Showing papers on "Conceptual design published in 2010"

The Design of Design: Essays from a Computer Scientist

Abstract: Making Senseof Design Effective design is at the heart of everything from software development to engineering to architecture. But what do we really know about the design process? What leads to effective, elegant designs? The Design of Design answers these questions. This new book by Fred Brooks contains extraordinary insights for designers in every discipline. Brooks pinpoints the constants inherent to all design projects and uncovers processes and patterns most likely to lead to excellence. Drawing on the observations and intuitions of dozens of exceptional designers, as well as his direct experiences in several design domains, Brooks argues convincingly that bold design decisions lead to better outcomes. The author tracks the evolution of the design process, delves into complex systems based on distributed design, and illuminates what makes a truly great designer. He examines the nuts and bolts that affect all design processes, including budget and other constraints, aesthetics, design empiricism, and tools, and then grounds this discussion in his own real-world examplescase studies ranging from home construction to IBMs Operating System/360. Throughout the book, Brooks reveals the keys to success that every designer, design project manager, and design researcher should know.

A functional failure reasoning methodology for evaluation of conceptual system architectures

Abstract: In this paper, we introduce a new methodology for reasoning about the functional failures during early design of complex systems. The proposed approach is based on the notion that a failure happens when a functional element in the system does not perform its intended task. Accordingly, a functional criticality is defined depending on the role of functionality in accomplishing designed tasks. A simulation-based failure analysis tool is then used to analyze functional failures and reason about their impact on overall system functionality. The analysis results are then integrated into an early stage system architecture analysis framework that analyzes the impact of functional failures and their propagation to guide system-level architectural design decisions. With this method, a multitude of failure scenarios can be quickly analyzed to determine the effects of architectural design decisions on overall system functionality. Using this framework, design teams can systematically explore risks and vulnerabilities during the early (functional design) stage of system development prior to the selection of specific components. Application of the presented method to the design of a representative aerospace electrical power system (EPS) testbed demonstrates these capabilities.

A new integrated design concept evaluation approach based on vague sets

Abstract: Design concept evaluation which is in the end of conceptual design is one of the most critical decision points in product development. It relates to the final success of product development, because a poor design concept can rarely be compensated at the later stages. Design concept evaluation is a complicated multi-criteria decision-making problem under uncertain environments. Vague set theory is superior to fuzzy set theory in dealing with uncertain and imprecise judgments of decision makers (DMs) due to its ability of supporting opposing evidences. In this paper, a new integrated design concept evaluation approach based on vague sets is presented. Linguistic variables are transformed into vague numbers by vague set theory. Modified weighted least squares model (WSLM) based on vague sets is proposed to aggregate all individual judgments in group decision-making. Vague cross-entropy integrated with the technique for order preference by similarity to ideal solution (TOPSIS) framework is proposed to rank the order of alternatives according to the synthetic vague decision matrix. Numerical example of design concept evaluation problem of a horizontal directional drilling (HDD) machine indicates that the proposed integrated approach is systematic and effective to solve design concept evaluation problem regardless of complexity of product.

A fuzzy integrated methodology for evaluating conceptual bridge design

Abstract: Choosing the most suitable superstructure is vital for the success of a small to medium-span highway bridge design. Numerous attributes must be considered and evaluated in terms of many different conflicting criteria in the conceptual design of a bridge, leading to a large set of subjective or ambiguous data. Furthermore, integrating experts' knowledge and experiences to make appropriate decisions is a commonly used method. In order to solve this problem, project managers and design engineers need to evaluate their initiative designs carefully and make accurate decisions. For this reason, a systematic decision process for selecting the best design idea by means of a novel integrated optimization-based methodology is proposed. In the first phase, Quality Function Deployment (QFD) is employed for translating the project requirements into design requirements. In the second phase, Technique for Order Performance by Similarity to Ideal Solution (TOPSIS) is utilized to select the best superstructure as an alternative, based on the weighted criteria achieved from the first phase. In this study the rating values regarding to each alternative and criteria throughout the phases are described in a fuzzy environment by means of linguistic variables. Finally, a case study is provided to illustrate the implementation process of the integrated methodology for bridge superstructure design. For this purpose, an expert team has been formed to collect and verify the expectations of the project, which located in Tehran, Iran. The results demonstrated that the proposed methodology could be successfully applied in the highway bridge projects as a useful tool to facilitate decision making.

