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320 || AWSAR Awarded Popular Science Stories - 2019
adhesive nature and it can distribute loads on a large area. Now, as the molten polymer cools it solidifies and a layer is formed known as lamina of FRPC. According to requirement, a number of these layers are stacked and an engineered material forms called as FRPC .The term ‘engineered’ associated with the composite material signifies that the properties of this material can be altered or achieved by changing the fiber directions in the composite.
Coming to incorporating smartness into these composites. The term smartness signifies the involvement of materials, which reacts to some external stimuli like pressure, temperature, electric potential and deforms in a particular sense. For example, consider the lighter we use in our kitchen to ignite the LPG (gas) stove. The lighter has a material called as quartz crystal which shows a phenomenon of generation of electric potential on one its pair of opposite faces, on the application of pressure on another pair of opposite
faces. This phenomenon is
called as piezoelectricity. Piezoelectricity is a reversible
phenomenon, that is, on
application of electric voltage
on the one set of opposite
faces the pressure can be felt
on other set of faces. While
using the lighter, we press the
central rod which applies the
pressure on the quartz crystal
and the crystal produces
electric voltage which, in turn,
produces the spark to ignite
the gas stove. In the current
research, Lead Zirconate
Titanate (PZT) fibers which also
show piezoelectricity are used
along with the carbon fiber.
The smart composite formed out of these fibers is fabricated as a patch. This patch
when applied on the structural components will ensure load on the components and make the PZT fibers to deform and hence to generate the electric voltage. This electric voltage will be compared with the standard calibrated stored voltage data. If the output data is within the safe limit the structure is said to be safe, if not the components can be repaired or changed in due time to avoid any accidents. This is not as simple as it looks. The broad research objective is, of course, of fabricating the smart composite patch but this broad objective is to be achieved by completing small complicated objectives.
Let’s discuss these small objectives in details. Objective 1. To study the effect of interaction between two fibers (carbon-carbon, carbon PZT, PZT-PZT) through the matrix. This objective is necessary to study the behaviour of fibers under different loading conditions. Also, this objective will give an insight into how the
loads get transferred through the matrix in the vicinity of the fiber if it gets broken. This is a crucial study because if a fiber in a composite gets broken the load-carrying capacity of the fiber becomes zero and, hence, the capacity of the whole composite decreases. Further loading will make other fibers to carry the burden of the load of the broken fiber and, hence, increases their chances to get overloaded and break. Objective 2. To study the effects of the arrangements of fibers in a composite. This objective will guide you to get the optimized arrangement of fibers both carbon and PZT. The fiber arrangement has an important role in fabricating the patch, as the patch has to
All of us have broken a stick into two if we bend it, but the same stick if we pull along
its length is difficult to break. The same kind of behaviour is observed in the fibers of many materials, that is, they are strong in one direction and week in other. To take the advantage of the high strength of fibers in one direction, the number of fibers is arranged in a particular direction where the strength is required and a molten polymer (resin) generally called as matrix is poured to hold all the fibers in place.