Early Stages Of Conceptual Design Research Articles

Design and testing of a Multi-Fuel industrial burner suitable for syn-gases, flare gas and pure hydrogen

The complete design and validation procedure of a novel Multi-Fuel heavy-duty burner is illustrated, starting from the conception and CFD analysis, up to an extensive experimental campaign assessing the actual performance of an industrial scale prototype.The need for an innovative burner to be employed in utility boilers comes from the context of energy transition with still increasing steam demand for process/industrial applications. The capability to burn a wide range of fuels, going from natural gas to flare-gases, syn-gases and fuels with even lower heating values, up to pure hydrogen, with high efficiency and low emissions is mandatory: it is shown and explained how all the above tasks are pursued starting from the early stage of conceptual design, leading to the development of a 2.5 MW prototype; then the burner operation is studied more in depth by CFD analysis, with particular attention to the implementation of MILD combustion regime: internal recirculation along with mixing, namely fuel dilution in flue gases leads to distributed volumetric reaction with oxygen, involving low peak temperatures with high conversion efficiency. Furthermore, numerical analysis helps to investigate the effectiveness of a central stabilizing flame, the coupling between furnace and burner in view of the tests, and also helps to evaluate different injection patterns for the fuel jets.As a final step, a 1.5 MW prototype is tested in a refractory lined furnace: the performance is assessed with natural gas, either pure or diluted with nitrogen to mimic a low heating value syn-gas, and with increasing percentage of hydrogen up to 95% as thermal input. Different levels of input to the central stabilizing flame are tested, and excellent flame stability of burner operation is proven. NOx emissions decrease for lower heating value fuels, increase for hydrogen/natural gas mixtures up to 35% H2, and remain almost constant above this threshold. Though, keeping a very low excess of air and almost no carbon monoxide in the exit flue gases, the absolute NOx levels compare very well with state of the art Ultra-Low-NOx industrial burners developed for standard fossil fuels. The presented data set can be relevant both for industrial designers, as a reference for heavy-duty burners operating with a wide range of fuels, up to pure hydrogen, and for academic researchers investigating on combustion, even in MILD regime.

EVALUATION OF WING STRUCTURES AT THE CONCEPTUAL STAGE OF TRANSPORT CATEGORY AIRCRAFT PROJECTS

The purpose of this research is to improve the approach for evaluating of new design solutions based on sensitivity analysis of takeoff mass (SFM) to initial changes in the basic project. The approach is based on the changes assessment in maximum takeoff mass of a developed project or an already existed basic variant of an aircraft with local design (project) changes, including the aerodynamic ones, that ensure the developing of a more advanced aircraft. In comparison with the existed known approaches based on the mass growth factors, which were considered constant, the proposed approach takes into account more exactly the dependence of the takeoff mass on the initial local change in mass in terms of their functional purpose, as well as the aerodynamic characteristics. This approach allows the designer to calculate more precisely the final maximum takeoff mass changes in the early (preliminary) stages of conceptual design when looking for new design solutions. On numerical examples, carried out on the examples of transport category airplanes, a significant dependence of the wing aspect ratio influence on fuel efficiency is shown. The considered approach using SFM with semi-analytical aerodynamic analysis combination is simple, reliable and convenient in the analysis and synthesis of a new project for the design process based on the base variant.

Introducing the Architecture Parametric Design Procedure: From Concept to Execution

The parametric design process is one of the modern architectural trends. It assists in the decision-making process during the early conceptual design stage. It introduces several design alternatives from which the designers can choose to achieve the most suitable design concept. Through this process, the BIM (Building Information Modelling) is considered as the stage of converting the preferred design concept to execution drawings and building information. Furthermore, the computerized digital fabrication stages will assist in building the desired model in different scales for the final decision to be taken. This paper spotlight the overall parametric design process workflow from the “design stage” (using Grasshopper which is a plugin in rhino parametric design software) passing through the Revit software that is responsible for the working drawings execution to the “manufacturing stage” using Simplify 3D software for the preparation of the mock-up digital fabrication model using 3D printing.