Airframe Design for Silent Fuel-Efficient Aircraft

Abstract: The noise goal of the Silent Aircraft Initiative, a collaborative effort between the University of Cambridge and Massachusetts Institute of Technology, demanded an airframe design with noise as a prime design variable and a design philosophy that cut across multiple disciplines. This paper discusses a novel design methodology synthesizing first-principles analysis and high-fidelity simulations, and it presents the conceptual design of an aircraft with a calculated noise level of 62 dBA at the airport perimeter. This is near the background noise in a well-populated area, making the aircraft imperceptible to the human ear on takeoff and landing. The all-lifting airframe of the conceptual aircraft design also has the potential for improved fuel efficiency, as compared with existing commercial aircraft. A key enabling technology in this conceptual design is the aerodynamic shaping of the airframe centerbody. Design requirements and challenges are identified, and the resulting aerodynamic design is discussed in depth. The paper concludes with suggestions for continued research on enabling technologies for quiet commercial aircraft.

Conceptual process planning - an improvement approach using QFD, FMEA, and ABC methods

Abstract: Conceptual process planning (CPP) is an important technique for assessing the manufacturability and estimating the cost of conceptual design in the early product design stage. This paper presents an approach to develop a quality/cost-based conceptual process planning (QCCPP). This approach aims to determine key process resources with estimation of manufacturing cost, taking into account the risk cost associated to the process plan. It can serve as a useful methodology to support the decision making during the initial planning stage of the product development cycle. Quality function deployment (QFD) method is used to select the process alternatives by incorporating a capability function for process elements called a composite process capability index (CCP). The quality characteristics and the process elements in QFD method have been taken as input to complete process failure mode and effects analysis (FMEA) table. To estimate manufacturing cost, the proposed approach deploys activity-based costing (ABC) method. Then, an extended technique of classical FMEA method is employed to estimate the cost of risks associated to the studied process plan, this technique is called cost-based FMEA. For each resource combination, the output data is gathered in a selection table that helps for detailed process planning in order to improve product quality/cost ratio. A case study is presented to illustrate this approach.

Design‐Driven Innovation Process Model

Abstract: Two applied research projects undertaken in Central Switzerland aimed to introduce design and design management into the strategy building and innovation processes of firms with little or no design experience and—on a theoretical level—to introduce design management into a generic innovation management model. Research with 11 variously-sized companies in a variety of industries revealed that many of the small and medium-sized enterprises (SMEs) do not engage in innovation activities in a systematic and proactive way in order to understand market and customer needs. They also lack a design management function that would coordinate the processes of product and service development, brand design, and communication to create a coherent market entry and customer experience for new products or services. Researchers explored the contribution of design research, design leadership, and design management to a generic innovation management model, and developed a design-driven innovation process model with six phases: impulse, research, development, strategy, implementation, and evolution. The model is designed to meet the needs of SMEs for easy implementation and cost and risk reduction. Further applied research is planned to validate the model.

N+3 Aircraft Concept Designs and Trade Studies

Abstract: MIT, Aerodyne Research, Aurora Flight Sciences, and Pratt & Whitney have collaborated to address NASA s desire to pursue revolutionary conceptual designs for a subsonic commercial transport that could enter service in the 2035 timeframe. The MIT team brings together multidisciplinary expertise and cutting-edge technologies to determine, in a rigorous and objective manner, the potential for improvements in noise, emissions, and performance for subsonic fixed wing transport aircraft. The collaboration incorporates assessment of the trade space in aerodynamics, propulsion, operations, and structures to ensure that the full spectrum of improvements is identified. Although the analysis focuses on these key areas, the team has taken a system-level approach to find the integrated solutions that offer the best balance in performance enhancements. Based on the trade space analyses and system-level assessment, two aircraft have been identified and carried through conceptual design to show both the in-depth engineering that underpins the benefits envisioned and also the technology paths that need to be followed to enable, within the next 25 years, the development of aircraft three generations ahead in capabilities from those flying today.

