Unified Design Method Research Articles

A unified cross-series marine propeller design method based on machine learning

Propeller design diagrams, like Bp-δ diagram, are widely applied in ship propeller design. However, different propeller series use various selection approaches, so comparisons between designs are only possible after individual candidates are chosen.This paper proposes a unified approach based on machine learning to allow efficient comparison and facilitate the selection of the optimal propeller amongst the available propeller series. The process starts by compiling propeller series data to generate a comprehensive dataset on propeller performance. This dataset is then used to train an Artificial Neural Network (ANN) model, which accurately predicts open-water propeller performance. Optimization techniques are applied to maximize propeller efficiency based on the specific needs of the vessel, while ensuring compliance with cavitation and noise constraints for safety. The model's accuracy is validated using data from the KRISO Container Ship (KCS), demonstrating the prediction's reliability. The method is then applied to select both open and ducted propellers for a variety of ship types to meet specific operational requirements. Ultimately, the optimized results are ranked by efficiency, offering an organized set of options for selecting the most suitable propeller. This approach eliminates the need for manual dataset correlation, significantly improving the efficacy of generating an outperforming initial design.

A unified optimization design method for multi-stage non-circular gear transmission based on periodic B-spline interpolation

This research introduces a novel and unified optimization design method for multi-stage non-circular gear transmission (MNCGT) to address the challenges in designing MNCGT for complex motion requirements. The method optimizes non-circular gears comprehensively, reducing design and manufacturing difficulties while ensuring the realization of specified transmission requirements. A unified parameterization method, grounded on periodic B-spline interpolation, is introduced to establish the transmission function of non-circular gears and map it to a finite unified variable space. This innovative approach effectively reduces the difficulty and constraints of MNCGT optimization design. The proposed method takes into account crucial factors such as non-circularity, smoothness, processing conditions, and contact ratio, which significantly impact the transmission performance and manufacturing feasibility of non-circular gears. The effectiveness and superiority of this method are demonstrated through two practical examples and a real-world application in a planetary gear transplant mechanism, highlighting its potential for solving complex engineering problems.

Unified machine-learning-based design method for normal and high strength steel I-section beam–columns

High strength steel is regarded as a promising construction material due to its superior mechanical properties. However, the codified failure load predictions for high strength steel welded I-section beam–columns are not accurate in some cases owing to the lack of relevant design codes for high strength steel structures. In addition, current design codes ignore the interaction effect of the cross-section plate elements, leading to the inaccuracy of codified predictive ultimate resistances for both normal and high strength steel beam–columns. In this paper, a unified and accurate design method was proposed based on machine learning for both normal and high strength steel welded I-section beam–columns failing by different failure modes. Firstly, a total of 812 experimental and numerical data on welded I-section beam–columns with various steel grades, geometric dimensions, including cross-section dimensions and member lengths, and failure modes, including global buckling, local buckling and local–global interactive buckling were collected to establish a database. Seven machine learning algorithms, including Decision Tree, Random Forest, Support Vector Machine, K-Nearest Neighbour, Adaptive Boosting, Extreme Gradient Boosting and Categorical Boosting were applied to develop regression models to predict failure loads. Based on the established database, each machine learning model was then trained and key hyperparameters were optimised. The model performance was evaluated through a series of statistical indicators and the feature importance analysis, and the evaluated results indicated that the XG-trained regression model had the highest level of accuracy. Finally, the predictions given by the XG-trained regression model were compared with those of the existing codified design provisions, as given in Eurocode and American codes. The evaluation results indicated that the codified predictive bearing capacities of I-section beam–columns were scattered and inaccurate, while the XG-trained regression model provided substantially improved failure load predictions.

