基于有限元和試驗(yàn)?zāi)B(tài)分析的振動篩動力學(xué)參數(shù)研究

1、第35卷2007年第1期 63Mining & Processing Equipment63分選鉆井振動篩是固相控制系統(tǒng)的重要設(shè)備,正向大型化、自動化、集成化、智能化方向發(fā)展,工作過程中的動力學(xué)問題越來越多,對動力學(xué)特性的要求也越來越高1。同時(shí),隨著非線性動力學(xué)理論、現(xiàn)代設(shè)計(jì)理論與方法、計(jì)算機(jī)軟硬件的迅速發(fā)展以及現(xiàn)代測試技術(shù)向數(shù)字化、智能化方向的發(fā)展,為振動篩進(jìn)行全面、系統(tǒng)的動力學(xué)設(shè)計(jì)和修改提供了可能2。國產(chǎn)鉆井振動篩出現(xiàn)的主要問題是:篩箱易損壞、橫梁和側(cè)板斷裂等。要想從根本上解決國產(chǎn)振動篩的上述問題,必須進(jìn)行振動篩的動力學(xué)設(shè)計(jì)。從工作條件上看,振動篩除受激振器的受迫振動外,還受到固相

2、顆粒的沖擊作用,受力相當(dāng)復(fù)雜。在振動篩動態(tài)設(shè)計(jì)過程中,有必要對振動篩的動力學(xué)特性進(jìn)行精確的分析和研究。振動篩動力學(xué)參數(shù)的確定可以通過理論和試驗(yàn)兩種方法得到,理論方法一般采用有限元法進(jìn)行幾何建模、劃分網(wǎng)格、數(shù)值求解,從而獲得固有頻率和主振型。試驗(yàn)?zāi)B(tài)分析技術(shù)是結(jié)構(gòu)動力學(xué)中的一種“逆問題”分析方法(相對于有限元分析的“正問題”分析方法,以試驗(yàn)或?qū)崪y數(shù)據(jù)為依據(jù),采用理論和試驗(yàn)分析相結(jié)合的方法,應(yīng)用參數(shù)估計(jì)和系統(tǒng)辨識的數(shù)學(xué)手段對實(shí)際結(jié)構(gòu)的動力學(xué)參數(shù)進(jìn)行辨識。文章首先采用有限元法分析,估計(jì)篩箱結(jié)構(gòu)的振動頻率和振型等有關(guān)動態(tài)特性參數(shù),再進(jìn)行試驗(yàn)?zāi)B(tài)分析對有限元模型進(jìn)行修改,再做分析,最終達(dá)到精確確定鉆井振

3、動篩的動力學(xué)參數(shù)。1篩箱動態(tài)特性的有限元分析P D Z S 型平動橢圓振動篩是由篩箱、激振器和彈簧等部件組成。采用一對齒輪強(qiáng)迫同步,在兩齒輪軸上裝有偏心塊,由此產(chǎn)生慣性力,使得篩箱產(chǎn)生振動。整個(gè)篩箱由4個(gè)螺旋彈簧支撐,篩箱側(cè)板支撐方向加有縱向加強(qiáng)肋板,側(cè)板中部和安裝彈簧支撐座處的外側(cè)襯有加強(qiáng)板。兩側(cè)板與6根L型加強(qiáng)板、1根出口端圓管加強(qiáng)梁、2根激振器保護(hù)筒梁、2根后端梁、27根縱向加強(qiáng)梁、后擋板等均通過焊接聯(lián)接,在兩側(cè)板外側(cè)四個(gè)角處,還焊有彈簧支撐板。為使篩箱在工作過程中處于平動,在設(shè)計(jì)時(shí)需保證激振力的合力作用線通過篩箱的質(zhì)心。篩箱的有限元網(wǎng)格是在Pro /Mechanica軟件Structu

4、re模塊中建立的。首先在Pro /Engineer軟件中建立篩箱各零件的三維模型,裝配并作相應(yīng)的簡化,然后通過A p p l i c a t i o n 菜單直接進(jìn)入P r o /M e c h a n i c a 軟件環(huán)境。由于篩箱零件主要以板材為主,因此在單元劃分時(shí),主要采用二維殼單元,局部結(jié)構(gòu)(如加強(qiáng)梁、篩網(wǎng)抬架采用梁單元,這樣既有效地減小了模型規(guī)模,又能保證計(jì)算的準(zhǔn)確性。按照篩箱與底座固結(jié)的實(shí)際位置施加彈簧單元邊界條件,這樣就形成了篩箱的有限元模型,如圖1所示。該模型的總結(jié)點(diǎn)數(shù)為640,梁單元數(shù)為110,殼單元數(shù)為論文編號:1001-3954(200701-0063-065基于有限元和

