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Selecting step sizes in sensitivity analysis by finite differencesThis paper deals with methods for obtaining near-optimum step sizes for finite difference approximations to first derivatives with particular application to sensitivity analysis. A technique denoted the finite difference (FD) algorithm, previously described in the literature and applicable to one derivative at a time, is extended to the calculation of several simultaneously. Both the original and extended FD algorithms are applied to sensitivity analysis for a data-fitting problem in which derivatives of the coefficients of an interpolation polynomial are calculated with respect to uncertainties in the data. The methods are also applied to sensitivity analysis of the structural response of a finite-element-modeled swept wing. In a previous study, this sensitivity analysis of the swept wing required a time-consuming trial-and-error effort to obtain a suitable step size, but it proved to be a routine application for the extended FD algorithm herein.
Document ID
19850025225
Document Type
Technical Memorandum (TM)
Authors
Iott, J. (Virginia Polytechnic Inst. and State Univ. Blacksburg, United States)
Haftka, R. T. (Virginia Polytechnic Inst. and State Univ. Blacksburg, United States)
Adelman, H. M. (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
September 5, 2013
Publication Date
August 1, 1985
Subject Category
STRUCTURAL MECHANICS
Report/Patent Number
NASA-TM-86382
L-15938
NAS 1.15:86382
Funding Number(s)
PROJECT: RTOP 506-53-53-07
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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