Fig. 3 The unstable symmetric free–free mode shape of the flying wing
Fig. 14 Distribution of Von Mises stresses along the wing (Pa): a) case 1, b) case 2, c) case 3, d) case 4, e) case 5, f) case 6, g) case 7, and h) case 8.
New fronts of research using Constructal Theory
“Body-freedom flutter characteristics of flying wing aircraft vary with engine placement. Here, we show why a certain design parameter (engine placement) influences the aeroelastic flight envelope of the aircraft. The approach is based on the constructal law and the principle that a design that avoids stress strangulations provides better access to the flows that inhabit the system. This is in sharp contrast with trial-and-error techniques such as optimization, which means to opt from among different choices, cases, and designs. Under the same flight condition, the flow of stresses through the aircraft wings is investigated for several configurations including those with maximum and minimum flutter speeds. The results reveal that when the stresses flow smoothly in the wings the stability of the aircraft improves. On the other hand, in the cases in which the engine location causes stress strangulation, the flutter speed decreases considerably. The most severe stress strangulation corresponds to the aircraft configuration with minimum flutter speed (i.e., engine placement at 20% span behind the reference line). The smoothest flow of stresses happens in the configuration with maximum flutter speed (i.e., engine placement at 80% span forward of the reference line).”
Link to the paper at AIAAJ
Peder Zane, journalist, writer, puts it in few words “Progress is real. It is natural. It is all around us.” in the recent edition of the News&Observer .
Next week at Villanova Constructal Theory: What the future holds – NSF Workshop and Franklin Institute Symposium the community will be addressing hot topics with the major players in Constructal Theory. @constructal @newsobserver @JPederZane
Duke professor and author Adrian Bejan. Duke Photography
Adrian Bejan, professor of mechanical engineering and materials science, describes his research into the constructal law of physics that he described in 1996 and how it applies to evolution in a talk given to prospective undergraduate students.
- Duke Engineering TALKS: Adrian Bejan, Design in Nature: Evolution & Technology, YouTube video
The paper, “The evolution of airplanes,”created a media stir earlier this year when it was published online by the Journal of Applied Physics. The authors contend that the similarities seen across aircraft designs are a manifestation of the same law that drives the evolution of biological creatures and terrain features like river basins.
Lead author Adrian Bejanof Duke University describes the methodology behind the paper and the predictive value of the constructal law, the theory he developed 19 years ago to explain the “oneness” he sees in the evolution of living and non-living systems.