Design theory and conceptual design: contrasting functional decomposition and morphology with parameter analysis

AbstractThe mechanism of design reasoning from function to form is suggested to consist of a two-step inference of the innovative abduction type. First is an inference from a desired functional aspect to an idea, concept, or solution principle to satisfy the function. This is followed by a second innovative abduction, from the latest concept to form, structure, or mechanism. The intermediate entity in the logical reasoning, the concept, is thus made explicit, which is significant in following and understanding a specific design process, for educating designers, and to build a logic-based computational model of design. The idea of a two-step abductive reasoning process is developed from the critical examination of several propositions made by others. We use the notion of innovative abduction in design, as opposed to such abduction where the question is about selecting among known alternatives, and we adopt a previously proposed two-step process of abductive reasoning. However, our model is different in that the two abductions used follow the syllogistic pattern of innovative abduction. In addition to using a schematic example from the literature to demonstrate our derivation, we apply the model to an existing, empirically derived method of conceptual design called “parameter analysis” and use two examples of real design processes. The two synthetic steps of the method are shown to follow the proposed double innovative abduction scheme, and the design processes are presented as sequences of double abductions from function to concept and from concept to form, with a subsequent deductive evaluation step.

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A Mathematical Functional Decomposition Approach Through Granularity Partition Process in Quotient Space

Volume 2: Advanced Manufacturing ◽

10.1115/imece2018-86217 ◽

2018 ◽

Author(s):

Y. T. Li ◽

Y. X. Wang

Keyword(s):

Conceptual Design ◽

Quotient Space ◽

Lower Layer ◽

Solution Space ◽

Decomposition Process ◽

Decomposition Approach ◽

Functional Decomposition ◽

Topological Structures ◽

Functional Reasoning ◽

Partition Process

Over the past decades, several methodologies have coalesced around the functional decomposition and partial solution manipulation techniques. These methodologies take designers through steps that help decompose a design problem and build conceptual solutions based on the intended, product functionality. However, this kind of subjective decomposition restricts solutions of conceptual design within designers’ intended the local, rather the whole, solution space. In such cases, the ability for AI-based functional reasoning systems to obtain creative conceptual design solutions is weakened. In this paper, a functional decomposition model based on the domain decomposition theory in quotient space is proposed for carrying out functional decomposition without needing functional reasoning knowledge to support. In this model, the functional decomposition is treated as a granularity partition process in quotient space composed of three variables: the domain granularities, the attribute properties, and the topological structures. The closeness degrees and the attribute properties in fuzzy mathematics are utilized to describe the fuzzy equivalence relations between the granularities in the up-layer and in the lower-layer of the functional hierarchies. According to the order characteristics in the partially sequential quotient space, based on the homomorphism principle, the attribute properties and the topological structures corresponding to the lower-layer of the functional hierarchies are constructed then. Here, the attribute properties are expressed with membership functions pointed to the lower-layer from the up-layer of the functional hierarchies, and the topological structures are expressed with matrixes and the directed function network represent the topological connections among the subfunctions in the lower-layer of the functional hierarchies. Through refining the functional decomposition process step by step, and traversing all tree branches and leaf nodes in the functional decomposition tree, the functional hierarchies are obtained. Since the functional decomposition process not need the user to indicate or manage desired functionality, the model presented in this paper can reduce designers’ prejudices or preconceptions on the functional hierarchies, as well as extend the solution space of conceptual design.

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Wind farm service vessels concept design. Part 1 – Mathematical model

Pomorstvo ◽

10.31217/p.31.2.5 ◽

2017 ◽

Vol 31 (2) ◽

pp. 111-118

Author(s):

Oleksandr V. Bondarenko

Keyword(s):

Mathematical Model ◽

Objective Function ◽

Conceptual Design ◽

Design Theory ◽

Wind Farm ◽

Statistical Design ◽

Cost Calculation ◽

Concept Design ◽

Design Variables ◽

Main Dimension

This paper describes the process of a conceptual design of the Wind farm service vessel. The optimization problem of the choice of principal particulars of the WFSV is formulated. For her decision, a genetic algorithm is used. A minimum of costs on repair and maintenance of wind farm is chosen as the objective function. The methodology of the optimization process such as objective function, design variables and used constraints is described. Furthermore, a mathematical model considering dimensions, powering, mass, stability, sea keeping and cost calculation is developed. Methodology of the estimation of economic efficiency, basis of what is made by the methods of statistical design, theory of probability and theory of reliability, is worked out. Software is worked out, giving an opportunity to visualize the process of functioning of the WFSV and wind farm. The methodology may be used in the conceptual design stages for selecting the main dimension of the WFSV.

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