【正文】 計劃：2012年11月12日2012年12月2日：教師下達畢業(yè)設(shè)計任務(wù)，學(xué)生初步閱讀資料，完成畢業(yè)設(shè)計開題報告。2013年3月4日2013年3月15日：確定總設(shè)計方案。2013年3月25日2013年4月5日：總體設(shè)計（完成參數(shù)計算及結(jié)構(gòu)分析計算后繪制草圖；裝配圖）。2013年4月29日2013年5月25日：畢業(yè)論文說明書撰寫和修改工作。設(shè)計出10噸位橋式起重機的大車部分。特色或創(chuàng)新之處對橋式起重機進行全面的了解，分析設(shè)計橋式起重機的大車機構(gòu)已具備的條件和尚需解決的問題我已學(xué)習(xí)機械數(shù)控專業(yè)三年之久，掌握了一些這專業(yè)的部分知識，老師也給了一些參照資料，可以進行這方面的研究。（2）進給部件的強度剛度校核需要對進給部件的強度和剛度有保證，滿足工作時的受力要求，需要進行校核計算。 Fatigue assessment。 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 logs to or out of road trains. A road passes along the log store. The saw mills are installed so that the reception sites are under the crane span. A schematic view of the crane is shown in Fig. 1.13506307/99/$一see front matter 1999 Elsevier Science Ltd. All rights reserved.PII: S 1 3 5 0一6307(98) 00041一7A series of assumptions may be made after examining the work of cranes: the height of the piles is considered to be a maximum。the store variation takes place from the side opposite to the saw mill。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 intensityIt 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 aswhere 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 blocksThe 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 to 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 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 ofa crane used for general purposes. At first, it involves the load pliance of log packs because ofprogressive 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。106 and the slope m= for elements 1 and 3 and m= for element 2. The possible values of the element endurance limits presented above overlap the ranges of load amplitude with nonzero probability, which means that these elements are subjected to fatigue damage accumulation. Then it is possible to conclude that fatigue calculations for the elements are necessary as well as fatigue fife prediction.6. Life predictionThe study has that some elements of the metalwork are subject to fatigue damage predict fives we shall take advantage of intrinsic fatigue curves, which are detailed in [5]and [6].