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Composites aiding physically challenged
Atul Mittal and Sangeeta Nangia
The Advanced Composites Mission of TIFAC launched
a project on developing ‘composites artificial
limbs for the physically handicapped’ in collaboration
with M/s Mohana Orthotics & Prosthetic Centre,
Chennai and the Department of Aeronautical Engineering,
Madras Institute of Technology (MIT). The below-the-knee
endoskeleton artificial limbs are lighter in weight
and better in appearance, and have improved gait
for the patients.
Artificial limbs are very effective in restoring normal
movement for victims of trauma, accidents and other amputees.
In addition to restoring lost functions, artificial limbs
can bring about cosmetic improvements for the patient
and build his self-confidence. Modern artificial limbs
have come a long way from the old wooden exoskeleton
types of artificial leg. The conventional exoskeleton
types are heavy and are not at all comfortable for the
patients. Advanced endoskeleton type artificial limbs
are now made from modern light materials and often incorporate
electronic and pneumatic mechanisms. Using technological
advances of space-age plastics such as composites, the
challenges of fabricating limbs that are considerably
lighter, stronger and more durable than the traditional
ones have been met. With rapid development of new plastics
and metal alloys such as co-polymers, composites, titanium
etc, there has been a significant headway to make lighter
and stronger artificial limbs with improved bio-compatibility.
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In
order to cater to societal needs with new technology, the
Advanced Composites Mission of TIFAC
has launched a
project on developed ‘composite artificial limbs
for the physically handicapped’ in collaboration
with M/s Mohana Orthotics and Prosthetic Centre in Chennai.
The Department of Aeronautical Engineering at the Madras
Institute of Technology (MIT) has been extending technology
support in terms of design, prototype development and complete
testing of composite limbs. The components have been designed
on the basis of theoretical analysis using CAD software
(CSA/NASTRAN) for typical compression loads at different
angles, momentary impact etc. The below-the-knee endoskeleton artificial limbs developed
under the project are lighter in weight, better in appearance
and have improved gait for the patients. This endoskeleton
limb consists of five parts: a FRP tubular structure
fabricated by filament winding of glass fibre in epoxy
matrix, top and bottom connectors made by injection moulding
of glass filled nylon, a polyurethane foot with composite
keel embedded in it and a polypropylene socket to accommodate
the amputee stump. A very innovative design approach
has been adopted for designing FRP keel for providing
improved strength and flexibility in the foot piece.
The socket made of polypropylene is patient specific
and does not create any problems like pressure sores
even for diabetic patients. All the five parts and the
socket are adjustable to meet individual requirements
and take care of static and dynamic alignment patterns.
The
evaluation of components and also of the entire endoskeleton
assembly for compressive and bending strength
is being carried out. A simulated endurance test is
being conducted for five-year service life of the artificial
limb considering an average stance duration of 0.5
seconds
for normal gait and three hours of walking time per
day. A 3-D modeling of the endoskeleton with all the
embedded
components considering actual properties of various
materials was also carried out. Such below–the-knee
artificial limbs would cost Rs 6,500 only as against
Rs 40,000 for
the imported ones.
The indigenously developed artificial limb looks like
a natural foot; it is sturdy, durable, waterproof and
made of locally available material. The unique design
of this composite limb permits walking, cycling, climbing
and even driving a vehicle by a person otherwise physically
challenged.
On
the occasion of TIFAC’s 12th Annual Day on
February 10, 2000, in New Delhi four such limbs were
handed over to handicapped persons by the Honourble Minister
for HRD and Science & Technology, Dr. Murli Manohar
Joshi, in the presence of Dr. APJ Abdul Kalam, Principal
Scientific Adviser to Government of India and Chairman-TIFAC,
and Prof. VS Ramamurthy, Secretary-Department of Science & Technology.
A whole lot of innovative technology inputs from MIT
have been instrumental in developing user friendly and
world-class artificial limbs with an excellent market
potential in India and abroad.
Source: TIFAC News, Vol. 8 No.3 July-Sep 2000
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