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Technology has become an integral part of life due to which there are new innovation and job created daily. This technology has changed the way we live it has bought improvement in everything around us, that also includes the field of travel also, because the need for men and material has increased in the recent years. The transport plays a major role in the functionality of industries, because it provides raw material and it helps in transport of the finished goods after production also.
One of such major transport modes is railways, it helps in speedy and mass transportation of both men and materials for the industries. But due to the daily usage and poor maintenance of railways track, it may lead to formation crack or breakage which will stand as a barrier for safety.
As the railways network present in a nation is very large, manual inspection of each and every track is impossible. So, varies method are present for inspection of the railways track which includes both destructive and non- destructive techniques.
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As the destructive technique needs collection of samples mostly Non-Destructive Techniques (NDT) methods are used. One of such method is ultrasonic testing method which helps in testing of railway track without any loss. In this method high frequency sound used for diagnosing of track which gives a highly précised value. For the reduction of time and human effort, this method is combined with live robot for the purpose of automatic inspection. This helps in development of the solution for any problem that is been encountered.
The Indian Railways has one of the largest railway networks in the world, crises-crossing over 1, 15,000 Km in distance all over India.
However, with regard to safety Indian Railways are not up to the global standards. According to recent survey 25% of track length is in need of replacement due to the development of cracks on it. Manual detection of cracks not fully effective owing to much time consumption and requirement of skilled technicians. Nondestructive testing (NDT) is the process of inspecting, testing, or evaluating materials, components or assemblies for discontinuities, or differences in characteristics without destroying the serviceability of the part or system.
Other tests are destructive in nature and are therefore done on a limited number of samples, rather than on the materials, components or assemblies actually being put into service. But discontinuities and differences in material characteristics are more effectively found by NDT.
The types of test methods are varying with the type of penetrating medium and or the equipment used to perform that test. The current NDT methods are:
Among those test methods, the six most frequently used test methods are MT, PT, RT, UT, ET and VT. In this project we used Ultrasonic method for Railway inspection.
Ultrasonic Testing (UT) uses high frequency sound energy to conduct examinations and make measurements used for flaw detection or evaluation, dimensional measurements, material characterization, etc., A typical UT inspection consists of pulsar/receiver, transducer, and display devices. A pulsar/receiver is an electronic device that can produce high voltage electrical pulse. Driven by the pulsar, the transducer generates high frequency ultrasonic energy.
The sound energy is introduced and propagates through the materials in the form of waves. When there is a discontinuity (such as crack) in the wave path, part of energy will be reflected back from the flaw surface. The reflected wave signal is transformed into electrical signal by the transducer and is displayed on a screen. In the applet below, the reflected signal strength is displayed versus the time from signal generation to when an echo was received. From the signal, information about the reflector location, size, orientation and other features can sometimes be gained.
Advantages of Ultrasonic Testing:
Limitations:
Calculation Of Design Torque:
𝑇 = 𝐹 ∗ 𝑅
Where T refers to Torque,
F refers to Force,
Force = Mass ∗ Accelaration due to gravity
𝐹 = 10 ∗ 9.81 = 98.1𝑁
R refers to Radius 0.0375m,
Torque = 98.1 × 0.0375
Torque= 3.67 N-m.
Power Calculation of the Motor:
𝑃 = 𝑉 ∗ 𝐼
Where ‘P’ refers to Power,
‘V’ refers to Voltage, ‘I’ refers to Current.
Here we have used Battery with 12Volts, 3Ampere.
𝑃𝑜𝑤𝑒𝑟 = 12 ∗ 3 = 36𝑊𝑎𝑡𝑡𝑠
Speed Calculation of a Motor:
𝑃 =
2𝜋𝑁𝑇
60
Where P refers to Power W,
T refers to Torque N-m,
N refers to speed of the Motor.
N= 60∗𝑃
2𝜋𝑇
= 36∗60
2𝜋∗1.839
Speed N = 93.7 rpm.
During the selection of motors which is capable of producing enough torque to drive the robot, it is always necessary to calculate the force applied between the tire and inclined surface to move a robot.
