Conceptual Design Phase Research Articles

Reliability-based topology optimization for fundamental frequency maximization with frequency band constraints

Resonance can be avoided by preventing the structural natural frequencies from falling within the operating frequency range. However, structural natural frequencies are influenced by uncertain parameters, such as material properties and geometric sizes. Therefore, it is essential to consider these uncertainties during the conceptual design phase. To address this problem, a novel reliability-based eigenvalue topology optimization model under frequency-band constraints is established, in which the uncertainties of the material properties and structural size are considered. Owing to the high computational costs of dealing with frequency-band reliability constraints, a frequency-band constraint shifting method (FBCSM) is proposed to ease the heavy computational burden without sacrificing accuracy. In addition, the sensitivities of simple and multiple eigenfrequencies with respect to the design and random variables are derived. The “bound formulation” and “robust formulation” are used to reduce the gray elements and checkerboard phenomenon. Four examples are used to determine the effectiveness of the proposed reliability-based eigenvalue topology model and FBCSM. The results confirmed their superiority in terms of validity and efficiency.

Random forest regression to predict design performance of concert halls

Over the last couple decades, machine learning (ML) and advanced computational strategies have been successful when employed in building physics problems. ML models have known applications in the operations of buildings, including real-time energy monitoring and automated mechanical systems. They can also be used to inform design decisions for complex problems during conceptualization. For acousticians and building designers, trained ML models could provide better insight on expected performance without requiring extensive calculations or room acoustic simulations. This presentation describes a computational method for predicting the design performance (i.e., mid-frequency reverberation time) of various concert halls. More specifically, a random forest (RF) regression model is trained on architectural and measured acoustical data to predict the reverberation time. The RF models are tuned and act as a surrogate model for predicting the mid-frequency reverberation time of concert halls that were not used in model training. The estimated reverberation times are then compared to calculations from conventional equations (i.e., Sabine and Norris-Eyring equations) and room acoustic simulations using ray-tracing methods. This work shows how acousticians and architects can employ ML strategies in the conceptual design phase to improve estimated performance accuracy without expending significant computational resources.

Artificial Intelligence as a pedagogical tool for architectural education: What does the empirical evidence tell us?

Artificial Intelligence (AI) applications in arts and design have beengrowing in popularity in recent years. Numerous AI program applications arepublicly available, both commercial and open source, offering a chance to convertthe textual description of a design or context into original content images. Whilemany research projects tackled AI use in architecture since 2015, there seems to bea lack of empirical evidence of its use in Architecture education as a tool for conceptgeneration. An experimental architecture design course took place in Fall 2022where 34 students utilised AI programs in the conceptual design phase to produceoriginal content images from narratives to help students generate concepts for theirbuildings. The designs of the experimental student groups are compared to anothercontrol group of 50 students which use more traditional conceptual design methodson a similar project in the same semester. This paper aims to highlight theopportunities and challenges of using AI tools in the concept generation phase inarchitecture design education by measuring their effectiveness to increase creativityin form finding. With the use of recent literature in architecture learning theoriesand pedagogies, this experimental approach will be critiqued to provide furtherinsights into AI’s role in architecture education.

A framework for integrating safety and environmental impact in the conceptual design of chemical processes

Abstract Multiple factors influence chemical process design and technology selection, including technical, economic, environmental, and safety considerations. Traditionally, a techno-economic analysis has been used to select a base case design, while safety and environmental impact have been subsequently assessed. This may leave out designs that exhibit better environmental and safety performance than the selected base case at a very early stage of design, where abundant opportunities for incorporating these objectives are present. Furthermore, although safety is an integral part of the overall sustainability of a chemical plant, historically it has been addressed separately from sustainability. Thus, there is a growing awareness for simultaneous consideration of these objectives during the conceptual process design phase of a project in order to select the most sustainable process route. The key to an effective sustainability assessment method for selecting the most sustainable process route involves the parsimonious selection of adequate metrics which define the sustainability profile of the process and an integrated multi-criteria decision-making (MCDM) framework. In this context, this work investigates gaps in conceptual process design and existing sustainability assessment methods through a review of existing environmental impact and safety assessment methodologies/tools. A possible workflow that incorporates both safety and environmental impact in a holistic multi-criterion decision-making framework (MCDM) has been proposed to select the most sustainable process route. The use of this framework is illustrated through a simple case study involving assessing solvent alternatives for palm oil recovery to highlight the scope and significance of the proposed framework.

