SAMPE Journal - May/June 2020 - 25
tween the core and the cladding produces the total
internal reflection condition on which fiber optics
is based8.
During the fiber manufacturing process, minute inhomogeneities are inherently introduced
along the length of the fiber. These slight variations
in refractive index create a random back-reflection
fingerprint when the fiber is interrogated using a
swept-wavelength laser, through a process known
as Rayleigh backscattering. This back-reflection
fingerprint is unique to each section of optical fiber and remarkably stable. External stimuli such
as strain or temperature causes a distortion in this
backscattering pattern of the fiber in a manner proportional to the stimulus being applied.
Luna's Optical Distributed Sensor Interrogator
(ODiSI) system takes advantage of the backscatter
phenomenon to measure strain and temperature.
The process, shown below in Figure 2, begins by
detecting the Rayleigh backscatter amplitude profile along the length of the entire sensor (Figure 2a).
Next, this backscatter signature is divided into segments called gages. Using an inverse Fourier transform, the data inside this gage-length is converted
to the spectral domain as shown in Figure 2b. By
running a cross-correlation between the measurement data and a baseline taken at a state of known
temperature or strain, a frequency shift in the spectral content of the gage can be observed as shown
in Figure 2c. This frequency shift corresponds to
the distortion of the backscatter signature of the
fiber and can be related to either strain or temperature by a set of coefficients9.
Figure 2. Frequency shift calculation process using Rayleigh backscatter.
(a) Backscatter signal amplitude along the length of the sensor. (b) Spectral content of a single gage along the sensor. (c) Cross-correlation giving
frequency shift relative to a baseline reference within the gage.
Complete Vacuum Bagging Consumables Line
Technical Sales and Service for:
Woven
Reinforcements
LOCTITE® FREKOTE®: Mold Release Products
LOCTITE®: Film and Paste Adhesives, Resins
BONDERITE®: Surface Treatment Systems
Prepregs, Film Adhesive,
Core Splice, TOWPREG
Critical wiping cloths,
Rymplecloth® and tack cloths
Epoxy and urethane tooling resins
and component systems
Peel Ply and
Release Fabrics
www.northerncomposites.com
Hampton NH | 603.926.1910
Greensboro NC | 336.373.5933
ISO 9001: 2008
AS9120A | AS9100C
w w w. s a m p e . o r g
M AY/J U N E 2 0 2 0
|
SAMPE JOURNAL
|
25
http://www.northerncomposites.com
http://www.sampe.org
SAMPE Journal - May/June 2020
Table of Contents for the Digital Edition of SAMPE Journal - May/June 2020
Table of Contents
SAMPE Journal - May/June 2020 - Cover1
SAMPE Journal - May/June 2020 - Cover2
SAMPE Journal - May/June 2020 - Table of Contents
SAMPE Journal - May/June 2020 - 2
SAMPE Journal - May/June 2020 - 3
SAMPE Journal - May/June 2020 - 4
SAMPE Journal - May/June 2020 - 5
SAMPE Journal - May/June 2020 - 6
SAMPE Journal - May/June 2020 - 7
SAMPE Journal - May/June 2020 - 8
SAMPE Journal - May/June 2020 - 9
SAMPE Journal - May/June 2020 - 10
SAMPE Journal - May/June 2020 - 11
SAMPE Journal - May/June 2020 - 12
SAMPE Journal - May/June 2020 - 13
SAMPE Journal - May/June 2020 - 14
SAMPE Journal - May/June 2020 - 15
SAMPE Journal - May/June 2020 - 16
