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Computational aspects of sensitivity calculations in transient structural analysisA key step in the application of formal automated design techniques to structures under transient loading is the calculation of sensitivities of response quantities to the design parameters. This paper considers structures with general forms of damping acted on by general transient loading and addresses issues of computational errors and computational efficiency. The equations of motion are reduced using the traditional basis of vibration modes and then integrated using a highly accurate, explicit integration technique. A critical point constraint formulation is used to place constraints on the magnitude of each response quantity as a function of time. Three different techniques for calculating sensitivities of the critical point constraints are presented. The first two are based on the straightforward application of the forward and central difference operators, respectively. The third is based on explicit differentiation of the equations of motion. Condition errors, finite difference truncation errors, and modal convergence errors for the three techniques are compared by applying them to a simple five-span-beam problem. Sensitivity results are presented for two different transient loading conditions and for both damped and undamped cases.
Document ID
19880012083
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Greene, William H. (NASA Langley Research Center Hampton, VA, United States)
Haftka, Raphael T. (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
September 5, 2013
Publication Date
April 1, 1988
Subject Category
Structural Mechanics
Report/Patent Number
NASA-TM-100589
NAS 1.15:100589
Accession Number
88N21467
Funding Number(s)
PROJECT: RTOP 506-43-51-02
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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