A Unified Design Method for Multi-Source Complementary Heating Systems Based on a Transient Simulation

Combining various sources to create a complementary system plays a key role in utilizing clean energy sources economically and mitigating air pollution during the heating season in Northern China. However, there is a lack of unified and reasonable design methods for such systems, resulting in the excessive capacity of equipment and the waste of energy. In this work, a unified design method is proposed to solve this problem. A generalized structure and its mathematical model are firstly established, enabling transient simulations on the TRNSYS platform. Then, a preliminary screening criterion for the system composition a general operation strategy is proposed. Finally, the system configuration is optimized by using the genetic algorithm. The method is successfully applied in a demonstration project in China. The results show that the coupling system consisting of a biomass boiler (384 kW), an air-source heat pump (430 kW) and a ground-source heat pump (369 kW) is the most economical, and the annual cost is 26.7% lower than that of a single-equipment system. Additionally, the sensitive factors that strongly affect the optimization results are explored. The establishment of the generalized structure and its mathematical model enables the quick calculation and convenient comparison of various schemes, and simplifies the complicated optimization problem of the capacity optimization of each piece of equipment. The proposed design method can reduce the annual cost to a minimum value, and thus it provides a theoretical basis for the large-scale application of clean energy sources for heating.

A unified design method for 2D auxetic metamaterials based on a minimal auxetic structure

Auxetic metamaterials are architected structures that possess a unique property known as a negative Poisson’s ratio. This remarkable characteristic enables them to expand or contract in a direction perpendicular to stretch or compression. Due to their exceptional attributes such as energy absorption and fracture resistance, these auxetic metamaterials hold great promise for various applications across multiple domains.However, the widespread development of these materials has been hindered by the absence of an efficient design method. Addressing this limitation, our work introduces a minimal 2D auxetic structure and a corresponding design approach that comprises two geometric transformations. This design method not only allows for the replication of existing auxetic structures but also facilitates the creation of novel structures. Additionally, it enables the classification of these structures into six distinct categories.To enhance the understanding and standardization of these structures, we propose a naming protocol and define their associated unit cell. Furthermore, we explore the possibilities of tessellations within this framework. Finally, we examine the auxetic structures from the perspective of surface strain, which is closely linked to the Poisson’s ratio, the Bulk modulus and compressibility.

Unified design method of time delayed PI controller for first order plus dead-time process models with different dead-time to time constant ratio

Unified design method of time delayed PI controller for first order plus dead-time process models with different dead-time to time constant ratio

Proportional-Integral Observer-Based State Estimation for Markov Memristive Neural Networks With Sensor Saturations.

This article investigates the resilient proportional-integral observer (PIO) problem for Markov switching memristive neural networks (MSMNNs) with randomly occurring sensor saturation within a finite-time interval. The Markov switching of memristive neural networks is regulated by a higher level deterministic switching signal, whose transition probabilities are piecewise time-varying and can be depicted by the average dwell-time strategy. Meanwhile, a Bernoulli stochastic process associated with an uncertain packet arriving rate is adopted to describe the randomly occurring sensor saturation. The aim is to design a resilient PIO such that the augmented dynamic has the property of stochastic finite-time boundedness while meeting the desired performance index. By applying the Lyapunov method and the average dwell-time scheme, sufficient criteria are established for MSMNNs, and a unified design method is presented for the existence of the PIO. Lastly, the attained theoretical results are validated via a numerical simulation.

Semiglobal Robust Consensus of General Linear MASs Subject to Input Saturation and Additive Perturbations.

This article considers the robust consensus problem of the general linear multiagent system (MAS) subject to both heterogeneous additive stable disturbances and input saturation. Distributed low gain feedback-based dynamic output feedback control protocols are proposed, which do not need the controller interaction. Algebraic Riccati equation and unified H∞ controller design method are employed to design the output feedback control protocols. It is established that under the assumption that each agent is asymptotically null controllable with bounded controls, semiglobal robust consensus can always be reached under the proposed controller. Furthermore, the design method specialized for leader-following consensus is addressed, under the assumption that the Laplacian matrix is diagonalizable, one can design the control protocol only with the number of follower agents. Finally, several simulations are provided to show the effectiveness of our results.