Total Tractive Effort, 𝑇𝐸 = Force necessary to overcome rolling resistance + Force necessary move a vehicle upon a slope + Force necessary to accelerate to final maximum speed in desired time.
Gross vehicle weight, 𝑅𝐺 : 10 kg(98.1 N)
Weight on each drive wheel : 24.5 N
Radius of wheel/tire 𝑅𝐷 : 0.0375m (37.5 mm)
Preferred top speed 𝑆𝑀 : 0.1 m/s
Preferred acceleration time : 5S
Maximum incline angle, α : 20
Working surface : Dirty/sandy
Determination of force necessary to overcome rolling resistance:
Rolling resistance is the force necessary to drive a vehicle over a particular surface.
Rolling Resistance (RR) = gross vehicle weight × surface friction
= 98.1 × 0.037
RR = 3.62 N
Determination of force necessary to move a vehicle upon a slope:
Grade resistance is the amount of force necessary to move a vehicle up a slope.
Grade resistance (GR) = gross vehicle weight × sin α
= 98.1 × sin 20
GR = 3.423 N
Force to accelerate to final maximum speed in preferred time:
Acceleration force is the force necessary to accelerate from a stop to maximum speed in a desired time.Acceleration force
(AF) = (gross vehicle weight × preferred maximum speed) /
(9.815 × time required to achieve a maximum speed )
98⋅1∗0⋅1
98.1∗5
= 0.2𝑁
AF = 0.2 N
The total tractive effort is the sum of the force necessary to overcome rolling resistance, force necessary to move a vehicle upon a slope and force necessary to accelerate to final maximum speed in preferred time.
Total Tractive Effort (TE) = 3.62 + 3.423 + 0.2 = 7.243N
TE = 7.243 N
To verify the vehicle will perform as designed in regards to tractive effort and acceleration , it is necessary to calculate the required wheel torque based on the tractive effort.
Wheel Torque, TR (N-m) = Total tractive effort × Radius of
Wheel × Resistance Factor
The resistance factor accounts for frictional losses between the wheels and their axles and the drag on the motor bearings.
Typical value range between 1.1 and 1.15.
TR = 7.243 × 0.0375 × 1.1
TR = 0.298 N-m.
Reality validation of Motor wheel torque:
To verify that the vehicle can transmit the required force from the drive wheel to the ground, the maximum tractive torque a wheel can transmit is equal to the normal load times the friction coefficient between the wheel and the ground times the radius of the drive wheel.
The maximum tractive torque = weight on the drive wheel*µ*
Radius of drive Wheel/tire (m)
= 24.5 ∗ 0.45 ∗ 0.0375
𝐓𝐦𝐚𝐱 = 0.413 N-33388m.
Since the total wheel torque calculated is less than the sum of the Maximum Tractive Torques for all drive wheels the slipping will not occur.
Ultrasonic test methods provide quantitative information regarding thickness of the component, depth of an indicated discontinuity, size of discontinuity etc. The output data is viewed by means of small web camera which is collected and the defects are identified by means of image processing system. It involves comparison of predefined data with acquired data and results are accomplished. When a machine detects the crack or a discontinuity in the railway track the high peak was shown in the machine that informs the detection of a crack. Due to the sensibility of the Ultrasonic testing even a minute crack in the inside of the track can be selected.
This project is made with pre-planning, that it provides flexibility in operation. This innovation has made the more desirable and economical. This project “Employment Of Ultrasonic Flaw Detection In Testing Of Railway Cracks” is designed with the hope that it is very much economical and help full to the Indian Railways and Public Safety. By using this automated control robot, testing can be done on both the top and sides of the railway tracks and also human work is reduced. Along with that ultrasonic testing method increases the accuracy of crack detection and results are viewed and stored by means of image processing system. The robot can also be programmed for different length of the tracks and testing can be done and the cracks are predicted in an easier way.
Employment Of Ultrasonic Flaw Detection In Testing. (2024, Feb 22). Retrieved from https://studymoose.com/document/employment-of-ultrasonic-flaw-detection-in-testing
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