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存檔編碼： 無錫太湖學院 2013 屆畢業(yè)作業(yè)周次進度計劃、檢查落實表 系別：信機系 班級：機械96 學生姓名： 夏宇峰 課題（設計）名稱： 十噸位橋式起重機總體設計 開始日期：2012年11月12日 周 次 起止日期 工作計劃、進度 每周主要完成內容 存在問題、改進方法 指導教師意見并簽字 備 注 1-3 2012年11月12日-2012年12月2日教師下達畢業(yè)設計任務，學生初步閱讀資料，完成畢業(yè)設計開題報告。 按照任務書要求查閱論文相關參考資料，填寫畢業(yè)設計開題報告書 存在問題：不了解課題，資源缺乏，對設計目的及要求不明 確，沒有實際設計能力。 改進方法：尋求導師的指導，自己上網查資料，多讀點起重 機方面的的書籍。 4-10 2012年12月3日-2013年1月20日 指導專業(yè)實訓 機械制造綜合實訓，機械零件加工方法和加工工藝編制 存在問題：知識能力欠缺，實際與理論相差較遠，動手能力 不足。 改進方法：及時的對自己的知識點查漏補缺，了解加工的工 序，理解工藝編制。 11-122013年1月21日-3月1日 指導畢業(yè)實習 到企業(yè)進行崗位實習，了解本專業(yè)的實踐知識 存在問題：缺乏實際動手能力。改進方法：向工廠師傅多請教，認真學習實際能力。 13 2013年3月4日-3月8日 查閱參考資料 查閱與設計有關的參考資料不少于10篇，其外文不少于5篇 存在問題：身邊資料欠缺，相關理論知識不足。 改進方法：利用周末的時間去校圖書館，新華書店等地方翻 閱書籍，并利用工作之余在網上搜索相關資料加以整理 14 2013年3月11日-3月15日 翻譯外文資料 翻譯外文資料（8000-10000字符） 存在問題：不了解專業(yè)詞匯，需要慢慢查找。 改進方法：翻閱字典并結合翻譯軟件，上網查找，向老師求 助等方法，不斷提升英語翻譯能力。 15 2013年3月18日-3月22日 橋式起重機主要參數的確定 對起重量，起升高度，跨度，各機構速度，軌距，基距的確定 存在問題：對各主要參數的選用和確定不明確。改進方法：查閱相關資料和詢問老師來確定主要參數。 16 2013年3月25日-3月29日 橋式起重機橋架結構的計算 計算包括主要尺寸，計算載荷，主梁最大彎矩和剪力等 存在問題：以前所學的知識，如材料力學，理論力學等遺忘 較多。 改進方法；重新翻閱書籍并向老師請教。 17 2013年4月1日-4月5日 對主要的焊縫進行計算 了解焊接符號，驗算焊縫是否合格 存在問題：對于焊接方面的知識不了解。改進方法：多向工廠師傅請教并自學焊接知識。 18 2013年4月8日-4月12日 對各計算進行總結歸類，便于查看 以上面計算結果進行分類，并以表格表示 存在問題：無很大問題，但總結歸類需細心。 周 次 起止日期 工作計劃、進度 每周主要完成內容 存在問題、改進方法 指導教師意見并簽字 備 注 19 2013年4月15日-4月19日 了解變頻調速的工作原理及發(fā)展現狀 通過了解變頻調速的工作原理及調速方式選用適合變頻器 存在問題：對變頻調速原理及優(yōu)勢并不太了解。 改進方法：通過觀察工廠帶變頻的機械并詢問別人來增加了 解程度。 20 2013年4月22日-4月26日 通過PLC進行對橋式起重機進行控制 根據I/0表格繪制輸入，輸出圖，主連接圖和梯形圖 存在問題：PLC方面了解不多。 改進方法：查閱有關PLC方面的書籍，能看懂梯形圖和輸入 輸出圖的工作原理。 21 2013年4月29日-5月3日 結論總結，不足之處和格式的完成 能總結本設計完成那些內容并看出不足之處 存在問題：需回顧全文并了解做了那些主要方面分析不足之 處。 改進方法：根據前面所做內容進行總結分析 22 2013年5月6日-5月10日 圖紙的繪制 包括總體裝配圖，橋架圖，端梁等圖紙的繪制 存在問題：畫圖能力不足。改進方法：多畫，多想，參考相關圖紙繪制并檢查不足之處。 23 2013年5月13日-5月17日 設計說明書（論文），摘要和小結編寫 完成設計說明書，摘要和小結 存在問題：說明書（論文）的格式不規(guī)范，摘要不合要求等 。 改進方法：按學院要求重新修改書面格式，重新編寫摘要。 24 2013年5月20日-5月25日 上交資料，準備答辯 整理所有資料，打印后上交指導教師，準備答辯 按指導老師要求結合學院要求整理書籍及資料 說明： 1、“工作計劃、進度”、“指導教師意見并簽字”由指導教師填寫，“每周主要完成內容”，“存在問題、改進方法”由學生填寫。 2、本表由各系妥善歸檔，保存?zhèn)洳椤?編號
無錫太湖學院
畢業(yè)設計（論文）
相關資料
題目： 十噸位橋式起重機總體設計
信機 系 機械工程及自動化專業(yè)
學 號： 0923283
學生姓名： 夏宇峰
指導教師： 陳炎冬（職稱：講師）
（職稱： ）
2013年5月25日
目 錄
一、畢業(yè)設計（論文）開題報告
二、畢業(yè)設計（論文）外文資料翻譯及原文
三、學生“畢業(yè)論文（論文）計劃、進度、檢查及落實表”
四、實習鑒定表
無錫太湖學院
畢業(yè)設計（論文）
開題報告
題目： 十噸位橋式起重機總體設計
信機 系 機械工程及自動化 專業(yè)
學 號： 0923283
學生姓名： 夏宇峰
指導教師： 陳炎冬 （職稱：講師）
（職稱： ）
2013年5月25日
課題來源
生產實踐所得 。目前國外起重機械總的發(fā)展趨勢是：發(fā)展快，水平高。如國外起重機在集成電路、微處理器、微型計算器及電子監(jiān)控技術等方面都有廣泛的運用，一些節(jié)能新技術得到了推廣，可靠性、安全性、舒適性、環(huán)保性能得到了高度重視，并向大型和微型化方向發(fā)展。經過多年的發(fā)展，我目前國外起重機械總的發(fā)展趨勢是：發(fā)展快，水平高。到目前，我國起重機械行業(yè)的產品種類已經超過1000個，并不斷有新的起重機械設備問世。借鑒國外起重機發(fā)展趨勢，我國起重機發(fā)展走勢應是：大力發(fā)展機電一體化產品，實現裝載機工作狀態(tài)的自動監(jiān)測和控制，實現平地機的激光導平自動控制，實現在有毒、有危險環(huán)境下起重機作業(yè)的遙控，大力提高產品的質量、可靠性和技術水平，大力發(fā)展起重機品種，加強新技術的應用，改善駕駛員的工作條件。
