On selecting single-level formulations for complex system design optimization

James T. Allison, Michael Kokkolaras, Panos Y. Papalambros

Research output: Contribution to journalArticlepeer-review


Design of complex products with several interacting subsystems or disciplinary analyses poses substantive challenges to both analysis and optimization, necessitating specialized solution techniques. A product or system may qualify as complex due to large scale or due to strong interactions. Single-level strategies for complex system optimization centralize decision-making authority, while multilevel strategies distribute the decision-making process. This article studies important differences between two popular single-level formulations: multidisciplinary feasible (MDF) and individual disciplinary feasible (IDF). Results presented aim at aiding practitioners in selecting between formulations. Specifically, while IDF incurs some computational overhead, it may find optima hidden to MDF and is more efficient computationally for strongly coupled problems; further MDF is sensitive to variations in coupling strength, while IDF is not. Conditions that lead to failure of MDF are described. Two new reproducible design examples are introduced to illustrate these findings and to provide test problems for other investigations.

Original languageEnglish (US)
Pages (from-to)898-906
Number of pages9
JournalJournal of Mechanical Design, Transactions of the ASME
Issue number9
StatePublished - Sep 2007
Externally publishedYes


  • Complex system design
  • Coupling strength
  • Fixed point iteration
  • Individual disciplinary feasible
  • Multidisciplinary design optimization
  • Multidisciplinary feasible

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Computer Science Applications
  • Computer Graphics and Computer-Aided Design


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