Download or read book Upper and Lower Bounds to Structural Deformations by Dual Analysis in Finite Elements written by G. Sander and published by . This book was released on 1967 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: Extensive comparison studies were run on different idealizations and on the use of different types of finite elements for the analysis of a single spar, a rectangular section box beam, a multispar swept wing and a centrally loaded rectangular plate. The results indicate that the principle of a dual analysis, with its capability to provide upper and lower bounds to the structural deflections, is of practical value. Convergence in the deflection pattern, from above and from below, is equally satisfactory. Convergence and evaluation of the stress output is sometimes more difficult. However, the more sophisticated elements generate stresses that are simpler to interpret and less sensitive to the geometrical subdivision pattern. The report contains the theory of the conforming displacement models and stress-diffusing equilibrium models required for obtaining strain energy bounds, with a description of the models that were operational in the numerical studies. It also contains a description of the ASEF, direct stiffness type, program.