Traditional Design Approaches Research Articles

Parameter design of grid-tied inverter using reinforcement learning

Grid-tied inverters have been widely adopted in distributed generation systems. The output current distortion and oscillation occur under certain conditions especially in the weak grid and multi-parallel inverters. To maintain the stability and ensure the dynamic and steady performance of current tracking, the controller parameters required iterative design and evaluation. Taking single phase inverter as an example, traditional design approaches are discussed first. Then, considering the difficulties in the parameter design process, deep reinforcement learning (DRL) is introduced to explore the optimal combination of controller parameters, by which the parameters of controllers can be automatically tuned. The realization of the DRL approach is discussed in detail and simulation validates the correctness of the attempt.

System-by-Design Paradigm-Based Synthesis of Complex Systems: The case of spline-contoured 3D radomes

This article provides a macrolevel overview of the System-by-Design (SbD) paradigm and then applies it to the design of a representative complex system. By introducing a set of archetypes of the SbD paradigm (i.e., Architecture-by-Design, Material-by-Design, Algorithm-by-Design, and Component-by-Design), the synthesis of large complex-shaped radomes is addressed by combining the Material-by-Design and the Architecture-by-Design concepts. The results of a numerical assessment are discussed to give the interested readers some insights on the SbD effectiveness and potentialities also in comparison with traditional design approaches.

Integration of Machine Learning and Coarse-Grained Molecular Simulations for Polymer Materials: Physical Understandings and Molecular Design.

In recent years, the synthesis of monomer sequence-defined polymers has expanded into broad-spectrum applications in biomedical, chemical, and materials science fields. Pursuing the characterization and inverse design of these polymer systems requires our fundamental understanding not only at the individual monomer level, but also considering the chain scales, such as polymer configuration, self-assembly, and phase separation. However, our accessibility to this field is still rudimentary due to the limitations of traditional design approaches, the complexity of chemical space along with the burdened cost and time issues that prevent us from unveiling the underlying monomer sequence-structure-property relationships. Fortunately, thanks to the recent advancements in molecular dynamics simulations and machine learning (ML) algorithms, the bottlenecks in the tasks of establishing the structure-function correlation of the polymer chains can be overcome. In this review, we will discuss the applications of the integration between ML techniques and coarse-grained molecular dynamics (CGMD) simulations to solve the current issues in polymer science at the chain level. In particular, we focus on the case studies in three important topics—polymeric configuration characterization, feed-forward property prediction, and inverse design—in which CGMD simulations are leveraged to generate training datasets to develop ML-based surrogate models for specific polymer systems and designs. By doing so, this computational hybridization allows us to well establish the monomer sequence-functional behavior relationship of the polymers as well as guide us toward the best polymer chain candidates for the inverse design in undiscovered chemical space with reasonable computational cost and time. Even though there are still limitations and challenges ahead in this field, we finally conclude that this CGMD/ML integration is very promising, not only in the attempt of bridging the monomeric and macroscopic characterizations of polymer materials, but also enabling further tailored designs for sequence-specific polymers with superior properties in many practical applications.

Application and improvement of iterative methodology for response based analysis of an FPSO mooring system in tropical cyclones

