Prolonging fatigue life of structural components through shape changes

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

About half of mechanical failures are due to repeated loading. Most of the failures are fatigue related and the fatigue problem has been of major concern in the design of structures. The failure due to fatigue is a function of, among other factors, the external loads, material behavior, geometry of the structure and the crack characteristics. In this paper, the relationship between structural geometry and number of life cycles to failure is investigated. The linear elastic fracture mechanics (LEFM) approach is integrated with shape optimal design methodology. The primary objective of the design problem is to enhance the life of the structure. The results from LEFM analyses are used in the fatigue model to predict the life of the structure before failure is deemed to have occurred. The shape of the structure is changed using the natural shape optimal design procedure where gradient-based nonlinear programming (NLP) techniques are used with the supplied sensitivity information to predict the required shape changes. Relevant issues such as problem formulation, finite element modeling, mesh generation and regeneration are discussed. Two design examples are solved and the results show that with proper shape changes the life of structural systems subjected to fatigue loads can be enhanced significantly.

Original languageEnglish (US)
Title of host publication7th AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
Pages1082-1092
Number of pages11
StatePublished - 1998
Event7th AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization, 1998 - St. Louis, United States
Duration: Sep 2 1998Sep 4 1998

Other

Other7th AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization, 1998
CountryUnited States
CitySt. Louis
Period9/2/989/4/98

ASJC Scopus subject areas

  • Aerospace Engineering
  • Mechanical Engineering

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  • Cite this

    Gani, L., & Rajan, S. (1998). Prolonging fatigue life of structural components through shape changes. In 7th AIAA/USAF/NASA/ISSMO Symposium on Multidisciplinary Analysis and Optimization (pp. 1082-1092). American Institute of Aeronautics and Astronautics Inc, AIAA.