Award Abstract #9861020
SBIR Phase I: Microminiature, High Resolution, Passive Peak Strain Detector for Smart Structures and Materials

NSF Org:	IIP Division of Industrial Innovation and Partnerships
Initial Amendment Date:	December 2, 1998
Latest Amendment Date:	December 2, 1998
Award Number:	9861020
Award Instrument:	Standard Grant
Program Manager:	G. Patrick Johnson IIP Division of Industrial Innovation and Partnerships ENG Directorate for Engineering
Start Date:	January 1, 1999
Expires:	June 30, 1999 (Estimated)
Awarded Amount to Date:	$99927
Investigator(s):	Steven Arms swarms@microstrain.com (Principal Investigator)
Sponsor:	MICROSTRAIN INC 310 HURRICANE LN UNIT 4 WILLISTON, VT 05495 802/862-6629
NSF Program(s):	EXP PROG TO STIM COMP RES
Field Application(s):	0308000 Industrial Technology
Program Reference Code(s):	CVIS, 5371, 1445, 1059
Program Element Code(s):	9150

ABSTRACT

9861020

This Small Business Innovation Research Phase I project is aimed at combining hermetically packaged differential variable reluctance transducers capable of peak strain detection (DVRT-PD's) with shape memory alloy (SMA) actuators to produce improved passive peak strain detectors which can withstand harsh environmental conditions (moisture, salt, and vibration) and can be reset for repeated uses. Critical civil and military structures require "smart" sensors in order to report their strain histories; this can help to insure safe operation after exposure to potentially damaging loads (such as earthquakes, hurricanes, military action, etc.). Sensors in smart structures generally require system power in order to operate, but if power outages occur, in a loss of key data may result. Therefore, sensors which can record peak information without power (passively) are needed. Previous passive peak strain detectors have relied on measuring the magnetic properties of transformation induced plasticity (TRIP) steels. However, these devices have several drawbacks, including bulky size, low resolution, high nonlinearity, and a one time use limitation due to material yielding. The research will address these problems by using modified, microminiature, DVRT PD's. A Phase 0 study was performed using bonded resistance strain gauges as a standard; DVRT-PD's were found to be repeatable, fast, and accurate.

Health monitoring has the potential to greatly enhance the safety and life of military, aerospace, and civil structures. Sensate structures equipped with passive networks of peak strain, acceleration, pressure, and torque measurement devices, could be interrogated for their response to test loads or potentially damaging events, and either replaced, or their embedded sensors reset for future interrogation. Applications include health monitoring of composite structures, aircraft, bridges, dams, and buildings. Military and commercial market potential for these systems is significant.

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