Purpose of This Research

Simulating an Earth Quake

Damaging Cement Samples

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Time (s)

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Above, a sample of cement with built in probes and a 1/4 Inch damage

Sawing into samples imitate cracks formed due to Earthquakes or

movement.

(Below) Data shows the change in resistance after induced damage.

Resistance increases by approximately a thousand Ohms.

• Using Fourier analysis, the change in resistance is tracked and shows at what frequency the

sample reacts to. This can be used to indicate what causes the vibration, man or nature.

Above are samples of cement and CNT epoxy board samples

Cement samples are sawn into at 1/8th of an inch increments

CNT epoxy are drilled into at 1/8th of and inch diameter increments.

Using a four probe Agilent Ohm meter, the electrical resistance and its

change after damage are recorded

Time (s)

Time (s)

Time (s)

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Hypothesis

Cement samples are shaken at up to 7g forces in

order to simulate the stress of an earthquake.

Electrical resistance sees a spike when vibrated.

Violent vibrations correlate to greater resistance

changes.

Damaged and undamaged samples show nearly

equal amounts of resistance change.

Carbon Nanotube Epoxy Resin is regarded as the future of engineering.

It is the go-to material for light weight durability.

CNT Epoxy is rested for its resistance change due to damage. To

simulate impacts to vehicles that use this materials.

Samples are drilled at 1/8th of an inch increments in diameter

After physical testing, this model is simulated using COMSOL

Multiphysics, and damages with different shapes and orientations.

Using electricity to measure damage in materials, this

research aims to use an alternate method of locating and indicating

the magnitude of damage in what are called, piezo-resistive

materials. This method of detecting damage uses a time saving and

cost effective approach as opposed to traditional methods.

Methodology

Damaging piezo-resistive material will increase its electrical

resistance. Using several probes, damage can be located and

magnitude can be predicted without being seen.

Probes are placed on cement and Carbon Nanotube (CNT) epoxy

resin samples.

Using an Agilent four-wire Ohm meter, resistance is recorded.

The materials are damaged and the change in resistance are

recorded on several probes.

Using the changes in resistance recorded by the probes,

location can be determined.

• Hoan bridge collapse, Dec. 2000. One of many failed/failing structures in America

where collapse could have been preventable if properly monitored.

Carbon Nanotube Epoxy

The following potion of this research was to learn

if there was correlation between the shape of the

damage and its change to the board’s resistance. The

change in resistance is greatly influenced by its shape

and orientation and it soon became apparent that a

cylindrical hole was the most effective method of

increasing the resistance.

Cone damages were simulated and compared to

cylindrical holes of equal volume.

• The dimension of this truncated

cone are 0.25”-0.75”-

0.03”(Middle and Right).

Regardless of the orientation of

this cone a cylinder of equal

volume (Left) has greater

resistance change.

• When shaped like

a normal cone,

with dimensions

0.81”-0.015”.

The damage

shows less

resistance change

than that of a

cylinder.

• These two board models show how percent difference between probes change when

a damage between them are placed at different locations.

Acknowledgments

To conclude, the piezo-resistive materials, CNT epoxy resin

and cement show clear signs of resistance change when damaged

or vibrated. The equipped probes measure resistance before and

after and can be used as an alert to signify a change in the

materials’ shape or whether the structure is being compromised.

The cement samples show clear signs of resistance change

when vibrated and also when cracked. Probes attached to buildings

can be used as useful indicators ‘see’ within the structure and

determine what may be in need for repairs.

Carbon Nanotube epoxy resin, used in modern vehicles and

many lightweight applications are strong but brittle and like cement,

show a clear change in resistance when damaged. The damage

can be picked up by probes on the board’s surface and are used to

locate magnitude of damage and location.

The use of resistance to measure damage has the potential

to be a remarkably useful tool in assessment of buildings and

vehicles. This method can be the next step to revolutionizing repair

and safety inspections.

Conclusion

Future research will focus on

placing probes on buildings and

vehicles.

Analyzing the change in

electrical resistance on building

pillars and frames.

Analyzing electrical resistance

change as vehicles using CNT

parts are damaged.

Studying projectile damage and

how it affects resistance.

Special Thanks to:

CUNY Research Scholars Program

Director of Research Dr. Alona Bach

Mentor: Dr. Mahmoud Ardebili

Analysis of Piezo Resistive Materials

By:Shivron Sugrim, Mentor: Doctor Mahmoud ArdebiliBorough of Manhattan Community College 199 Chambers st New York, NY, 10007

CUNY

Research

Scholars

Program