Effect of different system parameters on the design of the EU DEMO Vacuum Vessel Pressure Suppression System

The Vacuum Vessel Pressure Suppression System (VVPSS) is the safety system devoted to the mitigation of in-vessel Loss-Of-Coolant Accidents, which are considered among the Design-Basis Accidents for tokamak fusion reactors. The EUROfusion Consortium is performing the design of this system, as part of the conceptual design phase of the EU DEMO fusion reactor, including in the process its integration in the plant.This work reports the first parametric calculations carried out to evaluate the VVPSS response to a postulated double-ended guillotine rupture of a Breeding Blanket coolant feeder. The aim of the study is to characterize the role that key parameters play on the multiple systems involved in such an accidental event. Assessments scanned a broad range of design variables, some closely related to the suppression system itself, and others dependent on Primary Heat Transfer System features. The parameter space is mapped identifying the regions where the accident consequences are fully mitigated, in terms of peak pressure in the Vacuum Vessel (VV) and equilibrium pressure of both VV and VVPSS, providing a design tool to rapidly adapt the VVPSS to the evolving plant design.

Modelling activity in support of MITICA high voltage system protections

MITICA, the full-scale prototype of ITER Heating Neutral Beam (HNBs), has challenging requirements on its power supplies. In particular its unconventional high voltage system is designed to operate at high power and voltage (up to -1 MV dc and about 54 MW), with many interfaces and high voltage insulation technologies co-existing in a single plant. Moreover, the electrical system must manage frequent breakdowns between the accelerator grids during the operation, creating electrical fast transients characterized by extremely high voltage and current peaks. In the conceptual design phase suitable design provisions were conceived to limit the energy in the grids and to limit the overvoltage on specific components in the case of grids-breakdown. The integration tests of the power supplies showed the capability of the system to generate and sustain voltage as high as 700 kV; at higher voltage the voltage withstanding capability was not confirmed as some breakdowns occurred in the plant. Although the location of the breakdowns has not been identified yet, an impact of such breakdowns was highlighted as a couple of the components of the plant suffered a damage. This paper is focused on the analyses performed for the understanding of the fault occurred on the secondary bushing of the 1 MV insulating transformer dedicated to the supply of the Ion Source and Extraction Power Supply system (ISEPS). An extensive activity of modelling and simulation has been developed for explaining the dynamic occurred. The model is based on the stray parameters of the components, which were not easy to be estimated in the design phase, but which turn out to have relevant effects in local fast transient phenomena. After reaching a full understanding of the phenomena, the models have been used to support the conceptual design of an additional protection system for the transformer, for MITICA but also in view of the ITER installation.

Automatic Annotation of Functional Semantics for 3D Product Model Based on Latent Functional Semantics

To support effectively function-driven 3D model retrieval in the phase of mechanical product conceptual design and improve the efficiency of functional semantics annotation for 3D models, an approach for functional semantics automatic annotation for mechanical 3D product model based on latent functional semantics is presented. First, the design knowledge and function knowledge of mechanical product model are analyzed, and the ontology-based functional semantics for assembly product is constructed. Then, some concept about functional region is defined, and the 3D product model is decomposed into functional regions with different levels of granularity. The similarity of the functional region is evaluated considering multisource attribute information and geometric shape. Subsequently, the similarity based on latent functional semantics annotation model for functional regions is established, which is employed for annotating automatic latent functional semantics in the 3D product model structure. Finally, mechanical 3D models in the model library are used to verify the effectiveness and feasibility of the proposed approach.

Conceptual design modeling by the novel aircraft conceptual design and analysis system (ACDAS)

PurposeThroughout an aircraft development process, the conceptual design phase is an extremely important milestone; hence, the quality and success of this step directly affect the overall cost and lead time of the project. Because of this fact, the purpose of this study is to provide outputs and suggestions to the designing engineer regarding the requirements for reducing overall design time as well as costs and creating an ideal design at the early phases of the project by optimizing the aircraft development process.Design methodology approachThe system has been prepared parametrically and presents some performance specifications for the aircraft in the early phases of the design, for example, coefficients for lift CL as well as drag CD and weight as well as fuel estimations. The software uses a combination of well-known design techniques within just one platform in contrast to many other applications. Because of this feature, it is not needed to use different sub-platforms which would require an appropriate environment and even though would lead to complications with regard to the connectivity. The system also presents relevant information about the aircraft performance like velocity versus load factor (V-n) diagrams, maximum turn rate of climb, turn rate and climb angle graphs in contrast to many other open-source conceptual design platforms.FindingsIn this study, authentic General Dynamics F-16 Fighting Falcon and McDonnell Douglas F-15 Eagle data were used as input to the system, and advanced geometric and/or performance graphs were obtained and compared to the literature where a good agreement of the results was observed. These results with regard to the aircraft performance are typically product specific and quite rare in the literature. These data obtained by use of the software during the aircraft design are, thus, of major interest, especially for the design of new aerospace platforms. In this study, all of these graphs (especially the remarkable V-n diagram) are obtained on one platform.Originality valueThe aircraft conceptual design and analysis system software provides information and suggestions regarding the requirements for reducing the overall design time, reducing the design costs and creating an optimized design at the early phases of a project by optimizing the aircraft development process within just one convenient, that is, user friendly, platform, where it uses a combination of varying methodologies. Besides presenting one interface, which is quite typical for conceptual design tools, it allows applications of methods like vortex lattices and finite differences for obtaining aerodynamic performance parameters.

