scope:

One of the problems which has concerned and intrigued pressure vessel designers for a good many years has been the proper design of nonradial, or oblique holes and nozzle connections. One of the earlier and more successful investigators of this problem was Blair,' who in the late 1930's and early 1940's developed and proved his "tri-form" reinforcements for lateral and wye connections in penstocks. However, generally speaking, this form of reinforcement is not suitable for use in most conventional pressure vessels, particularly in applications where thermal stresses are a problem. Within the past few years, a number of papers have been issued providing data on various aspects of this problem, but generally speaking these investigations were of somewhat limited scope and seemingly did not deal adequately with the "fundamentals of the problem." Nevertheless, certain of these data fill significant gaps in the PVRC program data. Therefore, in the report which follows, use is made of all data available to us-both published and unpublished-which would appear to contribute significantly to an overall understanding of the problem.