科學依據
（1）課題科學意義
起重機械用來對物料作起重、運輸、裝卸和安裝等作業(yè)的機械設備，它可以完成靠人力無法完成的物料搬運工作，減輕人們的體力勞動，提高勞動生產率，在工廠、礦山、車站、港口、建筑工地、倉庫、水電站等多個領域部門中得到了廣泛的使用，隨著生產規(guī)模的日益擴大，特別是現代化、專業(yè)化的要求，各種專門用途的起重機相繼產生，在許多重要的部門中，它不僅是生產過程中的輔助機械，而且已成為生產流水作業(yè)線上不可缺少的重要機械設備，它的發(fā)展對國民經濟建設起著積極的促進作用。起重機械是起升，搬運物料及產品的機械工具。起重機械對于提高工程機械各生產部門的機械化，縮短生產周期和降低生產成本，起著非常重要的作用
在高層建筑、冶金、華工及電站等的建設施工中，需要吊裝和搬運的工程量日益增多，其中不少組合件的吊裝和搬運重量達幾百噸。因此必須選用一些大型起重機進行吊裝工作。通常采用的大型起重機有龍門起重機、門座式起重機、塔式起重機、履帶起重機、輪式起重機以及在廠房內裝置的橋式起重機等。
在道路，橋梁和水利電力等建設施工中，起重機的使用范圍更是極為廣泛。無論是裝卸設備器材，吊裝廠房構件，安裝電站設備，吊運澆注混凝土、模板，開挖廢渣及其他建筑材料等，均須使用起重機械。尤其是水電工程施工，不但工程規(guī)模浩大，而且地理條件特殊，施工季節(jié)性強、工程本身又很復雜，需要吊裝搬運的設備、建筑材料量大品種多，所需要的起重機數量和種類就更多。在電站廠房及水工建筑物上也安裝各種類型的起重機，供檢修機組、起閉雜們及起吊攔污柵之用。
(2) 國內外研究概況、水平和發(fā)展趨勢
經過多年的發(fā)展，我目前國外起重機械總的發(fā)展趨勢是：發(fā)展快，水平高。到目前，我國起重機械行業(yè)的產品種類已經超過1000個，并不斷有新的起重機械設備問世。借鑒國外起重機發(fā)展趨勢，我國起重機發(fā)展走勢應是：大力發(fā)展機電一體化產品，實現裝載機工作狀態(tài)的自動監(jiān)測和控制，實現平地機的激光導平自動控制，實現在有毒、有危險環(huán)境下起重機作業(yè)的遙控，大力提高產品的質量、可靠性和技術水平，大力發(fā)展起重機
展起重機展起重機品種，加強新技術的應用，改善駕駛員的工作條件。
國外發(fā)展現狀
目前國外起重機械總的發(fā)展趨勢是：發(fā)展快，水平高。如國外起重機在集成電路、微處理器、微型計算器及電子監(jiān)控技術等方面都有廣泛的運用，一些節(jié)能新技術得到了推廣，可靠性、安全性、舒適性、環(huán)保性能得到了高度重視，并向大型和微型化方向發(fā)展。
國內發(fā)展現狀和目標
應開發(fā)一機多用型的多功能產品，應開發(fā)技術先進、可靠性高、壽命長、施工質量好而且新技術含量高的產品。
相關業(yè)內人士指出，未來全球起重機行業(yè)將向重點產品大型化、高速化和專業(yè)化方向，系列產品模塊化、組合化、標準化和實用化方向及通用產品小型化、輕型化、簡易化和多樣化方向發(fā)展。為此我國起重機行業(yè)應加大研發(fā)投入，注重人才的培養(yǎng)和引進，切實增強行業(yè)的核心競爭力，積極參與國際市場競爭，以此來促進行業(yè)的進一步發(fā)展。
研究內容
箱形雙梁橋式起重機是由一個有兩根箱形主梁和兩根橫向端梁構成的雙梁橋架,在橋架上運行起重小車,可起吊和水平搬運各類物體,它適用于機械加工和裝配車間料場等場合。本次起重機設計的主要參數如下：起重量10t,跨度22.5m，起升高度為16m起升速度13m/min小車運行速度v=43.8m/min大車運行速度V=116.8m/min大車運行傳動方式為分別傳動;橋架主梁型式,箱形梁.小車估計重量4t，工作級別M6
研究的成果包括
（1）圖紙（CAD完成，包括仿真和機械系統(tǒng)）A0：4張；
（2）論文打印稿：1.5萬字及中英文摘要、開題報告；
（3）英翻中2000字。
擬采取的研究方法、技術路線、實驗方案及可行性分析
（1）實驗方案
對橋式起重機總體結構的布置及橋架結構和電氣部分的設計
（2）研究方法
對橋式起重機首先選擇好其基本參數，大小車及起升機構的布置方案，再對橋架主梁、端梁的尺寸如高度，厚度，加勁板間距等的計算，還有各種載荷，如均布載荷和固定載荷的計算，主梁上最大彎矩和剪力及其組合載荷也要進行考慮。電氣部分還需多加了解主要對橋式起重機變頻調速的特點包括起升機構大小車機構在變頻調速上的要點及PLC系統(tǒng)的設計。
研究計劃及預期成果
研究計劃：
第1步 熟悉課題的背景，收集資料，閱讀參考書；
第2步 閱讀參考書，翻譯外文資料，完成開題報告；
第3步 方案選擇及總體方案確定；
第4步 機械傳動系統(tǒng)設計計算；
第5步 設計計算及繪制機械系統(tǒng)裝配圖；
第6步 繪制零件圖；
第7步 整理撰寫論文；
第8步 準備答辯材料；
第9步 答辯；
預期成果：
達到預期的實驗結論：據給定的參數設計計算器總體結構的基本尺寸，然后對重要部分的尺寸進行大量的計算驗證，如載荷大小，梁的強度、剛度等看是否真正滿足要求以保證能投入實際生產運用中。
特色或創(chuàng)新之處
本章主要對箱形橋式起重機進行介紹，確定了其總體方案并進行了一些簡單的分析。箱形雙梁橋式起重機具有加工零件少，工藝性好、通用性好及機構安裝檢修方便等一系列的優(yōu)點，因而在生產中得到廣泛采用。我國在5噸到10噸的中、小起重量系列產品中主要采用這種形式，但這種結構形式也存在一些缺點：自重大、易下撓，在設計和制造時必須采取一些措施來防止或者減少。
已具備的條件和尚需解決的問題
研究的難點：
（1） 主梁上所受的彎矩和剪力的分布及其組合載荷的考慮
（2） 大小車變頻調速的特點和整體PLC系統(tǒng)的設計
指導教師意見
指導教師簽名：
