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296 || AWSAR Awarded Popular Science Stories - 2019
How Does Lightning Affect the Aircrafts and Wind Turbines?
Ms. Dhanya T. M.*
Email: dhanya.m@aero.iitb.ac.in
Lightning is the sudden electrical discharge between two points of opposite polarity. The electric discharge is so high
that every year it kills people and livestock. The data collected by NASA’s lightning image sensor between 1995 and 2002 shows that the lightning flashes per square kilometre per year can go as high as 70 in certain regions of the earth (https://geology.com/articles/lightning- map.shtml). Various other studies also show that the objects situated in the lower altitudes (2-5 km) of high lightning activity areas are more likely to be affected by lightning. So, the ascending and descending aircrafts as well as wind turbines are more likely to be struck by lightning.
When struck by lightning, if the whole body of the aircraft is made up of metal
(generally aluminium), the electric current enters the body and exits very fast as metal is a good electrical conductor. But, this is not the case if the structural material is not a metal. In the recent past, aircraft and wind turbine industries started using “composite material” for their structural applications as it has superior qualities like high strength to weight ratio, and corrosion resistance. Carbon fiber reinforced polymer (CFRP) is the most commonly used composite material by these industries. In CFRP, the carbon fibers are embedded inside a polymer (for example, epoxy) to form a sheet called lamina. The thickness of a lamina can be as slight as 0.1 mm. The laminae are stacked together to form a thicker sheet called laminate, which can be directly used in making body parts. The
* Ms. Dhanya T. M., PhD Scholar from Indian Institute of Technology, Bombay, is pursuing her research on “Response of Carbon Fiber Reinforced Polymers to Lightning Strike”. Her popular science story entitled “How do to how does Lightning Affect Aircrafts and Wind turbines?” has been selected for AWSAR Award.