EFFECTS OF ROTATIONAL SPEED, CENTER DISTANCE AND DIAMETER RATIOS ON THE DYNAMIC RESPONSE OF PULLEY-BELT SYSTEM DEPENDS ON VIBRATION ANALYSIS

This paper presents the dynamic response related to varying in indispensable parameters of pulley-belt system, a manufactured pulleybelt system has been built and experimental results have been obtained and analyzed accurately which reveal the effects of these parameters on indicated system. Manufactured system assembled from heavy steel structure, variable speed DC motor, speed measurement tool (tachometer), two shafts of 25 mm diameter, four pillow block ball bearings, V-belts and pulleys with different diameters (10, 15, 20, 25) cm. The fabricated system presents mechanical characteristics likes serial changing in rotational speed (500 to 2000) rpm, diameters ratios (1 to 2.5) and center distance (27 to 120) cm. accelerometer ADXL335 (3-axis) mounted on bearing brackets of drive and driven shafts and connected to Arduino type mega 2560 (microcontroller) which sending the data of vibration to the laptop in order to display it in Sigview software as a time and frequency domain band by FFT (fast fourier transform). Results showed the effects of change the values of rotational speed, center distance, and diameters ratios on vibration response of pulley-belt system.


INTRODUCTION
Machines are very essential in our lives and it simplified the people's works. Now we use machine to the maximum extent in our daily activities, machines are becoming more complex, faster, intricate, and delicate and production process that are interlinked and automated. The efficiency of machines depends on many factors like raw materials, accuracy, enduringness, intelligent design…etc. Pulley-belt machinery is a basic part in any industry, which need to appropriate design and calculate pulley's diameters, belt length and radius ratio before manufacturing. In this paper an experimental investigation of the dynamic response of pulley-belt system were studied using vibration monitoring analysis the effects of pulley center distance, r.p.m, Indrajit Chowdhury [2] presented Dynamic response of machine foundations considering soil damping and embedment paper proposes a method based on which a number of such deficiencies as cited above can be circumvented. Chitresh Nayak et al [3] Presented design and development of machine fault simulator (MFS) for fault diagnosis. This paper show how to industry and construction of machine contains most parts that get damaged and vibrate over time in plurality machines like motor .Gregor C epona et al [4] presented introduction of damping into the flexible multi body belt-drive model, Good agreement between the numerical result and the experimentally obtained data was found. Finally, the applicability of the belt-drive model was presented in a comparison with the pinned-pinned beam model. Chyuan-Jau Shieh [5] studied the effect of angular speed on behavior of a V-belt drive system. this paper shows the effect of rotate speed on the 3D friction contact surface behavior between v-belt st13mm and pulley Abdulshakoor et al. [6] Used vibration analysis for faults in V-belt 13mm, three faults are used side-cut-out, side-cut-in and loose. [7] monitored vibration for defect diagnosis on a machine tool (comprehensive case study). S.Ojha et al. [8] investigation the performance monitoring of vibration in belt conveyor system, this paper presents the vibration related faults diagnosis and maintenance of belt conveyor system. S. R. Algule et al [9] presented experimental study of unbalance in shaft rotor system using vibration signature analysis. Puneet Bansal et al [10] deals with monitoring and analysis of vibration signal in turning machine with one type of cutting tool and sample (mild steel and brass). B. Kiran Kumar et al [11] presented determination of unbalance in rotating machine using vibration signature analysis. Pravesh and Akhilesh [12] focused on fault diagnosis of ball bearing using time domain analysis and fast Fourier transformation. Arko Djajadi et al [13] Presented monitoring vibration of a model of rotating machine. The case study was a rotate shaft with balance and unbalance by add and reduce mass of balance. Sakshi Kokil et al [14] studied detection of fault in rolling element bearing using condition of monitoring by experimental approach. Dimitris et al [15] Practically studied maintenance topics of mechanical drivers and faults diagnosis of machine elements. This paper presents vibration monitoring using as a design technique, Results were taken from many experiments at different dimensions and values of center distance, radius ratio and speed, at constant tension 30N, and V13 belt type.