Simulation and design of passive residual heat removal system for Fluoride-Salt-cooled high-Temperature Advanced reactor (FuSTAR)

The new generation of reactor technology: Fluoride-Salt-cooled high-Temperature Advanced Reactor (FuSTAR), mainly applied to the steady supply of stable electricity and high-temperature process heat for remote, underground, and arid areas. So far, the design of neutron physics and thermal hydraulics of the core have been finished, but the heat transport system and Passive Residual Heat Removal System of FuSTAR still need to be designed and optimized. Given the complexity and consistency of the design, a unified design and optimization method is required, which can directly obtain detailed configurations and dimensions. In this paper, a design and optimization method - Multi-Layer Nonlinear Programming was proposed to obtain the optimal parameters, including vital thermodynamic values, the dimensions of heat exchangers, the configurations of pipelines, and the optimal equivalent parameters in the transient simulation. Finally, based on Multi-Layer Nonlinear Programming, the effectiveness of the Passive Residual Heat Removal System was demonstrated by the deterministic safety analysis. The detailed parameters of the Passive Residual Heat Removal System in this paper can provide references for subsequent experimental verification. Moreover, for any reactor relying on a heat transport system, researchers can directly obtain its excellent preliminary configurations by this method avoiding a lot of iteration and conflict design, which is conducive to the integrated modeling and simulation of a new generation of reactors.

Unified Flexural Resistance Design Method and Evaluation Frame for the B-Regions of RC Flexural Members—Theory and Application

The load and resistance factor design (LRFD) method is normally used to design B-regions of reinforced concrete (RC) flexural members. The design includes many checks corresponding to different limit states. The LRFD method requires many loop calculation steps in the design, demonstrating its relative inefficiency. It cannot be applied to compare limit states directly and quantitatively. Different design limit states are separated and isolated. How to improve the analytical calculation efficiency of the LRFD method and to realize direct and quantitative comparisons between limit states are very important problems in structural engineering. This paper presents an innovative unified flexural resistance design (UFRD) method and a unified flexural resistance evaluation (UFRE) frame to solve these problems to some extent. The main contents include the unified flexural resistance (UFR) principles, formulas for the unified flexural resistance design (UFRD) method, the operation procedure to facilitate its usage, the UFRE framework to compare limit states, and three examples. The results show that the UFRD method can provide the same design outcomes as the LRFD one. However, UFRD calculations are simpler, requiring at most 20% of the calculation steps of the LRFD method. The UFRE frame can make different limit states compare with each other directly and quantitatively, which cannot be realized by the LRFD method. It helps expose some potential and insufficient flexural resistance hazards for some limit states, such as the only 10% relative strength reservation of one example. Thus, the UFRD method and the UFRE frame supplement and develop the LRFD method to some degree. The simplicity and practicality of the approach and the frame make them appropriate for many applications.

Hierarchical Structure Objects Information Systems Decision Support Developing Process

Application of methods for designing decision support information systems for hierarchical systems is considered. Determining the interaction parameters of methods for designing decision support information systems for managing hierarchical production and technical systems is an urgent scientific problem, the which solution makes a significant contribution to the development of technologies for designing decision support systems. The process of operation of a decision support system for the analysis of hierarchies using the full graphical interface technology, a functional model of an expert information system for the analysis of hierarchical structures is presented. Hierarchical production and technical systems are complex, which entails great complexity in the development of decision support information systems to manage them. This complexity creates the problem of 'crisis' in the development of such systems for hierarchical production and technical systems. Despite many advantages and a long history of successfully applying the unified design method to the development of information systems, it does not completely overcome the problem of this crisis. To overcome this problem for hierarchical production and technical systems, it is proposed to modify the unified design method and use the synergistic effect from the combined use of structural, object and visual modelling methods in the form of a new design method - a modified system design process. The article presents the scheme and algorithm of the proposed method, the results of the analysis of its application. The possibility of its application to systems with a hierarchical structure is established. Unlike traditional models of information systems, the decision support information system model built according to the new method successfully integrates various subject areas of knowledge due to its visibility and support for object-oriented design technologies, which allows it to be effectively used to create an expert information system model for complex technical systems.

