IIW History 1948-1958

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organisation of an international investigation on the fatigue strength of butt– welded joints on steel, the programme of which has been drawn up on a statis– tical basis. To make possible the comparison of the results obtained in the various participating laboratories, it has been decided that, as a first part of the work, one country alone will be responsible for supplying the steel plates neces– sary, which will be carefully checked, and for making all the welds to be tested as well as for machining the testpieces t aken from these welds. The testpieces will be distributed in such a way that each participating country will receive a representative selection of the welds on which experiment s are t o be made. Consequently, the only factor which will then be relevant, as regards the results obtained in each laboratory, will be the testing machines and the way in which the completion of the fatigue test is evaluated. In the second phase of the invest– igation, each laboratory will make up its own collection of '"velded testpieces and these will be exchanged between the various laboratories so that each will test some of its own testpieces and some of those from other participating labor– atories. The description of such a programme of t ests may serve as a conclusion to this report on nearly ten years of work by Commission X III. The behaviour under fatigue of welded constructions was a little known subject , which was often studied by means of methods which could scarcely be compared. Thanks to the IIW, it has been possible to obtain closer agreement bet ween the various concep– tions, to collect information on accidents up to then considered to be confiden– tial, to start work on the unification of methods and finally to undert ake invest– igations at a truly international level. The value of this cooperation is the more obvious as these investigations require the use of large scale testing equipment, which is consequently scarce, and a great deal of lengthy experimental work is necessary to reach a better understanding of the behaviour of welded construc– tions subjected to dynamic loading.