Modeling for Conceptual Design: An Aeroelastic Approach

As design requirements and affordability for future aircraft become increasingly demanding, aircraft design processes will be required to explore a larger design space and capture multi-disciplinary effects during conceptual design to effectively assess the benefits of new technologies. Lockheed Martin is currently participating in the ESAVE (Efficient Supersonic Air Vehicle Exploration) AFRL program which is developing MDO-based improvements to the fighter strike conceptual design process. This paper discusses the program progress to date of both conceptual design process improvements for fighter/strike aircraft and the application of the resultant MDO process to a specific design problem. The fighter/strike design process involves many coupled discipline interactions due to demanding mission performance requirements. The ESAVE program has focused on capturing the discipline interactions required for the active structures and variable cycle engine technologies. Initial results demonstrate that integration of these structural and propulsion technologies in an MDO-based framework expands the traditional fighter/strike design space and can potentially provide significant performance improvements compared to conventional conceptual design processes.

An expert system for the conceptual design of bridges

A multi-objective feedback approach for evaluating sequential conceptual building design decisions

Empirical sizing guidelines such as tail volume coefficients have long been used in the early aircraft design phases for sizing stabilizers, resulting in conservatively stable aircraft. While successful, this results in increased empty weight, reduced performance, and greater procurement and operational cost relative to an aircraft with optimally sized surfaces. Including flight dynamics in the conceptual design process allows the design to move away from empirical methods while implementing modern control techniques. A challenge of flight dynamics and control is the numerous design variables, which are changing fluidly throughout the conceptual design process, required to evaluate the system response to some disturbance. This research focuses on addressing that challenge not by implementing higher order tools, such as computational fluid dynamics, but instead by linking the lower order tools typically used within the conceptual design process so each discipline feeds into the other. In thisresearch, flight dynamics and control was incorporated into the conceptual design process along with the traditional disciplines of vehicle sizing, weight estimation, aerodynamics, and performance. For the controller, a linear quadratic regulator structure with constant gains has been specified to reduce the user input. Coupling all the disciplines in the conceptual design phase allows the aircraft designer to explore larger design spaces where stabilizers are sized according to dynamic response constraints rather than historical static margin and volume coefficient guidelines.

The objective of this research project is the development of a second generation in-duct sorbent injection technology as a cost-effective compliance option for the 1990 Clean Air Act Amendments. Research focused on the Advanced Coolside Process, which has shown the potential of exceeding the performance targets of 90% SO{sub 2} removal and 60% sorbent utilization. In Task 5, Conceptual Process Design and Economic Evaluation, the economics of the CONSOL Advanced Coolside Process as a Clean Air Act compliance option were evaluated. A conceptual process design for full-scale, coal-fired applications is described. Advanced Coolside is compared to conventional Limestone Forced Oxidation (LSFO) wet FGD technology. The process economics for coal sulfur levels ranging from 1.0% to 3.5% (as-received) and plant sizes ranging from 160 to 512 gross MW were investigated, In addition, the economics of on-site versus off-site lime hydration and the cost sensitivity to delivered pebble lime and hydrate prices are investigated, Advanced in-duct sorbent injection enjoys a capital and levelized cost advantage relative to LSFO in all cases examined in this study. As a result of this study and others made during this contract, the following conclusions can be made: (1) The capital cost of Advanced Coolside is 55% to 60% less than that of LSFO and varies slightly depending on coal sulfur content and plant size. (2) The total levelized SO{sub 2} control cost advantage relative to LSFO varies from 15% to 35% over the range of coal sulfur contents and plant sizes evaluated. This cost advantage is sensitive to sorbent transportation charges. As a result, the economics are site-specific. (3) The experimental optimizations based on interim economic analyses were the key to capital and levelized cost reductions.

The major concern in the architecture, engineering, and construction (AEC) industry is time, cost, and quality. The design for industrial building project usually complex, particularly in a field of mechanical and piping process due to the large involvement of project stakeholders. The case company, which is the specialist supplier of industrial piping solution in Thailand, reported the issue of redesigns regarding to their poor project management of conceptual design process in construction project that effect to their work performance and customer satisfaction. Thus, the purpose of this study was to improve the process of conceptual design using project management concept to reduce the number of redesign in the conceptual design phase for storm drainage design projects. The new conceptual design process was introduced in 4 stages-Initialization, Identification, Translation, and Specification. These stages were clearly defined their input, process (with project management plans, tools and techniques such as checklist, tree diagram, 3D model system and expert judgment), and output.
 
