皮帶機(jī)參考文獻(xiàn)翻譯

1、Dynamic characteristics of conveyor beltsHOU You-fu, MENG Qing-ruiSchool of Mechanical and Electrical Engineering, China University of Mining & Technology, Xuzhou, Jiangsu 221116, ChinaAbstract: The dynamic characteristics of a belt conveyor are determined to a large extent by the properties of

2、the belt. This paper describes experiments designed to establish the dynamic properties of belting material. The dynamic elastic modulus, viscous damping and rheological constants of the belt were measured. Several properties were studied as a function of the tensile loading on the belt. These inclu

3、ded longitudinal vibration, the natural vibration frequency in the transverse direction and the response to an impulse excitation. Vibration response was observed under several different excitation frequencies. Most of these properties have not been tested previously under conditions appropriate for

4、 the ISO/DP9856 standard. Two types of belt were tested, a steel reinforced belt and a fabric reinforced belt. The test equipment was built to provide data appropriate for designing belt conveyors. It was observed that the stress wave propagation speed increased with tensile load and that tensile lo

5、ad was the main factor influencing longitudinal vibrations.Key words: experimental investigation; dynamic characteristics; conveyor belt1 IntroductionBelt conveyors are, in most cases, the most cost-effective solution for handling bulk material mass flows over short and medium conveying distances. T

6、he belt is a key component of these conveyors and its dynamic characteristics determine the working performance to a great extent. At present,experimental research on the dynamic characteristics of conveyor belts is mainly concentrated on testing dynamic elastic modulus and viscous damping following

7、 the ISO/DP9856 standard. Little research on other dynamic parameters has been carried out.F. Langebrake et al. tested the breaking and splice strength of steel cord belts by using a large magnetic flux leakage tester1. Blazej et al. tested the tensile strength of the belt and the strength parameter

8、s of the rubber used for the adhesive-bond joint in splices by using a ZP40 testing machine2. Hou et al. reviewed the experimental research work on the dynamic characteristics of the belt published over the past two decades. They considered that the test piece used in the previous research work, bas

9、ed on the ISO/DP9856 standard, was too small (50 mm×300mm) to acquire reliable test data and suggested that a larger one should be adopted3. This paper describes the design and construction of an apparatus to investigate the dynamic characteristics of conveyor belting. Two types of belt, a fabr

10、ic belt and a steel cord belt, commonly used in coal mines were examined.2 Experimental2.1 ParametersThe main parameters studied by the experiments are:1) The dynamic performance parameters of the belt.2) The relationship between the stress wave propagation speed and the tension force on the belt.3)

11、 The dynamic response characteristics of the belt under different tension forces and exciting frequencies.4) The natural frequency of transverse vibration of the belt.2.2 MethodsThe first step is pretreatment of the test piece,which includes the measurement of its size and peeling two ends off for g

12、ripping. Then the test piece is installed on the test apparatus and kept in tension for 24 hours under a given tension force. Each individual test is repeated ten times and the average value is reported as the final test data.1) By using the shock response method, the stress wave propagation speed C

13、 was found and used tocalculate the dynamic elastic modulus Ed. Acceleration sensors were fixed at certain points to record the response signal. The stress wave propagation time t can be obtained by comparison of the signals of an impact force and the response signals picked up by the acceleration s

14、ensors. The stress wave propagation speed C can be calculated and Ed is then given by the equation , where is the density of the belt.2) The rheological constant , of the belt is obtained by analyzing the shock and vibration signals from displacement and acceleration sensors mounted at the same plac

15、e. The viscous damping ç, of the belt can be calculated by the relationship between ,çand E d .3) The response signals of the belt were tested under different tensile loads and exciting frequencies by mounting two displacement and two acceleration sensors at specified places and then analy

16、zing the interaction between the respective signals.4) The natural frequency for transverse vibration of the belt was identified by using a swept sine-wave excitation.2.3 ApparatusThe data from the experiments carried out in this paper are intended to assist in engineering applications.To acquire re

17、liable test data, the apparatus is built to simulate a real belt conveyor. The main features of the apparatus are as follows (see Fig. 1):1) The test piece is supported on carrying idlers,just as real conveyor belts are.2) The distance between two carrying idlers is approximately the same as in actu

18、al belt conveyors.3) The test piece is placed horizontally so that the sag is similar to that of actual belt conveyors.4) The test piece is tensioned by a screw nut.5) The longitudinal exciting force is applied by a vibration exciter. The signals were recorded with a TEAC MR 30 tape recorder and wer

19、e analyzed with an HP3562A dynamic signal analyzer. The test pieces included fabric belts and steel cord belts commonly used in coal mines. The cross sections of the belts are shown in Fig. 2. The design parameters of the belts are given in Table 1.3 Results3.1 Propagation speed of a stress wave alo