Lower Extremity Posture Assistive Wearable Devices: A Review

Many work-related tasks demand able-bodied employees to assume uncomfortable postures for long periods. This can lead to work-related musculoskeletal disorders. The situation demands the employees to be physically empowered while ensuring their agility and flexibility. In that context, wearable bodyweight support systems have come to the forefront as a futuristic solution to reduce the stress on the human body when assuming sitting and/or crouched postures. Recently, heightened attention on these posture assistive devices was evident with an increasing number of products, patents, and research articles. However, reviews of such wearable posture assistive devices for the lower limbs are lacking in the literature. Thus, this article specifically focuses on reviewing existing methods and technologies to assist workers in the industrial or service sectors to work in uncomfortable or crouched postures. Systematic reviews and meta-analyses extension for scoping reviews method was used to identify and analyze 43 unique designs from research and patent databases. The critical review of the technologies was performed after classifying these devices into commercial phase, lab/research phase, and conceptual design phase. This review has comprehensively covered the trends and patterns of the modern developments in posture assistance and includes future directions for the research community. Holistically, this article serves as a reference to set up a benchmarking system for wearable posture assistive devices.

Hazard Identification and Safety Requirements Derivation from a Functional Safety Perspective for UAS Conceptual Design: Based on the UK AAIB's Accident Investigation Reports on Unmanned Aircraft Systems

With the 4th Industrial Revolution, the utilization of unmanned aircraft systems is increasing day by day in various fields. However, unmanned aircraft systems are vulnerable to functional errors due to their unique characteristics, such as remote control and automatic flight. In the event of an accident, the system operator and the general public may be injured, and the system manufacturer may be disadvantaged by the Product Liability Act. In addition, with the establishment of international standards related to risk management and functional safety, such as ISO/IEC/IEEE 16085, IEC 61508, and ARP4761, risk analysis and countermeasures have become essential when developing systems. It is time to ensure functional safety at the conceptual design phase to protect public safety and manufacturers' interests. This study reviews international standards to confirm the importance of identifying functional safety hazards and managing requirements. In addition, it also analyzes the accident investigation reports of the UK AAIB to identify hazards of unmanned aircraft systems and derive safety requirements.

Biologically Inspired Design Concept Generation Using Generative Pre-Trained Transformers

Abstract Biological systems in nature have evolved for millions of years to adapt and survive the environment. Many features they developed can be inspirational and beneficial for solving technical problems in modern industries. This leads to a specific form of design-by-analogy called bio-inspired design (BID). Although BID as a design method has been proven beneficial, the gap between biology and engineering continuously hinders designers from effectively applying the method. Therefore, we explore the recent advance of artificial intelligence (AI) for a data-driven approach to bridge the gap. This paper proposes a generative design approach based on the generative pre-trained language model (PLM) to automatically retrieve and map biological analogy and generate BID in the form of natural language. The latest generative pre-trained transformer, namely generative pre-trained transformer 3 (GPT-3), is used as the base PLM. Three types of design concept generators are identified and fine-tuned from the PLM according to the looseness of the problem space representation. Machine evaluators are also fine-tuned to assess the mapping relevancy between the domains within the generated BID concepts. The approach is evaluated and then employed in a real-world project of designing light-weighted flying cars during its conceptual design phase The results show our approach can generate BID concepts with good performance.