Response based analysis (RBA) is an advanced alternative to traditional design approach for mooring systems of floating structures, which reduces uncertainty associated with extreme responses. In the traditional approach, mooring analysis is performed for specified sets of extreme metocean conditions, representing typically a return period of 100 years. In RBA, the dynamic analysis is carried out over a long-term database of metocean conditions and statistics of the responses are used to identify responses associated with a return period of 100 years. Whilst the RBA has a more rigorous probabilistic basis, it is also computationally demanding. An “Iterative methodology” has been developed recently, comprising a combination of time domain (TD), frequency domain (FD) and probabilistic analyses of the structural system into a single iterative process, to minimise the number of time-consuming simulations through distinguishing between “mild” and “severe” response events. In the study, the “iterative methodology” is applied for RBA of the mooring system of a turret moored FPSO in the tropical cyclone environment of the North West Shelf of Australia. In the first stage, the time-efficient FD analysis is utilised to identify the contribution of all the storms to the 100-year response. In the second stage, an iteration process is set up, in which only the most contributing response events (tropical cyclones) and sea states are analysed by TD simulations. The iterations proceed by selecting the next most contributing storm until the convergence of the 100-year response is achieved. Application of the iterative methodology leads to significant reduction in computational time and makes RBA feasible as a part of the usual design process by using fully coupled TD analysis. Further optimisation can be achieved through a new method of applying thresholds to metocean parameters, which can reduce the analysis effort further. In the case study considered, it is found that 61% of metocean time history could be excluded from any dynamic analysis by applying a variable storm-dependent threshold. Among the remaining intervals, only 5.2% need to be re-analysed by TD simulations. Several methods for assessing errors in the convergence process are compared, and a sensitivity analysis on the number of storms that should be selected at each iteration step is performed.

Sustainable design of tailings dams using geotechnical and geomorphic analysis

ABSTRACT Geomorphic landform design for mine waste structures has been proposed as a sustainable alternative to traditional design approaches for decades. Over this time, the focus on mine closure and related sustainability approaches has grown steadily. Many geotechnical engineers and responsible mining companies understand the obligation to design and construct structures that will perform well in the long term. Concepts and tools are provided in this paper that will assist engineers in achieving their long-term goals. This research evaluates four tailings dam designs in terms of their geotechnical stability and long-term geomorphology: two traditional designs (uniform slope and platform-bank) and two geomorphic-inspired designs (catena and horseshoe). All four designs were subjected to two- and three-dimensional (3D) stability analysis, as well as 3D landscape evolution modeling (geomorphic analysis). Results indicated that the horseshoe-style geomorphic tailings dam design performed better than the others for each of the analyses completed. The horseshoe design consisted of interspersed catena slopes and uniform slopes, which resulted in a type of buttressing effect that enhanced the geotechnical stability of the dam while also reducing and focusing surface erosion.

A framework for ‘configuring participation’ in living labs

Abstract In recent years, ‘living lab (LL)’, a design approach that actively involves users as partners from the early stage of the design process, has been attracting much attention. Compared with the traditional participatory design or co-design approaches, one of the distinctive features of the LL approach is that the process of and opportunity for user participation tends to be long-term and complex. Thus, LL practitioners must appropriately plan and design effective integration of user participation into the design process to promote co-creation with users. In other words, LL practitioners are required to ‘configure user participation’ for the effective promotion of co-creation. However, to date, the knowledge on how to properly configure long-term and complex user participation in LLs has not been systematically clarified, nor have its methodologies been developed. This study develops a novel framework for configuring user participation in LLs. Through a literature review and analysis on LL case studies, we identified the 11 key elements in five categories that should be considered while configuring user participation in LLs. Furthermore, on the basis of the identified elements, we developed a novel framework for configuring user participation in LLs, which is called the participation blueprint. We have demonstrated its use and have also discussed its theoretical and practical contributions to the LL and co-design research community.

Analysis of software solutions for creating models by a generative design approach

With the constant development of new technologies and designs, the idea of a generative design approach arose. Generative design allows to create an infinite number of new designs in a relatively short time without the constraints associated with the imagination of the designer. Designs created by a generative design approach create optimized products that meet the specific needs of their end users. The parts created in this way are often lighter, stronger and less expensive in terms of their subsequent production. Generative design software applications are often more intuitive to work with than traditional CAD systems, and no additional knowledge associated with operating the software is required. The main goal of generative design is to save time in the design process, save material by creating optimal structures, and thus save money by developing cost-effective products. The product software only adds material where it is needed, which is typical of the additive production of organic shapes and forms. The product created in this way is more efficient for production compared to the traditional design and production approach. The article points out the current state of development of this rapidly expanding design technology with a description of software solutions used for the implementation of a generative design approach on illustrative examples of created design products.

