【正文】 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。 這種類(lèi)型的起重機(jī)大約 1000 臺(tái)以上工作在俄羅斯森林工業(yè)的企業(yè)中。 搬運(yùn)強(qiáng)度 據(jù)了解，每年的搬運(yùn)強(qiáng)度是不規(guī)律的，不能被視為 一個(gè)平穩(wěn)過(guò)程。 設(shè) ? ?()nnF t P t???。最大的壓縮應(yīng)力發(fā)生在變形的最大角度，在內(nèi)部看來(lái) 。這個(gè)電動(dòng)機(jī)以 。第一是作為一獨(dú)特的振蕩講（閉 環(huán)），二是為一套加載周期期間一個(gè)運(yùn)行周期。起重機(jī)金屬制成的材料為合金鋼 09g2s，此材料有一個(gè)持久極限 120 MPa 和屈服強(qiáng)度 350 兆帕斯卡。 通過(guò)分析起重機(jī)載重表明，一些金屬材料受到較大動(dòng)態(tài)載，從而導(dǎo)致疲勞損傷的積累，其次是疲勞失效。這是從這個(gè)表中至少?gòu)?qiáng)度要件為 3 。如果初次分配每個(gè)獨(dú)立的任期有一個(gè)正態(tài)分布，那么載重周期為一年的平均數(shù)和標(biāo)準(zhǔn)偏差總數(shù)的都是平等的，大致為 423096 和650 。首先，當(dāng)負(fù)載被提升時(shí)，壓力增加到最高值。因此，以同時(shí)懸掛的速度，森林龍門(mén)式起重機(jī)受到較小的動(dòng)應(yīng)力與類(lèi)似的一般用途的起重機(jī)相比而言。頂端的桁架受到最大的壓縮應(yīng)力。使用運(yùn)行時(shí)間的起重機(jī)和評(píng)價(jià)周期時(shí)間，與實(shí)際增加一個(gè)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。 疲勞評(píng)估 。 the height of the piles is considered to be a maximum。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。1999年 Elsevier公司科學(xué)有限公司。當(dāng)處理超過(guò)原木從森林運(yùn)出的速度時(shí)，起重機(jī)的工作需要在的大量的木材之上進(jìn)行操作，相當(dāng)于在大量的木材上這個(gè)鋸木廠(chǎng)賺取的很少； 裝載木塊的數(shù)量 這個(gè)運(yùn)行裝置，如夾緊，吊裝，轉(zhuǎn)移，降低，和釋放負(fù)載可被視為起重機(jī)的一個(gè)運(yùn)行周期（加載塊）。垂直載荷用來(lái)測(cè)量懸掛負(fù)載，并且斜交加載由一個(gè)牽引力所形成，配備了一臺(tái)測(cè)力計(jì)。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 。 當(dāng)最高負(fù)荷從制動(dòng)負(fù)荷時(shí)降低 ， 是最大負(fù)荷情況配合制動(dòng)手推車(chē)與 同 的調(diào)整制動(dòng)器 。 首先，將它從已知的概率論考慮，除了給出了獨(dú)立的泊松系數(shù)，還給出了一個(gè)隨機(jī)變量與泊松分布的參數(shù) K）。內(nèi)在的疲勞曲線(xiàn)是我們預(yù)測(cè)生命應(yīng)采取的優(yōu)勢(shì)，其中詳見(jiàn)于表 [5]和表 [6].通過(guò)以下內(nèi)在疲勞曲線(xiàn)的理論，我們根據(jù)觀(guān)察到壽命分布密度得到數(shù)正態(tài)分布的數(shù)據(jù)。 （ 3）選擇適當(dāng)材料根據(jù)疲勞數(shù)據(jù)。那個(gè)相當(dāng)大的局部應(yīng)力所造成彎曲的地方也能促進(jìn)疲勞損傷累積。用微分的手段統(tǒng)計(jì)樣本周期振幅的值的分布情況，由此得出估計(jì)參數(shù)列于于表 4 中。 當(dāng)一個(gè)固定的負(fù)荷解除時(shí)，加快速度，裝載在鋼絲繩上的吊具和金屬幾乎是相同的情況下快速吊起一堆捆扎的木材。 起重機(jī)梁的器件在受到最大壓力和軸向載荷較弱的時(shí)候，另一方 面，所遭受的主要是斜負(fù)荷。根據(jù)下面適當(dāng)?shù)南拗浦亟ǘɡ恚枰D(zhuǎn)移大量噸數(shù)。 因此，在春季和秋季搬運(yùn)木頭的可能性越來(lái)越小，冬天搬運(yùn)的可能性越來(lái)越大，然而在冬天搬運(yùn)強(qiáng)度強(qiáng)于預(yù)想的，在夏天的情況下，更多足夠長(zhǎng)的木材就地被處理的比運(yùn)出去的要多的多。這些設(shè)備的安裝就是為了這個(gè)轉(zhuǎn)貨地點(diǎn)在起重機(jī)的跨度范圍之內(nèi)。 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 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.} 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 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 12 s and oscillate about an average within %. 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 character ized by two harmonic processes with periods 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 1314%.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 w hen loads originating from various types of loading bine. 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 mon operation cycle duration of the crane has a sufficient scatter with average value } , to reduce these oscillograms uniformly a filtration was implemented to these signals, and all repeated values, . 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 necess ary 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 ca