Validating integrated environmental solutions software for air temperature of a typical Malaysian recessed wall façade office building

Technological advances have assisted in the development of modern software tools which can be used to assess and improve the energy efficiency of a building at the early stage of conceptual design. However, this study aims at validating the accuracy of one of the paramount building simulation software Integrated Environmental Solutions - Virtual Environment (IES-VE), widely used today. The methodology of this study involves physical measurements and simulation exercises. A longitudinal physical measurement was carried out using HOBO ware U-12 in 5 different points of the room space from 18th October to 4th December 2016. But, for validation, a critical atmospheric day (21st November 2016) was selected for the comparison. The room air temperature was first measured before comparing it to the simulated air temperature obtained from IES<VE>. After several analyses, the comparison of the measured room air temperature and simulation results showed similarity, discrepancy, closeness, significance, and accuracy. The investigation findings revealed a percentage discrepancy of 11.03%, which is less than the threshold of 20% between the measured and simulated air temperature of the case study model. Other findings show that: R2 = 0.98, MBE = 0.8, °C and RMSE = 1.70°C are all within the acceptable values of significance between the two data. These results signify that IES-VE is valid, accurate, and applicable for this study’s further Building Performance Simulation (BPS)

A novel function-structure concept network construction and analysis method for a smart product design system

The rapid growth of data and the requirement of designers to track massive data to obtain design stimuli have posed challenges to conceptual design, thereby promoting the development of data-driven design. Concept networks precisely capture design information from a large volume of unstructured and heterogeneous textual data and saliently decrease time and labor cost for designers to read texts, which creates new opportunities for developing a smart product design system. To advance data-driven design, this study proposes the novel function-structure concept network (FSCN) construction method, which combines sentence parsing and word/phrase extraction to integrate functional and structural information. Furthermore, a network analysis method is proposed to explore design information associations that contain both explicit and implicit associations together and thereby recommend them simultaneously to designers as inspirational stimuli to support design ideation. This approach can enhance designers' capabilities to build associations between design information, conceive new design ideas during conceptual design, and increase creativity for solving design problems. The proposed FSCN construction and analysis method can be used as an auxiliary tool to visualize associations among design information so as to inspire idea generation in the early stage of conceptual design. An illustrative example was used to validate the practicability of the proposed methodology. The code of the proposed method is available at https://github.com/KWflyer/FSCN.

NEW DESIGN HEURISTICS IN THE DIGITAL ERA

AbstractIn the digital era, products’ forms do not necessarily follow their function. Design fixation may happen when a designer attempts to generate diverse concepts. New design heuristics for digital design were extracted to support designers in the early conceptual design stage. Ten design heuristics were extracted from 998 RedDot award-winning concept designs (2013-2017) through a five-step process. It was preliminarily tested by four practitioners and proved to have positively influenced their conceptual design.

Some Shape, Durability and Structural Strategies at the Conceptual Design Stage to Improve the Service Life of a Timber Bridge for Pedestrians

The use of wood in the construction of bridges has increased in recent decades thanks to the characteristics of this material, i.e., environmentally-friendly and suitability within natural landscapes. Nevertheless, timber constructions may be affected by degrading effects due to biological and/or abiotic agents, and may be exposed to impacts or vibrations due to external forces such as wind, earthquakes or walking pedestrians. Consequently, bridge performance with respect to these aspects should be assessed from the early design stage. Within this context, in this study, some shape, structural and durability strategies dealing with the design of timber bridges for pedestrians are investigated in order to extend the service life of these constructions. More precisely, a methodology consisting of three steps, to be applied at the early conceptual design stage, is proposed. The three fundamental steps to be considered in the preliminary design of timber bridges are: (i) main boundary constraints and load-bearing system; (ii) durability; (iii) vibration levels. In the study, the presented methodology is applied and described for the design of a pedestrian and cyclist timber bridge over the Gravina torrent, in Apulia (Italy).

Towards an automated decision support system for the identification of additive manufacturing part candidates

As additive manufacturing (AM) continues to mature, an efficient and effective method to identify parts which are eligible for AM as well as gaining insight on what values it may add to a product is needed. Prior methods are naturally developed and highly experience-dependent, which falls short for its objectiveness and transferability. In this paper, a decision support system (DSS) framework for automatically determining the candidacy of a part or assembly for AM applications is proposed based on machine learning (ML) and carefully selected candidacy criteria. With the goal of supporting efficient candidate screening in the early conceptual design stage, these criteria are further individually decoded to decisive parameters which can be extracted from digital models or resource planning databases. Over 200 existing industrial examples are manually collected and labelled as training data; meanwhile, multiple regression algorithms are tested against each AM potential to find better predictive performance. The proposed DSS framework is implemented as a web application with integrated cloud-based database and ML service, which allows advantages of easy maintenance, upgrade, and retraining of ML models. Two case studies of a hip implant and a throttle pedal are used as demonstrating examples. This preliminary work provides a promising solution for lowering the requirements of non-AM experts to find suitable AM candidates.

