NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Improved Displacement Transfer Functions for Structure Deformed Shape Predictions Using Discretely Distributed Surface StrainsIn the formulations of earlier Displacement Transfer Functions for structure shape predictions, the surface strain distributions, along a strain-sensing line, were represented with piecewise linear functions. To improve the shape-prediction accuracies, Improved Displacement Transfer Functions were formulated using piecewise nonlinear strain representations. Through discretization of an embedded beam (depth-wise cross section of a structure along a strain-sensing line) into multiple small domains, piecewise nonlinear functions were used to describe the surface strain distributions along the discretized embedded beam. Such piecewise approach enabled the piecewise integrations of the embedded beam curvature equations to yield slope and deflection equations in recursive forms. The resulting Improved Displacement Transfer Functions, written in summation forms, were expressed in terms of beam geometrical parameters and surface strains along the strain-sensing line. By feeding the surface strains into the Improved Displacement Transfer Functions, structural deflections could be calculated at multiple points for mapping out the overall structural deformed shapes for visual display. The shape-prediction accuracies of the Improved Displacement Transfer Functions were then examined in view of finite-element-calculated deflections using different tapered cantilever tubular beams. It was found that by using the piecewise nonlinear strain representations, the shape-prediction accuracies could be greatly improved, especially for highly-tapered cantilever tubular beams.
Document ID
20130000578
Acquisition Source
Armstrong Flight Research Center
Document Type
Technical Publication (TP)
Authors
Ko, William L.
(NASA Dryden Flight Research Center Edwards, CA, United States)
Fleischer, Van Tran
(NASA Dryden Flight Research Center Edwards, CA, United States)
Date Acquired
August 27, 2013
Publication Date
November 1, 2012
Subject Category
Structural Mechanics
Report/Patent Number
DFRC-E-DAA-TN6507
NASA/TP-2012-216060
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
No Preview Available