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DYNAMIC MODULUS TESTING for PROTECTIVE TEXTILESFILIZ AVSAR
LAWSON-HEMPHILL (USA)LAWSON - HEMPHILLLAWSON - HEMPHILL
Smart Quality ControlSmart Quality Control
Aramid. Reg.
PROTECTIVE TEXTILES
BASIS OF BALLISTIC PREVENTION
Protective textiles, especially the ones that are used inBallistic Prevention need to stop the projectile flight in theshortest distance possible. For that, high modulus (veryhigh strength and low elasticity) materials needed.
Earlier: Silk and Nylon 6.6 used
1970’s: Aramids and ultra high modulus PE (UHMPE)
Kevlar by Dupont and Twaron by Teijin Aramid
Dyneema by DSM and Spectra by Honeywell
The basis of the ballistic prevention is to extract maximumenergy from the incoming projectile.
Absorption of kinetic energy of the projectile is related to:
1- Wave propagation (transversely and longitudinally)
2- Frictional Energy Dissipation
When selecting a fiber for the ballistic protection, thedominating selection parameter is the WAVEPROPAGATION VELOCITY.
This parameter determines the speed of spreading theenergy on ballistic impact.
-1
1
3
5
7
9
11
13
15
0 20 40 60 80 100 120 140 160
Specific Energy Absortion (index)
So
nic
Ve
loc
ity
(10
00
m/s
)
Aramid, Bal.grade.
Aramid , Reg.grade S-glass
Dyneema SK65
Dyneema SK75
Dyneema S 76K
Polyamide
Wave Propagation
DYNAMIC MODULUS TESTING with DMT
Lawson- Hemphill Dynamic Modulus Tester, DMT isdesigned to measure the Sonic Velocity, c throughmaterials. DMT can be used to test yarns as well asstrips of almost any materials with these options:
1- DMT Fiber Scanner Option for YARN testing
2- DMT Planar Mount Option for MATERIAL testing
Lawson-Hemphill Dynamic Modulus Tester, DMT
Steel Wire (c=5.06km/sec) Paraaramid (c=7.23km/sec)
UHMPE (c=7.59km/sec) Nylon Tirecord (c=3.63km/sec)
DMT Operation Principle
PULSERECEIVER
PULSERECEIVER
PULSETRANSMITTER
PULSETRANSMITTER
TIMINGCIRCUITTIMINGCIRCUIT
METER
SAMPLE
ReceiveTransducer
TransmitTransducer
Turn Off Turn On
QC for OTHER TECHNICAL TEXTILES
Transportation Textiles
Medical Textiles
Geotextiles
Contact information
LAWSON-HEMPHILLA TMl Group Company1658 GAR Highway, Unit 6Swansea, MA 02720-USA
Tel: + 1 508 679 5364Fax: + 1 508 679 5396 www.testingmachines.com
www.lawsonhemphill.com
The biggest growth areas for Technical textiles aretransport Textiles, followed by Geotextiles, ProtectiveTextiles and Medical Textiles. Below are some examplesof instruments for Quality Control of Technical Textiles byLawson-Hemphill.
Force & Shrinkage Tester
Textured Yarn Tester
Artificial heart valve
Tirecord
Hot Draw Force Tester
POY PES Draw Force Results
VELOCITY OF THE WAVE PROPAGATION
SONIC VELOCITY of STEEL WIRE
Sonic Velocity of Steel Wire as measured by Lawson-Hemphill Dynamic Modulus Tester, DMT is shown below.
Steel Wire Density = 7800kg/m3
Young’s Modulus = c2
���Young’s Modulus = c2
���
Young’s Modulus = 5060 * 7.8 * 102 3
Young’s Modulus = 5060 * 7.8 * 102 3
Young’s Modulus = 2 * 10 Pa11
Young’s Modulus = 2 * 10 Pa11
Sonic Velocity (5.06km/sec)
0
50
100
150
200
250
0 100 200 300 400 500
Transit Time (microsec)
Sep
ara
tio
n(c
m)
Velocity of the wave propagation, c is:
1- Directly proportional to the square root of the modulus
2- Inversely proportional to the square root of the fiberdensity
Velocity of the propagation for Aramids is ~8km/sec
Velocity of the propagation for Nylon is ~2km/sec
Up to 4 times the volume of the aramid fiber can beinvolved in the wave propagation and energy dissipation.
Young’s ModulusC =
