VTechWorks staff will be away for the Thanksgiving holiday beginning at noon on Wednesday, November 27, through Friday, November 29. We will resume normal operations on Monday, December 2. Thank you for your patience.

Browsing by Author "Kogiso, N."

Now showing 1 - 2 of 2
  • Design of Composite Laminates by a Genetic Algorithm with Memory
    Kogiso, N.; Watson, Layne T.; Gürdal, Zafer; Haftka, Raphael T.; Nagendra, S. (Department of Computer Science, Virginia Polytechnic Institute & State University, 1994)
    This paper describes the use of a genetic algorithm with memory for the design of minimum thickness composite laminates subject to strength, buckling and ply contiguity constraints. A binary tree is used to efficiently store and retrieve information about past designs. This information is used to construct a set of linear approximations to the buckling load in the neighborhood of each member of the population of designs. The approximations are then used to seek nearby improved designs in a procedure called local improvement. The paper demonstrates that this procedure substantially reduces the number of analyses required for the genetic search. The paper also demonstrates that the use of genetic algorithms helps find several alternate designs with similar performance, thus giving the designer a choice of alternatives.
  • Thumbnail Image
    Genetic Algorithms with Local Improvement for Composite Laminate Design
    Kogiso, N.; Watson, Layne T.; Gürdal, Zafer; Haftka, Raphael T. (Department of Computer Science, Virginia Polytechnic Institute & State University, 1993)
    This paper describes the application of a genetic algorithm to the stacking sequence optimization of a composite laminate plate for buckling load maximization. Two approaches for reducing the number of analyses are required by the genetic algorithm are described. First, a binary tree is used to store designs, affording an efficient way to retrieve them and thereby avoid repeated analyses of designs that appeared in previous generations. Second, a local improvements scheme based on approximations in terms of lamination parameters is introduced. Two lamination parameters are sufficient to define the flexural stiffness and hence the buckling load of a balanced, symmetrically laminated plate. Results were obtained for rectangular graphite-epoxy plates under biaxial in-plane loading. The proposed improvements are shown to reduce significantly the number of analyses required for the genetic optimization.