Automating the conceptual design process: “from black box to component selection”

Abstract: Conceptual design is a vital part of the design process during which designers first envision new ideas and then synthesize them into physical configurations that meet certain design specifications. In this research, a suite of computational tools is developed that assists the designers in performing this nontrivial task of navigating the design space for creating conceptual design solutions. The methodology is based on automating the function-based synthesis paradigm by combining various computational methods. Accordingly, three nested search algorithms are developed and integrated to capture different design decisions at various stages of conceptual design. The implemented system provides a method for automatically generating novel alternative solutions to real design problems. The application of the approach to the design of an electromechanical device shows the method's range of capabilities and how it serves as a comparison to human conceptual design generation and as a tool suite to complement the skills of a designer.

NDARC-NASA Design and Analysis of Rotorcraft Theoretical Basis and Architecture

Abstract: The theoretical basis and architecture of the conceptual design tool NDARC (NASA Design and Analysis of Rotorcraft) are described. The principal tasks of NDARC are to design (or size) a rotorcraft to satisfy specified design conditions and missions, and then analyze the performance of the aircraft for a set of off-design missions and point operating conditions. The aircraft consists of a set of components, including fuselage, rotors, wings, tails, and propulsion. For each component, attributes such as performance, drag, and weight can be calculated. The aircraft attributes are obtained from the sum of the component attributes. NDARC provides a capability to model general rotorcraft configurations, and estimate the performance and attributes of advanced rotor concepts. The software has been implemented with low-fidelity models, typical of the conceptual design environment. Incorporation of higher-fidelity models will be possible, as the architecture of the code accommodates configuration flexibility, a hierarchy of models, and ultimately multidisciplinary design, analysis and optimization.

The Roles of Sketches in Early Conceptual Design Processes

Abstract: Design sketches are believed to play essential roles in early conceptual design processes. Exploration of how sketches are essential for the formation of new design ideas is expected to bring important implications for design education and design support systems. Little research has been done, however, to empirically examine the ways in which designers cognitively interact with their own sketches. Using a protocol analysis technique, we examined the design thoughts of an architect from the following point of view; how he drew depictions, inspected depicted elements, perceived visuo-spatial features, and thought of non-visual functional or conceptual information. The findings suggest that design sketches serve not only as external memory or as a provider of visual cues for association of non-visual information, but also as a physical setting in which design thoughts are constructed on the fly.

Design of the CLIC Main Linac Accelerating Structure for CLIC Conceptual Design Report

Abstract: The design of the CLIC main linac accelerating structure has been refined based on an improved understanding of the high-gradient limits given by rf breakdown and pulsed surface heating. In addition, compact couplers have been developed and HOM damping loads have been designed. The rf design has also been made consistent with details of the present manufacturing procedure, based on bonded asymmetrical disks, and with requirements coming from integration of the accelerating structure in the two-beam module [1]. This completion and refinement of the structure design has been made to produce the self-consistent parameter set required for preparation of the CLIC conceptual design report (CDR). RF DESIGN Over the past few years, there has been significant progress in demonstrating the feasibility of accelerating structures operating at 100 MV/m [2]. Very recently tests have also shown that structures with damping features can reach within 80 to 90% of the gradients of undamped structures [3]. Based on these results, a program to further improve the rf design and incorporate further features has been made. In this report the modification and further development of the rf design of the CLIC main linac accelerating structure [4] is described.

From User Requirements to Conceptual Design in Warehouse Design: A Survey

Abstract: Conceptual design and requirement analysis are two of the key steps within the data warehouse design process. They are to a great extent responsible for the success of a data warehouse project since, during these two phases, the expressivity of the multidimensional schemata is completely defined. This paper proposes a survey of the literature related to these design steps and points out pros and cons of the different techniques in order to help the reader to identify crucial choices and possible solutions more consciously. Particular attention will be devoted to emphasizing the relationships between the two steps describing how they can be jointly used fruitfully.

Creative patterns and stimulation in conceptual design

Abstract: Conceptual design is a creative process. Designers create functions to satisfy customer needs and behaviors and forms to fulfill their functions. Although cognitive processes are at the center in developing new ideas, they are rarely taken into account in research and development of design support methods and systems. It is conceivable that if one understands how cognitive processes are stimulated to generate design ideas, then more effective methods and tools can be developed to support conceptual design. In this article, a cognitive model of conceptual design is developed to capture the relationships among design entities, design operations, and cognitive processes. A protocol analysis is performed to evaluate the model, and a cognitive experiment carried out to study the creative patterns and stimulating relationships. The results show that designers exhibit patterns of creative design behavior, and that these patterns can be captured and instilled into the design process to promote creativity.

