本文關(guān)鍵詞： 橋式起重機(jī) 裂紋 平衡臺車 CAE仿真　出處：《武漢科技大學(xué)》2011年碩士論文　論文類型：學(xué)位論文

【摘要】：近20年以來,我國起重機(jī)行業(yè)發(fā)展迅猛。由于起重機(jī)在設(shè)計(jì)、制造、使用、維護(hù)等各環(huán)節(jié)中出現(xiàn)的各種問題,同時(shí)也由于起重機(jī)本身屬于間歇性動作機(jī)械,具有短暫、重復(fù)和周期性工作的特點(diǎn),起重機(jī)的鋼結(jié)構(gòu)會產(chǎn)生反復(fù)的彎曲、剪切應(yīng)力,啟動和制動時(shí)還要承受額外的沖擊載荷,因此而產(chǎn)生的起重機(jī)鋼結(jié)構(gòu)裂紋甚至斷裂會導(dǎo)致發(fā)生各種人身傷亡事故。 在我國現(xiàn)有的起重機(jī)械中,特別是使用年限較長或工作特別頻繁的起重機(jī),裂紋等缺陷時(shí)有發(fā)生,其裂紋長度從幾毫米到幾百毫米不等。由于起重機(jī)金屬結(jié)構(gòu)件一般體積較大、造價(jià)較高等客觀因素,因此不可能發(fā)現(xiàn)缺陷就立即進(jìn)行更換。雖然發(fā)現(xiàn)產(chǎn)生裂紋,但是很多橋式起重機(jī)仍然在生產(chǎn)第一線服役,這樣的設(shè)備無疑是人們頭頂?shù)囊幻墩◤�。裂紋的發(fā)生具有時(shí)間不確定性,若發(fā)生鋼梁突然脆性斷裂,其后果不堪設(shè)想,這也給安全生產(chǎn)帶來了很大的隱患。所以對起重機(jī)金屬結(jié)構(gòu)裂紋擴(kuò)展的檢測、分析以及控制的研究,對于保障安全生產(chǎn)有著重要的意義。 某鋼鐵企業(yè)冷軋廠生產(chǎn)用的多臺大跨度橋式起重機(jī),額定起重量為45/15t,跨度為37.5m。投入使用僅僅1年,發(fā)現(xiàn)四臺吊車的大車運(yùn)行平衡臺車鋼結(jié)構(gòu)出現(xiàn)若干裂紋,嚴(yán)重威脅到起重機(jī)的正常運(yùn)行和企業(yè)的正常生產(chǎn)。通過對該起重機(jī)平衡臺車進(jìn)行現(xiàn)場實(shí)測,應(yīng)用無損探傷技術(shù),掌握了該平衡臺車的裂紋分布情況,對該起重機(jī)實(shí)際運(yùn)行狀態(tài)下典型部位的應(yīng)力歷程進(jìn)行了測試,掌握了該起重機(jī)現(xiàn)場運(yùn)行過程中的第一手資料。 采用有限元前處理軟件HyperMesh建立了該起重機(jī)橋架結(jié)構(gòu)及平衡臺車的整體有限元分析模型。通過分析該起重機(jī)的運(yùn)行特點(diǎn),運(yùn)用CAE仿真技術(shù)對該起重機(jī)橋架特別是平衡臺車在典型工況下應(yīng)力分布規(guī)律進(jìn)行了研究。在CAE仿真過程中,應(yīng)用Solidworks軟件,根據(jù)起重機(jī)橋架與平衡臺車鋼結(jié)構(gòu)幾何特征,采用合適的單元類型,建立了橋式起重機(jī)橋架以及平衡臺車的三維CAE仿真模型,并應(yīng)用OptiStruct對多種典型載荷工況進(jìn)行了有限元仿真計(jì)算,結(jié)合測試結(jié)果,表明啃軌側(cè)向力是影響平衡臺車強(qiáng)度的主要因素。通過CAE仿真分析,模擬出了該起重機(jī)運(yùn)行過程中的啃軌力的大小�，F(xiàn)場實(shí)測及CAE仿真分析結(jié)果表明,在側(cè)向啃軌力的作用下,平衡臺車腹板與軸承座焊接處的應(yīng)力水平較高,超過材料的疲勞許用應(yīng)力,且由于啃軌力隨機(jī)變化,在一個(gè)工作循環(huán)內(nèi)該處的應(yīng)力變幅循環(huán)數(shù)遠(yuǎn)遠(yuǎn)高于工作循環(huán)數(shù),使得該處很快達(dá)到疲勞壽命,出現(xiàn)裂紋,這便是該起重機(jī)運(yùn)行僅1年平衡臺車即出現(xiàn)大量裂紋的主要原因。 針對該大跨度橋式起重機(jī)平衡臺車疲勞強(qiáng)度低的現(xiàn)狀,本課題提出了該平衡臺車的改進(jìn)方案,并對改進(jìn)方案在危險(xiǎn)載荷工況作用下的應(yīng)力場進(jìn)行了CAE仿真分析,表明按照該方案改進(jìn)平衡臺車后,原始結(jié)構(gòu)開裂部位的應(yīng)力水平下降了50%,已低于材料的疲勞極限,該方案已實(shí)施運(yùn)行3年,運(yùn)行效果良好。
[Abstract]:Over the past 20 years, China's rapid development of the industry. Because the crane crane in the design, manufacture, use, maintenance and other problems in various aspects, but also because the crane itself belongs to the mechanical action of intermittent, with short, repeated and periodic work, steel structure heavy machine will produce repeated bending the shear stress, but also bear the impact load additional starting and braking, the resulting crane crack in steel structure and fracture will lead to various casualty accidents.
In our country the existing hoisting machinery, especially the longer life or work especially frequent crane, cracks and other defects occur, the crack length from a few millimeters to several hundred millimeters. The crane metal structure general large volume, high cost and other objective factors, it is not possible to find defects immediately replacement. Although found cracks, but many cranes still in the production of the first line service, this equipment is undoubtedly one of the head of a bomb. The occurrence of cracks with time uncertainty, if there is a sudden brittle fracture of steel beam, the consequences be unbearable to contemplate, it also brings great danger to the safety in production. So the detection of extended the crane metal structure crack, analysis and control, has important significance for guaranteeing safe production.
