TWI Industrial Member Report Summary 348/1987
By T R Gurney
The objective of this work was to study the influence of spectrum shape and block length (the number of cycles between successive applications of the peak stress), and also of the clipping ratio (i.e. the ratio of maximum to r.m.s. stress), on the fatigue behaviour of plates with non-load-carrying attachments fillet welded to their edges. Since the work was exploratory in nature several different spectra were used, all being based on the two parameter Weibull distribution. All the tests were under tensile loading and were, in general, camed out at two stress levels (Smax = 175 and 275N/mm2). The results have been assessed with particular reference to the accuracy both of Miner's rule and of an alternative cumulative damage rule proposed by the author. As a result of this work a new tentative rule, based upon a combination of the other two rules, is proposed.