Abstract
Thin-walled, unstiffened and stiffened shell structures made of fibre composite materials are frequently applied due to their high stiffness/strength to weight ratios in all fields of lightweight constructions. One major design criterion of these structures is their sensitivity with respect to buckling failure when subjected to inplane compression and shear loads. This paper describes how the structural analysis program BEOS (Buckling of Eccentrically Orthotropic Sandwich shells) is combined with the optimization procedure SAPOP (Structural Analysis Program and Optimization Procedure) to produce a tool for designing optimum CFRP-panels against buckling. Experimental investigations are used to justify the described procedures.
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Abbreviations
- C, C b :
-
material stiffness matrices (shell, beam stiffener)
- f :
-
objective function
- F cr :
-
buckling load
- g:
-
vector of inequality constraints
- K,K g ,\(\tilde K^{mn} \) :
-
stiffness matrix, geometrical stiffness matrix, condensed stiffness matrix
- n s ,n b :
-
vector of stress resultants (shell, beam stiffener)
- N x ,N y ,N xy :
-
membrane forces of the shell
- P x ,P y ,P xy :
-
membrane forces of the stiffener
- r x ,r y ,r xy :
-
radii of curvature
- ℜn :
-
n-dimensional Euclidean space
- W :
-
strain energy
- u, v, w :
-
deformations inx, y, z direction
- x, y, z :
-
global coordinate system
- x :
-
vector of design variables
- y, z :
-
right-hand side, left-hand side eigenvector
- δ:
-
variational symbol
- δ k i :
-
Kronecker's delta
- e s ,e b :
-
strain vectors (shell, beam stiffener)
- λ, λcr :
-
load factor, buckling load factor
- Π, Πe :
-
total energy, external potential energy
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A (^) sign above a variable points out that this variable belongs to the prebuckling state.
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Seibel, M., Geier, B., Zimmermann, R. et al. Optimization and experimental investigations of stiffened, axially compressed CFRP-panels. Structural Optimization 15, 124–131 (1998). https://doi.org/10.1007/BF01278498
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DOI: https://doi.org/10.1007/BF01278498