Abstract
Since the times of Plato (424?-347 BC) and Aristotle (384-322 BC), the form has been considered as a fundamental notion of not only the physical universe, but also the spiritual world. The forms and perfect shapes are like jewels in the rock—their search and discovery make up the highest delight to human beings. This is what constituted the motive and driving force of science and scientists beginning from Pythagoras (ca. 570-ca. 500 BC), Archimedes (ca. 287-ca. 212 BC), Euclid (ca. 330-ca. 260 BC) and all that came after. In the introduction to the present article, a brief account of Plato’s theory of forms and Aristotle’s addition to this theory are given; the theory of optimum shapes of elastic bodies can be considered as a footnote to the Plato’s theory. In the framework of the theory of elasticity, the optimal shape of a body is the shape that meets the principle of equal strength or equistrength advanced by this author in 1963. According to this principle, the safety criterion like ultimate or failure stress is simultaneously satisfied in the utmost part of the body—this body or structure is called equistrong in this case. The equistrong structure has a minimum weight for a given material and safety factor, or a maximum safety factor for a given material and weight. As distinct from traditional problems, there are no existence theorems for equistrong shapes—a success in their search depends on skills of a researcher. In the present paper, a summary of common equistrong shapes and structural elements is brought out, namely: equistrong cable of bathysphere, equistrong tower or skyscraper, equistrong beam by Galileo Galilei, equistrong rotating disk, equistrong heavy chain, equistrong pressure vessels, equistrong arcs, plates and shells, equistrong underground tunnels, equistrong perforated plates, and others. A variety of the swept wings of aircrafts is found out to be equistrong; the front and rear edges of such wings are rectilinear in the plan view, and their chord in the flight direction depends on the task of an aircraft; the equistrong design exists for any task, from transport aviation to hypersonic jet fighters. Some new equistrong shapes of elastic solids with any number of infinite branches being pulled out of a body are also discovered for plane strain and plane stress.
Similar content being viewed by others
References
Bienzeno, C.B. and Grammel, R., Engineering Dynamics. Vol. II. Elastic Problems of Single Machine Elements, Glasgow: Blackie&Sons Ptd., 1956.
Cherepanov, G.P., An Inverse Elastic-Plastic Problem under Plane Strain, Mekh. Mashinostroenie, 1963, no. 1, pp. 63–71.
Cherepanov, G.P., To the Solution of Some Problems of the Theory of Elasticity and Plasticity with an Unknown Boundary, J. Appl. Math. Mech., 1964, vol. 28, no. 1, pp. 141–144.
Cherepanov, G.P., Some Problems with an Unknown Boundary in the Theory of Elasticity and Plasticity, Applications of the Theory of Functions of a Complex Variable in Continuum Mechanics. vol. 1, Moscow: Nauka, 1965.
Cherepanov, G.P., Equistrong Mine in a Rock, in Problems of Rock Mechanics, Erzhanov, A., Ed., Alma-Ata: Nauka, 1966, pp. 166–178.
Cherepanov, G.P., One Inverse Problem of the Theory of Elasticity, Eng. J. Solid Mech., 1966, no. 3, pp. 118–130.
Cherepanov, G.P. and Liberman, L.K., Mathematical Method of Optimal Design in Mining, Mining J., 1971, no. 9, pp. 987–992.
Cherepanov, G.P., Inverse Problems of the Plane Theory of Elasticity, J. Appl. Math. Mech., 1974, vol. 38, pp. 963–979.
Cherepanov, G.P. and Tagizade, A.G., Extension of Plates and Shells of Uniform Strength, Lett. Appl. Eng. Sci.,1975, no. 3, pp. 64–69.
Cherepanov, G.P. and Tagizade, A.G., Bending of Plates and Shells of Uniform Strength, Lett. Appl. Eng. Sci., 1975, no. 2, pp. 38–43.
Vigdergauz, S., Integral Equations of the Inverse Problem of the Theory of Elasticity, J. Appl. Math. Mech., 1976, vol. 40, no. 3.
Cherepanov, G.P., Smolsky, V.M., and Tagizade, A.G., Optimum Design of Some Engineering Materials, Izv. Acad. Sci. Armenian SSR, 1976, vol. 29, pp. 248–265.