EXPERIMANTAL SETUP AND VIBRATION MEASURMENT
Machine was manufactured with personal experience by researchers, it consisted of heavy structure steel frame, steel pulleys, DC motor variable speed, shafts, pillow bearings ,tachometer and tools for precision measurements as shown in figure 1. Page 576

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Copyright  2017 Al-Qadisiyah Journal For Engineering Sciences. All rights reserved.
Vibration sensors ADXL335 (3axis accelerometer) [16] with sensitivity of 300 mv/g, this sensor can read a range of 0.5 Hz to 1600 Hz for the X and Y axes, and a range of 0.5 Hz to 550 Hz for the Z axis output, sensors mounted geometrically on bearing brackets of drive and driven shafts .Y-direction of sensor will be with axil direction of shaft .X and Z will be radial on shaft horizontal and vertical respectively as show in Figure2 Sensors connected to Arduino type mega which have CPU 16 MHz sending the data of vibration after calibration process to the laptop to display it in software model (Sigview) as a time and frequency domain band by FFT (fast Fourier transform). To know the magnitudes of rotate speeds need to rpm gauge (Tachometer DT-2234A) photo type with reflective tape on rotate parts as shown above. Initial tension should be at a constant value of 30N in each cases, this value determined as installation tension (optimal) by the manufacturing company (Super Star belts), also this magnitude investigated by tensile test device and PID-ANSYS, data of tensioned belt deals as hyper-elastic material by Moony-Revilin model.

VIBRATIONS ANALYSIS
Vibration can be used to detect and diagnose problems on rotating equipment ranging from electric motors to large crushing machines used for mining and processing. Because each part is in a case of motion has an individual frequency. FFT has important features to show for each part its frequency, also frequency of faults which are unavoidable due to the errors and accuracy in manufacturing or May temporarily develop in the system due to the operating conditions. The most encounter faults existing in the pulley belt system described in the following table [17] . Having in mind that the fundamental frequency is shaft revolution in rpm 1X. Page 578 Copyright  2017 Al-Qadisiyah Journal For Engineering Sciences. All rights reserved.
To recognize healthy conditions from bad or faulty conditions of operating machines, time domain waveform will be as shown in Figure 3. Faulty conditions waveform will give incomprehensible signal and more peaks in FFT at different frequencies. While at good conditions wave form will be consistent and sinusoidal often. While at a good conditions waveform will be consistent, sinusoidal often, and low and low number of peaks in FFT will appear. Page 579 Copyright  2017 Al-Qadisiyah Journal For Engineering Sciences. All rights reserved.

VIBRATION MEASUREMENT TEST
Three cases of change parameters each one has four results which will be existed the dynamic response of change each parameter separately, the following table illustrates the methodology.Where: (C) the center distance between drive and driven shafts, (I) radius ratio, (N) rotating speed of motor in rpm, (Ti) initial belt tension. It is necessary to check belt-resonance state which in FFT shows high peaks at 1X in the radial directions. 18N initial tension, 1500 rpm (25Hz), 10x10 cm pulleys diameters, and center distance 37 cm. figure below of stroboscope camera picture shows belt resonance state. Resonance state depends on belt initial tension, center distance and rotating speed.

RESULTS AND DISCUSSIONS
Case 1:-running speed changes : Figures (5),(6),(7) show response due to rpm increases at (X,Y,Z) direction respectively, meanwhile the results show general increase in any peak of each founded fault as rpm increase, and it gave high increase in horizontal directions (X 1 , X 2 ). Page 580

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Copyright  2017 Al-Qadisiyah Journal For Engineering Sciences. All rights reserved.  Page 581 Copyright  2017 Al-Qadisiyah Journal For Engineering Sciences. All rights reserved.  Case 2:-center distance changes: Figures (7), (8), (9), shows increasing in vibration due to increase length of belt (center distance), and there is signification change in FFT peaks due the change center distance cases with center distance values: (37, 47, 57, 67) cm, this behavior happened while no resonance state done in the conditions of (1500 rpm, pulleys 10x10 cm, initial tension 30N) at above center distance.