unique aspect of this work by combining the results of RSM with CFD, where low porosity (ε = 0.1), low applied heat flux (Q = 100 × 103 W/m2) and low location jet ratio (LRVin = 0.26) were achieved the aim of the optimum hydrothermal performance (NumP/NumS = 25-30 times and Tb Reduction% = 83.5%-89.5%) and the thermodynamical performance (EG Reduction% = 93%-96% and CoPCarnot = 2.3-6.5 times). Thus, a valuable procedure for the optimal design of the hydrothermal and thermodynamical performance for porous multi-jet impingement cooling is proposed.

Solving a Multi-Objective Optimization Problem of a Two-Stage Helical Gearbox with Second-Stage Double Gear Sets Using the MAIRCA Method

This paper provides a novel application of the multi-criteria decision-making (MCDM) method to the multi-objective optimization problem (MOOP) of creating a two-stage helical gearbox (TSHG) with second-stage double gear sets (SDGSs). The aim of the study is to determine the optimum major design components for enhancing the gearbox efficiency while reducing the gearbox volume. In this work, three primary design parameters are chosen to accomplish this: the gear ratio of the first stage and the coefficients of the wheel face width (CWFW) of the first and second stages. Additionally, the study is conducted with two distinct objectives in mind: the lowest gearbox volume and the maximum gearbox efficiency. Moreover, phase 1 and phase 2, respectively, are the two stages of the MOOP. Phase 2 handles the MOOP to identify the ideal primary design factors as well as the single-objective optimization problem to minimize the difference between the variable levels. Additionally, the Multi-Attributive Ideal–Real Comparative Analysis (MAIRCA) approach is selected to deal with the MOOP. The results of the study are utilized to determine the ideal values for three crucial design parameters in order to create a TSHG with SDGSs.