 This was validated with 30 pilot projects of storm drainage design in factories and warehouses. The results revealed that, the total number of redesign was reduced from 102 to 24 under the satisfied of company?s KPI. In addition, the total cost of redesign was decreased form THB 1,326,000 to THB 31,200. Furthermore, the total design time from the start to finish the specification output was reduced from 327 days to 212 days. Therefore, the proposed solution was proved to be practical and fully implemented by the company.

Genetics-based design is an effective approach to develop novel products for conceptual design. It could reduce innovation blindness by providing logically structured procedure. However, the major challenge of genetics-based engineering method is that how to identify what information is genetic information and how to use it in a conceptual design process. To solve this problem, this article proposes a conceptual design method driven by product genes. First, a functional expansion model is established based on analyzing the conceptual design process. Second, to respectively compare the functions and structure schemes in the model to biological traits and proteins, a product gene definition composed of behaviors and attributes is put forward. Then, a modeling and coding method of product genes is given analogous to that of biological genes. Third, operation technologies of product genes are analyzed, including breakdown, crossover, recombination, transcription, and translation. Based on this, a conceptual design method driven by product genes is advanced. Finally, an example shows that this method is able to extract key information of products and gives a method of how to use the information in a conceptual design process. Moreover, structure schemes obtained through this method are of high feasibility and have more possibilities of innovation.

To support automatic requirements mining and concept design for engineering designers, we proposed a knowledge-based method called D-mapping (Design Mapping). In our method, the design problem-solving processes are represented as mappings between functional and physical domains. For requirements mining, the earliest process of concept design, mappings take place inside the functional domain, and thus it is a self-mapping process. For physical architecture design, the later process of concept design, mappings take place between the functional and physical domains, and thus it is a cross-domain mapping process. We built a knowledge-based expert system to assist designers in those processes. The knowledge base of our expert system is based on amounts of Chinese patent texts and built using natural language processing technologies. The knowledge inference engine of our expert system is constructed based on various machine learning algorithms. The proposed method and the system can be proved to be novel and effective in case studies.

Computer-aided conceptual design (CACD) aims to increase efficiency and quality of design work but with little essential progress due to the gap between abstract concept and detailed structure. In order to tackle the problem concerned with conceptual design process and automation, this paper introduces the concept of functional surface as the information carrier to link together product function and structure and describes a product genetic model to represent and organize product information. Functional surface is used to formalize the product gene, a varied-length coding scheme for functional surface and product gene is proposed, and the design process model for conceptual design is established based on product gene. Finally, a prototype system for CACD is introduced to demonstrate how a product can be designed based on the proposed model.

After the analysis of design process of mechanical products, the paper pointed out that the structure design is the key of the connection between conceptual design and detail design process. The paper introduced a method that based on conceptual information knowledge unit for structure design of products. It defined knowledge unit and structure unit, and encapsulation of conceptual information into knowledge (structure) unit to realize the information interconnection and drive mechanism from conceptual design to structure design thus making knowledge structure unit become the main carrier representing product design knowledge; expressed design rules and design knowledge based on knowledge units to establish knowledge library of product design; and then expressed different mechanic structure through combination and variation of knowledge (structure) units during the design process to realize product design; finally, analyzed the structure features of multi-cavity injection mold systems (from 1-cavity mold to multi-cavity mold), and expressed the mold structure by knowledge units, based on which the method of multi-cavity plastic injection mold system design was realized.

The Architecture/Engineering/Construction (AEC) industry is one of the multidisciplinary domains in which collaboration among related parties is of utmost importance1. Despite the intense flow of information between design and LCC (Life Cycle Cost) professionals, there is a lack of research to better understand and manipulate these processes. Architecture design and LCC management is a process of planning a tangible building and cost on a tangible land through intangible work. Due to this characteristic of design work, conventional design management was conducted around the drawings as the final outcome, but actual individual processes of design and LCC (Life Cycle Cost) planning for facility were excluded. As a result, design work and LCC planning completely depended on the individual abilities and experiences of each architect and LCC planner. Even organization of information required for design and LCC process are considered to belong to the domain of individual ability. Therefore, this study proposes an integrated system development methodology of design and LCC process for an information oriented design and LCC management system, which allows architects and LCC planners to easily access information to be provided in each design stage and its relevant LCC planning process, and for design and cost management companies to improve the performance through the systematic storage and usage of data after the completion of an educational project. This research analyzes actual design and LCC processes in currently active companies and proposes a standard design and LCC process, and then examines input and output information for each task in the process in order to propose an information oriented standard design and LCC process. Based on this, Data Flow Diagram (DFD) and Entity Relationship Diagram (ERD) is designed for an information oriented design and LCC management system.

