Optimization of shell buckling incorporating Karhunen-Loève-based geometrical imperfections
The optimization of shell buckling is performed considering peak normal force and absorbed internal energy in the presence of geometrical imperfections implemented through Karhunen-Loève expansions. Initially, the mass of a shell is minimized in the presence of random initial imperfections by allowing cutouts in the material, subject to constraints on the average peak force and average internal energy. Then, robustness is considered by minimizing the coefficient of variation of the normal peak force while constraining the average peak force and average internal energy. LS-OPT® is used both to generate an experimental design and to perform a Monte Carlo simulation (96 runs) using LS-DYNA® at each of the experimental design points. The effect of imperfections when minimizing the mass is not large, but when considering robustness, however, the optimal design has a substantially increased hole size and increased shell thickness, resulting in a heavier design with maximal robustness within the constraints.
KeywordsKarhunen-Loève expansions Geometrical imperfections Buckling optimization
Unable to display preview. Download preview PDF.
- Arbocz J, Abramovich H (1979) The initial imperfection databank at the Delft University of Technology. Part 1. Technical Report LR-290, Delft University of Technology, Department of Aerospace EngineeringGoogle Scholar
- Bushnell D (1985) Computerized Buckling Analysis of Shells. Marthinus Nijhoff, DordrechtGoogle Scholar
- Ghanem RG, Spanos PD (1991) Stochastic finite elements—a spectral approach. Revised Edition, Dover, 2003. Springer, New YorkGoogle Scholar
- Livermore Software Technology Corporation (LSTC) (2004) LS-DYNA manual version 970. Livermore, CAGoogle Scholar
- Livermore Software Technology Corporation (LSTC) (2006) LS-DYNA version 971. Livermore, CAGoogle Scholar
- Roux WJ, Craig KJ (2006) Validation of structural simulations considering stochastic process variation. Paper 06M-67, SAE Congress, Detroit, USAGoogle Scholar
- Schenk CA, Schuëller GI (2005) Uncertainty assessment of large finite element systems. Lecture Notes in Applied and Computational Mechanics, Vol.24. Springer, Berlin, HeidelbergGoogle Scholar
- Stander N, Roux WJ, Eggleston TA, Craig KJ (2006) LS-OPT v3.1 User’s manual, Livermore Software Technology Corporation. Livermore, USAGoogle Scholar
- TrueGrid Manual (2005) XYZ Scientific Applications. Livermore, CAGoogle Scholar