Experimental response of a large-scale two-storey steel building equipped with low-yielding friction joints

The recent earthquakes have underlined the need for more advanced design philosophies able to avoid or reduce direct and indirect costs related to the occurrence of destructive seismic events. According to the traditional seismic design approach, under rare and very rare seismic events, the onset of damage to structural components is usually accepted. However, to address social expectations and the need for resilient buildings, recently, novel low-damage design philosophies have been proposed. These are based on the introduction of friction devices able to dissipate large amounts of energy with negligible damage. The cost of repair of these devices is typically only related to the re-tightening of bolts and, eventually, the substitution of friction shims. Noteworthy examples of this technology are the Sliding Hinge Joints (SHJs), developed at the University of Auckland, and the FREEDAM joints, developed at the University of Salerno within the framework of a homonym research project.In the last two decades, significant efforts have been devoted to understanding the seismic behaviour of such connections. The novelty of this work consists in investigating, for the first time, the seismic response of a large-scale building mock-up equipped with FREEDAM joints. The mock-up has been tested with a sequence of five accelerograms using the pseudo-dynamic testing method. The results have confirmed that FREEDAM connections provide large energy dissipation and rotation supply with almost no damage. The experimental results have been used to verify the accuracy of a numerical model developed with the software OpenSees, showing the capabilities of current simplified phenomenological modelling approaches in capturing the actual structural response.

Deep learning based multistage method for inverse design of supercritical airfoil

In the preliminary aerodynamic design phase of transonic wing, inverse design of supercritical airfoils plays an important role in acquiring practical results. However, traditional inverse design approach in transonic regime highly dependents on the manual design experience and physical model simulation, which is time consuming and poses a challenge for its applications in engineering problems. In order to relieve these drawbacks, a novel method is proposed for inverse design of supercritical airfoils based on Wasserstein generative adversarial network (WGAN), genetic algorithm (GA) and deep convolutional neural network (DCNN). This method consists of three stages. First, design characteristics of transonic pressure coefficient (CP) distribution in physics are well captured and imitated by WGAN. Then, GA is used to select task-oriented CP via adjusting controllable latent variables in generator of WGAN. Next, physical-existing CP selected by GA is recovered to corresponding airfoil by DCNN with high efficiency and accuracy. Cases using the dataset sampled based on RAE2822 airfoil are carried out to show effectiveness of submodules involved. Finally, design performance of proposed multistage method is further verified by specific design goals. Test cases indicate that selected CP by GA according to the aerodynamic design criteria can be accurately reflected on inverse designed airfoils, which are confirmed by well agreements between high-fidelity simulation result and selected CP. The proposed method is a promising design approach that can quickly achieve optimal airfoils without significant loss of accuracy.

Recovery-based design of buildings for seismic resilience

Design of buildings for earthquakes plays a central role in community resilience and is guided by building codes to incorporate performance-based design criteria as an alternative to the traditional prescriptive design approach. This change is indicative of an ongoing shift in design philosophy to address a broad range of performance targets such as financial and functionality objectives, in addition to safety. While this represents an important step forward, the next step warrants an approach that not only defines and achieves performance targets through traditional risk-based approaches, but also prepares for cases in which such targets are not achieved, and the building must recover from reduced functionality. Here we show that design enhancements based on improving recoverability, rather than reducing risk, can significantly improve building resilience in terms of the loss of functionality experienced after seismic events of varying intensity, while also producing financially attractive design alternatives to decision makers. The comparative evaluations presented herein illuminate the relative effectiveness of one such design in terms of resilience, while quantifying performance through metrics that are vital to the decision making process. We demonstrate that designing buildings for recoverability represents a viable design philosophy from both resilience and financial loss perspectives. A link between the vast and continually expanding repertoire of structural technologies capable of enhancing building recovery and the ever-growing concern for resilience in building design can be further developed and strengthened through continued investigation of recovery-enhancing structural technologies through the lens of resilience both at the building and community levels.