Conceptual Architectural Design at Scale: A Case Study of Community Participation Using Crowdsourcing

Architectural design decisions are primarily made through an interaction between an architect and a client during the conceptual design phase. However, in larger-scale public architecture projects, the client is frequently represented by a community that embraces numerous stakeholders. The scale, social diversity, and political layers of such collective clients make their interaction with architects challenging. A solution to address this challenge is using new information technologies that automate design interactions on an urban scale through crowdsourcing and artificial intelligence technologies. However, since such technologies have not yet been applied and tested in field conditions, it remains unknown how communities interact with such systems and whether useful concept designs can be produced in this way. To fill this gap in the literature, this paper reports the results of a case study architecture project where a novel crowdsourcing system was used to automate interactions with a community. The results of both quantitative and qualitative analyses revealed the effectiveness of our approach, which resulted in high-level stakeholder satisfaction and yielded conceptual designs that better reflect stakeholders’ preferences. Along with identifying opportunities for using advanced technologies to automate design interactions in the concept design phase, we also highlight the challenges of such technologies, thus warranting future research.

Optimal Design of a Canopy Using Parametric Structural Design and a Genetic Algorithm

The structural performance of any building design is often dependent on the geometrical shape, which affects its behavior and stability. Structural consideration and optimization in the conceptual stage of the design process can lead to better solutions and design exploration. In this paper, a design approach for generating and structurally optimizing the geometrical form in the conceptual design phase is presented. The method is applied to a canopy of an ecological island (waste collection center in Rome, Italy). We demonstrate how parametric structural design can facilitate the decision-maker to generate and analyze the optimal design solutions rapidly in the conceptual stage of the design process. Fully parametric models are created in a Rhinoceros3D® environment and interfaced with in-house built algorithms, and Finite Element simulations are performed in DubalRFEM. An ecological island’s canopy has been completely redesigned with a Genetic Algorithm and a Dynamic Relaxation Algorithm, resulting in a free-form shape-resistant structure. Finally, the shape-optimized canopy meets various requirements (structural, functional, formal) that improve structural efficiency and design collaboration, such as in the role of the architect and engineer in the design process and in the relationship between the designer and design tools.

The role of virtual reality technology in conceptual design: positioning, applications, and value

ABSTRACT Virtual reality (VR) is a popular information technology in design and manufacturing. In the conceptual design stage, VR has been proved to be an auxiliary tool with great potential. However, the development of VR in the conceptual design has not been systematically investigated. This study conducted a review of the application of VR in the conceptual design stage on design activities and cognitive needs in recent 18 years. This study proposed a framework of design activities and cognitive needs in the conceptual design stage based on the design information cycle model. The technical characteristics are analysed and role of VR in each phase of conceptual design is discussed. Then the principle and application value in developments of VR technology for conceptual design are analysed. Finally, the research directions and application scheme of VR in conceptual design in the future are discussed.

Lightweight creativity methods for idea generation and evaluation in the conceptual phase of lightweight and sustainable design

Regarding the implementation of lightweight design in products, there are various guidelines, principles and methods that support the developers methodically throughout the entire design process. Such methods often pursue the goal of optimizing an existing product by reducing the amount of consumed material (e.g., topology optimization). A more effective way to apply lightweight design lies in fostering the creativity and intuitiveness of engineers to develop miscellaneous concepts with the capability to provide far greater mass reductions in contrast to smaller efficiency enhancements. Supported through the breakdown of assemblies via thinking in terms of functions along the paradigm of systems engineering, existing creativity techniques (e.g., “brainstorming” or “6-hats-method”) and evaluation methods (e.g., “point scoring”) for idea generation and evaluation have been analyzed and rethought from a lightweight and sustainable design perspective resulting in so called lightweight creativity methods (LWCM). The methods were tested on a use case from the field of robotics, which enabled the identification of the potential of LWCM for a lightweight and sustainable design.

Topology Optimization of Strength-Safe Continuum Structures Considering Random Damage

Spacecraft in the aerospace field and military equipment in the military field are at risk of being impacted by external objects, which can cause local damage to the structure. The randomness of local damage is a new challenge for structural design, and it is essential to take random damage into account in the conceptual design phase for the purpose of improving structure’s resistance to external shocks. In this article, a random damaged structure is assumed to have damages of the same size and shape at random locations, and the random damage is considered as multiple damage conditions of the structure. In order to improve the randomness and comprehensiveness of the multiple damage conditions, the stacking strategy is used to generate the distribution of the damage area. Following this strategy, the topology optimization design of the random damaged structure, which is to minimize the weight of the structure with a constraint on the stress of the structure under multiple damage conditions, is formulated based on the independent continuous mapping (ICM) method. The dual sequence quadratic programming (DSQP) algorithm combined with the stress globalization method is adopted to solve the optimization problem. The numerical examples demonstrate the effectiveness and applicability of the proposed method in the topology optimization of strength-safe continuum structures.

