Because of mathematical difficulties which make the solution of differential equations of the theory of elasticity impossible in many cases, the author has been impelled to seek some other method of approach than one of pure mathematical analysis. The method outlined in this paper is of this character and may with some qualifications be applied to problems of two-dimensional stress, bending of plates, bending of cylindrical shells, the general case of three-dimensional stress, and a great variety of others. Essentially, the method consists in replacing the continuous material of the elastic body being studied by a framework of bars arranged according to a definite pattern, the elements of which are endowed with elastic properties suitable to the type of problem. This framework is then analyzed, according to the procedure outlined in the paper for various types of elastic problems. Examples of the application of the principles involved are also given.

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The author obtained the edge effects for a conical shell using an asymptotic approach appropriate for thin shells. Considering that convenient solutions to the same problem are available without the asymptotic approximation, 6 the writer (and any other engineer interested in the potential uses of the paper) would like information concerning the advantages, if any, of the author's technique as compared to the standard one. Because the transcendental functions used in Reference 6 are tabulated therein and are, therefore, as easy to use as the exponential functions in the paper, the writer does not consider this point to be material. A comment by the author on this matter would be desirable, and enhance the usefulness and value of the paper. PLANE-FRAMEWORK METHODS FOR PLATES IN EXTENSIONbDiscussion by Alexander P. Hrennikoff ALEXANDER P. HRENNIKOFF,12 F . ASCE.-The writer is interested in this further extension of the framework method by the authors responsible for much of its recent development. The following comments on the proposed Type One framework model are intended to elucidate the role played by some significant factors.The model considered is an elaboration of McCormick's square model, in which the square shape of the cell is replaced by a more versatile oblong shape. The in-plane flexural rigidity attributed to the side bars of the rectangular cells is, of course, necessary to make the model conform to the deformability of a plate with an arbitrary value of Poisson's ratio. However, a February, 1966, by Jack R. Vinson (Proc. Paper 4657).