The design and testing of an optimal beam composed of unimodal elements
Abstract
Flexural structures are intrinsically inefficient from a structural weight point of view. This is largely due to an ineffective use of the material of the beam elements. The variation of the stresses in the transverse direction of a beam is palliated by the use of I type cross sections. However, in the presence of shear loads, the bending moment varies along the longitudinal direction of the beam and, consequently, flexural systems are usually largely understressed. The present theory is based on the finding that a beam element is structurally equivalent to two basic elements acting in parallel. A 'moment' element which carries the average bending moment, and a 'shear' element, which carries the differential part of the bending moment distribution. Since these unimodal elements are uniformly stressed they are very efficient structural elements. Theoretical results have shown that in many cases substantial weight reductions can be expected when unimodal elements are employed to carry flexural loads. This paper describes the design and the practical implementation of an optimal beam composed of unimodal elements. Preliminary results indicate that the success of these structures depends largely on a judicious design of the unimodal components.
 Publication:

Israel Society of Aeronautics and Astronautics, 31st Israel Annual Conference on Aviation and Astronautics
 Pub Date:
 February 1990
 Bibcode:
 1990isaa.conf...76F
 Keywords:

 Beams (Supports);
 Bending Moments;
 Flexing;
 Load Carrying Capacity;
 Shear Stress;
 Structural Weight;
 Weight Reduction;
 Loading Moments;
 Moment Distribution;
 Optimization;
 Structural Members;
 Structural Mechanics