A network science-based assessment methodology for robust modular system architectures during early conceptual design

ABSTRACTThis article describes a methodology to assess, during the early conceptual design stage, the robustness, and modularity of engineering system architectures, which integrates concepts from network science with engineering systems. The application specifically focuses on the architecture of the power, propulsion, and cooling systems of a naval ship. The methodology incorporates a binary Design Structure Matrix as the basis for an assessment of redundancy and modularity effects on robustness, in response to the disruption of modules in the architecture. Robustness is used to drive the module selection, which supports the formulation of a robust module configuration subject to the level of redundancy in the system architecture. The case study results demonstrated that redundancy promotes robustness of the architecture and enables modularity; however, high levels of redundancy in comparison to medium level redundancy does not significantly improve robustness. The novel contribution of this article relates to the combined quantitative assessment of redundancy, modularity and robustness in a collective methodology. This methodology supports conceptual design decision making, allowing early prediction of compliance of requirements that enable cost, development time and survivability targets to be achieved.

Conceptual studies on spectroscopy and radiation diagnostic systems for plasma control on DEMO

The roadmap to the realization of fusion energy describes a path towards the development of a DEMO tokamak reactor, which is expected to provide electricity into the grid by the mid of the century (Romanelli, 2013). The DEMO diagnostic and control (D&C) system must provide measurements with high reliability and accuracy, not only constrained by space restrictions in the blanket, but also by adverse effects induced by neutron, gamma radiation and particle fluxes. In view of the concept development for DEMO control, an initial selection of suitable diagnostics has been obtained (Biel et al., 2019). This initial group of diagnostic consists of 6 methods: Microwave diagnostics, thermo-current measurements, magnetic diagnostics, neutron/gamma diagnostics, IR interferometry/polarimetry, and a variety of spectroscopic and radiation measurement systems. A key aspect for the implementation, performance and lifetime assessment of these systems on DEMO, is mainly attributable to their location, that must be well protected, and meet their own set of specific requirements. With this in mind, sightline analysis, space consumption and the evaluation of optical systems are the main assessment tools to obtain a high level of integration, reliability and robustness of all this instrumentation; essential features in future commercial fusion power nuclear plants. In this paper we concentrate on spectroscopic and radiation measurement systems that require sightlines over a large range of plasma regions and inner reactor surfaces. Moreover, this paper outlines the main results and strategies adopted in this early stage of DEMO conceptual design to assess the feasibility of this initial set of diagnostic methods based on sightlines and the integration of these needed for DEMO D&C.

Evaluating the reduced flight deck crew concept using cognitive work analysis and social network analysis: comparing normal and data-link outage scenarios

The aim of the present paper is to demonstrate how a subset of methods from Cognitive Work Analysis (CWA) in combination with Social Network Analysis (SNA) can be used to analyse the effects of a reduced crew in a legacy system of a commercial airliner’s two-pilot-crew operations. Whereas existing research approaches have used different methodological approaches such as classical workload evaluations, we focus on social organisation and cooperation at early conceptual design stages. A case study of Reduced-Crew Operations (RCO) in commercial aviation highlights how Work Domain Analysis, Control Task Analysis and Social Organization and Cooperation Analysis were applied to allocate functions and identify future automation requirements. Furthermore, the SNA shows the possible interactions in future RCO. The effect of technological failure on the network architecture’s resilience is also explored. A proposal on how to react to a data-link outage and break-up in RCO is made with respect to limitations in technology. In this way, the work can foster identifying automation requirements and related possible failures at early stages in the design process.

Model-Based Systems Engineering for Aircraft Design With Dynamic Landing Constraints Using Object-Process Methodology

We present a model-based systems engineering (MBSE) framework using object-process methodology (OPM, ISO 19450) for civil transport aircraft design with dynamic landing constraints. The framework integrates the aircraft system development life cycle processes into a holistic MBSE model, incorporating into it the specific aircraft dynamic loads model-based design (MBD) domain. Using this framework, we also perform model-based requirements analysis, validation, and verification. The model parameter set is governed by a unified format used for both the MBSE and MBD domains. The resulting model enables aircraft design processes to start being formalized at the early conceptual design stage and carry on to detailed design, adding value to system lifecycle processes by integrating and streamlining the MBSE and MBD domains into a more holistic framework with seamless transition between these two major stages.

