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Title: Measuring mine roof bolt strains

Abstract

A mine roof bolt and a method of measuring the strain in mine roof bolts of this type are disclosed. According to the method, a flat portion on the head of the mine roof bolt is first machined. Next, a hole is drilled radially through the bolt at a predetermined distance from the bolt head. After installation of the mine roof bolt and loading, the strain of the mine roof bolt is measured by generating an ultrasonic pulse at the flat portion. The time of travel of the ultrasonic pulse reflected from the hole is measured. This time of travel is a function of the distance from the flat portion to the hole and increases as the bolt is loaded. Consequently, the time measurement is correlated to the strain in the bolt. Compensation for various factors affecting the travel time are also provided.

Inventors:
 [1]
  1. Lakewood, CO
Issue Date:
Research Org.:
National Energy Technology Laboratory (NETL), Pittsburgh, PA, Morgantown, WV (United States)
OSTI Identifier:
865930
Patent Number(s):
4601207
Assignee:
United States of America as represented by Secretary of (Washington, DC)
Patent Classifications (CPCs):
F - MECHANICAL ENGINEERING F16 - ENGINEERING ELEMENTS AND UNITS F16B - DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS, WEDGES, JOINTS OR JOINTING
G - PHYSICS G01 - MEASURING G01N - INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
measuring; mine; roof; bolt; strains; method; strain; bolts; type; disclosed; according; flat; portion; head; machined; drilled; radially; predetermined; distance; installation; loading; measured; generating; ultrasonic; pulse; time; travel; reflected; function; increases; loaded; consequently; measurement; correlated; compensation; various; factors; affecting; provided; mine roof; ultrasonic pulse; predetermined distance; roof bolt; flat portion; travel time; roof bolts; pulse reflected; time measurement; /73/405/

Citation Formats

Steblay, Bernard J. Measuring mine roof bolt strains. United States: N. p., 1986. Web.
Steblay, Bernard J. Measuring mine roof bolt strains. United States.
Steblay, Bernard J. Wed . "Measuring mine roof bolt strains". United States. https://www.osti.gov/servlets/purl/865930.
@article{osti_865930,
title = {Measuring mine roof bolt strains},
author = {Steblay, Bernard J},
abstractNote = {A mine roof bolt and a method of measuring the strain in mine roof bolts of this type are disclosed. According to the method, a flat portion on the head of the mine roof bolt is first machined. Next, a hole is drilled radially through the bolt at a predetermined distance from the bolt head. After installation of the mine roof bolt and loading, the strain of the mine roof bolt is measured by generating an ultrasonic pulse at the flat portion. The time of travel of the ultrasonic pulse reflected from the hole is measured. This time of travel is a function of the distance from the flat portion to the hole and increases as the bolt is loaded. Consequently, the time measurement is correlated to the strain in the bolt. Compensation for various factors affecting the travel time are also provided.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1986},
month = {1}
}

Patent:

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