Fatigue reliability design and assessment of reactor pressure vessel structures: Concepts and validation

Traditional design approaches using safety factors are intended to account for uncertainties due to the lack of available data in engineering practice. However, the direct use of safety factor to represent uncertainties often causes conservative results, and it is not intuitive to describe the reliability of these structures through safety factor. To deal with the issue, this research revisits the initial consideration and intent of the safety factor for static strength and adjustment factor for fatigue design curve in the ASME code. Three conversion models applying to reactor pressure vessel (RPV) materials are proposed on basis of the stress–strength, load–life and strength–damage interference theories, which elaborate the relationship between safety/adjustment factors and structural reliability. The dispersion of strength and fatigue life is quantified, and then implemented to elaborate safety and adjustment factors with reliability respectively, which verifies the validity of safety assessment methods in the ASME code. Moreover, the safety/adjustment factor design under required reliability level is achieved, has the advantages of intuitiveness and convenience, which provides a reference for the reliability and safety design of RPV.

Mechanical Analysis With Thermal Effects for High-Speed Permanent-Magnet Synchronous Machines

The high-speed permanent-magnet synchronous machine (HSPMSM) has stricter mechanical restrictions and more intense interactions between multiphysical fields due to high-speed and high-power density characteristics. This article focuses on the thermal effect on mechanical strength and stiffness. As the change of material properties with temperature and the thermal stress caused by thermal expansion properties, this article presents the relationship of the stress and critical speed with two thermal effects obtained by analytical equations and verified by finite-element analysis. The results show that thermal effects could reduce the safety factors of the stress and critical speed, thus increasing the possibility of rotor damage and resonance. To achieve more accurate mechanical, a reasonable machine design is proposed, focusing on the influence of actual uneven thermal distribution. Comparing with a traditional design approach, the new one is more applicable for the HSPMSM design, which considers the assembly method and the operation condition, especially the thermal effects. The fluid-thermal-stress-mode coupling calculation is realized. The experiment has been implemented to verify the validity of this design process. The studies of the thermal effects on mechanical characteristics offer a new idea for designing and debugging practical machines.

Pseudo‐dynamic testing of a full‐scale two‐storey steel building with FREEDAM connections

AbstractThe recent earthquakes have underlined the need for more advanced design philosophies able to avoid or reduce direct and indirect costs deriving from the occurrence of destructive seismic events. In fact, the traditional seismic design approach is based on performance levels implying the onset of damage which can be, in many cases, difficult to repair. In order to address social expectations and the need for resilient buildings, recently, novel low‐damage design philosophies have been proposed. These are based on the introduction, in particular points of the structure, of friction dampers able to dissipate large amounts of energy and to protect the structural members from damage. This is the case, for instance, of the Sliding Hinge Joints (SHJs), developed by the research group of the University of Auckland in 2005, or of the FREE from DAMage joints (FREEDAM), developed starting from 2009 at the University of Salerno.Many experimental and analytical research efforts have been devoted to understanding the response of such connections. Nevertheless, currently there is still a lack of knowledge dealing with their seismic response in full‐scale buildings. In order to provide a contribution to fill this knowledge gap, an experimental program is currently ongoing at the STREngTH (STRuctural Engineering Testing Hall) Laboratory of the University of Salerno dealing with the pseudo‐dynamic testing of a full‐scale two‐storey steel building equipped with FREEDAM joints. The mock‐up has been subjected to a sequence of five accelerograms and the results have confirmed that FREEDAM connections provide large energy dissipation capacity and plastic rotation supply, thanks to their regular and plumb hysteretic loops. The experimental results have been complemented with numerical models developed with the software OpenSees.