The cold rolling mill with an iron and steel enterprise multi big span bridge crane rated lifting weight is 45/15t, the span is 37.5m. put into use in just 1 years, found four crane crane operation balance trolley steel structure have some cracks, a serious threat to the normal production and operation enterprises crane. Through the field test of the crane balance trolley, nondestructive testing technology, mastered the balance trolley of the crane crack distribution, the actual operation condition of the typical parts of the stress process were tested, mastered the crane field during the operation of the first hand information.
A finite element analysis model of the crane structure and balanced car by using the finite element pre-processing software HyperMesh. Through the analysis of the operating characteristics of the crane, using CAE simulation technology of the crane bridge especially balance bogie in the typical working conditions of stress distribution are studied. The CAE simulation process, the application of Solidworks software according to the crane, trolley and balance geometry steel structure characteristics, using the appropriate unit types, established a three-dimensional simulation model of CAE bridge crane trolley and balance, and the application of OptiStruct of various typical loading conditions were analyzed by finite element simulation, combined with the test results, show that the rail gnawing lateral force is the main factor affecting the strength of the car balance through CAE simulation, simulation of the size of the crane rail gnawing force during operation. The actual measurement and CAE simulation Analysis results show that the lateral track biting force, balance trolley and the bearing seat of the welding point with high stress level, more than the material allowable stress and fatigue, due to random variation of the force of rail gnawing, in a working cycle of the stress amplitude is much higher than the cycle number of cycles, the they soon reached the fatigue life of crack, this is the main reason for the crane running only 1 years is the emergence of a large number of car balance crack.
In view of the large span bridge crane trolley balance of low fatigue strength, this paper puts forward the improved scheme of the balance of the trolley, and the improved scheme is in danger of loading the stress field was simulated in CAE, that in accordance with the scheme to improve the balance after the car, the original structure cracking stress level decreased 50%, has been lower than the fatigue limit of material, the program has been running for 3 years, the operation effect is good.

【學(xué)位授予單位】：武漢科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2011
【分類號】：TH215

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