5、試驗(yàn)?zāi)B(tài)分析的振動篩動力學(xué)參數(shù)研究*朱維兵西華大學(xué)機(jī)械工程與自動化學(xué)院四川成都610039摘要:以P D Z S 型平動橢圓振動篩為計(jì)算實(shí)例,建立了篩箱系統(tǒng)動態(tài)特性分析的有限元模型,用工程分析軟件Pro /Mechanica對篩箱的動態(tài)特性作分析研究,計(jì)算了篩箱的低階固有頻率、模態(tài)振型;應(yīng)用試驗(yàn)?zāi)B(tài)分析技術(shù),采用一點(diǎn)激振,多點(diǎn)拾振的測試方法,對整體振動篩進(jìn)行了實(shí)測,獲得了振動篩固有頻率、阻尼比和主振型,為鉆井振動篩動力學(xué)設(shè)計(jì)和動力學(xué)修改提供了參考。敘詞:鉆井振動篩有限元法試驗(yàn)?zāi)B(tài)分析固有頻率*四川省制造與自動化重點(diǎn)實(shí)驗(yàn)室基金項(xiàng)目(SZD-Z02244。作者簡介:朱維兵,1971年生,博士,副教

6、授;現(xiàn)從事現(xiàn)代機(jī)械設(shè)計(jì)方面的教學(xué)和研究工作。圖1篩箱有限元網(wǎng)格圖表1篩箱前5階模態(tài)分析結(jié)果階數(shù)模態(tài)頻率(Hz431.28出口端縱向加強(qiáng)梁的彎曲振動5出口端L 型加強(qiáng)板的彎曲振動本欄目編輯趙斌基于有限元和試驗(yàn)?zāi)B(tài)分析的振動篩動力學(xué)參數(shù)研究第35卷2007年第1期 64Mining & Processing Equipment64分選504,彈簧單元數(shù)為4。利用Pro /Mechanica軟件的Structure模塊,建立該模型的質(zhì)量矩陣M 和剛度矩陣K ,求解可得篩箱模態(tài)振型及固有頻率,前五階模態(tài)分析結(jié)果如表1所示。2振動篩試驗(yàn)?zāi)B(tài)分析在進(jìn)行模態(tài)試驗(yàn)分析時(shí),首先要確定被測物體的固定方式。

7、固定方式一般有兩種:一種是按照其實(shí)際工作狀況的方式約束,二是懸吊式。由于本次試驗(yàn)對象是中型平動橢圓振動篩,由底座、支撐彈簧、篩箱、激振器及其它配套裝置組成。模態(tài)試驗(yàn)可在實(shí)際工作狀態(tài)、電機(jī)停轉(zhuǎn)的空載狀態(tài)下進(jìn)行?？紤]到鉆井振動篩在激振器激勵(lì)下運(yùn)動的振動頻率范圍。一般認(rèn)為3,靠近激振源激振頻率的模態(tài)對結(jié)構(gòu)振動影響較大,遠(yuǎn)離激振源激振頻率的模態(tài)對結(jié)構(gòu)振動影響較小。因此,試驗(yàn)頻段的上限一定要大于激振頻率。結(jié)合前面篩箱結(jié)構(gòu)的有限元分析結(jié)果,選取試驗(yàn)頻段為激振器激振頻率附近的1530Hz的頻段(激振器激振頻率=22.33Hz。篩箱是一個(gè)由若干型材和板材構(gòu)成的組合結(jié)構(gòu),因此存在著篩箱總體振動和篩箱局部結(jié)構(gòu)的振

8、動問題。為了提高測試精度,防止漏掉振型,激振點(diǎn)和測點(diǎn)的選擇應(yīng)考慮4:(1激振點(diǎn)的激振要避開各階模態(tài)的節(jié)點(diǎn)和節(jié)線,以免遺漏模態(tài);(2應(yīng)能夠提供足夠的能量,把需要頻段中的模態(tài)全部激發(fā)出來,使各測試的信號有良好的信噪比。為此,參考前面有限元分析的結(jié)果在篩箱上布置146個(gè)測點(diǎn),共438個(gè)自由度。激勵(lì)信號可采用隨機(jī)信號、脈沖信號等,在本次試驗(yàn)中根據(jù)現(xiàn)場條件,采用單點(diǎn)激振、錘擊脈沖信號法,測試分析系統(tǒng)框圖,如圖2所示。用橡皮錘敲擊篩箱中部激發(fā)篩箱總體振動,用磁電式速度傳感器在146個(gè)測點(diǎn)處拾振。試驗(yàn)采用力錘(含力傳感器激勵(lì),磁電式速度傳感器進(jìn)行響應(yīng)測量;用電荷放大器對速度傳感器輸出的電信號進(jìn)行放大;由于信