年 月 日
教研室（學科組、研究所）意見
教研室主任簽名：
年 月 日
系意見
主管領導簽名：
年 月 日
英文原文
Fatigue life prediction of the metalwork of a travelling gantry crane
V.A. Kopnov
1. Introduction
Fatigue failures of elements of the metalwork of traveling gantry cranes LT62B are observed frequently in operation. Failures as fatigue cracks initiate and propagate in welded joints of the crane bridge and supports in three-four years. Such cranes are used in the forest industry at log yards for transferring full-length and sawn logs to road trains, having a load-fitting capacity of 32 tons. More than 1000 cranes of this type work at the enterprises of the Russian forest industry. The problem was stated to find the weakest elements limiting the cranes' fives, predict their fatigue behavior, and give recommendations 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.
1350-6307/99/$一see front matter 1999 Elsevier Science Ltd. All rights reserved.
PII: S 1 3 5 0一6307(98) 00041一7
A series of assumptions may be made after examining the work of cranes:
·if the monthly removal of logs from the forest exceeds the processing rate, i.e. there is a creation of a log store, the crane expects work, being above the centre of a formed pile with the grab lowered on the pile stack;
·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;
·the store of logs varies; 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=1.4 times more than the total volume of removal because of additional transfers.
2.1. 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 non-stationary 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 complex 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 full-length 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,.
2.2. 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 11.5 min and standard deviation to 1.5 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 compared 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;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 understood
as 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﹛＜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 t 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 has
the 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 11-45 MPa). The top chord of the truss is subjected to the largest compression stresses.The local bending stresses caused by the pressure of wheels 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 compressed than the top one (gauge 17-75 and 10-20 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 compression stresses take place in the carrying angles of the interior panel; 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 loads.1, to vertical loads pports of the crane gmmg rise to on the other
