03-08-2013, 01:52 PM
LED-LDR Based Railway Crack Detection Scheme
LED-LDR Based Railway.pdf (Size: 974.69 KB / Downloads: 398)
Basic rationale:
Transport is a key necessity for specialization that allows production
and consumption of products to occur at different locations. Transport has
throughout history been a spur to expansion as better transport leads to
more trade. Economic prosperity has always been dependent on increasing
the capacity and rationality of transport. But the infrastructure and
operation of transport has a great impact on the land and is the largest
drainer of energy, making transport sustainability and safety a major issue.
In India, we find that rail transport occupies a prominent position in
providing the necessary transport infrastructure to sustain and quench the
ever-burgeoning needs of a rapidly growing economy. Today, India
possesses the fourth largest railway network in the world. However, in
terms of the reliability and safety parameters, we have not yet reached truly
global standards. The principal problem has been the lack of cheap and
efficient technology to detect problems in the rail tracks and of course.
Statistics to justify the problem:
The Indian Railways, today has 113,617 kilometres (70,598 mi).of
total track over a route of 63,974 kilometres (39,752 mi) and 7,083 stations.It has the world's fourth largest railway network after those of the United
States, Russia and China. The railways traverse the length and breadth of
the country and carry over 30 million passengers and 2.8 million tons
of freight daily. It is the world's second largest commercial or utility
employer, with more than 1.36 million employees. Despite boasting such
impressive figures, we find that Indian rail network is still on the growth
trajectory trying to fuel the economic needs of our nation.
Survey of contemporary solutions:
The prompt detection of the conditions in rails that may lead to a
crack or rather a break now plays a critical role in the maintenance of rails
worldwide. The understanding of these mechanisms is constantly
improving and the evolution of a range of complementary (Non Destructive
Testing)NDT techniques has resulted in a number of tools for us to choose
from. Among the inspection methods used to ensure rail integrity, the
common ones are visual inspection, ultrasonic inspection and eddy current
inspection. Ultrasonic Inspections are common place in the rail industry in
many foreign countries. It is a relatively well understood technique and was
thought to be the best solution to crack detection.
Justification of the proposed solution:
As mentioned in the literature survey, we find that the commonly
employed rail crack detection schemes in foreign countries are usually
ultrasonic or eddy current based techniques which boast of reasonably good
accuracy in most cases. However, the one characteristic which the above
mentioned methods have in common is that they are both expensive, which
makes them ineligible for implementation in the current Indian scenario.
Also, ultrasonics can only inspect the core of materials; that is, the method
cannot check for surface and near-surface cracking where many of the
faults are located. In addition, ultrasonic inspection of rails is usually
restricted to low speeds of around 20-30mph, which limits the viability
of testing many tracks regularly.
Advantages of the proposed solution:
The currently existing technical solutions offered by many companies
in the detection of cracks in rails involve periodic maintenance coupled
with occasional monitoring usually once a month or in a similar timeframe.
Our project however possesses the inherent advantage of facilitating
monitoring of rail tracks on a daily basis during nights when the usual train
traffic is suspended. Further, we believe that the simplicity of our idea and
the easy-availability of the components make our project ideal for
implementation on a large scale with very little initial investment. The
simplicity of our project ensures robustness of operation and also the
design has been carefully modified to permit rugged operation. Another
disadvantage that can be attributed to the conventional commercially
available testing equipments is that they are heavy which poses a practical
limitation. However, this important disadvantage has been rectified in our
project as the design is simple and sensible enabling the device to be easily
portable.
Light Emitting Diode:
A light-emitting diode (LED) is a semiconductor light source. LEDs
are used as indicator lamps in many devices and are increasingly used for
other lighting. Introduced as a practical electronic component in
1962, early LEDs emitted low-intensity red light, but modern versions are
available across the visible, ultraviolet and infrared wavelengths, with very
high brightness.
When
a
light-emitting diode is
forward biased (switched
on), electrons are able to recombine with electron holes within the device,
releasing energy in the form of photons. This effect is
called electroluminescence and the color of the light (corresponding to the
energy of the photon) is determined by the energy gap of the
semiconductor. LEDs are often small in area (less than 1 mm2), and
integrated optical components may be used to shape its radiation pattern.
LEDs present many advantages over incandescent light sources
including lower energy consumption, longer lifetime, improved robustness.