NDTech Newsletter
#8
Websites
- NDT of composites
Non-destructive
characterization of heat damage in graphite-epoxy composites
is available at http://www.dtic.dla.mil/iac/ntiac/gamsoar.html
Information on the use of
Lamb waves to monitor damage in composites can be found at
http://physics.wm.edu/~seale/research.html
Surface inspection system
used for visual enhancement of impact damage and interlayer
corrosion on aircraft structures can be found at
http://www.netcore.ca/~diffract/dais.html
Sandia National Laboratories
are currently adapting commercial NDT techniques to identify
poorly manufactured wind turbine blades and use modal
techniques to monitor the structural integrity of turbine
structure. Further details about this environmentally
friendly energy producing system can be found at
http://www.sandia.gov/Renewable_Energy/wind_energy/nrg.html
The Ultrasonic Testing
Online Journal at http://www.ultrasonic.de
focuses on ultrasonic testing of fiber reinforced
materials.
Ultrasonic and radiographic
NDT of butt fusion welds in polyethylene pipe can be
downloaded at http://www.ultrasonic.de/article/twi/twi.html
Information on the
characterization and degradation of composites, the
measurement and control of interface strengths in composites
or even the mechanical behavior of high temperature ceramic
composites is available at http://www.seas.ucla.edu/~ajit/NDE.html
A brief overview of the
research areas and benefits of microwave NDT techniques,
described at http://www.lance.colostate.edu/depts/ee/Research/amntl/benefits.html
Conference
Announcement
Ninth International
Symposium on Nondestructive Characterization of
Materials
The 9th Symposium will be
held June 28-July 2, 1999 in Sydney, Australia. Co-Chairmen
for the Symposium are Robert Green and Boro Djordjevic from
The Johns Hopkins University Center for NDE, and Don Price
from CSIRO, Telecommunications & Industrial Physics,
Sydney, Australia. The objective of the symposia is to focus
on the science and technology of nondestructive evaluation
applied to materials characterization.
Papers are solicited that
are related to the application of nondestructive techniques
for optimization of the processing and properties of
materials. Papers that address issues of current and future
interests are also encouraged. For a listing of paper topics
and other information, please visit the website:
http://www.cnde.com. Proceedings will be
published.
One page abstracts - title,
authors, and body of abstract - should be approximately 300
words with the name, mailing address, phone number, fax
number, and email address of the principal author at the
bottom of the page.
The deadline for submission
of abstracts is December 4, 1998 with full manuscripts due
June 29, 1999. Abstracts should be submitted to:
Ms. Debby Manley, Center for
NDE
102 Maryland Hall
The Johns Hopkins University
Baltimore, MD 21218, USA
Phone: 410.516.7126
Fax: 410.516.7249
Email: cnde@jhu.edu
Healthy
Hoses?
Hoses are critical to the
operation of hydraulic, power train, and auxiliary machinery
aboard ship, in tanks of trucks, and in industrial machining
and extended applications. The average Navy vessel has over
200 industrial grade hoses aboard. Hose failures can be
catastrophic in terms of readiness, personnel, and equipment
safety, and scheduled replacement can be very expensive if
the life of the hose has not been realized. Current hose
health examination is solely by visual inspection.
Replacement strategies include replacement by schedule, the
result of a visual inspection, or replacement after
failure.
Replacement by inspection, a
conditioned based maintenance (CBM) approach using
nondestructive evaluation methods, is always the lowest cost
solution if the inspection method is reliable.
Currently there is no technology available to inspect hoses
with high probability of defect detection. Visual
inspections fail to see delaminations in interior hose
layers, interior cracks/cuts that can lead to fracture
failure, wall thinning, and reinforcing mesh rupture. A
device that can reliably find these types of hose defects in
a CBM strategy could potentially save millions of dollars in
scheduled replacement and/or damage repair. Unfortunately,
no NDE techniques have been developed for in-service
inspection of hoses.
Tires are constructed of
materials and reinforcements that are similar to hoses. NDE
of tires, unlike hoses, has received significant
development. Patents have been issued for resonant,
shearographic, radiographic, electromagnetic, microwave and
ultrasonic inspection techniques and equipment for
reinforced tires. Techniques are available to detect
virtually any type of tire defect. Equipment to perform tire
inspections is commercially available, and tire
manufacturers and retreaders regularly perform NDE on tires.
These methods, however, were developed for inspecting tires
that have been removed from service. Some techniques can
perform inspections with the tire mounted on the wheel, but
most require removing the tire. Removing a hose from service
for inspection is not cost effective.
One possible way to
nondestructively examine industrial hoses in service is
microwave inspection. Microwave testing detects changes in
dielectric properties associated with defects. Microwave
sensors, typically rectangular waveguides or coaxial lines,
detect flaws by analyzing the reflected electromagnetic
energy. The reflected signal is proportional to the
dielectric signature of the layered hose materials. Aging,
cracking, chemical degradation, delaminations, wall
thickness, and permeation are detected by sensing the
dielectric signature change they induce in the hose
material. NDE can be done in real time, and can be set to
provide accept/reject alarms.