Multidisciplinary Modeling and Optimization Method of Remote Sensing Satellite Parameters Based on SysML-CEA

To enhance the efficiency of system modeling and optimization in the conceptual design stage of satellite parameters, a system modeling and optimization method based on System Modeling Language and Co-evolutionary Algorithm is proposed. At first, the objectives of satellite mission and optimization problems are clarified, and a design matrix of discipline structure is constructed to process the coupling relationship of design variables and constraints of the orbit, payload, power and quality disciplines. In order to solve the problem of increasing non-linearity and coupling between these disciplines while using a standard collaborative optimization algorithm, an improved genetic algorithm is proposed and applied to system-level and discipline-level models. Finally, the CO model of satellite parameters is solved through the collaborative simulation of Cameo Systems Modeler (CSM) and MATLAB. The result obtained shows that the method proposed in this paper for the conceptual design phase of satellite parameters is efficient and feasible. It can shorten the project cycle effectively and additionally provide a reference for the optimal design of other complex projects.

Structural optimization design of a bolster based on a simulation-driven design method

Abstract A simulation-driven design method which uses multiple optimization methods can effectively promote innovative structural design and reduce the product development cycle. Meanwhile, the sub-model technology which has more detailed simulation and optimization analysis can enormously improve the efficiency of modelling and solving. This study establishes a general workflow of structural optimization for a stainless-steel metro bolster by combining the simulation-driven design method and sub-model technology. In the sub-model definition phase, the end underframe sub-model which contains the bolster is obtained based on the whole car body finite element (FE) model, and the effectiveness of the end underframe sub-model is also proved. In the conceptual design phase, the topology path inside the bolster is obtained by the topology method and the optimized structure of the inner ribs inside the bolster is determined according to manufacturing processes and design experiences. In the detailed design phase, the thickness of each part of the bolster is determined by size optimization. The simulation analyses indicate that the requirements of static strength and fatigue strength are fulfilled by the optimized bolster structure. Besides, the weight can be reduced by 11.18% and the weld length can be decreased by 17.79% compared with the original bolster structure, which means that not only the lightweight design goal is achieved, but also the welding quantity and manufacturing difficulty are greatly reduced. The results show the effectiveness of the simulation-driven design method based on the sub-model technology in the structural optimization for key parts of rail transit vehicles.

Thermal-hydraulic analysis of alternative cable-in-conduit conductors for the European DEMO hybrid central solenoid

A hybrid design of the Central Solenoid is under study within the conceptual design phase of the European DEMO fusion reactor. It is based on HTS conductors in the innermost high-field layers, and Nb3Sn and NbTi conductors for field values below 15 T. Since the resistance of the stainless steel jacket to mechanical fatigue drives the whole magnet design, alternative layouts of the cable-in-conduit conductors are aimed at decoupling the mechanical and hydraulic functions of the jacket itself. Thus, a reduced steel thickness, a smaller radial build of the coil and a larger magnetic flux are achievable. In this work, we analyse a new cable design based on filled conductors and tight He channels, both for the HTS and the LTS layers, and study their thermal-hydraulic performance by means of numerical simulations. After having introduced the geometrical and material details of the considered conductors, we describe the model and assumptions made for estimating the AC losses, assumed as the only heating source. Finally, we discuss the resulting minimum temperature margin of the conductors and provide useful insights for future activities on conductor development.

Design Features and Simulation of the New-Build HELOKA-US Facility for the Validation of the DEMO Helium-Cooled Pebble Bed Intermediate Heat Transport and Storage System

For the EU-DEMO Helium-Cooled Pebble Bed (HCPB) concept, an indirect coupled design (ICD) with a molten salt (MS) loop as an intermediate heat transport and storage system (IHTS) is considered for the conceptual design phase. The IHTS with an energy storage decouples the primary heat transport system (PHTS) that undergoes pulse and dwell power cycles from the power conversion system (PCS), and thus can provide stable power to the turbine and grid. However, the maintenance of stable He and MS parameters during transitions from dwell to pulse and vice versa is challenging for the design of the MS loop, and the real performance of the helium–MS heat exchanger (He/MS HX) shall be verified. To investigate such components and conditions, a new R&D infrastructure HELOKA-US (Helium Loop Karlsruhe—Upgrade Storage) is under construction for the validation of prototypical components and the MS loop operation under stationary and transitional conditions. This paper provides the design features of Phase 1a of the project and the simulation results with EBSILON on the power generation phase.