Theoretical and Experimental Studies of Whirling Speeds of Pultruded Composite Shafts

Project Title

Theoretical and Experimental Studies of Whirling Speeds of Pultruded Composite Shafts

Project Area of Specialization Mechanical EngineeringProject Summary

Whirling of Shafts apparatus (TM1001) shows how shafts vibrate transversely and ‘whirl’ at a certain rotation frequency. This helps engineers understand possible problems with long shafts and allow for them in their designs. The equipment is in two parts and fi ts on a bench or desktop. The main part is a solid alloy frame that holds a variable speed motor which turns the horizontal test shaft. Two bearings hold the shaft, one bearing at the ‘driven end’ and the other bearing at the ‘tail end’ of the shaft. The tail end bearing slides in its housing to allow the shaft length to change as it ‘whirls’. Similar to a beam on two simple knife-edge supports, both bearings allow free angular shaft movement (free ends condition). Also supplied with the equipment are extra bearings that restrict angular movement when fi tted, to give ‘fi xed ends’. Two movable nylon bushes help to prevent the shaft whirling amplitude from reaching excessive levels. A movable cord plate allows students to control the shaft in some experiments, to help reach the second mode whirl speed. A sensor at the driven end measures the shaft speed and sends its signal to the control and instrumentation unit display. A removable safety guard with magnetic interlock surrounds the shaft and only allows the motor to work when fi tted. The separate control andi nstrumentation unit contains the drive for the variable speed motor and a display to show the shaft speed. It also includes a trigger output for the optional stroboscope. When used in a darkened classroom, the optional stroboscope gives an impressive demonstration of how the shaft shape changes as it reaches its whirling speeds. Supplied with the apparatus is a set of test shafts of diff erent length and diameter to show how these properties aff ect whirling and its ‘critical speed’. Also supplied is a set of weights to show how concentrated loads aff ect whirling. One weight has an extra hole to make it an eccentric load. This helps to show the phase diff erence between the load and the defl ection (you need the optional stroboscope to see this clearly).

Project Objectives

By the study of various literature reviews, it has been concluded that, this method of acquiring vibration data with the help of VIBSCANNER and then analyzing its spectrographs is very latest as compared to ancient times when these equipment’s were not available for vibration analysis of the whirling shafts and other rotating machinery. This is a modern technique to record the vibration characteristics of stationary as well as rotating parts of the system. By knowing the amplitude and natural frequency of the shaft to reduce the failure on the rotating shaft before the break down occurs on it. This can be helpful for the rotating parts of various machines or instruments which are running at very high speed. Now, this can be easily judged that up to which diameter and rotating speed the system is running safely with which a major breakdown can be prevented to occur. As we analyze the various spectrographs of amplitudes and frequencies of the shaft with changing parameters in the running condition of the system to compare its values. So, from the above study some facts can be concluded in the study of vibrations which might be very helpful for condition monitoring of rotating parts of machines and other mechanical installments. These may be giving as below

Project Implementation Method

Experimental analysis plays most important role in the research work. Experimental approach is being carried out and justify the theoretical and experimental analysis or by using different techniques. Experimental setup is being be made to measure the natural frequency and amplitude of the different diameter shafts To study the dynamic characteristics of the specimens including parameter like natural frequencies and amplitudes of the shaft various combinations of shaft diameter and rotating speeds are made. The lengths of all the shafts are taken equal. For changing speeds of the rotating shafts, speed variator has been taken into consideration.

Benefits of the Project

Vibration is a mechanical phenomenon in which oscillation occurs about equilibrium points. It is a displacement or movement in one direction and then back to again in the opposite direction. For example, the musical Instruments that may be plucked. With the passage or Era of time vibration has become major issue for the machinery and industries. Everyone knows that the vibration has some merits and demerits. But in modern technology age we can never eliminate whole vibrations in a machine. Some specific amount of vibration depending upon the quantity always remains there. This paper tries to focus on the analysis of the effects produced on the whirling shaft of different diameters while running at the different speeds. The objective of the study is to find the effect of different diameters rotating at different speeds on the amplitude and natural frequency of the shaft. Also forced vibration analysis of the shaft is done. Some parameters are also studied that are responsible for the failure of the system before breakdown, and the effect of the resonance frequency of the shaft. Using the vibscanner instrument a spectrograph is produced to the study the effects on amplitude and natural frequency of the whirling shaft. vibration factors on it. This spectrograph is transferred to computer with the help of OMNITREND to better analyze the data

Technical Details of Final Deliverable

• Basic whirling demonstration • The eff ect of shaft length and diameter • The eff ect of end conditions (fi xings) • Loaded shaft (one and two masses) • Eccentric loading

Electrical supply: 220 VAC to 240 VAC phase to neutral or phase to phase 50 Hz to 60 Hz at 1 A Note: Please state your electrical supply type on order. Bench or desktop space needed: 1500 mm x 800 mm Note: This equipment can create large vibrations, so you must use it on a strong, good-quality laboratory bench.

Operating Conditions Operating environment: Laboratory or classroom S t o r a g e t e m p e r at u r e r a n g e : –25°C to +55°C (when packed for transport) O p e r at i n g t e m p e r at u r e r a n g e : +5°C to +40°C O p e r at i n g r e l at i v e h u m i d i t y r a n g e : 80% at temperatures < 31°C decreasing linearly to 50% a

Nett dimensions and weight: Main unit: 1460 mm long x 270 mm high x 400 mm front to back and 35 kg Control and instrumentation unit: 400 mm wide x 180 mm high x 360 mm front to back and 8 kg Packed volume and weight: Approximately 0.35 m3 and 50 kg Mild steel shafts: 1 x 3 mm diameter x 750 mm 1 x 3 mm diameter x 900 mm 1 x 6 mm diameter x 900 mm 1 x 7 mm diameter x 900 mm (for use with the weights) Weights: 2 x 300 g 1 x 400 g 1 x 300 g with hole (eccentric weight)

Final Deliverable of the Project Hardware SystemCore Industry HealthOther Industries Transportation Core Technology OthersOther Technologies Shared EconomySustainable Development Goals Decent Work and Economic GrowthRequired Resources

Item Name	Type	No. of Units	Per Unit Cost (in Rs)	Total (in Rs)
			Total in (Rs)	52900
Inductive proximity sensor	Equipment	1	1400	1400
Arduino Uno x 2	Equipment	1	1000	1000
TFT screen	Equipment	1	2000	2000
ADXL accelerometer	Equipment	1	450	450
Motor Speed Controller DC	Equipment	1	1600	1600
DC high speed spindle motor	Equipment	1	3500	3500
Universal Bearings x 2	Equipment	1	4000	4000
Flexible sockets x 3	Equipment	1	1800	1800
Shaft bushes x 6	Equipment	1	2400	2400
Sheet Metal And steel materials	Equipment	1	7500	7500
Structural fabrications	Equipment	1	20000	20000
Rubber beading and paddings	Equipment	1	250	250
Miscellaneous items	Miscellaneous	1	5000	5000
Thesis Report	Miscellaneous	1	2000	2000