Program of the Fatigue Data Sheet Project for engineering materials Manufactured in Japan

Fatigue strength of materials is recognized as one of the most important parameters to be considered in designing machines and structures with higher reliability. Efforts have been made, for many years, to determine how and why failure occurs by fatigue, and it would seem that we have already an abundant quantity of experimental data applicable to engineering needs. However, the fatigue strength of materials is generally inftuenced by many metallurgical, geometrical, and environmental factors, and this diversity of factors makes it in reality difficult to find appropriate engineering data amongst the accumulation of test results.

The work of compilation and analysis of the various experimental results has been found to be fruitful, and several fatigue data sheets have been published in Japan. Typical of these are those prepared by the Japan Society of Mechanical Engineers (Vol. I in 1961, Vol. II in 1965, and Vol. III in 1974), the Society of Steel Construction of Japan (1968), and the Japan Society for the Promotion of Science (1970). Since these data sheets are based on test results acquired independently in different laboratories for different purposes, a lack of consistency is sometimes inevitable. Systematic work to generate reliable fatigue data seems to be necessary in order to comprehend properly the characteristics of fatigue in materials in practical applications.

The National Research Institute for Metals, having undertaken since 1968 the production of long-term creep data sheets, necessary for the same reasons as mentioned above for fatigue, decided to engage also in the planning of a systematic and coordinated test program for the preparation of fatigue data sheets on engineering materials manufactured in Japan. The planning was started in 1968, immediately after the opening of the creep data sheet test program. A new laboratory for fatigue testing was established at NIMS in 1970 and completed by the installation of testing facilities by 1973. The laboratory is equipped with 7 large-sized fatigue testing machines, 42 conventional fatigue testers, and 27 high- and low-cycle testers for elevated temperature fatigue. Some brief explanations of the testing facilities are given in the appended Table 1.

The NIMS fatigue data sheets program is aimed at the establishment of a standardized presentation of the fundamental fatigue properties of the metallic materials manufactured in Japan which are used to construct mechanical or structural components in which fatigue is of importance. For this purpose, test materials are sampled by NIMS from the current commercial products of representative manufacturers in this country, and fatigue tests are carried out at NIMS according to standard test procedures (see Table 2 for materials tested). The data sheets will serve as valuable guide, not only for design engineers having a particular interest in material strength or life assessment, but also for investigators in the field of materials technology who are interested in the improvement of materials quality.

The program is composed of three parts, each of them corresponding to a distinct technical range of applications, these being machines, large structures, and high temperature equipments, respectively entitled "Fatigue Properties of Materials for Machine Structural Use", "Fatigue Properties of Welded Joints", and "Elevated Temperature Fatigue Properties of Materials for Machines and Structures". These three subthemes are promoted separately, but conducted in mutual accord, in conjunction with the work for the NIMS Creep Data Sheets.

In order to determine the most effective direction for the program, an advisory committee for the data sheets was instituted at NIMS in 1975, in cooperation with leading specialists from related academic and industrial societies in Japan. To this is attached a technical advisory committee, composed of three subgroups of specialists, for the purpose of planning the program of each subtheme in the best way. The structures for these committees are given in Appendix A.