The loading of the metalwork of such a crane, transferring full-length logs, differs from that of
a crane used for general purposes. At first, it involves the load compliance of log packs because of
progressive detachment from the base. Therefore, the loading increases rather slowly and smoothly.The 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 load should always be balanced. The possibility of slack being sufficient to accelerate an electric drive to nominal revolutions is therefore minimal. Thus, the forest traveling gantry cranes are subjected to smaller dynamic stresses than in analogous cranes for general purposes with the same hoisting speed. Usually, when acceleration is smooth, the detachment of a load from the base occurs in 3.5-4.5 s after switching on an electric drive. Significant oscillations of the metalwork are not observed in this case, and stresses smoothly reach maximum values.
When a high acceleration with the greatest possible clearance in the joint between spreader andgrab takes place, the tension of the ropes happens 1 s after switching the electric drive on, the
clearance in the joint taking up. The revolutions of the electric motors reach the nominal value in
O.}r0.7 s. The detachment of a load from the base, from the moment of switching electric motors
on to the moment of full pull in the ropes takes 3-3.5 s, the tensions in ropes increasing smoothly
to maximum. The stresses in the metalwork of the bridge and supports grow up to maximum
values in 1-2 s and oscillate about an average within 3.5%.
When a rigid load is lifted, the accelerated velocity of loading in the rope hanger and metalwork
is practically the same as in case of fast hoisting of a log pack. The metalwork oscillations are characterized by two harmonic processes with periods 0.6 and 2 s, which have been obtained from spectral analysis. The worst case of loading ensues from summation of loading amplitudes so that the maximum excess of dynamic loading above static can be 13-14%.Braking a load, when it is lowered, induces significant oscillation of stress in the metalwork, which can be }r7% of static loading. Moving over rail joints of 3} mm height misalignment induces only insignificant stresses. In operation, there are possible cases when loads originating from various types of loading combine. The greatest load is the case when the maximum loads from braking of a load when lowering coincide with braking of the trolley with poorly adjusted brakes.