9、號中混有電壓波動及其它環(huán)境噪聲等原因造成的高頻干擾,故采用低通濾波器進(jìn)行濾波。動態(tài)數(shù)據(jù)采集系統(tǒng)采用D a t a Physics公司16通道Signalcalcmobilyzerdynamic signalanalyzer440,模態(tài)分析軟件采用Signalstar。數(shù)據(jù)采集的參數(shù)設(shè)置為:對每一通道,采用低通抗混濾波,根據(jù)采樣定理選取采樣頻率為2500Hz,采樣數(shù)據(jù)長度為16384點(diǎn),激勵(lì)和響應(yīng)窗函數(shù)分別采用力窗和響應(yīng)窗。進(jìn)行數(shù)據(jù)處理時(shí),首先需要確定觸發(fā)系統(tǒng)。脈沖信號采用信號觸發(fā),即當(dāng)有一脈沖信號過來時(shí),才進(jìn)行一次觸發(fā)平均。為減少隨機(jī)誤差,應(yīng)進(jìn)行多次平均?？紤]到篩箱結(jié)構(gòu)的阻尼較小,頻響函數(shù)的半

10、功率帶較窄,故應(yīng)盡量提高頻率分辨率。針對現(xiàn)場振動篩實(shí)際運(yùn)行情況,對振動篩進(jìn)行了1530Hz頻率范圍模態(tài)參數(shù)抽取,通過模態(tài)分析計(jì)算可得到振動篩的模態(tài)參數(shù):固有頻率、主振型和阻尼比,表2列出了模態(tài)分析結(jié)果,各階振型如圖3?？梢?有限元法和試驗(yàn)?zāi)B(tài)分析的結(jié)果是吻合的,因此可以確定試驗(yàn)結(jié)果真實(shí)可靠。模態(tài)分析共得到3階模態(tài)參數(shù),對于不同的固有頻率,相應(yīng)主振型的振動描述如下:第一階主振型為側(cè)板的一階彎曲振動,第二階主振型為側(cè)板的二階彎曲振動,第三階主振型為出口端縱向加強(qiáng)梁的彎曲振動。由于所得3階彈性模態(tài)都在激振頻率(22.33Hz附近,容易引起篩箱側(cè)板的共振,故需對其結(jié)構(gòu)進(jìn)行適當(dāng)修改,使其模態(tài)頻率遠(yuǎn)離激振

11、頻率。另外,連接試驗(yàn)振動篩兩側(cè)的圓管加強(qiáng)梁剛度過低,所以振動篩動態(tài)設(shè)計(jì)中要予以重點(diǎn)考慮,以防止類似現(xiàn)場中廣泛存在的側(cè)板斷裂故障發(fā)生。圖2測試分析系統(tǒng)框圖表2篩箱模態(tài)分析結(jié)果階數(shù)模態(tài)頻率(Hz模態(tài)阻尼比(%118.453.56224.32.563圖3基于有限元和試驗(yàn)?zāi)B(tài)分析的振動篩動力學(xué)參數(shù)研究(下轉(zhuǎn)第65頁第35卷2007年第1期 65Mining & Processing Equipment65分選湘潭鋼鐵集團(tuán)公司于2000年在生產(chǎn)系統(tǒng)改造過程中,安裝了5臺CCJ/A系列除塵器,在使用過程中,由于除塵器一直很難保證處于穩(wěn)定良好的運(yùn)行狀態(tài),并存在噪聲大的問題。為了徹底解決這些問題,特參

12、考有關(guān)資料,組織相關(guān)人員,進(jìn)行分析和討論,并根據(jù)我礦的實(shí)際情況對CCJ /A系列沖激式除塵器進(jìn)行改造。改造后基本保證除塵器的運(yùn)行率為98%以上,保證了操作崗位粉塵基本消除;且原來的噪聲大、不方便操作和維護(hù)等問題都得到有效解決。1基本參數(shù)、結(jié)構(gòu)及原理CCT /J系列除塵器基本參數(shù),見表1。CCJ /A系列除塵器其原理(見圖1是通過水流相對運(yùn)動激起水花與除塵器利用壓差吸引過來的粉塵碰撞而結(jié)合,從而達(dá)到除塵的目的。2CCJ /A 系列除塵器系統(tǒng)故障原因分析分析、討論表明現(xiàn)有除塵系統(tǒng)的不足之處:論文編號:1001-3954(200701-0065-066提高CCJ/ A 系列沖激式除塵器穩(wěn)定性和效率的