20、ng the beltThe stress wave propagation time can be obtained from the recorded impact force and response signals.The stress wave propagation speed can be calculated from the time. The results are shown in Table 2.The data in Table 2 show that the stress wave propagation speed varies with the belt typ

21、e and with tensile load. The speed increases nonlinearly with an increase in tension. Under lower tension the stress wave propagation speed increases more quickly. As the tension force increased above a threshold the stress wave propagation speed changed only slightly.The stress wave propagation spe

22、ed in the steel cord belts is greater than that of the fabric belts for a given tensile load.3.2 Dynamic parameters of the beltsThe dynamic elastic modulus of the belts can be calculated from . The results are shown in Table 3.The rheological constant of the belts can be found by analyzing the accel

23、eration and displacement from an impact; the results are shown in Table 4. Viscous damping coefficients can be calculated using the relationship between dynamic elastic modulus, the rheological constant and the viscous damping; the results are shown in Table 5 .From Tables 3, 4 and 5, it can be seen

24、 that the dynamic performance parameters of the belts vary over a large range as the tensile load changes. This indicates that because of viscoelastic behavior the dynamic characteristics of the belt vary under different boundary conditions.3.3 Natural frequency of transverse vibration of the beltTh

25、e natural, transverse, vibration frequency is that frequency where the response of the belt to a swept sine wave excitation is greatest. The results of swept sine wave tests are shown in Table 6.The data in Table 6 show that the natural frequency for transverse vibration in the two types of belt inc

26、reases slightly with an increase in the tensile force in a nonlinear way. The natural frequency for transverse vibration of the steel cord belt is greater than that of the fabric belt. According to belt transverse vibration theory, the steel cord belts are suitable for high speed belt conveyors.3.4

27、Response characteristics under different exciting frequenciesHarmonic excitation was applied to the belt at different frequencies (5 Hz, 10 Hz, 15 Hz, 20 Hz, 25 Hz and 30 Hz) under various tensile loadings. The longitudinalvibration of steel cord belts was measured.The results are shown in Figs. 3 a

28、nd 4.From Figs. 3 and 4, it can be seen that:1) The basic frequency of the longitudinal vibration of the belt is the same as the exciting frequency.2) Waveform in the time domain varies with the exciting frequency under the same tension force.Higher-frequency harmonics decrease gradually with an inc

29、rease of the exciting frequency. At an exciting frequency of 30 Hz the longitudinal vibration is close to a first harmonic waveform.3) By comparing the longitudinal vibration waveform shown in Fig. 3 with the one in Fig. 4 under the same exciting frequency, it can be seen that the higher-frequency h

30、armonic components are more obvious when the tension is greater. Different vibration waveforms have different effects on dynamic stress. Higher frequency harmonics intensify vibration of the belt and lead to increased dynamic stress. This is also the harmful effect from excessive tension.3.5 Respons

31、e to shock excitationThe vibration response of steel cord belts to an impulse excitation is shown in Fig. 5. It can be seen that the response decays exponentially, similar to the response characteristics of an elastic body. This indicates that the vibration characteristics of the belts are mainly de

32、termined by the elastic properties of the framework material of the belts.6 ConclusionsThe following conclusions can be drawn from the results of the experimental investigation:1) Stress wave propagation speed increases nonlinearly with an increase in tension in the belts.For the same tension force,

33、 the stress wave propagation speed of the steel cord belt is greater than that ofthe fabric belt.2) The dynamic performance parameters of the belts, including the dynamic elastic modulus, the rheological constant and the viscous damping, vary with tension force.3) The natural frequency of the transv

34、erse vibration in the belts slightly increases with the tensile load in a nonlinear way. The natural frequency of the transverse vibration in the steel cord belt is greater than that in the fabric belt.4) Tension force on the belt is the main factor that influences longitudinal vibration: The effect

35、 of excitation frequency is smaller. This indicates that more attention should be paid to controlling tensile loading in belt conveyor design.5) Steel cord belts have the same response characteristic to shock excitation as an elastic body. This indicates that the vibration characteristics of a belt

36、are mainly determined by the elastic properties of its framework material.AcknowledgementsThe authors would like to gratefully acknowledge Prof. Zhang Yong-zhong for his valuable contributions.References1 Langebrake F, Klein J, Gronau O. Non-destructive testing of steel-cord conveyor belts. Bulk Sol

37、ids Handling,1998, 18(4): 565569.2 Blazej R, Hardygora M. Modeling of shear stresses in multiply belt splices. Bulk Solids Handling, 2003, 23(4):234241.3 Hou Y F, Huang M, Zhang Y Z. Dynamic Performanceand Control Technology of Belt Conveyor. Beijing: Coal Industry Press, 2004. (In Chinese )輸送帶的動態(tài)特性