The car industry is very large, and the designs are usually evolutionary in character with much convergence of approaches and technology. Car stylists play a particular role in the concept stage of the design process. Key parts of their work have proved incompatible with computer-aided design (CAD) support, despite its advantages. The primary objective of the work described has been to devise techniques that provide effective CAD support for the stylists' concept design processes, without inhibiting the fluidity and richness of a sketch-based approach. Various methods for doing this have been developed and used by stylists and design students. The work on sketch mapping as a usable tool is described, and is contrasted with the more conventional direct modelling approach that is seen to have limitations. There is a brief description of work in progress on deriving forms directly from sketches. The extension of the resources available to support concept design through the use of non-concept scanning technology is described, and initial experiments illustrated. As a conclusion there is the outline proposal for a hybrid technique combining conventional sketches, sketch mapping, sketch modelling and non-contact scanning techniques.

Conceptual product design involves a series of the designer’s creative thinking processes and consecutive communication with other disciplines are required in this stage to reach a final solution. During this stage, for example, different format of dialogues between designers and engineers, salesmen and customers are required to collect information about the product concept. For the product designers, the decision making procedure in this stage is the configuration inside the black box where designers’ mental activities are frequently misunderstood. Another problem usually found in the conceptual product design stage is that product designers are ignorant of the product requirements defined by others due to insufficient communication. In order to enhance the performance of the conceptual product design, a novel approach based on genetic algorithm (GA) is presented in this paper. Using GA, a dialogue module is established to reproduce feasible design solutions and the evaluation of these alternatives are then calculated inside the dialogue module. The process of conceptual product design is similar to the idea evolution with implementation of GA. An application of the proposed method is also presented briefly in this paper.

In order to improve the design of products and reduce design changes, cost, and time to market, life cycle engineering has emerged as an effective approach to address these issues in today's competitive global market. As over 70% of the total life cycle cost of a product is committed at the early design stage, designers can substantially reduce the life cycle cost of products by giving due consideration to the life cycle implications of their design decisions. During the early design stages there may be competing requirements. In addition, detailed information is scarce and decisions must be made quickly. Thus, both the overhead in developing parametric life cycle cost (LCC) models for a wide range of concepts or requirements, and the lack of detailed information make the application of traditional LCC models impractical. A different approach is required because a traditional LCC method should be incorporated in the very early design stages. This paper explores an approximate method for providing the preliminary life cycle cost. Learning algorithms trained to use the known characteristics of existing products can perhaps allow the life cycle cost of new products to be approximated quickly during the conceptual design phase without the overhead of defining new LCC models. Artificial neural networks are trained to generalise product attributes and life cycle cost data from pre-existing LCC studies. Then, the product designers query the trained artificial model with new high-level product attribute data to obtain an LCC for a new product concept quickly. Foundations for the learning LCC approach are established, and then an application is provided. This paper has been developed to provide designers with LCC information to guide them in conceptual design.

Although the product life cycle cost (LCC) is mainly committed by early design stages, designers do not consider the costs caused in subsequent phases of life cycle. The estimating method for the product life cycle cost in early design processes has been required because of both the lack of detailed information and time for a detailed LCC for a various range of design concepts. This paper suggests an approximate LCC method that allows the designer to make comparative LCC estimation between the different product concepts. The product attributes at the conceptual design phase and LCC factors are introduced and the significant product attributes are determined by statistical analysis. Neural network algorithms are applied to estimate LCC by considering the identified product attributes as inputs and the LCC as output. Trained learning algorithms for the known characteristics of existing products will quickly give the estimation of LCC for new product concepts. The estimation for maintenance and energy costs of electronic appliances is shown as an example. The proposed method provides the good estimation for the LCC and gives the guidelines leading to cost-effective design decision-making at the early design stage.