Orthogonal Adjacent-Order Filtering Element-Based Wideband Transmissive Linear-to-Circular Polarization Converter

This article proposes a unified design method for a highly efficient wideband transmissive linear-to-circular polarization converter composed of two orthogonal adjacent-order bandpass filtering elements for the first time. First, the linear-to-circular polarization converter is constructed to convert two orthogonal linearly polarized (LP) spatial waves split from a 45°-slant incident plane wave into a desired circularly polarized (CP) wave. Taking advantage of the wideband filter synthesis method and phase shifter theory, polarization converter elements with prescribed specifications [e.g., fractional bandwidth (FBW) and Chebyshev passband ripple] are then synthesized by the corresponding low-characteristic-impedance bandpass filtering networks with the loading of shunt short-circuited stubs on quarter-wavelength transmission line (TL) sections. The adjacent-order phase difference function with a natural ±90° value at a center frequency can be simultaneously manipulated by a filtering bandwidth. The theoretical axial ratio (AR) curve is calculated by the synthesized magnitude responses and phase deviation (PD) function. The design guideline is then summarized. Finally, based on the third- and fourth-order bandpass filtering networks, a prototype of the proposed linear-to-circular polarization converter operating at 5 GHz with a designable 70% 3 dB AR bandwidth is implemented, fabricated, and tested by the free-space measurement method. The transmitted CP wave with three in-band AR minima and relatively stable angular performances can be efficiently converted from the incident LP spatial wave as well verified in the experiment. The AR curves and design requirements of different adjacent-order bandpass filtering combinations are further explored according to the proposed design guideline.

Effect of nano-serpentine and nano-La2O3 on the frictional properties of PTFE composites in seawater environment

PurposeThis paper aims to investigate the tribological properties of polytetrafluoroethylene (PTFE) composites modified by nano-serpentine and nano-lanthanum oxide in a seawater environment.Design/methodology/approachIn this paper, seven PTFE composites were prepared by unified design method and vacuum thermoforming method, and their hardness, water absorption and tribological properties were measured under seawater environment. The modification effects and thermal stability of the materials were analyzed by Fourier transform infrared spectroscopy, thermal gravimetry and differential scanning calorimetry. This paper analyzed the wear mechanism of PTFE composites by scanning electron microscopy and energy spectroscopy.FindingsThe results showed that the hardness of the PTFE composites were all improved, but the water absorption was increased with the increase of additives. The modification of nano-serpentine was successful and the thermal stability of PTFE composites was better. The lowest coefficient and minimum wear rate are 0.0267 and 8.67 × 10−5 · mm3 · (N · m)−1 respectively, which is 34.9% and 76% less than the pure PTFE.Originality/valueThe analysis showed that the wear mechanism of PTFE composites was abrasive wear and a small amount of adhesive wear, and when the additive content was appropriate, it easily formed a transfer film on the surface mating parts.

Principle and Unified Design of Circularly Polarized Quadruple Inverted-F Antenna With Miniaturized Size and Enhanced Front-to-Back Ratio

The fundamental working principle of front-to-back ratio (FTBR) enhancement of the quadruple inverted-F antenna (QIFA) is clearly revealed for the first time, and a unified design method is then proposed in this article. The characteristic mode analysis (CMA) demonstrates that the QIFA actually operates in two orthogonal modes, and analytical derivation validates that each mode acts as a pair of parallel magnetoelectric (ME) short dipoles for radiation. More specifically, the FTBR of the antenna is determined by the amplitude ratio and phase difference of the two pairs of equivalent ME dipoles. The equivalent model and analytical method can greatly facilitate the design. First, by leading or lagging phase of either characteristic mode through excitation, the beam direction can be flexibly prescribed as forward and backward. Second, the bending direction and bending degree of radiators, respectively, determine the phase and amplitude of its equivalent magnetic dipole, by which the FTBR can be improved. A practical design is carried out with the proposed method, and the antenna achieves an electrically small size of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.068\lambda _{0} \times 0.068\lambda _{0} \times 0.052\lambda _{0}$ </tex-math></inline-formula> and an FTBR of 12.3 dB.

