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Proceedings Paper

Development of smart solid state structural damage assessment systems for underground facilities
Author(s): John S. Dunning; Larry D. Thompson
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Paper Abstract

Quantitative data on the stress-strain behavior of walls and roofs of underground mines are unavailable. It is established practice to use roof bolts to support roofs and ribs in mines. The U.S. Bureau of Mines and Strain Monitor Systems, Inc. are jointly developing smart materials and passive or active detection systems capable of monitoring the stress/strain history of mine roofs with the goal of detecting structural damage. The systems can be designed for a passive mode to monitor peak strain or an active mode for a real-time alarm response, the smart materials to be used in this application are TRIP (TRansformation Induced Plasticity) steels. TRIP steels are materials which change state from austenitic, nonmagnetic to a martensitic, ferromagnetic phase as the material undergoes straining. There is a direct correspondence of the peak strain level experienced in the material with the percentage of ferromagnetism, hence monitoring the relative amount of the ferromagnetic content will indicate the level of strain (and therefore stress). The phase transition that accompanies the straining is irreversible so the monitor material indicates the peak strain until that value is subsequently exceeded. Materials research discussed will cover the selection of compositions with a suitable ferromagnetic response and the development of thermomechanical treatments to achieve high tensile strength required for this application. Tensile properties and related phase changes are described with preliminary system designs and proposed installation techniques.

Paper Details

Date Published: 12 May 1995
PDF: 12 pages
Proc. SPIE 2447, Smart Structures and Materials 1995: Industrial and Commercial Applications of Smart Structures Technologies, (12 May 1995); doi: 10.1117/12.209330
Show Author Affiliations
John S. Dunning, U.S. Bureau of Mines (United States)
Larry D. Thompson, Strain Monitor Systems, Inc. (United States)

Published in SPIE Proceedings Vol. 2447:
Smart Structures and Materials 1995: Industrial and Commercial Applications of Smart Structures Technologies
C. Robert Crowe; Gary L. Anderson, Editor(s)

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