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Webbing is a woven fabric that is distinguishable by its various
material compositions, strength variations and widths. The webbing
process essentially involves yarns that are woven via looms to
create strips. While it is generally comparable to rope for its
harnessing function, webbing is an extremely versatile component
used in an array of industry applications, ranging from military
apparel to automotive parts. Typically, webbing is fabricated in
solid or tubular form, with each type having different applications
and functions. While ropes are typically thick in texture,
PRET webbing is
produced in extremely lightweight parts. The primary materials used
in the production of webbing include variations of polyester, nylon,
and polypropylene. Cotton webbing is also available and is commonly
used in commercial applications, including clothing apparel. Webbing
is also customizable in a series of colors, designs and prints, and
manufacturers can fabricate reflective webbing for safety
applications.
Standard Industry Applications
Webbing is found across various sectors. Standard
RPET
webbing applications and associated industries include:
Seatbelts and harnesses; automotive industry
Hiking, backpack and harnessing gear; sporting good retail
apparel
Safety bands and tapes; hospital and medical
industry
Upholstery (seat bases); furniture manufacturing
Uniform (suspenders) and accessories for various professions,
e.g. police and military
Web Processing: Solid (Flat) and Tubular
Solid webbing is also known as flat webbing and is fabricated in
varying degrees of thickness. Distinguished by its flat aesthetic,
solid webbing is commonly used for applications like seatbelts. It
is lightweight though it is susceptible to tearing, as stress from
use tends to affect the outer surface of the material. Solid webbing
is generally too stiff to function in applications that require
knots, which is why this type of webbing is best suited for
applications where the material can be sewn into a larger product.
Backpack straps, for instance, are examples of this type of solid
webbing.
Tubular webbing is thicker and more durable than solid
PP webbing
and is composed of two sheets of fabric. It is suitable for
knotting applications (like a rope for hoisting) and carries tension
better than solid webbing. For functions like climbing, experts
recommend utilizing tubular webbing that is woven into a continuous
loop.
Common Webbing Materials
Below are the common webbing materials and some examples of
webbing, and types and uses. While nylon and polyester have similar
properties to each other, there are some key differences.
Nylon Webbing
Nylon Webbing is a high strength elastic material that is commonly
used for belt applications (specifically, flat nylon). This material
tends to stretch approximately 2% the length of the webbing when it
is wet. When looking at how to make nylon webbing, experts warn that
nylon webbing should not be exposed to water continuously, as the
material tends to absorb liquid and may harbor mildew if it is not
maintained properly.
Polyester Webbing
Polyester webbing is durable and similar in aesthetic to nylon.
This material is suitable for use for applications that require
lifting heavy loads. Polyester webbing has low water-absorption and
is more mildew and rot-resistant than nylon. This webbing is
commonly used in applications including racing harnesses and
seatbelts.
Polypropylene Webbing
This type of webbing is typically used for outdoor applications.
Some products fabricated with this
Nylon
webbing include window nets and plastic bags. Polypropylene
webbing is comparable to nylon, though it is generally lighter.
Additionally, it is fabricated with U.V. protection and is water-
resistant. This material is processed in varying degrees of
thickness, although it has low abrasion resistance. According to
experts, it is most suitable for medium-strength operations.
Additional Considerations: Replacement & Maintenance
Professionals recommend inspecting the material on an annual
basis, especially where the component is utilized as a safety
restraint application. Webbing installed as belts and harnesses in
the racing industry, for example, will begin to lose elasticity and
tear after consistent use and exposure to certain elements, such as
oil and heat. Replacement is recommended accordingly, ranging from
2-5 years or sooner if the application is used regularly, as with
seatbelts and chair seats (cotton chair webbing).
Maintenance is another essential webbing consideration. As a
rule, most webbing should be kept clean and dry, although some
materials, like polypropylene are water-proof. A mild detergent is
recommended to clean webbing, though it is also essential to
remember that the aforementioned materials are manufactured in
colors, which may fade or bleed when exposed to certain conditions
or cleaner treatments. Therefore, consult the manufacturer for the
best maintenance approach.
Textile webbing straps are usually connected to a load by
insertion of a bolt or fitting through a looped end in the strap.
The strength and efficiency of such a connection are analyzed in
this paper. Several simplifying assumptions, e.g., a linear
elongation- load characteristic for the webbing, negligible
friction, etc, are made. The analytical results are compared with
test data for Nylon and Dacron webbing straps with various end-loop
configurations. The comparison shows that the analysis of loop
strength and efficiency is approximately correct. Both theory and
test data indicate the need for close specification of loop
configuration parameters during design.
Webbing structures are essential to the safety of engineering
systems that routinely endure excessive sunlight exposure.
Particularly damaging is the ultra-violet (UV) component of sunlight
that may degrade polymer chains, thereby compromising mechanical
strength. Despite considerable progress in structural health
monitoring, UV damage sensors for
Jacquard
webbing structures are still lacking. To fill this gap, we
propose a simple and fast fabrication process for a nylon webbing
structure that exhibits photochromic responses to UV irradiation.
The photochromic webbing structure is fabricated by coating a nylon
strap with a photochromic polymer. The photochromic webbing
structure demonstrates high sensitivity to a wide range of UV
irradiation energy. In addition, the webbing structure maintains
photochromism even after photodegradation due to extreme UV
irradiation (equivalent to 72 h of sunlight exposure). Our analysis
indicates that a photochromic dye concentration of 1.00% is optimal
for UV sensing. The proposed photochromic webbing could facilitate
health monitoring of industrial, aeronautical, and aerospace
structures.