A general unified method for calculating fire resistance of CFST columns considering various types of steel and concrete

Due to the advantages of CFST structures, various types of steel (e.g., ordinary/high strength/stainless steel, etc.) and concrete (e.g., ordinary/high strength/ultra-high performance/recycled concrete, etc.) are used in them, and fire safety design is an indispensable part in the structural design of CFST. However, there is still a lack of a simple unified fire design method that can consider different materials and their combinations at the same time. Based on the unified calculation method of fire resistance of CFST based on average temperature proposed by the authors, this paper focuses on enhancing the generality and accuracy of the unified method, with specific attention paying to the prediction of material properties degradation effect and cross-sectional average temperature under fire. For the prediction of material properties degradation effect with considering various types of steel and concrete, two methods, namely the global equivalent method and the segmented equivalent method, are proposed to convert arbitrary temperature reduction factor models defined at material level to the corresponding equivalent models defined at CFST section level. After validating with various types of steel and concrete material properties reduction factor models given in the previous literature, it turns out that the equivalent models generated by the two methods can well approximate the temperature-induced degradation effect at CFST section level. As for the prediction of average temperature with considering various types of steel and concrete, an incremental calculation method to calculate the average temperature of steel tube and concrete core is proposed, which is compatible with various thermal property models for different types of steel and concrete without any intermediate conversion techniques. In the meantime, this incremental calculation method can be adopted for CFST members with or without protection and is also consistent with the temperature calculation formulas for steel structures given in Code. In conclusion, the improvements made in this paper can expand the application scope of the previously proposed unified method to various types of concrete materials and thus enhance the generality of the method.

A unified similarity criterion and design method for geometrically distorted scale models of thin-walled hull girder structures

For large scale thin-walled hull girder structures, the similar scale models of them cannot​ generally satisfy an equal scale ratio between the main dimension and plate thickness. Also, when the scale models are scaled to a too small dimension, the scale models have to be further simplified by reducing the number of the stiffeners to make enough room for welding operations. The purpose of this study is to develop a unified similarity criterion and a standard design method for such geometrically distorted scale models of large scale thin-walled hull girder structures. Based on an actual 11,4000DWT crude oil carrier hull girder structure, the proposed similarity criterion and design method was applied and validated. Numerical results show that the proposed similarity criterion and design method can guarantee a good similarity of the ultimate strength between scale models and prototype under combined loads. Also, we have derived the required condition that the proposed similarity criterion and design method can be applied to. To make a further verification of the numerical results and the proposed method, we designed and manufactured a geometrically distorted scale model for a large thin-walled box girder. A physical collapse test for the box girder was conducted to verify the reliability and accuracy of the numerical model.

Unified Modeling, Analysis, and Design of Isolated Bidirectional CLLC Resonant DC–DC Converters

Due to the bidirectional power transmission, high power density, and high efficiency, bidirectional CLLC resonant converters are attracting more and more research attention in electric vehicles and energy storage systems. However, the existing models are difficult to unify the bidirectional circuits to analyze and design the circuit factors, and thus the parameter design approach and bidirectional synchronous rectification (SR) become rather complex and cumbersome. Especially in asymmetric parameter design, a lot of calculations or iterations are needed, which seriously increase the difficulty of design. To address this concern, a bidirectional unified modeling, analysis, and design method is proposed in this article. By selecting appropriate and quantitative bidirectional circuit factors, this model unifies the forward and reverse circuits and establishes the relationship between them, which greatly simplifies the calculation or iteration of the parameter design and the complexity of bidirectional SR. In addition, this parameter design method makes the bidirectional gain reach a higher range and reduces the range of bidirectional switching frequency. Finally, this unified modeling, analysis, and design method is verified in bidirectional CLLC resonant converters including symmetrical full-bridge, asymmetrical full-bridge, symmetrical half-bridge, and asymmetrical half-bridge CLLC, respectively.

