【正文】 塊一段時期。內在的疲勞曲線是我們預測生命應采取的優(yōu)勢，其中詳見于表 [5]和表 [6].通過以下內在疲勞曲線的理論，我們根據觀察到壽命分布密度得到數正態(tài)分布的數據。然后在平均值可承受的范圍內視察要件 1 和 3 1ES? = 41 兆帕斯卡。 首先，將它從已知的概率論考慮，除了給出了獨立的泊松系數，還給出了一個隨機變量與泊松分布的參數 K）。 該雨流循環(huán)計數方法給出了最終裁決。 當最高負荷從制動負荷時降低 ， 是最大負荷情況配合制動手推車與 同 的調整制動器 。從按下開關到繩索完全拉緊這一刻，需要 s的時間，緊張的繩索慢慢的增加倒最長。這是抓斗所存在的所限制，這意味著不允許繩索從吊具座下降 。最高壓力值將達到到 h0MPa和痛苦（計 8日和 9 ） 。垂直載荷用來測量懸掛負載，并且斜交加載由一個牽引力所形成，配備了一臺測力計。函數 f（ t）反復被定義，假設 V （ t ）是在運作周期內轉移貨物的數量。 裝載木塊的數量 這個運行裝置，如夾緊，吊裝，轉移，降低，和釋放負載可被視為起重機的一個運行周期（加載塊）。非平穩(wěn)流動的道路列車的性質在 23 家企業(yè)中已經研究 5 年的時間，結果已經表明在年復一年中，對于每個企業(yè)來說，每個月的搬運強度都是不同的。當處理超過原木從森林運出的速度時，起重機的工作需要在的大量的木材之上進行操作，相當于在大量的木材上這個鋸木廠賺取的很少； 限制起重機壽命的問題即最弱的要素被正式找到之后，預測其疲勞強度，并給制造商建議，以提高起重機的壽命。1999年 Elsevier公司科學有限公司。一 3 m3, with the nominal volume of one pack being 25 m3. Then, knowing the total volume of a processed load for a month or year, it is possible to determine distribution parameters of the number of operation cycles for these periods to take advantage of the methods of renewal theory [1]. According to these methods, a random renewal process as shown in Fig. 2 is considered, where the random volume of loads forms a flow of renewals: In renewal theory, realizations of random:， having a distribution function F(t), are understoodas moments of recovery of failed units or request receipts. The value of a processed load:， after}th operation is adopted here as the renewal moment. Let F(t)=P﹛ n? ＜ t﹜ . The function F(t) is defined recurrently, Let v(t) be the number of operation cycles for a transferred volume t. In practice, the total volume of a transferred load is essentially greater than a unit load, and it is useful therefore totake advantage of asymptotic properties of the renewal process. As follows from an appropriate limit renewal theorem, the random number of cycles v required to transfer the large volume t hasthe normal distribution asymptotically with mean and variance. without dependence on the form of the distribution function 月 t) of a unit load (the restriction is imposed only on nonlattice of the distribution). Equation (4) using Table 2 for each averaged operation month,function of number of load cycles with parameters m,. and 6,., which normal distribution in Table 3. Figure 3 shows the average numbers of cycles with 95 % confidence intervals. The values of these parameters for a year are accordingly 12,719 and 420 cycles. 3. Strain measurements In order to reveal the most loaded elements of the metalwork and to determine a range of stresses, static strain measurements were carried out beforehand. Vertical loading was applied by hoisting measured loads, and skew loading was formed with a tractor winch equipped with a dynamometer. The allocation schemes of the bonded strain gauges are shown in Figs 4 and 5. As was expected, the largest tension stresses in the bridge take place in the bottom chord of the truss (gauge 1145 MPa). The top chord of the truss is subjected to the largest pression local bending stresses caused by the pressure of w heels of the crane trolleys are added to the stresses of the bridge and the load weights. These stresses result in the bottom chord of the I 一 beam being less pressed than the top one (gauge 1775 and 1020 MPa). The other elements of the bridge are less loaded with stresses not exceeding the absolute value 45 MPa. The elements connecting the support with the bridge of the crane are loaded also irregularly. The largest pression stresses take place in the carrying angles of the interior panel。when processing exceeds the log removal from the forest, the crane expects work above an operational pile close to the saw mill with the grab lowered on the pile。 Fatigue assessment。 the height of the piles is considered to be a maximum。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 prediction The 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]. Following the theory of intrinsic fatigue curves, we get lognormal life distribution densities for the inspected elements. The fife averages and standard deviations are fisted in Table 5. The lognormal fife distribution densities are shown in Fig. 7. It is seen from this table that the least fife is for element 3. Recollecting that an average number of load blocks for a year is equal to 12,719, it is clear that the average service fife of the crane before fatigue cracks appear in the welded elements is sufficient: the fife is years for element 1, years for element 2, and h years for element 3. However, the probability of failure of these elements within threefour years is not small and is in the range . These pro