SAMPE Journal - May/June 2020 - 17
SAMPE Journal - May/June 2020 - 18
SAMPE Journal - May/June 2020 - 19
SAMPE Journal - May/June 2020 - 20
SAMPE Journal - May/June 2020 - 21
SAMPE Journal - May/June 2020 - 22
SAMPE Journal - May/June 2020 - 23
SAMPE Journal - May/June 2020 - 24
SAMPE Journal - May/June 2020 - 25
SAMPE Journal - May/June 2020 - 26
SAMPE Journal - May/June 2020 - 27
SAMPE Journal - May/June 2020 - 28
SAMPE Journal - May/June 2020 - 29
SAMPE Journal - May/June 2020 - 30
SAMPE Journal - May/June 2020 - 31
SAMPE Journal - May/June 2020 - 32
SAMPE Journal - May/June 2020 - 33
SAMPE Journal - May/June 2020 - 34
SAMPE Journal - May/June 2020 - 35
SAMPE Journal - May/June 2020 - 36
SAMPE Journal - May/June 2020 - 37
SAMPE Journal - May/June 2020 - 38
SAMPE Journal - May/June 2020 - 39
SAMPE Journal - May/June 2020 - 40
SAMPE Journal - May/June 2020 - 41
SAMPE Journal - May/June 2020 - 42
SAMPE Journal - May/June 2020 - 43
SAMPE Journal - May/June 2020 - 44
SAMPE Journal - May/June 2020 - 45
SAMPE Journal - May/June 2020 - 46
SAMPE Journal - May/June 2020 - 47
SAMPE Journal - May/June 2020 - 48
SAMPE Journal - May/June 2020 - 49
SAMPE Journal - May/June 2020 - 50
SAMPE Journal - May/June 2020 - 51
SAMPE Journal - May/June 2020 - 52
SAMPE Journal - May/June 2020 - 53
SAMPE Journal - May/June 2020 - 54
SAMPE Journal - May/June 2020 - 55
SAMPE Journal - May/June 2020 - 56
SAMPE Journal - May/June 2020 - 57
SAMPE Journal - May/June 2020 - 58
SAMPE Journal - May/June 2020 - 59
SAMPE Journal - May/June 2020 - 60
SAMPE Journal - May/June 2020 - 61
SAMPE Journal - May/June 2020 - 62
SAMPE Journal - May/June 2020 - 63
SAMPE Journal - May/June 2020 - 64
SAMPE Journal - May/June 2020 - 65
SAMPE Journal - May/June 2020 - 66
SAMPE Journal - May/June 2020 - 67
SAMPE Journal - May/June 2020 - 68
SAMPE Journal - May/June 2020 - Cover3
SAMPE Journal - May/June 2020 - Cover4
https://www.nxtbook.com/nxtbooks/sampe/journal_20241112
https://www.nxtbook.com/nxtbooks/sampe/journal_20240910
https://www.nxtbook.com/nxtbooks/sampe/journal_20240708
https://www.nxtbook.com/nxtbooks/sampe/journal_20240506
https://www.nxtbook.com/nxtbooks/sampe/journal_20240304
https://www.nxtbook.com/nxtbooks/sampe/journal_20240102
https://www.nxtbook.com/nxtbooks/sampe/journal_20231112
https://www.nxtbook.com/nxtbooks/sampe/journal_20230910
https://www.nxtbook.com/nxtbooks/sampe/journal_20230708
https://www.nxtbook.com/nxtbooks/sampe/journal_20230506
https://www.nxtbook.com/nxtbooks/sampe/journal_20230304
https://www.nxtbook.com/nxtbooks/sampe/journal_20230102
https://www.nxtbook.com/nxtbooks/sampe/journal_20221112
https://www.nxtbook.com/nxtbooks/sampe/journal_20220910
https://www.nxtbook.com/nxtbooks/sampe/journal_20220708
https://www.nxtbook.com/nxtbooks/sampe/journal_20220506
https://www.nxtbook.com/nxtbooks/sampe/journal_20220304
https://www.nxtbook.com/nxtbooks/sampe/journal_20220102
https://www.nxtbook.com/nxtbooks/sampe/journal_20211112
https://www.nxtbook.com/nxtbooks/sampe/journal_20210910
https://www.nxtbook.com/nxtbooks/sampe/journal_20210708
https://www.nxtbook.com/nxtbooks/sampe/journal_20210506
https://www.nxtbook.com/nxtbooks/sampe/journal_20210304
https://www.nxtbook.com/nxtbooks/sampe/journal_20210102
https://www.nxtbook.com/nxtbooks/sampe/journal_20201112
