In Reply to: Textile reinforcements posted by Chris Pastore on 06/23/00 at 11:36 AM:
Excellent question. You are correct - to date there have been very few 'high volume'
applications for structural textile composities. The reason for this lack of commercialiization
is largely cost, or more specifically, performance/cost.
For the benefit of other readers, structural textile composites are textile structures (braids,
weaves, knits) produced with very strong fibers (carbon, aramid, etc) and reinforced with
metal, polymer, or ceramic matrices.
Structural textile composites are expensive for a variety of reasons. First, the fibers themselves
are generally costly, particularly the high performance types. Carbon fiber, for example, can
be bought in the $7.00/lb range as "tow" (yarn). Extra processing is required to make the tow
into a usable textile, and further labor and/or processing is required to manufacture a 'preform'
that can be infiltrated with matrix. Each of these steps adds cost to the material, the result of
which is a material costing in the area of $30/lb processed. Labor costs strongly influence the
final component costs. This is reason that much composite processing is done in extremely
low labor rate countries like Mexico or China.
High volume steel can be purchased for $0.28/lb, and processed through stamping, forging,
or welding. The resulting structure is very cost effective, given steel's tensile modulus of 30
million psi and yield strength of at least 40,000 psi. Total cost for steel structures (using
automation) is as low as $1.00/lb fully processed.
The only real opportunities for structural textile composites are situations where someone will
pay an extreme premium for reduced weight. Aircraft, aerospace, and sporting goods are
examples of very wieght conscious industries.
When technologies are developed to allow 'net shape' manufacture of structural textile
composites without extensive intermediate steps, their applications will explode. But
labor content and inherent material costs are currently prohibitive for high volume