【正文】 babilities cannot be neglected, and services of design and maintenance should make efforts to extend the fife of the metalwork without permitting crack initiation and propagation. 7. Conclusions The analysis of the crane loading has shown that some elements of the metalwork are subjectedto 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. 中文翻譯 龍門式起重機金屬材料的疲勞強度預測 摘要 內在的疲勞曲線應用到 龍門式起重機金屬材料的 疲勞壽命預測問題。疲勞評估 。一個起重機示意圖顯示在圖 1中 。 |機械故障分析 6（ 1999） 131141 表 1 搬運強度（ %） 表 2 轉移儲存量 通過一年的觀察，從 118各搬運值的觀察所了解到的數(shù)據(jù)進行分析，并且有可能評價相關的搬運強 度（噸）參考年度的裝載量的百分比。使用運行時間的起重機和評價周期時間，與實際增加一個數(shù)量的周期比，很容易得出比較大的誤差，因此，最好是作為如下。已正態(tài)分布漸近與均值和方差，確定抽樣數(shù)量的周期 v 而不依賴于整個的形式分布函數(shù)的 ()Ft ，（ 只對不同的格式分配進行限制）。頂端的桁架受到最大的壓縮應力。起重機的豎向載荷主要是由牽引力引起的。因此，以同時懸掛的速度，森林龍門式起重機受到較小的動應力與類似的一般用途的起重機相比而言。該金屬金工振蕩的特點是有兩個諧波在 2秒的過程當中，這些已經(jīng)在前面的分析中獲得。首先，當負載被提升時，壓力增加到最高值。應該指出的是，直線圖的周期振幅與減少事后的非零平均數(shù)相等于直線圖為零時的平均數(shù)。如果初次分配每個獨立的任期有一個正態(tài)分布，那么載重周期為一年的平均數(shù)和標準偏差總數(shù)的都是平等的，大致為 423096 和650 。 根據(jù)表 [ 4 ] ，有效應力集中系數(shù)是接受的 KF = ， 給出了一個平均的價值，可承受的極限，作為 1ES? =67的強度創(chuàng)傷。這是從這個表中至少強度要件為 3 。 （ 4）使用內在疲勞曲線的方法計算疲勞強度。 通過分析起重機載重表明，一些金屬材料受到較大動態(tài)載，從而導致疲勞損傷的積累，其次是疲勞失效。 該項研究的一些金屬材料受到疲勞損傷的累積。起重機金屬制成的材料為合金鋼 09g2s，此材料有一個持久極限 120 MPa 和屈服強度 350 兆帕斯卡。 每個月裝貨塊平均數(shù)值很快就獲得了，因此它是有可能找到適當?shù)奶攸c， 如果采取中央極限周期，不僅為每月裝載量，而且也為每月或每年的裝載周期。第一是作為一獨特的振蕩講（閉 環(huán)），二是為一套加載周期期間一個運行周期。 在 運行 中，有可能的情況下，當源自不同類型的負荷加載結合起來 。這個電動機以 。 第二個特點是物質吊裝的加快導致低低效率。最大的壓縮應力發(fā)生在變形的最大角度，在內部看來 。 表 3 運作周期的正太分布 3 .應變測量 為了顯示大多數(shù)金屬的負載元素，并且確定一系列的壓力，事前做了靜態(tài)應變測量。 設 ? ?()nnF t P t???。 每月搬運價值的分布 Q（ t） ，被相對強度 q（ t）表示為 其中 Q是每年的裝載量的記錄存儲，是設計的最大存儲原木值 Q以百分比計算，其中為考察起重機等于 萬立方米每年， 和容積載重搬運為 10 ％ 的起重機，得到的數(shù)據(jù)列在表 2 中，總量 56000立方米每年，用 K表示。 搬運強度 據(jù)了解，每年的搬運強度是不規(guī)律的，不能被視為 一個平穩(wěn)過程。如果每月從森林移動的原木超過加工率，即是有一個原木存儲的倉庫，這個起重機期待的工作，也只是在原木加工的實際堆數(shù)在所供給原木數(shù)量的中心線以下； 這種類型的起重機大約 1000 臺以上工作在俄羅斯森林工業(yè)的企業(yè)中。疲勞失效分析表明，一些元件的故障是自然的系統(tǒng)因素，并且不能被一些隨意的原因所解釋。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 b rought 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 remova l 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 in