Some Refinements to Wing Redundant Structure Analysis Methods
Abstract
Some of the trends in the design of wings and control surfaces for high speed vehicles have brought about a need for modifications in the methods of analysis for stress distribution and flexibility. A few characteristics typical of such structures are low aspect ratio, large angle of sweep, thinness, and the use of thick skins, sometimes stiffened by closely spaced integral spars and sometimes forming sandwich structure. The present report outlines some modifications that can be applied to the matrix force method when the effects of some of these characteristics are important. These refinements do not, of course, affect the application of the method to more conventional structures. It has already proven to be adequate without the refinements for most of the structures handled to date. The report is concerned with applications of the matrix force method to wing structures idealized as consisting of capstrips carrying axial load only, interconnected by shear panels which can carry shear only. The refinements being introduced are for the purpose of taking into account the Poisson,s ratio effect in the case of thick skin wings and for improving upon the handling of the stress coupling effect in the case of non-orthogonal ribs and spars. A system of choosing unit redundant load distributions is also discussed. These refinements have all been treated in some form or another by other authors. However, previous methods of accounting for the Poisson's ratio effect apparently have, except in certain special cases, neglected the fact that while the strain is the same in a spar cap, say, and in the adjacent cover material in the same direction, the stresses may be different because of a state of biaxial stress in the cover. A way of taking this into account has been included. The question of whether this difference can be significant has not yet been resolved, and it may turn out to be negligible in all practical cases.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1961
- Accession Number
- ADA377088
Entities
People
- I. W. Jones
Organizations
- Grumman