Hostname: page-component-cd9895bd7-dzt6s Total loading time: 0 Render date: 2024-12-29T12:38:40.415Z Has data issue: false hasContentIssue false
  • English
  • Français

Design of Transparencies

Published online by Cambridge University Press:  04 July 2016

J. S. Przemieniecki
J. S. Przemieniecki*
Affiliation:
Bristol Aircraft Limited
Get access Rights & Permissions [Opens in a new window]

Summary:—

A study of engineering problems encountered in the design of transparencies for supersonic aircraft is presented with a special emphasis on the effects of kinetic heating. The paper is written primarily with optical transparencies in mind but many of the general principles discussed are equally applicable to the design of radomes for elevated temperature applications.

The first parts of the paper consider briefly the methods of calculating temperature distribution in transparent panels subjected to kinetic heating (or cooling) and this leads naturally to discussion of the effects of the non-uniform temperature distribution, differential expansion and the edge restraints preventing thermal deformations. Methods of calculating thermal stresses are suggested through the concept of the “ self-equilibrating ” temperature distribution; the main attention, however, being concentrated on the derivation of simple engineering formulae rather than on the mathematical rigour of the solution.

The choice of design cases for combined pressure and thermal loading is considered and it is shown that, in general, deceleration manoeuvres combined with outward pressure constitute the design criteria for transparencies. The effects of various parameters on the magnitude of thermal stresses are analysed; these include the effects of altitude, temperature, deceleration and material properties. It is shown that, for given material and panel geometry, the thermal stresses depend mainly on the following parameters: total temperature change, acceleration (or deceleration), and the Biot number based on the panel thickness.

Practical design aspects are also considered, such as choice of materials, strength, panel geometry, mounting of panels and the fail-safe design. Finally, testing of transparencies under pressure and thermal loading is briefly discussed, together with possible methods of strain measurements, and a tentative proving procedure for transparencies is suggested.

Type
The Structural Effects of Kinetic Heating
Information
The Aeronautical Journal , Volume 63 , Issue 587 , November 1959 , pp. 620 - 636
Copyright
Copyright © Royal Aeronautical Society 1959

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1.Monaghan, R. J. (1955). Formulae and Approximations for Aerodynamic Heating Rates in High Speed Flight, Unpublished Ministry of Supply Report, Oct. 1955.Google Scholar
2.Hill, P. R. (1957). A Method of Computing the Transient Temperature of Thick Walls from Arbitrary Variation of Adiabatic-Wall Temperature and Heat Transfer Coefficient. N.A.C.A. Tech. Note 4105, Oct. 1957.Google Scholar
3.Przemieniecki, J. S. Design Charts for Transient Temperature and Thermal Stress Distributions in Thermally Thick Plates. (To be published.)Google Scholar
4.Buglia, J. J. and Brinkworth, H. (1958). A Comparison of Two Methods for Calculating Transient Temperatures for Thick Walls. N.A.C.A. Tech. Note 4343, August 1958.Google Scholar
5.Paschkis, V. and Baker, H. D. (1942). A Method for Determining Unsteady-State Heat Transfer by Means of an Electrical Analogy. Trans. ASME, Vol. 64, No. 2, pp. 105–112, Feb. 1942.Google Scholar
6.Nadai, A. (1925). Die Elastische Flatten. Julius Springer Verlag, Berlin, p. 264, 1925.Google Scholar
7.LoveA, E. H. A, E. H. (1952). Mathematical Theory of Elasticity. Cambridge University Press, 4th Edition, p. 558, 1952.Google Scholar
8.Williams, M. L. (1955). Large Deflection Analysis for a Plate Strip Subjected to Normal Pressure and Heating. Journal of Applied Mechanics, pp. 458–464, Dec. 1955.Google Scholar
9.Williams, M. L. (1958). Further Large Deflection Analysis for a Plate Strip Subjected to Normal Pressure and Heating. Journal of Applied Mechanics, pp. 251–258, June 1958.Google Scholar
10.Parkes, E. W. (1956). Panels Under Thermal Stress. Aircraft Engineering, Vol. 28, pp. 180–186, June 1956.CrossRefGoogle Scholar
11.Timoshenko, S. (1940). Theory of Plates and Shells, McGraw-Hill, pp. 125–133, 1940.Google Scholar
12.Thompson, A. S. (1952). Thermal Stress in Power Producing Elements. Journal of the Aeronautical Sciences, Vol. 19, No. 7, pp. 476–480, July 1952.CrossRefGoogle Scholar
13.Timoshenko, S. (1940). Theory of Plates and Shells, McGraw-Hill, pp. 53–54, 1940.Google Scholar
14.Maulbetsch, J. L. (1935). Thermal Stresses in Plates. Journal of Applied Mechanics, Vol. 2, pp. 141–146, 1935.Google Scholar
15.Timoshenko, S. (1940). Theory of Plates and Shells. McGraw-Hill, pp. 176–180, 1940.Google Scholar
16.Bijlaard, P. P. (1959). Thermal Stresses and Deflections in Rectangular Sandwich Plates. Journal of the Aeroj Space Sciences, Vol. 26, pp. 210–218, 1959.CrossRefGoogle Scholar
17.Timoshenko, S. and Goodier, J. N. (1951). Theory of Elasticity, Chapter 14. McGraw-Hill, New York, 2nd Edition, 1951.Google Scholar
18.Melan, E. and Parkus, H. (1953). Wärmespannungen. Springer Verlag, Wien, pp. 56–70, 1953.CrossRefGoogle Scholar
19.Aleck, B. J. (1949). Thermal Stresses in a Rectangular Plate Clamped Along an Edge. Journal of Applied Mechanics, pp. 118–122, 1949.Google Scholar
20.Durelli, A. J. and Tsao, C. H. (1955). Determination of Thermal Stresses in Three-Ply Laminates. Journal of Applied Mechanics, Vol. 22, pp. 190–193, June 1955.Google Scholar
21.Mylonas, C. (1955). Discussion to reference 20. Journal of Applied Mechanics, Vol. 22, p. 611, Dec. 1955.CrossRefGoogle Scholar
22.Hahner, C. H. and Kerper, M. J. (1957). Inorganic Transparencies for Aircraft Enclosures. AGARD Report No. 161, Nov. 1957.Google Scholar
23.Charles, R. J. (1958). Static Fatigue of Glass: Parts I and II. Journal of Applied Physics, Vol. 29, pp. 1549– 1560, Nov. 1958.CrossRefGoogle Scholar
24.Preston, F. W. (1942). Mechanical Properties of Glass. Journal of Applied Physics, Vol. 13, p. 623, 1942.Google Scholar
25.Russell, A. E. (1957). Safety in Relation to Structural Damage. Proceedings of the 6th Anglo-American Aeronautical Conference, Folkestone, Royal Aeronautical Society, 1959.Google Scholar
26.Golubovic, G. (1959). Differentes Applications des Vernis Photoelastiques dans le Domaine des Constructions. Delft Conference of the Stress Analysis Group, Institute of Physics (Great Britain), 1959.Google Scholar