Holistic Design of Energy Pile Bridge Deicing System With Ontology-Based Multiobjective Decision Making

Even though the energy piles have been applied for the bridge deicing system, the traditional design approach is commonly a single-domain and objective-oriented method and is consequently lacking means to comprehensively consider all the relevant factors, such as life-cycle cost, investment payback cycle, carbon emissions, etc. This paper presents a holistic design scheme for the energy pile deicing system of bridge decks. In this paper, a holistic designing tool, namely, OntoBDDS, was developed based on ontology method and SWRL rules. It can automatically provide financial, safety, and heat flux information for designers to evaluate and optimize the design scheme of a deicing system in the early design stage of a bridge. After semantic and syntactical validation of the OntoBDDS system, a case study was also conducted to demonstrate how to leverage knowledge query to provide a series of design alternatives autonomously through considering different design parameters. This case study also verified the practicability and feasibility of the OntoBDDS holistic decision-making system and indicated its potential to be applied for other engineering problems when dealing with multiobjective holistic design making.

An efficient design of dual-axis MEMS accelerometer considering microfabrication process limitations and operating environment variations

PurposeThis paper aims to present an efficient design approach for the micro electromechanical systems (MEMS) accelerometers considering design parameters affecting the long-term reliability of these inertial sensors in comparison to traditional iterative microfabrication and experimental characterization approach. Design/methodology/approachA dual-axis capacitive MEMS accelerometer design is presented considering the microfabrication process constraints of the foundry process. The performance of the MEMS accelerometer is analyzed through finite element method– based simulations considering main design parameters affecting the long-term reliability. The effect of microfabrication process induced residual stress, operating pressure variations in the range of 10 mTorr to atmospheric pressure, thermal variations in the operating temperature range of −40°C to 100°C and impulsive input acceleration at different input frequency values is presented in detail. FindingsThe effect of residual stress is negligible on performance of the MEMS accelerometer due to efficient design of mechanical suspension beams. The effect of operating temperature and pressure variations is negligible on energy loss factor. The thermal strain at high temperature causes the sensing plates to deform out of plane. The input dynamic acceleration range is 34 g at room temperature, which decreases with operating temperature variations. At low frequency input acceleration, the input acts as a quasi-static load, whereas at high frequency, it acts as a dynamic load for the MEMS accelerometer. Originality/valueIn comparison with the traditional MEMS accelerometer design approaches, the proposed design approach focuses on the analysis of critical design parameters that affect the long-term reliability of MEMS accelerometer.

Optimization of shell and tube heat exchanger using the water cycle algorithm

The shell and tube heat exchangers (STHEs) are used to transfer the thermal energy between two or more media. Due to its importance for conserving energy, numerous studies of heat exchanger design optimization have been carried out. The traditional design approaches are usually time-consuming, and may not guarantee to produce an economically optimal solution. A complete optimization procedure was conducted to find the minimum cost of the heat exchanger system. Heat exchanger design optimization was carried out using a recently proposed optimization algorithm called the water cycle algorithm (WCA). Three design variables are considered consisting of the shell inside diameter, tube outer diameter, and baffle spacing. The total annual costs which include the investment costs and the operating costs will be considered as the objective function.

Application of Taguchi Robust Design for optimizing tensile strength response of Ukam-plant fibre reinforced cashew nut shell liquid (CNSL) composite by the effects of control parameters

