In general, only the most commonly used materials and elements are included in this publication. Until a structural material or element has been used for some time and in considerable quantities, the strength properties will probably vary considerably as manufacturing processes are improved and modified. In such cases, special rulings should be obtained by the material user from the procuring or certificating agency. These rulings will be used upon specimen tests and will eventually from a basis for standard accepted strength properties. However, in the interest of timely availability of data, in some cases relatively new data for established metals, and data for relatively new metals, have been added to this document, particularly for elevated-temperature conditions. Although information has been scarce in some cases, the evaluation of these data has been based on the best possible engineering judgment, and the data are considered sufficiency reliable for design use. In establishing curves for percent of room-temperature property versus temperature, curves were drawn no higher than 5 percent above the minimum data obtained at a given temperature except where they are noted to be typical curves. When these percentage s are multiplied by room-temperature minimum to get design values, they can be considered realistic and conservative.

In addition to the strength of the materials and elements themselves,

There are contained herein some of the more commonly herein some of the more commonly used methods and formulas by which the strengths of various structural components are calculated. In some cases the methods presented are empirical and subject to further refinement. Likewise, it is expected that material can be added from time to time as the methods of handling new problems become more uniform and reliable, for example, in dealing with problems where creep behavior may be important.

Where available, applicable references are listed at the end of the handbook. The numbers of the reference correspond to the paragraph to which they most generally apply. In general, specific mention of the references in not made.

Engineers making use of the material contained herein are invited to submit comments and suggestions as to the expansion and improvement of the document. Such comments should be submitted to Chairman, Mil-HDB-5 Panel, Federal Aviation Agency, Washington 25, D.C.