https://www.nxtbook.com/nxtbooks/sampe/journal_20200910
https://www.nxtbook.com/nxtbooks/sampe/journal_20200708
https://www.nxtbook.com/nxtbooks/sampe/journal_20200506
https://www.nxtbook.com/nxtbooks/sampe/journal_20200304
https://www.nxtbook.com/nxtbooks/sampe/journal_20200102
https://www.nxtbook.com/nxtbooks/sampe/journal_20191112
https://www.nxtbook.com/nxtbooks/sampe/journal_20190910
https://www.nxtbook.com/nxtbooks/sampe/journal_20190708
https://www.nxtbook.com/nxtbooks/sampe/journal_20190506
https://www.nxtbook.com/nxtbooks/sampe/journal_20190304
https://www.nxtbook.com/nxtbooks/sampe/journal_20190102
https://www.nxtbook.com/nxtbooks/sampe/journal_20181112
https://www.nxtbook.com/nxtbooks/sampe/journal_20180910
https://www.nxtbook.com/nxtbooks/sampe/journal_20180708
https://www.nxtbook.com/nxtbooks/sampe/journal_20180506
https://www.nxtbook.com/nxtbooks/sampe/journal_20180304
https://www.nxtbook.com/nxtbooks/sampe/journal_20180102
https://www.nxtbook.com/nxtbooks/sampe/journal_20171112
https://www.nxtbook.com/nxtbooks/sampe/journal_20170910
https://www.nxtbook.com/nxtbooks/sampe/journal_20170708
https://www.nxtbook.com/nxtbooks/sampe/journal_20170506
https://www.nxtbook.com/nxtbooks/sampe/journal_20170304
https://www.nxtbook.com/nxtbooks/sampe/journal_20170102
https://www.nxtbook.com/nxtbooks/sampe/journal_20161112
https://www.nxtbook.com/nxtbooks/sampe/journal_20160910
https://www.nxtbook.com/nxtbooks/sampe/journal_20160708
https://www.nxtbook.com/nxtbooks/sampe/journal_20160506
https://www.nxtbook.com/nxtbooks/sampe/journal_20160304
https://www.nxtbook.com/nxtbooks/sampe/journal_20160102
https://www.nxtbook.com/nxtbooks/sampe/journal_20151112
https://www.nxtbook.com/nxtbooks/sampe/journal_20150910
https://www.nxtbook.com/nxtbooks/sampe/journal_20150708
https://www.nxtbook.com/nxtbooks/sampe/journal_20150506
https://www.nxtbook.com/nxtbooks/sampe/journal_20150304
https://www.nxtbook.com/nxtbooks/sampe/journal_20150102
https://www.nxtbook.com/nxtbooks/sampe/journal_20141112
https://www.nxtbook.com/nxtbooks/sampe/journal_20140910
https://www.nxtbook.com/nxtbooks/sampe/journal_20140708
https://www.nxtbook.com/nxtbooks/sampe/journal_20140506
https://www.nxtbook.com/nxtbooks/sampe/journal_20140304
https://www.nxtbook.com/nxtbooks/sampe/journal_20140102
https://www.nxtbook.com/nxtbooks/sampe/journal_20131112
https://www.nxtbook.com/nxtbooks/sampe/journal_20130910
https://www.nxtbook.com/nxtbooks/sampe/journal_20130708
https://www.nxtbook.com/nxtbooks/sampe/journal_20130506
https://www.nxtbook.com/nxtbooks/sampe/journal_20130304
https://www.nxtbook.com/nxtbooks/sampe/journal_20130102
https://www.nxtbook.com/nxtbooks/sampe/journal_20121112
https://www.nxtbook.com/nxtbooks/sampe/journal_20120910
https://www.nxtbook.com/nxtbooks/sampe/journal_20120708
https://www.nxtbook.com/nxtbooks/sampe/journal_20120506
https://www.nxtbook.com/nxtbooks/sampe/journal_20120304
https://www.nxtbook.com/nxtbooks/sampe/journal_20120102
https://www.nxtbook.com/nxtbooks/sampe/journal_20111112
https://www.nxtbook.com/nxtbooks/sampe/journal_20110910
https://www.nxtbook.com/nxtbooks/sampe/journal_20110708
https://www.nxtbook.com/nxtbooks/sampe/journal_20110506
https://www.nxtbook.com/nxtbooks/sampe/journal_20110304
https://www.nxtbook.com/nxtbooks/sampe/journal_20110102
https://www.nxtbookmedia.com