Empirical Studies of Functional Decomposition in Early Design

This paper aims to explore metrics for evaluating the effectiveness of functional decomposition methods regarding problem space exploration at the early design stage. Functional decomposition involves breaking down the main purpose of a complex problem or system into a set of more manageable sub-functions, leading to a clearer understanding of the problem space and its various aspects. While various metrics have been used to evaluate functional decomposition outcomes, little literature has focused on assessing its effectiveness in problem space exploration. To address the gap, this research introduces three metrics for problem space evaluation defined by functional models: quantity of unique functions (M1), breadth and depth of the hierarchical structure (M2), and relative semantic coverage ratio of the problem space (M3). An example study is conducted to illustrate the evaluation process, comparing functional analysis with and without explicit human-centric considerations using a power screwdriver as a case product. The analysis in the example study reveals that the breadth of the hierarchical structure (part of M2) is marginally larger in the condition with explicit human-centric considerations (Condition A) compared to the condition without such considerations (Condition B). However, no significant differences are observed in terms of other metrics. The qualitative analysis based on semantic comparisons suggests that Condition A facilitates participants in generating a diverse set of functions supporting user safety requirements more effectively than Condition B. Overall, the example study demonstrates the evaluation process for each metric and discusses their nuances and limitations. By proposing these metrics, this research contributes to benchmarking and evaluating the effectiveness of different methods in promoting functional analysis in engineering design. The metrics provide valuable insights into problem space exploration, offering designers a better understanding of the efficacy of their functional decomposition methods in early design stages. This, in turn, fosters more informed decision-making and contributes to the advancement of functional analysis methodologies in engineering design practices.

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Improve Syntax Correctness and Breadth of Design Space Exploration in Functional Analysis

She

Belanger

Bartels

et al. 2022

Journal of Mechanical Design

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Functional analysis aims to decompose complex product main functions into manageable sub-functions. Novice and experienced designers have reported challenges with functional analysis such as high cognitive loads, and difficulties in identifying and expressing functions. Recently, interest in explicitly considering users during functional modeling has grown to enhance analysis completeness, but how this addresses commonly reported challenges is not clear. This research proposes and assesses a simple way to streamline user considerations for novice designers (i.e., embedding requirements into a user workflow explicitly) as a potential mitigation for some challenges in functional analysis at physical product early design stage. Analyses of the results indicate that workflow helps novice designers generate significantly more functions with correct syntax. In addition, the exploration space is prominently broader (especially at higher levels) when a workflow is presented as measured by the geometry of the generated tree diagrams. These results suggest that strategically incorporating user considerations in functional analysis, even in a simple way, has a positive effect in addressing commonly reported challenges of functional analysis. The better outcome from the functional analysis will likely be instrumental in later systematic conceptual design.

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Empirical Studies of Functional Decomposition in Early Design

Cited by 4 publications

References 34 publications

Tangible Augmented Reality and Engineering Product Dissection

Tangible Augmented Reality and Engineering Product Dissection

Evaluating the effectiveness of functional decomposition in early-stage design: development and application of problem space exploration metrics

Improve Syntax Correctness and Breadth of Design Space Exploration in Functional Analysis

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