【正文】 ctedto large dynamic loads, which causes fatigue damage accumulation followed by fatigue procedure of fatigue hfe prediction proposed in this paper involves tour parts: (1) Analysis of the operation in practice and determination of the loading blocks for some period. (2) Rainflow cycle counting techniques for the calculation of loading cycles for a period of standard operation. (3) Selection of appropriate fatigue data for material. (4) Fatigue fife calculations using the intrinsic fatigue curves approach. The results of this investigation have been confirmed by the cases observed in practice, and the manufacturers have taken a decision about strengthening the fixed elements to extend their fatigue lives. References [1] Feller W. An introduction to probabilistic theory and its applications, vol. 2. 3rd ed. Wiley, 1970. [2] Rychlik I. International Journal of Fatigue 1987。 the maximum stresses reach h0 MPa (gauges 8 and 9). The largest tension stresses in the diaphragms and angles of the exterior panel reach 45 MPa (causes 1 and hl. The elements of the crane bridge are subjected, in genera maximum stresses and respond weakly to skew loads. The suhand, are subjected mainly to skew , to vertical loads pports of the crane gmmg rise to on the other The loading of the metalwork of such a crane, transferring fulllength logs, differs from that of a crane used for general purposes. At first, it involves the load pliance of log packs because of progressive detachment from the base. Therefore, the loading increases rather slowly and second characteristic property is the low probability of hoisting with picking up. This is conditioned by the presence of the grab, which means that the fall of the rope from the spreader block is not permitted。the total volume of a processed load is on the average k= times more than the total volume of removal because of additional transfers. . Removal intensity It is known that the removal intensity for one year is irregular and cannot be considered as a stationary process. The study of the character of nonstationary flow of road trains at 23 enterprises Sverdlesprom for five years has shown that the monthly removal intensity even for one enterprise essentially varies from year to year. This is explained by the plex of various systematic and random effects which exert an influence on removal: weather conditions, conditions of roads and lorry fleet, etc. All wood brought to the log store should, however, be processed within one year. Therefore, the less possibility of removing wood in the season between spring and autumn, the more intensively the wood removal should be performed in winter. While in winter the removal intensity exceeds the processing considerably, in summer, in most cases, the more fulllength logs are processed than are taken out. From the analysis of 118 realizations of removal values observed for one year, it is possible to evaluate the relative removal intensity g(t) as percentages of the annual load turnover. The removal data fisted in Table 1 is considered as expected values for any crane, which can be applied to the estimation of fatigue life, and, particularly, for an inspected crane with which strain measurement was carried out (see later). It would be possible for each crane to take advantage of its load turnover per one month, but to establish these data without special statistical investigation is difficult. Besides, to solve the problem of life prediction a knowledge of future loads is required, which we take as expected values on cranes with similar operation conditions. The distribution of removal value Q(t) per month performed by the relative intensity q(t) is written as where Q is the annual load turnover of a log store, A is the maximal designed store of logs in percent of Q. Substituting the value Q, which for the inspected crane equals 400,000 m3 per year, and A=10%, the volumes of loads transferred by the crane are obtained, which are listed in Table 2, with the total volume being 560,000 m3 for one year using K,. . Number of loading blocks The set of operations such as clamping, hoisting, transferring, lowering, and getting rid of a load can be considered as one operation cycle (loading block) of the crane. As a result to investigations, the operation time of a cycle can be modeled by the normal variable with mean equal to min and standard deviation to min. unfortunately, this characteristic cannot be simply used for the definition of the number of operation cycles for any work period as the local processing is extremely irregular. Using a total operation time of the crane and evaluations of cycle durations, it is easy t o make large errors and increase the number of cycles pared with the real one. Therefore, it is preferred to act as follows. The volume of a unit load can be modeled by a random variable with a distribution function(t) having mean22 m3 and standard deviation 6。the store variation takes place from the side opposite to the saw mill。 the height of the piles is considered to be a maximum。 fives, predict their fatigue behavior, and give remendations to the manufacturers for enhancing the fives of the cranes. 2. Analysis of the crane operation For the analysis, a traveling gantry crane LT62B installed at log yard in the Yekaterinburg region was chosen. The crane serves two saw mills, creates a log store, and transfers log