Vibration Analysis of a Motorbike to find Transmission to Hands and Back

Muhammad Usman Assignment 2 2015-ME-12
Mechanical Vibration 7th
Semester Page 1 of 29
Vibration Analysis of a Motorbike to find Transmission to Hands
and Back
Student Details
Your Full Name Muhammad Usman
Registration No. 2015-ME-12
Group Details
Baran Shafqat 2015-ME-01
Abstract
This report is the demonstration of the analysis of Vibration and its transmission to the various
parts of the human body. In the 70 cc motorbike the source of generating such kind of vibration is
Engine and it is transmitted to the parts that are in contact with the engines and further the
vibrations are transmitted to the parts of human body when a person is riding it. In this study, three
different accelerometer were used by placing them at three different position i.e. engine, handle
and seat of the motorbike and vibrations were analysed at different throttle positions for 4 gears.
For finding the maximum gear ratio and a throttle position against maximum vibrations, the
vibrations were recorded and the transmission was analysed using MATLAB software. Against 30
to 40 % throttle position the amplitude for accelerometer when placed at handle, seat and engine
was 27mm/s2
, 15mm/s2
and 45mm/s2
respectively. Similarly, against full throttle position the
results were 15mm/s2
, 19mm/s2
etc. the results for acceleration transmissibility raised from 40%
to 74% for seat and 17 to 30% for handle of the bike by changing gear ratio from 1 to 4.
1. Introduction
In machines the analysis of vibration is of greater concern. As vibrations imparts a major role in
the failure of system and in disturbing the human comfort so vibration analysis and its
transmissibility to the various parts of the contacted surfaces is very important. In this study both
vibrations and acceleration transmissibility are considered as along with the force the magnitude
of the transmission is also significant. The Engine in the motorbike is the source of vibration
because of the reciprocating motion of the piston in the cylinder and the motion of crank case
mechanism. These vibrations are then transmitted to the human spinal cord, back, legs and necks
etc. These vibrations are to be measured with the help of accelerometers by placing them at three
positions i.e. handle, seat and engine surface. And then at certain throttle positions the readings
are to be noted and further analysis is to be made against different gear ratio. It is then to analyse
that for what gear ratio the transmissions are maximized and meet the vibration standards as set by
International organization for standardization ISO, in order to check the comfort zones. And to
take measures of controlling vibrations and transmission ability factor from the systems, if any of
the uncertainty is seen deviating from the standards.

2. Literature Review
2.1. Details of the Accelerometer used in the Mobile Phone
Table 1 Accelerometers details
Bike Position Handle Seat Engine
Mobile Phone Name Samsung GT Samsung Galaxy C5 Samsung-SM-A
Model Number 19082 SM-C5000 SM-G920A
Build Number JZO54K.I9082XXAMF2 R28H717MZ5Z G920AUCU3BOJ9
Android Version 4.1.2 5.1.1 3.1.2
Kernel Version 3.0.31.1170506 ------------------ 3.10.61.5927475
Table 2 Features of accelerometer
Device Accelerometer
Application Installed Physics Tool Box Accelerometer
Version 3.1.2
Data Stored Multi sensor data files
Functions reports CSV files
Vibration Measuring Dimensions 3D- vibration measures
Rate of Sampling 5-100 samples per second
2.2. Vibration Transmissibility
The extent for measuring the vibration that is transmitted form the source to base of the system
when forcing frequency and natural frequency coincides is known to be as vibration
transmissibility[1]. The transmissibility of vibration in a system is measured in terms of
displacement and force transmissibility.[2]
In the experimental analysis there is a need of minimum vibration transmissibility so that the
comfort level of human being is to be achieved.
2.3. Transmission of Vibration to Human Body
Vibration severity in either machinery or human body is described by International Organization
for Standardization (ISO). It plays a vital role in providing the range of comfort zone for human
being and checking the level of severity of vibration for any system or machinery[3]. It also
provides a range for every parts of human body thus displaying acceptable level of vibration that
is required by the body for avoiding any dis comfortability.[4] Below here is the figure that
displays the acceptable range frequency by the human parts of body.

