Stresses, presents in a clear and concise manner a method of determining the
stresses in regions of geometry changes, at least for a body of revolution.
(2) Experimental Methods. Experimental methods are defined as
means of determining stresses using strains and/or displacements measured on
the actual structure or model of the structure. Experimental procedures are
acceptable methods for determining the stress conditions in areas where
classical methods are not available. Further, by the proper use of model
techniques, experimental methods may be used for the complete stress analysis
of the entire vessel.
CAUTION:
If modeling techniques are employed, a 1 to 1 correlation
between the model behavior and the actual vessel under
the anticipated loadings must be established and form a
conspicuous part of the method justification.
Besides the comprehensive bibliography of books dealing with experimental
methods, the designer should be aware of newly developing experimental
procedures as presented by the publication Experimental Mechanics, the
monthly Journal of the Society for Experimental Stress Analysis.
(3) Computer Programs. Computer Programs are tools allowing either
numerical solutions of classical methodology or a nodal analysis of the
actual structure approximated by a network of "finite elements." computer
codes have been written which allow the solution of heretofore "unsolvable"
problems. To a great extent, the development of computer technology has
allowed the implementation of the concept of design by analysis which forms
the basis of Section VIII, Division 2. Pressure vessels, for the most part,
are complicated structures and detailed stress analyses using classical
methods require long and tedious calculations. For certain geometric
configurations, there exist no "classical" methods of solution. During the
last decade literally thousands of computer programs have been written to
carry out hundreds of different types of analysis. In the area of shell
analysis alone, there are probably close to 1000 programs that are in use.
Many programs are proprietary possessions of individual companies and others
are, for one reason or another, unavailable. However, almost all programs
developed by government funding are available from certain government
collection agencies. These agencies are:
(a)
The Argonne Reactor Code Center at the Argonne National
Laboratory (AEC)
(b)
The COSMIC Computer Center at the University of Georgia
(NASA)
(c) The Air Force Flight Dynamics Laboratory at Wright-
Patterson Air Force Base.
These agencies will supply a listing and cost of available programs upon
request. References 11 through 15 give an overall view of the state of the
art of computer technology applicable to pressure vessel analysis.
Finally, the designer is again cautioned that justification of the use of a
certain program to carry out the required design analysis remains the burden
of
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