Wheeler, L.T., On the Role of Constant-Stress Surfaces in the Problem of Minimizing Elastic Stress Concentration, J. Solids Struct., 1976, vol. 12, pp. 779–789.
Cherepanov, G.P. and Ershov, L.V., Fracture Mechanics, Moscow: Mashinostroenie, 1977.
Vigdergauz, S., On a Case of the Inverse Problem of Two-Dimensional Theory of Elasticity, J. Appl. Math. Mech., 1977, vol. 41, no. 5, pp. 902–908.
Wheeler, L.T., On Optimum Profiles for the Minimization of Elastic Stress Concentration, ZAMM, 1978, pp. 235–236.
Cherepanov, G.P., Mechanics of Brittle Fracture, New York: McGraw-Hill, 1978.
Mirsalimov, V.M., Equistrong Excavation in Rock, FTPRPI, 1979, no. 4, pp. 24–29.
Banichuk, N.V., Shape Optimization of Elastic Solids, Moscow: Nauka, 1980.
Cherepanov, G.P., Stress Corrosion Cracking, in Comprehensive Treatise of Electrochemistry. V. 4. Electrochemical Materials Science, Bockris, O.M., Ed., New York: Plenum Press, 1981, pp. 333–406.
Ostrosablin, N.I., An Equistrong Hole in a Plate Under Non-Uniform Stress State, J. Appl. Mech. Tech. Phys., 1981, no. 2, pp. 155–163.
Vigdergauz, S., Equistrong Hole in a Half-Plane, Mech. Solids, 1982, vol. 17, no. 1, pp. 87–91.
Wheeler, L.T. and Kunin, I.A., On Voids of Minimum Stress Concentration, J. Solids Struct., 1982, vol. 18, pp. 85–89.
Vigdergauz, S., An Inverse Problem of the Three-Dimensional Theory of Elasticity, Mech. Solids, 1983, vol. 18, no. 2, pp. 83–86.
Vigdergauz, S., Effective Elastic Parameters of a Plate with a Regular System of Equistrong Holes, Mech. Solids, 1986, vol. 21, no. 2, pp. 165–169.
Cherepanov, G.P. and Annin, B.D., Elastic-Plastic Problems, New York: ASME Press, 1988.
Vigdergauz, S., The Geometrical Characteristics of Equistrong Boundaries of Elastic Bodies, J. Appl. Math. Mech., 1988, vol. 52, no. 3, pp. 371–376.
Wheeler, L.T., Stress Minimum Forms for Elastic Solids, ASME Appl. Mech. Rev., 1992, vol. 45, pp. 110–125.
Vigdergauz, S., Optimal Stiffening of Holes under Equibiaxial Tension, Int. J. Solids Struct., 1993, vol. 30, no. 4, pp. 569–577.
Cherepanov, G.P., Optimum Shapes of Elastic Solids with Infinite Branches, J. Appl. Mech. Transactions ASME, 1995, vol. 62, pp. 419–422.
Savruk, M.P. and Kravets, V.S., Application of the Method of Singular Integral Equations to the Determination of the Contours of Equistrong Holes in Plates, Mater. Sci., 2002, vol. 38, no. 1, pp. 34–52.
Cherepanov, G.P. and Esparragoza, I.E., Equistrong Tower Design, Theor. Appl. Mech., 2007, pp. 3–9.
Cherepanov, G.P., Fracture Mechanics, Izhevsk-Moscow: IKI, 2012.
Odishelidze, N., Criado-Aldeanueva, F., and Sanchez, J.M., A Mixed Problem of Plate Bending for a Regular Octagon Weakened with a Required Full-Strength Hole, Acta Mech., 2013, vol. 224, pp. 183–192.
Cherepanov, G.P., Methods of Fracture Mechanics: Solid Matter Physics, Dordrecht: Kluwer Publ., 1997.
Author information
Authors and Affiliations
Corresponding author
Additional information
Original Text © G.P. Cherepanov, 2015, published in Fizicheskaya Mezomekhanika, 2015, Vol. 18, No. 5, pp. 114-123.
Rights and permissions
About this article
Cite this article
Cherepanov, G.P. Optimum Shapes of Elastic Bodies: Equistrong Wings of Aircrafts and Equistrong Underground Tunnels. Phys Mesomech 18, 391–401 (2015). https://doi.org/10.1134/S1029959915040116
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1134/S1029959915040116