38、摘要：帶式輸送機(jī)的動態(tài)特性在很大程度上決定于輸送帶的特性。本論文敘述了輸送帶的動態(tài)性能的設(shè)計試驗(yàn)。輸送帶的動態(tài)彈塑性，粘性阻尼和流變參數(shù)已測定。包括縱向振動，橫向振動的固有頻率和受迫振動幾類特性被作為輸送帶的拉力函數(shù)來研究。觀察在幾種不同的干擾頻率下的振動響應(yīng)。大多數(shù)特性以前并沒有在ISO/DP9856標(biāo)準(zhǔn)下適當(dāng)?shù)臏y定。測試的是鋼絲繩芯帶和編織物帶。建立測試裝置為帶式輸送機(jī)的設(shè)計提供合理的參數(shù)。應(yīng)力波傳播速度隨負(fù)荷的加載快速上升，這也是縱向振動的主要因素。關(guān)鍵詞：實(shí)驗(yàn)研究；動態(tài)特性；輸送帶。1. 簡介在大多數(shù)情況下帶式輸送機(jī)是解決大量塊狀材料的中短距離運(yùn)輸?shù)母咝史桨?。帶是輸送機(jī)的關(guān)鍵部分，它

39、的動態(tài)特性在很大程度上決定了輸送機(jī)的工作狀況。目前，輸送帶的動態(tài)特性試驗(yàn)主要集中在檢測基于ISO/DP9856標(biāo)準(zhǔn)的彈性系數(shù)和粘性阻尼。其它的動態(tài)特性則少有涉及。F. Langebrake及其他人用磁通量泄漏測試法檢測了鋼絲繩芯帶的破壞和連接強(qiáng)度。Blazej及合作者用ZP40的測試儀器檢測了用粘結(jié)劑粘合處橡膠接頭的拉伸強(qiáng)度和強(qiáng)度參數(shù)。Hou等人評估了過去20年來公布的對動態(tài)特性的研究成果，認(rèn)為之前的基于ISO/DP9856標(biāo)準(zhǔn)的研究所選的試件太小（50mm×300mm),難以獲得可靠的實(shí)驗(yàn)結(jié)果，并建議應(yīng)采用更大的試件。本論文敘述了一種輸送帶動態(tài)特性測試儀器的設(shè)計。并檢測了兩種形式的

40、輸送帶：編織物帶和鋼絲繩芯帶。2.實(shí)驗(yàn)2.1參數(shù) 實(shí)驗(yàn)研究的主要參數(shù)：1) 帶的動態(tài)性能參數(shù)；2) 應(yīng)力波的傳播速度與張緊力之間的關(guān)系；3) 在不同的張緊力和激振頻率下的動態(tài)響應(yīng)特性；4) 帶橫向振動的固有頻率；2.2方法 第一步被測件的預(yù)處理，包括尺寸測量，剝?nèi)啥艘员憷o。然后將受測件置于測試儀器上，在給定張力下張緊24小時。每一單獨(dú)的測試重復(fù)10次，并取平均值作為最終的實(shí)驗(yàn)數(shù)據(jù)。1) 用振動應(yīng)答法測得應(yīng)力波傳輸速度C，并用以計算動態(tài)彈性模量Ed，加速傳感器安置在特定點(diǎn)來記錄響應(yīng)信號。應(yīng)力波傳播時間t可由壓力和加速度傳感器采集的信號對比獲得；應(yīng)力波傳播速度C可以計算出，Ed可由公式得到是帶

41、的密度2) 流變學(xué)的常數(shù)通過分析安裝在同一地方的加速度和位移傳感器采集的振動信號獲得。帶的粘性阻尼可由，Ed之間的關(guān)系來計算。3) 在特定位置安裝位移和加速度傳感器，在不同載荷和激振頻率下測得信號并分析兩者之間的相互關(guān)系。4) 通過正弦波的激勵來分析橫向振動的固有頻率。2.3測試設(shè)備由本論文試驗(yàn)測得的數(shù)據(jù)可以用于輔助工程應(yīng)用。為獲得可靠的實(shí)驗(yàn)數(shù)據(jù)，測試設(shè)備盡量模擬真實(shí)的帶式輸送機(jī)。測試設(shè)備的主要部分如下(圖 1 )。1) 試件如皮帶機(jī)一樣被放置在承載托輥上。2) 兩承載托輥之間的距離與真正皮帶機(jī)相似。3) 試件水平放置使垂度與真實(shí)皮帶機(jī)上一致。4) 試件由螺母予以張緊。5) 縱向激勵由激振器產(chǎn)生。由TEAC MR 30膠帶記錄數(shù)據(jù)，由HP3562A動態(tài)信號分析器分析試驗(yàn)數(shù)據(jù)