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Curved Displacement Transfer Functions for Geometric Nonlinear Large Deformation Structure Shape PredictionsFor shape predictions of structures under large geometrically nonlinear deformations, Curved Displacement Transfer Functions were formulated based on a curved displacement, traced by a material point from the undeformed position to deformed position. The embedded beam (depth-wise cross section of a structure along a surface strain-sensing line) was discretized into multiple small domains, with domain junctures matching the strain-sensing stations. Thus, the surface strain distribution could be described with a piecewise linear or a piecewise nonlinear function. The discretization approach enabled piecewise integrations of the embedded-beam curvature equations to yield the Curved Displacement Transfer Functions, expressed in terms of embedded beam geometrical parameters and surface strains. By entering the surface strain data into the Displacement Transfer Functions, deflections along each embedded beam can be calculated at multiple points for mapping the overall structural deformed shapes. Finite-element linear and nonlinear analyses of a tapered cantilever tubular beam were performed to generate linear and nonlinear surface strains and the associated deflections to be used for validation. The shape prediction accuracies were then determined by comparing the theoretical deflections with the finiteelement- generated deflections. The results show that the newly developed Curved Displacement Transfer Functions are very accurate for shape predictions of structures under large geometrically nonlinear deformations.
Document ID
20170001992
Acquisition Source
Armstrong Flight Research Center
Document Type
Technical Publication (TP)
Authors
Ko, William L. (NASA Armstrong Flight Research Center Edwards, CA, United States)
Fleischer, Van Tran (NASA Armstrong Flight Research Center Edwards, CA, United States)
Lung, Shun-Fat (Jacobs Technology, Inc. Edwards AFB, CA, United States)
Date Acquired
March 3, 2017
Publication Date
March 1, 2017
Subject Category
Structural Mechanics
Report/Patent Number
AFRC-E-DAA-TN26921
NASA/TP-2017-219406
Report Number: AFRC-E-DAA-TN26921
Report Number: NASA/TP-2017-219406
Funding Number(s)
CONTRACT_GRANT: NND08RR01B
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Keywords
displacement theory
displacement functions
deflection equations

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