Fig. 1 Human body parts frequency ranges
2.4. Vibration Analysis Techniques
There are several methods/ techniques for the vibrational analysis of a system. Each technique has
its own features [5]. These techniques are as explained below Time Domain Techniques Frequency
Domain Time- Frequency Domain [6] in which the vibrations in a system are analysed. The
frequency and time domain of vibrational analysis demonstrates the how significant are the number
of vibrations in a system.
3. Experimental Setup
Motorbike of 70 cc was used for the conduction of the experiment. The reciprocating motion of
piston into the cylinder is the reason of high vibrations in the bike and also the motion of camshafts
and crank shafts are the other source of producing vibrations. Such vibrations, were recorded by
using accelerometers (whose descriptions are mentioned as above in the tables) thus placing them
at three different positions on the motor bike i.e. handle, engine and seat. The figures for the
experimental setup are shown as below: -

Fig. 2 Accelerometer on Handle of Bike
Fig. 3 Accelerometer placed on the Engine of Bike
Fig. 4 Accelerometer placed onto the seat of the Bike
4. Methodology
The vibration analysis was carried out on the 70 cc motor bike and three different accelerometers
were used for the purpose of taking the readings from the experimentation. Kinetic Sensor Pro was
the software that was used for taking all the reading by accelerometer. Measuring of the magnitude
of acceleration that is to be transmitted from the engine to various other parts of the bike, is needed
to be recorded. Initially the motorbike was oriented in a horizontal position and three
accelerometers were placed at the three different positions on to the bike. They were tied up with

the Handle, Seat and Engine of the bike in such a way that they remain fixed in their position i.e.
having no other motion in them. Z axes is to be set vertical and must be in parallel position for all
the accelerometers. The bike was then started and accelerometers were set on simultaneously.
Initially the accelerometers are to be calibrated for finding the results accuracy. After calibration,
first by putting the first gear the values of accelerometers were recorded by changing the throttle
position from zero to maximum slowly in correspondence to the measured time by the stopwatch.
Then the values are imported onto the Excel files using Sensor Kinetic Pro software. After this,
the gear is changed to second, third and fourth and by adopting the same method the values are
recorded by the accelerometers by altering the throttle position from 0 to 100% for certain interval
of time about 10 seconds for every positions i.e. Handle, Seat and Engine of the motorbike. At
least five number of trails are to be taken for attaining the better accuracy of the readings and then
average is obtained for good data. These values which are to be saved into the Excel files and
further then imported to the Analysis Software i.e. MATLAB software. By writing the code in the
Mat Lab the plots and charts are drawn about different axes for different sampling rates.
5. Results
Based upon the experimental data plotting was made onto the MATLAB and different trends were
obtained between different parameters by adopting certain number of trials. For a throttle position
ranging from 30 to 40% the magnitude of acceleration was found to be in a range of 27 to 30
mm/s2
along x- direction. By increment of throttle position say 70 to 80% the acceleration value
decreased to 10 to 14 mm/s2
. At higher gear ratio the value of acceleration also increases. Thus for
90% throttle the value of acceleration was 27 to 30 mm/s2
with a percentage increase of 24%.
These trends were obtained for the horizontal x – axis and almost similar trends were obtained for
the y-axis. Major fluctuations were seen along the z-axis. The value of acceleration was obtained
in a range of 55-60mm/s2
at a throttle position of 42- 45% while it decreases to 50mm/s2
at a
throttle position of 95 to 98% and it was seen for the fourth and fifth trials that the value of
acceleration come out to be 26mm/s2
in a full throttle. The design of bike seat should be in such a
way that minimum amount of transmissibility of force must be there so that the comfort of human
body must be in accordance.
5.1. Repeatability of the Experiments

Fig. 5 Graph of accelerations for engine
Fig. 6 Graph of accelerations for engine along y-axis

Fig. 7 Graph of accelerations for engine along z-axes
Fig. 8 Graph of accelerations for handle

Fig. 9 Graph of accelerations for handle along y-direction
Fig. 10 Graph of accelerations for handle along z-direction

Fig. 11 Graph of accelerations for seat along x-direction
Fig. 12 Graph of accelerations for seat

Fig. 13 Graph of accelerations for seat along z-direction
5.2. Gear Ratio 1
Fig. 14 Time domain response for seat

