A Study on Structural Optimum Design Based on Qualitative Sensitivities

Masao Arakawa, Hiroshi Yamakawa

Research output: Contribution to journalArticlepeer-review


An optimum design method is considered as a method whose results are the most reasonable from various standpoints in the prescribed mathematical formulation. However, its formulations present difficulities in choosing objective functions, setting allowances to constraints and so on, because they are greatly concerned with the results of optimization. In this study, we proposed concepts of qualitative sensitivities and qualitative optimality compared to quantitative concepts, and proposed a general algorithm of the qualitive optimization method. We newly defined three kinds of fuzzy language and assigned fuzzy sets to each of them and assigned them to each candidate of discrete design variable. We propose fuzzy reasoning rules by using these two kinds of fuzzy sets. We also extend the proposed algorithm to multiobjective optimization. Through the numerical example of a single objective problem, we obtained almost the same solution as in quantitative methods, and efficiencies were confirmed for this case. Also through the example to multiobjective problem, the new method was shown to have more flexibility in deciding in deciding the preferred objective functions compared to the conventional method.

Original languageEnglish
Pages (from-to)422-429
Number of pages8
JournalNihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C
Issue number558
Publication statusPublished - 1993
Externally publishedYes


  • Design Engineering
  • Fuzzy Reasoning
  • Fuzzy Set Theory
  • Optimum Design
  • Qualitative Sensitivity
  • Sensitivity Analysis

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Industrial and Manufacturing Engineering


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