Microwave methods offer
potential for hose nondestructive evaluation (NDE) that can
identify critical hose defects at low cost with minimal
operator training. Microwave NDE devices are roughly the
size and weight of a flashlight.
TRI/Austin, working with the
Colorado State University (CSU) applied microwave
nondestructive test laboratory (AMNTL), has been awarded a
Phase I SBIR to develop a hose NDE device using a microwave
NDE approach. The work is being done for the Office of Naval
Research and the Naval Surface Warfare Center.
For more information, please
contact:
Jennifer Haven or Jake Easter
Texas Research Institute Austin, Inc.
9063 Bee Caves Road
Austin, Texas 78733-6201
Phone: 512.263.2101
Fax: 512.263.3530
Post
Inspection: Developer Powder Removal*
ASTM E-1417, paragraph 7.7
reads, "Components shall be cleaned after examination to
remove developers and other examination material residues,
if these are detrimental to subsequent operation of the
components' subsequent function."
The logic behind this rule
was recently covered in a bulletin published by BabbCo,
S.A., a French company with whom we have been associated
since about 1952.
The technical bulletin was
written by BabbCo's Patrick Dubosc, a 20-year-plus veteran
of marketing inspection penetrants. Dubosc has approved our
translation:
Inspected Parts Should be
Free of Developer Residue
It is important to remove
developer following penetrant inspection. Penetrant users
should be aware of two reasons why developer residue on
inspected parts might create problems.
Fine developer powder can
interfere with additional high precision processing of
inspected parts. Or, when a part is installed in a
lubricated assembly, developer particles remaining on a part
can create problems throughout the assembly, and shorten the
working life of its components.
Problems may also arise from
the fact that penetrant developers will attract and retain
atmospheric moisture.
Certain developers contain
wetting agents which, when combined with moisture, can lead
to elevated pH levels. This, in turn, can lead to corrosion,
e.g. pits on the surface of certain alloys.
Depending on the
application, it is advisable to remove developer residue
from inspected parts, at least, to reduce the possibility of
corrosion. A simple cloth wipe will suffice in most
cases.
However, in certain
applications, greater attention should be paid to
eliminating all traces of developer, such as before
additional precision processing or before installing a part
in a lubricated assembly.
*Abstracted from "Penetrant
Progress" Sherwin Inc. Newsletter - August 1998
NDE
Technical Papers
Techincal Reports and papers
given below are available from the National Technical
Information Service, U.S. Department of Commerce,
Springfield, Virginia 22151, USA. Phone (703) 487-4600. Fax
(703) 321-8547.
Email address: For
information, info@ntis.fedworld.org
To order, orders@ntis.fedworld.org
General
1) Searching for the quicker
NDT solution - Hobbs, C.
Materials World, v.5 (11), (Nov 1997), p. 652
2) An evaluation of NDT
methods - Stephens, P.
Metallurgia, v.64 (11), (Nov 1997), p. 368-370
3) Reliability analysis with
nondestructive inspection - Hong, H.P.
Structural Safety, v.19 (4), (1997), p. 383-396
4) The role of
non-destructive examination in improving the quality for
pipeline and pressure vessels - Palaniappan, M. and
others
International Journal of Pressure Vessels and Piping, v.73
(1), (Aug 1997), p. 33-38
Miscellaneous
Techniques
5) Free form breakthrough -
a portable laser scanning system - Coyne, B.
Quality Today, (Jan 1998), p. s6-s9
6) Impact-echo: the complete
story - Sansalone, M.
ACI Structural Journal, v.94 (6), (1997), p.
777-786
Ultrasonic and
Acoustic
7) Ultrasonic weld
inspections: theory and procedures - Anonymous
Iron and Steel Engineer, v.74 (11), (Nov 1997), p.
69-71
8) The LORUS technique for
corrosion detection in hard-to-access locations -
Hoppenbrouwers, M.B. and others
INSIGHT. Non-Destructive Testing and Condition Monitoring,
v.39 (12), (Dec 1997), p. 858-859
9) Application of the
ultrasonic method for the control of thermosetting polymer
materials - Kalkis, V. and others
Mechanics of Composite Materials, v.33 (3), (1997), p.
282-292
10) A PC-Based near
real-time ultrasonic imaging system for flaw
characterization - Anand, R.S. and others
Journal of Testing and Evaluation, v.25 (6), (1997), p.
529-535
Optical and
Ultraviolet
11) ESPI - a viable NDE tool
for plant extension - Gryzagoridis, J. and others
International Journal of Pressure Vessels and Piping, v.73
(1), (Aug 1997), p. 25-32
Thermal and
Infrared
12) Thermography offers a
clearer view - Baker, A.
World Cement, v.28 (12), (Dec 1997), p. 32-36
Acoustic
Emission
13) Fiber fragmentation and
acoustic emission - Wanner, A. and others
Journal of Acoustic Emission, v.14 (3-4), (Jul-Dec 1996), p.
S47-S60
14) Acoustic emission
monitoring as a nondestructive testing technique in
reinforced concrete - Hearn, S.W. and others
ACI Materials Journal, v.94 (6), (1997), p.
510-519
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