4. Fatigue loading analysis
Strain measurement at test points, disposed as shown in Figs 4 and 5, was carried out during the work of the crane and a representative number of stress oscillograms was obtained. Since a common operation cycle duration of the crane has a sufficient scatter with average value } 11.5min, to reduce these oscillograms uniformly a filtration was implemented to these signals, and all repeated values, i.e. while the construction was not subjected to dynamic loading and only static loading occurred, were rejected. Three characteristic stress oscillograms (gauge 11) are shown in
Fig. 6 where the interior sequence of loading for an operation cycle is visible. At first, stresses
increase to maximum values when a load is hoisted. After that a load is transferred to the necessary location and stresses oscillate due to the irregular crane movement on rails and over rail joints resulting mostly in skew loads. The lowering of the load causes the decrease of loading and forms half of a basic loading cycle.
4.1. Analysis of loading process amplitudes
Two terms now should be separated: loading cycle and loading block. The first denotes one distinct oscillation of stresses (closed loop), and the second is for the set of loading cycles during an operation cycle. The rain flow cycle counting method given in Ref. [2] was taken advantage of to carry out the fatigue hysteretic loop analysis for the three weakest elements: (1) angle of the bottom chord(gauge 11), (2) I-beam of the top chord (gauge 17), (3) angle of the support (gauge 8). Statistical evaluation of sample cycle amplitudes by means of the Waybill distribution for these elements has given estimated parameters fisted in Table 4. It should be noted that the histograms of cycle amplitude with nonzero averages were reduced afterwards to equivalent histograms with zero averages.
4.2. Numbers of loading cycles
During the rain flow cycle counting procedure, the calculation of number of loading cycles for the loading block was also carried out. While processing the oscillograms of one type, a sample number of loading cycles for one block is obtained consisting of integers with minimum and maximum observed values: 24 and 46. The random number of loading cycles vibe can be described
by the Poisson distribution with parameter =34.
Average numbers of loading blocks via months were obtained earlier, so it is possible to find the appropriate characteristics not only for loading blocks per month, but also for the total number of loading cycles per month or year if the central limit theorem is taken advantage of. Firstly, it is known from probability theory that the addition of k independent Poisson variables gives also a random variable with the Poisson distribution with parameter k},. On the other hand, the Poisson distribution can be well approximated by the normal distribution with average}, and variation },. Secondly, the central limit theorem, roughly speaking, states that the distribution of a large number of terms, independent of the initial distribution asymptotically tends to normal. If the initial distribution of each independent term has a normal distribution, then the average and standard deviation of the total number of loading cycles for one year are equal to 423,096 and 650 accordingly. The values of k are taken as constant averages from Table 3.
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 failures.The 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;9:119.
[3] Piskunov V(i. Finite elements analysis of cranes metalwork. Moscow: Mashinostroyenie, 1991 (in Russian).
[4] MU RD 50-694-90. Reliability engineering. Probabilistic methods of calculations for fatigue of welded metalworks.
Moscow: (iosstandard, 1990 (in Russian).
[5] Kopnov VA. Fatigue and Fracture of Engineering Materials and Structures 1993;16:1041.
[6] Kopnov VA. Theoretical and Applied Fracture Mechanics 1997;26:169.
中文譯文
起重機金屬材料的疲勞強度預測
v.a.科普諾夫
1.緒論
??頻繁觀測龍門式起重機LT62B在運作時金屬元件疲勞失效。引起疲勞裂紋的故障沿著起重機的橋梁焊接接頭進行傳播，并且能夠支撐三到四年。這種起重機在森林工業(yè)的伐木林場被廣泛使用，用來轉移完整長度的原木和鋸木到鐵路的火車上，有一次裝載30噸貨物的能力。 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。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。
2.起重機運行分析
??為了分析，在葉卡特琳堡地區(qū)的林場碼頭選中了一臺被安裝在葉卡特琳堡地區(qū)的林場碼頭的龍門式起重機LT62B， 這臺起重機能夠供應兩個伐木廠建立存儲倉庫，并且能轉