13、措施肖文志1廖洪剛2鄧奕11湘潭湖南工程學(xué)院數(shù)理系湖南湘潭4111042湘潭鋼鐵集團(tuán)公司湘鄉(xiāng)白云石礦摘要:結(jié)合沖激式除塵器和泡沫式除塵器的工作原理,以較低成本對沖激式除塵器進(jìn)行改造,降低除塵器的運(yùn)行成本和提高除塵器的運(yùn)行效率。敘詞:沖激式泡沫式粉塵改造表1型號耗水量(m 3/h充水容積電機(jī)功率數(shù)量溢流蒸發(fā)排灰水(m 3(kW(臺CCJ /A-144942012001.2304CCJ /A-157560017003711.進(jìn)水管道2.室13.上葉片4.室25.通氣管6.溢流管7.溢流箱8.水池9.儲水箱10.下葉片圖1CCJ /A 系列除塵器工作原理圖(上接第64頁3結(jié)論(1先利用Pro /Me

14、chanica軟件進(jìn)行有限元分析可以減少模態(tài)試驗(yàn)的預(yù)試驗(yàn)時(shí)間,能較為準(zhǔn)確地選定激勵(lì)點(diǎn)和測試點(diǎn)。(2通過試驗(yàn)?zāi)B(tài)分析,得到了試驗(yàn)振動篩的動力學(xué)參數(shù):固有頻率、主振型和阻尼比。與有限元法分析結(jié)果一致,因此結(jié)果是可靠和真實(shí)的。同時(shí)詳細(xì)分析了各階主振型的振動形態(tài),為振動篩的動力學(xué)設(shè)計(jì)和動力學(xué)修改提供了依據(jù)。(3由于所得3階彈性模態(tài)都在激振頻率附近,容易引起篩箱側(cè)板的共振,故需對其結(jié)構(gòu)進(jìn)行適當(dāng)修改,使其模態(tài)頻率遠(yuǎn)離激振頻率。另外,試驗(yàn)振動篩連接兩側(cè)板的圓管加強(qiáng)梁剛度過低,這可能是振動篩側(cè)板易斷裂的一個(gè)重要原因,在動態(tài)設(shè)計(jì)中要予以重點(diǎn)考慮,同時(shí)對防止現(xiàn)場廣泛存在的側(cè)板斷裂故障提供了借鑒意義。(4通過有限元

15、法和試驗(yàn)?zāi)B(tài)分析技術(shù)獲得振動篩的動態(tài)特性參數(shù),進(jìn)行振動篩動態(tài)特性參數(shù)的修改,從而進(jìn)行振動篩的優(yōu)化設(shè)計(jì),為解決鉆井振動篩現(xiàn)場存在的問題提供了強(qiáng)有力的理論支持。參考文獻(xiàn)1茹軍,胡欽峰,張明洪.鉆井液振動篩整機(jī)動態(tài)檢測中的若干問題.石油礦場機(jī)械,2003(32傅志方.振動模態(tài)分析與參數(shù)辨識.北京:機(jī)械工業(yè)出版社,1990.3張傳濤,閆國興,張明洪.MN-1型三電機(jī)自同步振動篩試驗(yàn)?zāi)B(tài)分析.礦山機(jī)械,2005(73劉建文.直線振動篩篩框模態(tài)分析和故障診斷研究.礦山機(jī)械,2004(7(收稿日期:2006-07-25(修改稿日期:2006-11-03d c d c d c d c d c d c d c

16、d c d c d c d c d c d c d c d c d c d c d c d c d c d c d c d c d c d c d c d c d c d c d c 提高CCJ /A 系列沖激式除塵器穩(wěn)定性和效率的措施【Descriptors】Hierarchical fuzzy control Decouple Ball mill Pow-dering systemStudy to the Foundry of High Manganese Steel Liner with Copper Alloy Mould.NIU XianMing et al.(22-24 in or

17、der to get the high manganese steel liner without heat treatment, the paper analyses the heat transmission process between the liner and the copper alloy mould, calculates the density of the heat current conducted from the alloy mould, designs the structure of the copper alloy mould and the distribu

18、tion of the cooling water groove. The employment result shows that the copper alloy mould processes the advantage of long lifespan and low cost. 【Descriptors】Liner Cal-culation for the heat transmission Design to the structure of the cop-per alloy mouldDevelopment and Optimization of the Grinding Me

