THE CHOICE BETWEEN TEXTILES AND TAPE LAMINATES
THE CHOICE BETWEEN TEXTILES AND TAPE LAMINATES
The main factors to weigh in deciding whether to use a textile composite or a
conventional tape laminate are mechanical properties and the ease and cost of manufacture.
Generally speaking, textiles are somewhat inferior in stiffness and strength for sheet
applications; superior in any application, including sheet applications, requiring high strain
to failure, high work of fracture, or damage or impact tolerance; and superior when triaxial
loads must be carried. Their relative cost depends very much on the state to which
applicable textile technologies have been developed for the particular application. If parts
can be manufactured automatically to net shape, or the number of joints reduced by forming
integral structures, or robotic manufacture substituted for manual set-up and handling, then
textiles become increasingly cost competitive. In short, whether textiles are the better choice
depends strongly on the application and the class of textile chosen.
In the following, quasi-laminar textiles will frequently be compared with so-called
"equivalent tape laminates."These are laminates configured to have the same volume
fraction of in-plane fibers in all orientations and plies of thickness roughly equal to the
thickness of tows in the textile in the through-thickness direction.
In other instances, data are unavailable for equivalent tape laminates. Estimates of
the penalty in stiffness or strength associated with using a textile will then be inferred from
comparisons of measurements for textiles with data for unidirectional tape laminates, with
due allowance for reduction of aligned fiber volume fraction in the former.
All the following remarks reflect the current status of textiles and their
manufacturing technology. The reader should be prepared to update the relative merits of
textiles as research and development progress. This is an active and dynamic field.
3.1 Handling and Fabricability
The main handling advantage of textiles is that they are manufactured as dry fiber
preforms that hold together when they leave the textile machinery without any polymer or
other matrix. The textile preform can be shipped, stored, draped (within limits that depend
on the kind of fabric), and pressed into shaped molds. As described in Section 2, the
finished product can be formed in the mold by resin transfer molding (RTM), reaction
injection molding, resin film infusion (RFI), or the melting of commingled thermoplastic
fibers, which are all cost competitive processes. Separate preforms can easily be joined by