Fig. 15 Time domain response of engine
Fig. 16 Time domain response of Handle

Fig. 17 Time domain response

Fig. 20 RMS time domain vibration analysis

5.3. Gear Ratio 2
Fig. 23 Time Domain Response for Seat
Fig. 24 Time Domain Response for Handle

Fig. 25 Time Domain Response

Fig. 28 RMS Time Domain Response

5.4. Gear Ratio 3

5.5. Gear Ratio 4

Fig. 48 RMS Time Domain response
6. Discussion
After obtaining all the trends of the results from the MATLAB software, it was observed that there
have been shift of the magnitudes of acceleration for different gear ratio. Though, the magnitude
of acceleration was observed in all the three axes yet significant values were obtained in the z-
axes. Starting from the small gear ratio and moving towards the larger ones the amplitude of
acceleration also varied significantly. The transmission of the vibration was also a great concern
that have been transmitted from the Engine of the motor bike to the handle and seat of the bike.
Roughly a percentage of 20 – 30% more exposure of vibration transmission was observed to the
seat than the transmission observed to the handle of the bike. So for that, the seat of the bike must

be comfortable or may act as damper enough, in order to avoid any discomfort ability to the human
body.
Position of
Accelerometer
Handle
Gear Ratio 1 2 3 4
Time 3.50 1.75 4.10 7.0 5.0 2.75 3.20 3.1 5.4 8 8.2 7.15
Peak Vibration
Value
4.15 2.12 7.39 5.16 5.58 1.81 6.03 2.8 3.65 3.49 6.1 6.16
Acceleration
Transmissibility
0.11 0.15 0.19 0.238 0.241 0.056 0.30 0.1 0.18 0.154 6.16 0.32
Accelerometer
Position
Seat
Ratio of Gear 1 2 3 4
Time 3.50 1.75 4.10 7.0 5.0 2.75 3.20 3.1 5.4 8 8.2 7.15
Peak Vibration
Value
16.69 4.528 16.28 5.99 13.8 2.9 10.6 6.04 9.88 16.02 15.6 13.52
Acceleration
Transmissibility
0.429 0.322 0.419 0.27 0.59 0.14 0.54 0.30 0.50 0.704 0.76 0.71
Position Engine
Gear Ratio 1 2 3 4
Time 3.50 1.75 4.10 7.0 5.0 2.75 3.20 3.1 5.4 8 8.2 7.15
Peak Vibration
Value
38.89 14.08 38.89 21.67 23.1 20.8 19.7 18.3 19.6 22.7 20.5 19.2
Acceleration
Transmissibility
-- -- -- -- -- -- -- -- -- -- -- --
7. Conclusion
Vibration Analysis and the transmission with its contacted parts are of great significant in the
machines that are to be designed and machined. This is required to gain the comfort zone and avoid
any kind of failure in the system. The vibration analysis of the motorbike was done in order to see
the magnitude of acceleration and the transmissibility from the source to the other parts of the bike
was noticed only in the z axis. Though the bike reading were obtained to be multi-dimensional,
however the reading in the vertical were considered because of its greater values. And further its
effect was noticed on the human body. All the data from the accelerometer was imported into
MATAB software for plotting of amplitude for different number of trails. As by changing the gear

ratio from 1 to 4 the acceleration transmissibility was observed that increased from the range of 40
to 74% for the seat and 17 to 30% for the handle. Such data can be used further for improvising
the effect of transmissibility and vibration effect produced by the Engine on to the bike seat and
handle of motor bike, for attaining the comfort zone of human being and also avoiding any kind
of failure in the bike parts.
References
1. patilshiv407, vibration isolation. 2017.
2. Milovanović, On the relative and absolute transmissibility of a vibration isolation system
subjected to base excitation. 2008.
3. patilshiv407, Whole-Body Vibration Analysis Object (Human Body Vibrations Option).
2018.
4. Kiiski J1, H.A., Järvinen TL, Kannus P, Sievänen H, Transmission of vertical whole body
vibration to the human body. 2008.
5. Patidar, S. and P. Kumar Soni, An Overview on Vibration Analysis Techniques for the
Diagnosis of Rolling Element Bearing Faults. 2013.
6. GOLNARAGHI, W.Q.W.F., ASSESSMENT OF GEAR DAMAGE MONITORING
TECHNIQUES USING VIBRATION MEASUREMENTS. 2001.

Vibration Analysis of a Motorbike to find Transmission to Hands and Back

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Vibration Analysis of a Motorbike to find Transmission to Hands and Back

Similar to Vibration Analysis of a Motorbike to find Transmission to Hands and Back (20)

More from Muhammad Usman

More from Muhammad Usman (7)

Recently uploaded

Recently uploaded (20)

Vibration Analysis of a Motorbike to find Transmission to Hands and Back