A Methodology for Identifying Environmentally Conscious Guidelines for Product Design

Abstract: A reverse engineering methodology is presented for identifying environmentally conscious design guidelines for use in the conceptual stages of product design. Environmentally conscious principles and guidelines help designers improve environmental impacts of products by making better decisions during conceptual design stages when data for life cycle analysis (LCA) are sometimes scarce. The difficulty in using the current knowledge base of guidelines is that it is not exhaustive and conflicts are not well understood. In response, the authors propose a general method for expanding the current set of guidelines and for understanding potential environmental tradeoffs. The method helps designers extract environmentally conscious design guidelines from a set of functionally related products by combining reverse engineering with LCA. The guidelines and LCA results can then be used to inform subsequent design cycles without repeating the process. Although in environmentally conscious design, reverse engineering is commonly applied to studies of disassembly and recyclability, the methodology and case study herein show how reverse engineering can be applied to the utilization stage of a product’s life cycle as well. The method is applied to an example of electric kettles to demonstrate its utility for uncovering new design guidelines.

Conceptual Seismic Design of Cable-Stayed Bridges

Abstract: Cable-stayed bridges can be a very effective means of bridging large distances in both seismic and non-seismic regions. Their design, analysis, and construction can be very challenging, and fortunately there is a considerable amount of literature that can assist engineers with both the analysis and detailed design of cable-stayed bridges. It is less common, however, to find simple recommendations for the conceptual design of cable-stayed bridges, in particular for seismic loading. As such, this article reviews and discusses some of the important conceptual design considerations for cable-stayed bridges, first for gravity loads and then for seismic excitation. The advantages and disadvantages of different cable-stayed bridge solutions are highlighted, with review of deck sections, tower configurations in both the longitudinal and transverse direction, deck-to-pier connections, and cable arrangements, amongst other things. Reference is made to a number of real cable-stayed bridge solutions. After reviewing ...

The process model to aid innovation of products conceptual design

Abstract: Currently, designers often pay little attention to integrated innovation during the design process of products. In addition, the product assistance design systems mainly focus on the detailed design phrase and the construction function of mathematics models are often been neglected. In order to solve these problems, this paper proposes a conceptual design process model to aid multi-stage innovation of product design based on the integration of the essential rules of the Axiomatic Design (AD) model, Function-Behaviour-Structure (FBS) model, and the guideline of functional creative thinking logics. By utilising the function tree and functional structure tree as the mediums to express the design information and by applying the conflict solving strategies of Extensic theory, the conceptual design process is defined as an integrated system with five stages and four mappings. The integrated logical processes of this model are described with mathematical language. Thus, the whole transformation from design experiences to design principles and to mathematical model finally to aided design system is realized perfectly in the proposed process model. The meaningful exploration on the nature and practical processes of product conceptual design is carried out in this research.

Aircraft Conceptual Design Using Vehicle Sketch Pad

Abstract: Vehicle Sketch Pad (VSP) is a parametric geometry modeling tool that is intended for use in the conceptual design of aircraft. The intent of this software is to rapidly model aircraft configurations without expending the expertise and time that is typically required for modeling with traditional Computer Aided Design (CAD) packages. VSP accomplishes this by using parametrically defined components, such as a wing that is defined by span, area, sweep, taper ratio, thickness to cord, and so on. During this phase of frequent design builds, changes to the model can be rapidly visualized along with the internal volumetric layout. Using this geometry-based approach, parameters such as wetted areas and cord lengths can be easily extracted for rapid external performance analyses, such as a parasite drag buildup. At the completion of the conceptual design phase, VSP can export its geometry to higher fidelity tools. This geometry tool was developed by NASA and is freely available to U.S. companies and universities. It has become integral to conceptual design in the Aeronautics Systems Analysis Branch (ASAB) here at NASA Langley Research Center and is currently being used at over 100 universities, aerospace companies, and other government agencies. This paper focuses on the use of VSP in recent NASA conceptual design studies to facilitate geometry-centered design methodology. Such a process is shown to promote greater levels of creativity, more rapid assessment of critical design issues, and improved ability to quickly interact with higher order analyses. A number of VSP vehicle model examples are compared to CAD-based conceptual design, from a designer perspective; comparisons are also made of the time and expertise required to build the geometry representations as well.