Retraction Note: Stability of slope rainfall condition based on GIS and nutrition intervention of football training

This paper mainly studies the problems related to the evaluation of high slope intelligent area under rainfall conditions and, through the unified design method, saturation unsaturation theory, marginal equilibrium neural network theory, and GIS, based on Fengjie area, studies the rainfall conditions and the evaluation of high and low slope stability in intelligent area. This paper provides a positive research and practice way for GIS intelligence and is establishing an intelligent regional evaluation system based on GIS platform. As the goal of high slope stability research under rainfall conditions, the intelligent regional evaluation map based on slope stability can become an important basis for Fengjie region to prevent and control global disasters. Although football training is scientific, scientific and reasonable use of nutrition intervention measures can improve the training efficiency of football players, increase the time of athletes to bear the extreme sports load, delay the fatigue of sports, and ultimately improve the performance of athletes. This study is based on the investigation and field test of nutritional intervention of football players and puts forward and proves the practical basis and empirical effect of nutritional supplements in football players. The purpose is to provide an effective basis for supporting football players’ nutritional supplements through targeted case studies. According to the research of GIS, it is applied to the slope rainfall and football training nutrition intervention, which can effectively improve the slope rainfall and football training nutrition intervention.

Theorem for the design of deployable kirigami tessellations with different topologies.

The concept of kirigami has been extensively utilized to design deployable structures and reconfigurable metamaterials. Despite heuristic utilization of classical kirigami patterns, the gap between complex kirigami tessellations and systematic design principles still needs to be filled. In this paper, we develop a unified design method for deployable quadrilateral kirigami tessellations perforated on flat sheets with different topologies. This method is based on the parametrization of kirigami patterns formulated as the solution of a linear equation system. The geometric constraints for the deployability of parameterized cutting patterns are given by a unified theorem covering different topologies of the flat sheets. As an application, we employ the design method to achieve desired shapes along the deployment path of kirigami tessellations, while preserving the topological characteristics of the flat sheets. Our approach introduces interesting perspectives for the topological design of kirigami-inspired structures and metamaterials.

Evaluation of Negative Skin Friction on Bridge Abutment Piles

Piles are used to transfer loads of structures to deeper and stronger soil layers through skin friction and/or end bearing. Surcharge loads, site grading, or dewatering may induce downward movement of soil adjacent to piles installed in a compressible medium. This movement creates negative skin friction stresses acting downward at the pile-soil interface, which applies additional loads “drag forces” to the pile causing a maximum axial load in the pile shaft at the “neutral plane”. To evaluate the development of drag forces, a comprehensive field monitoring program was conducted over four years for three instrumented abutment H-piles as part of a three-span bridge project. The soil settlement and changes in pore water pressure in the soil adjacent to the piles due to the construction of an approach embankment were monitored using multiple-point extensometers and vibrating wire piezometers. The piles’ elastic settlement and strains were measured using single-point extensometers and vibrating wire strain gauges. The field measurements are presented and discussed in terms of responses time histories and load distribution along one pile shaft. In addition, the calculated forces from vibrating wire strain gauges are compared with the unified design method prediction considering the total stress method (α-method) for cohesive soils. The results show that the maximum drag force was developed after the complete dissipation of excess pore water pressure and that the location of neutral plane varied during the embankment construction stages. Employing the total stress method in the unified design method provided a reasonable prediction of the drag force and the neutral plane’s location.