This paper focuses on the application of Taguchi Robust Design to determine the optimum tensile strength of Ukam-Plant Fibre Reinforced CNSL Composite using indigenous or locally sourced vegetable or plant based natural fibres (Ukam-plant fibres) that are Lignocellulose as potential raw material. Tensile tests were conducted on the replicated samples of Ukam-Plant Fibre Reinforced CNSL Composite to obtain the optimum properties. Hounsfield Mosanto Tensometer, a universal testing machine was used to conduct tensile tests to determine the control factor levels quality characteristics considered necessary to optimize the mechanical property being investigated. Methodology of traditional and experimental design approach of Taguchi was used for the larger the better to obtain the highest signal to noise ratio (SN ratio) for the quality characteristic being investigated and also to correlate the control factors (fibre condition i.e. untreated, silane treated and alkaline treated, volume fraction and fibre size). Minitab 16 software was used for statistical analysis to fine-tune conclusions and produce quantitative estimates. The optimum settings were as follows: alkaline treatment, volume fraction of 50%, and 50mm of fibre size which resulted in 18.69MPa optimum tensile strength. The experimental results obtained agreed satisfactorily with the Minitab 16 software predictions. The mechanical property studied revealed that composite depends significantly on the reinforcement combination of control parameters.

A design approach to reduce hull weight of naval ships

ABSTRACT Hull weight is a design parameter affecting the whole performances of a ship, being related to building costs, operational costs, maintenance and durability, and not least to satisfaction of functional requirements. Naval ships are no exception and impact of hull weight is crucial to fulfil mission requirements. In the light of the above, weight reduction is one of the main design drivers and it should be duly accounted for since the concept design phase. In this paper, a design approach intended for pre-contractual design phases is presented. It takes advantage of recent developments and trends of construction rules as well as of nowadays-available computation potential to update and improve the traditional scantling design approach, applied since decades by designers. The complexity and computational burden is kept to a minimum to provide a user-friendly procedure applicable in everyday working practice. Designers’ experience and judgment continue to drive the whole process. A Visual Basic support software has been developed with worksheet interfaces to implement the proposed scantling design procedure. Test cases showed significant weight reductions with respect to as-built ships and to scantling obtained by applying traditional design procedures.

Анализ особенностей проектирования на основе применения модульных элементов максимальной готовности

Introduction. In the middle of the 20th century, technological progress made it possible to enlarge the building elements of buildings as much as possible, which led to the development of new industrial construction systems and increased production rates. However, to date, the issue has not been completely resolved and remains relevant. Modular construction is not sufficiently widely spread today, but many design experts predict its widespread introduction in the near future. The factor that decelerates the development of modular construction is the lack of theoretical foundations in the field of modular design, as well as significant differences from traditional design approach. Materials and methods. The purpose of this work is to develop the theoretical fundamentals of modular design based on the study of regulatory documents, Russian and foreign sources of research works, as well as the implemented projects. The task is to determine the fundamental features of modular elements of maximum readiness: principles of modular design, parameters of a modular element, advantages and disadvantages of a modular system, features of the design processes. Results. The theoretical basis of modular design includes basic concepts, principles and features; the conceptual design process is described using the case of development of an information model; parameters of modular elements of maximum readiness are presented, and the influence of modular items on the life cycle of a construction facility is analyzed. Conclusions. The presented system of principles of design based on modular elements of maximum readiness and parameters of modular elements allow us to systematize the established theoretical aspects of modularity, which make it possible to make modular buildings. The author formulates a new approach to design, which affects the entire life cycle and serves as the basis for new areas of engineering activities and scientific research.

An Overview of Co-Design: Advantages, Challenges and Perspectives of Users’ Involvement in the Design Process

Co-design is currently one of the most emergent approaches within design practices. Building on participatory design tradition and User-Centered approach, this approach affirmed in the literature's headlines as well as got adopted in a wide range of practices. Being described as capable toincrease general processes’ effectiveness by ensuring compatibility between users’ needs and products/services’ features scholars emphasize the advantages of replacing traditional top-down design approaches with a co-design one. While highlighting the advantages the field literature alsoindicates several challenges stemming from the adoption of co-design, generally revolving around the need to root the approach into a theoretical framework. According to an analysis of some main contributions developed in the literature, this paper aims to point out potential developments for the field, building on the analysis of the development of the approach throughout decades and analysing the challenges that practitioners and scholars are currently facing. A constructivist approach built on cultural psychology theory is finally argued as a theoretical framework capable to provide an advancement for the field.