19、dia System. .XIAO QingFei et al.(28-31 The paper puts forward the grinding media system and analyses the existed problem, introduces the studying development about the for-eign and domestic grinding media system and gets several pieces of conclusion, which shows that the in China the suitable fillin

20、g rate of the media, precise size of the steel ball, accurate loading and adding approach for the steel ball, suitable shape of the media and reasonable material are the optimal selection in the grinding media system.【Descriptors】Grinding media system Filling rate Fine grinding media Accurate loadin

21、g and adding approach for the steel ball Study to the Material and Quality of the Hammerhead of the Ham-mer Crusher.YIN JinGuang(32-33 The paper introduces the process for studying the material and quality of the hammerhead of the hammer crusher. According to the kinetic analysis to the hammerhead a

22、nd the energy condition for crushing, it deduces the calculation formula of the hammerhead quality, which offers the theoretic reference for determining the hammerhead quality. In addition, the high-chrome manganese tungsten alloy is selected as the material of the hammerhead, which has good anti-ab

23、rasion properties, strong toughness properties and long lifespan, is a perfect material for the hammerhead. 【Descriptors】 Hammer crusher High-chrome manganese tungsten alloy Quality of the hammerhead Discussion of the Build-Up Welding Repair Technique Applied to the Roller Surface of Roller Press.SH

24、I LiYan et al.(34-35 The paper briefly introduces the roller press about its working prin-ciple and basic structure, discusses and studies the build-up welding repair technique applied to the roller surface, and puts forward the matter need to attention in the employment course. 【Descriptors】Build-u

25、p welding repair Roller press Application and discussion Realization of Variable Frequency Control to the Vibration Mill with the Communication between OMRON PLC and the Upper-Position Processor.SU Dan et al.(43-45 The paper offers the approach to design the program for realizing the communication b

26、etween OMRON programmable controller and the upper-position processor by VC+6.0, and provides the approach to realize the communication between the computer and the PLC with RS232 tandem communication port. The scheme has been success-fully applied to the variable frequency control to the vibration

27、mill.【Descriptors】Upper-position processor PLC Tandem communi-cation Vibration millInnovating the Grinding Technique to Improve the Product Quality.ZOU JunPun et al.(59-61 According to the properties and characteristic of the cement output from the vertical kiln and current grinding technique status

28、, the paper suggests that on condition that the inner quality of the chamotte is ensured, the barrel mill with big ratio of the length to the diameter is guaranteed, pretreatment to the material before grinding and the in-novation to the greatly fine grinding technique are applied to improvethe fine

29、 grinding degree, proportion of each grade and particle shape, thus, the product quality could increase. 【Descriptors】Grinding technique Pretreatment Fine grinding degree Product quality the Analysis to the Finite Element and Testing Mode. .ZHU WeiBing(63-65 The PDZS type translation elliptical vibr

30、ation screen serving as the calculation example, the paper establishes the finite element model for analyzing the dynamic characteristic of the screen box system, makes the analytical study to the dynamic characteristic of the screen box with the engineering analysis software Pro / Mechanica, calcul

31、ates the low-order natural frequency and modal vibration shapes of the screen box. In addition, applying the testing modal analysis technique and the testing approach that is the vibration is excited at one point and picked up at multi-point, it makes actual measurement to the whole vibration screen

32、, thus gets the natural frequency, damping ratio and main vibration type of the vibration screen, which offers the reference for the dynamic design and the dynamic improvement to the drilling vibration screen. 【Descriptors】Drilling Vibration screen Finite element approach Modal analysis Natural freq

33、uency Measurement to Improve the Stability and Efficiency of CCJ/A Serial Swashing Dust Catcher.XIAO WenZhi et al.(65-66 Combining the working principle of the swashing dust catcher and that of the foamy one, the paper innovates the swashing dust catcher with low cost, so as to decrease the operatio

34、n cost of the dust catcher and increase the operation efficiency. 【Descriptors】Swashing Foamy Dust InnovationOptimization to the Simulation of the Movement of the ZRBF Vi-bration Screen Surface with Matlab. .FANG ZhiHua et al.(67-70 According to the movement differential equation for the vibration s

35、ystem of three freedom of ZRBF vibration screen, the paper applies the powerful and perfect common numerical analysis, matrix algo-rithm and drawing function of Matlab to makes the simulative analysis to the movement track on the screen surface, which could help to select the suitable exciting point

36、 and exciting force so as to makes the optimization design, meanwhile, it offers the convenient and efficient computer optimization approach for actual engineering application.【Descriptors】Matlab simulation ZRBF vibration screen Movement of screen surfaceDomestic Current Study Status and Prospect of the Automatic Medi-cine Feeding System of the Concentrator for the C