The integration of digital tools in mathematics education is
considered both promising and problematic. To deal with this issue,
notions of webbing and instrumental orchestration are developed.
However, the two seemed to be disconnected, and having different
cultural and theoretical roots. In this article, we investigate the
distinct and joint journeys of these two theoretical perspectives.
Taking some key moments in recent history as points of departure, we
conclude that the two perspectives share an importance attributed to
digital tools, and that initial differences, such as different views
on the role of digital tools and the role of the teacher, have
become more nuances. The two approaches share future challenges to
the organization of teachers’ collaborative work and their use of
digital resources.
The following guest article was inspired by an enlightening
conversation between SRN editor Denise Donaldson and Dave Sander,
CPST-I and engineer (formerly with Evenflo, but employed elsewhere
at the time this article was written).
Have you ever given close attention to the webbing used for car
seat harnesses, LATCH straps, or vehicle seat belts? If so, you may
have noticed that some are wider or feel thicker, smoother, or
rougher than others. You may have also noticed that some have
stripes (actually called panels), and that those panels vary in
appearance and number.
If you have noted these things, I congratulate you on your keen
sense of observation! These differences are not random or
decorative; each detail in webbing has been intentionally designed
to affect how it will perform, especially in a crash.
FMVSS 213 stipulates certain webbing characteristics of CRs. It
defines the minimum width of the
webbing used in harnesses, tethers, and LA straps. It also
says that new webbing must meet a minimum strength requirement of
11,000 Newtons for harness webbing and 15,000 Newtons for LA and
tether webbing. To get an idea of how strong that is, you could
basically pick up a Honda Accord with a strap made out of LA or
tether webbing!
CR manufacturers purchase this strong webbing, and most also do
their own internal testing to doubly ensure compliance with the
standard. FMVSS 213 specifies that this be done using what’s called
a quasi-static test. This is simply a test in which the webbing must
not break, at the specified load, when a device attached to the ends
pulls it apart at a slow and steady rate.
The quasi-static test is beneficial as a consistent benchmark
for measuring performance criteria among all the different webbings
that a company might use. However, CR manufacturers also assess
webbing during dynamic testing of car seats during sled tests run at
a very high rate of speed. Quasi-static results typically do not
match these high-speed results, in that the amount of elongation (or
stretch) seen during the quasi-static test is likely to differ from
the amount during a sled test—it could be more or less. Since the
amount of stretch is a key characteristic with respect to how
webbing manages crash forces, it is helpful to know the results of
both types of testing.
Now back to the guts of the story. We’ve observed that webbing
comes in different styles with varying construction. Why? Because,
depending on the configuration of the fibers (threads), webbing will
stretch to varying extents when loaded by crash forces, such as in a
sled test or actual car crash. Rather than considering one type the
best, engineers make use of this variability.
Like car seats, webbing types can perform differently in FMVSS
213 crash testing, and the actual car seat it is attached to will
further differentiate the results. Sometimes the webbing
selected during car seat design may even cause the CR to crack
during the development and testing phases. By simply making a better
choice for the type of webbing, the same car seat may pass testing
without any other changes to the CR being needed. When looking at
the performance criteria in FMVSS 213, differences in harness
webbing can influence the results of the test dummy head injury
criterion (HIC) score and Chest G injury criteria, as well as the
head and knee excursion (forward movement).
As CPSTs know, the management of crash forces requires give and
take. While one goal is to hold a CR in place, injury may
result if the body isn’t allowed to slow down gradually enough.
Therefore, while webbing used for LATCH installation must be strong
and hold the car seat in place, car seat engineers carefully select
the kinds of webbing used for a particular car seat model to balance
the CR’s overall performance.
For instance, some car seat models may have tether or lower
anchor webbing that has a relatively high elongation in order to
enhance the performance of the CR structure. While this would
increase some excursion measurements (a negative effect), this might
be a net-positive tradeoff if it lowers the dummy HIC or chest Gs
enough (a positive effect). In fact, because tethers do such a good
job of supporting a CR and controlling head excursion, there is
usually some room to use webbing that stretches more if the overall
effect is a more structurally sound CR that measures better HIC and
chest Gs in testing—a tradeoff that is likely to translate to
better outcomes for real children in crashes.
Webbing variations can also be especially useful to engineers in
the late stages of CR development. To CR engineers, these final
stages are all about tweaking or “turning the dials” until you get
the best performance possible in all the measurable categories: HIC,
chest G’s, head excursion, knee excursion, and structure.
What does turning the dials mean? Well, before a car seat is
even made, developers use a variety of tools, like computer-aided
design programs and 3-D printed models, to predict a CR’s fit,
performance, and function, because changes made after a CR is molded
are very costly. But, until it has been physically made, it is
difficult to really know for sure how a CR will perform in every
test configuration. So CR manufacturers have a few go-to ways to
tweak performance during the final development stage. Having a wide
selection of webbing to try is an important one of those, giving
them so-called “dials” to turn. By matching the right webbing to a
CR, manufacturers can fine-tune it so it performs to its best
potential.
I hope this sheds some light on how CR manufacturers choose
webbing, just one of the many factors that can influence the
performance of a car seat. In particular, consider this when asked
why owners are prohibited from swapping components of different car
seats, even if the parts are from the same manufacturer. When it
comes to webbing (and other parts, as well), rest assured that there
were important reasons the CR developers used the particular type
that they did for each model. So, even if parts seem similar to the
untrained eye, making changes to a CR that are not approved by the
manufacturer can truly have negative consequences on performance.
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