The Development of an Ordinary Least Squares Parametric Model to Estimate the Cost Per Flying Hour of ‘Unknown’ Aircraft Types and a Comparative Application †

The development of a parametric model for the variable portion of the Cost Per Flying Hour (CPFH) of an ‘unknown’ aircraft platform and its application to diverse types of fixed and rotary wing aircraft development programs (F-35A, Su-57, Dassault Rafale, T-X candidates, AW189, Airbus RACER among others) is presented. The novelty of this paper lies in the utilization of a diverse sample of aircraft types, aiming to obtain a ‘universal’ Cost Estimating Relationship (CER) applicable to a wide range of platforms. Moreover, the model does not produce absolute cost figures but rather analogy ratios versus the F-16’s CPFH, broadening the model’s applicability. The model will enable an analyst to carry out timely and reliable Operational and Support (O&S) cost estimates for a wide range of ‘unknown’ aircraft platforms at their early stages of conceptual design, despite the lack of actual data from the utilization and support life cycle stages. The statistical analysis is based on Ordinary Least Squares (OLS) regression, conducted with R software (v5.3.1, released on 2 July 2018). The model’s output is validated against officially published CPFH data of several existing ‘mature’ aircraft platforms, including one of the most prolific fighter jet types all over the world, the F-16C/D, which is also used as a reference to compare CPFH estimates of various next generation aircraft platforms. Actual CPFH data of the Hellenic Air Force (HAF) have been used to develop the parametric model, the application of which is expected to significantly inform high level decision making regarding aircraft procurement, budgeting and future force structure planning, including decisions related to large scale aircraft modifications and upgrades.

A Framework for Determining the Life Time Energy Consumption of a Product at the Concept Design Stage

As the world's population continues to increase so too does the demand for energy. The problem with this is that most countries’ energy comes from carbon based sources, which accounts for more than a third of the world's greenhouse gas emissions. Manufacturing of products is one of the largest contributors to environmental impacts such as CO2 emissions. Designers and manufacturers play a significant part in determining a products environmental footprint. New methods are needed to assist designers to shift from the traditional method of design, which is cradle-to-gate to the whole product life cycle of cradle-to-grave. This paper presents a framework to assist designers in determining the energy consumption of product concept(s) at the early conceptual design stage. The presented methodology can help designers to understand the impact a decision has in the design stage on the whole product life cycle.

Goal model analysis of autonomy requirements for Unmanned Aircraft Systems

Designing Unmanned Aircraft Systems (UASs) for optimal autonomy while meeting user requirements is quite challenging. Researchers have focused on improving autonomy algorithms and verification methods to ensure safe and reliable autonomous behavior in UASs, but little research has been conducted on requirements engineering for UASs to answer design questions and explore the trade space for using autonomy to satisfy user requirements. This paper introduces a method to determine an optimal set of autonomous capabilities that satisfies UAS user requirements in the early stages of conceptual design. The method uses a modified Autonomy Requirements Engineering (ARE) process that applies quantitative measures and statistical analysis to Goal-Oriented Requirements Engineering (GORE). We demonstrate this method in a case study of a “disaster robot,” i.e., a hazard response UAS for which the autonomy requirements were optimized using a goal model developed in the Goal-oriented Requirement Language (GRL), as implemented in the modeling tool jUCMNav. The high-level goals of the hazard response UAS—system performance, cost, and safety—were evaluated using the formula-based GRL strategy evaluation algorithm resident in jUCMNav version 6.0. An autonomy trade space study was conducted through a Design and Analysis of Simulation Experiments (DASE). Our designed simulation experiment inserted the number of trials (evaluation strategies) and inputs into the goal model, and evaluation data were analyzed to optimize design factors based on user weightings of the response variables. This paper presents a structured method of ARE for UASs, which could be adopted more broadly across other domains, demonstrating how to optimize autonomous capabilities for different design conditions.

Conceptual design of sacrificial sub-systems: failure flow decision functions

This paper presents a method to conceptually model sacrificing non-critical sub-systems, or components, in a failure scenario to protect critical system functionality through a functional failure modeling technique. Understanding the potential benefits and drawbacks of choosing how a failure is directed in a system away from critical sub-systems and toward sub-systems that can be sacrificed to maintain core functionality can help system designers to design systems that are more likely to complete primary mission objectives despite failure events. Functional modeling techniques are often used during the early stage of conceptual design for complex systems to provide a better understanding of system architecture. A family of methods exists that focuses on the modeling of failure initiation and propagation within a functional model of a system. Modeling failure flow provides an opportunity to understand system failure propagation and inform system design iteration for improved survivability and robustness. Currently, the ability to model failure flow decision-making is missing from the family of function failure and flow methodologies. The failure flow decision function (FFDF) methodology presented in this paper enables system designers to model failure flow decision-making problems where functions and flows that are critical to system operation are protected through the sacrifice of less critical functions and flow exports. The sacrifice of less critical system functions and flows allows for mission critical functionality to be preserved, leading to a higher rate of mission objective completion. An example of FFDF application in a physical design is a non-critical peripheral piece of electrical hardware being sacrificed during an electrical surge condition to protect critical electronics necessary for the core functionality of the system. In this paper, a case study of the FFDF method is presented based on a Sojourner class Mars Exploration Rover (MER) platform.

