Automated Structural Optimization System (ASTROS). Volume 3. Applications Manual

Johnson, Erika; Neill, D. J.

doi:10.21236/adb130470

Cited by 39 publications

(22 citation statements)

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“…The sensitivity of this new constraint to a design variable is (18) where the fact that has been used, since db at**},-db…”

Section: Optimization With Mode Shape Constraintsmentioning

confidence: 99%

“…If only certain degrees of freedom are to be constrained, then only those freedoms appear in the vector calculations of Eqs. (17) and (18). Common choices for the prescribed eigenvector would include a mode shape from the initial design (enforcing minimum change), an experimental mode shape (enforcing correlation), or a region of zero vibration (enforcing a nodal line).…”

Section: Aw Dbmentioning

confidence: 99%

“…The goal is to enable the vector norm calculations of Eqs. (17) and (18) to measure differences in mode shape only, separate from differences in sign or normalization. To accomplish this, both the current eigenvectors and the prescribed eigenvectors ({0},-and {0*},) must reflect the same sign and normalization convention for all optimization iterations.…”

Section: Aw Dbmentioning

confidence: 99%

“…' 18 This wing is to undergo weight minimization subject to a constraint on its second frequency (/ 2 > 8 Hz). The mode tracking task is more difficult than in example 1, because the mode shapes are less well differentiated.…”

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confidence: 99%

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Mode tracking issues in structural optimization

1995

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Within the context of optimization of the structural dynamics properties of finite element models, methodology is developed for the tracking of eigenpairs through changes in the structural eigenvalue problem. The goal is to eliminate difficulties caused by "mode switching" (i.e., frequency crossing). Out of several candidate methods, two methods for mode tracking are successful. The first method, the higher order eigenpair perturbation algorithm, is based on a perturbation expansion of the eigenproblem. It iteratively computes changes in the eigenpairs due to parameter perturbations with the important feature of maintaining the correspondence between the baseline and perturbed eigenpairs. The second method is a cross-orthogonality check method, which uses mass orthogonality to reestablish correspondence after a standard reanalysis.

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“…The sensitivity of this new constraint to a design variable is (18) where the fact that has been used, since db at**},-db…”

Section: Optimization With Mode Shape Constraintsmentioning

confidence: 99%

Section: Aw Dbmentioning

confidence: 99%

Section: Aw Dbmentioning

confidence: 99%

mentioning

confidence: 99%

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Mode tracking issues in structural optimization

1995

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“…The original wing model consisted of a reasonable box with 14 bays, showing good aspect ratios in most of the elements. Then, the wing was modelled in a simpler form with Material for all wings is Aluminum: E = 10,000,000 lb/In 2 , v -0.33, Q -0.1 lb/in 3 . All values decreasing from root to tip.…”

Section: A) High Aspect Ratio Wing Modelmentioning

confidence: 99%