SketchSoup: Exploratory Ideation Using Design Sketches

AbstractA hallmark of early stage design is a number of quick‐and‐dirty sketches capturing design inspirations, model variations and alternate viewpoints of a visual concept. We present SketchSoup, a workflow that allows designers to explore the design space induced by such sketches. We take an unstructured collection of drawings as input, along with a small number of user‐provided correspondences as input. We register them using a multi‐image matching algorithm, and present them as a 2D interpolation space. By morphing sketches in this space, our approach produces plausible visualizations of shape and viewpoint variations despite the presence of sketch distortions that would prevent standard camera calibration and 3D reconstruction. In addition, our interpolated sketches can serve as inspiration for further drawings, which feed back into the design space as additional image inputs. SketchSoup thus fills a significant gap in the early ideation stage of conceptual design by allowing designers to make better informed choices before proceeding to more expensive 3D modelling and prototyping. From a technical standpoint, we describe an end‐to‐end system that judiciously combines and adapts various image processing techniques to the drawing domain—where the images are dominated not by colour, shading and texture, but by sketchy stroke contours.

Features from a Single Vector Pressure Stroke

Freehand sketching in a real-time 3D styling system presents a different way to create a 3D model from the traditional CAD system. Strokes are the most common and useful objects in the expression of a stylist’s intention by using the gesture commands and in the construction of geometries. Not only are they sketched freely as drawing on a paper with a pen, but also they can be converted automatically into spline curves and then can be used to form a surface. Therefore, it is necessary to investigate the features of stroke, the extraction and identification of these features, and the applications. Here, the features from a single vector pressure stroke have been discussed in detail according to their applications in an automotive freehand styling system in the early stage of conceptual design. The features have been divided into three parts: the input features, the calculable feature, and the added features. Over a hundred features have been defined and classified with the geometry or performance attributes. The features proposed have been applied in the identification of gesture commands, the expression of art vector stroke by pseudoantialiasing method, and a novel method to generate a spatial curve directly by the pressure of stroke in AutoSketch system.

Enhanced Sequence Diagram for Function Modelling of Complex Systems

This paper introduces a novel method referred to as Enhanced Sequence Diagram (ESD) to support rigorous functional modelling of complex multidisciplinary systems. The ESD concept integrates an exchanges based functional requirements reasoning based on a coherent graphical schema, integrated with the system operational analysis based on a sequence diagram. The effectiveness of the method to support generic function modelling of complex multidisciplinary systems at the early conceptual design stages is discussed in conjunction with an electric vehicle powertrain example, followed by an assessment of potential impact for broader application of the method in the industry.

Modeling of natural circulation for the inherent safety analysis of sodium cooled fast reactors

The paper discusses a set of developed integrated one-dimensional models of thermal-hydraulic processes that contribute to the removal of decay heat in a BN-type reactor. The assumptions and constraints involved in one-dimensional equations of unsteady natural convection in closed circuits have been analyzed. It has been shown that the calculated values of the primary circuit sodium temperature and flow rate in conditions with a loss of heat sink and with a forced circulation of the primary coolant are in a reasonable agreement with the results of a benchmark experiment in the PHENIX reactor. The model makes it possible to assess the effects general thermophysical and geometrical parameters and the selected technology have on the efficiency of passive heat removal by the natural coolant convection in the reactor tank and in the emergency heat removal system's intermediate circuit and by the heat transfer through the reactor vessel. The model is a part of an integrated algorithm used to assess the inherent safety level of advanced fast neutron reactors and is intended primarily to develop, at the early conceptual design stage, the recommendations and requirements with respect to the reactor equipment parameters leading to an increase in the reactor inherent safety. The model will be used to identify the set of quantitative thermal-hydraulic criteria that have an effect on the dynamics of emergency transients leading to a potential loss of integrity by the reactor safety barriers, and to formulate such limits for the defined criteria as would cause, if observed, the requirement for the safety barrier integrity to be met under any combination of the accident initiating events.