Description / Abstract:
PURPOSE AND SCOPE OF VOLUME 1
Volume 1 provides material characterization, test methodology,
and data development guidelines adaptable to a wide variety of
needs for polymeric matrix composite materials. It includes methods
for obtaining data for constituent materials (i.e., fibers,
matrices), combined material forms (e.g., prepreg), and cured
lamina and laminates. Information is provided on the range of test
types, environmental conditioning methods, and data handling
techniques commonly used during composite structure development
programs. Although this Volume includes guidelines for testing at
some higher structural complexity levels (i.e., laminates, joints,
etc.), the principal focus is material-level property
characterization. Particular emphasis is given to statistical
methods typically used for the determination of property values, as
well as the specific requirements for data published in Volume 2 of
the handbook.
It must be emphasized that this handbook differentiates between
material basis values (material allowables) and design values.
Material basis values, being a statistical lower-bound estimate of
a property of a composite material system, are the focus of this
handbook, and this Volume in particular. See Figure
Design values which directly satisfy regulatory requirements,
while often rooted in material basis values, are application
dependent, and must account for many additional considerations that
can affect the strength and stiffness of the structure. Also, when
establishing design values for a specific application there may be
additional certification or procurement agency requirements that go
beyond CMH-17 (for guidance see CMH-17 Volume 3, Chapter 3).
While the process of establishing structural design values for
an application can begin with the data contained in Volume 2, most
applications require collection of additional data, especially data
from the laminate or higher structural complexity levels. Also, the
ability to manufacture material equivalent to that from which the
data in Volume 2 were obtained typically must be proven to the
certifying or procuring agency, which usually involves limited
testing and data comparison. General guidelines for such material/
process equivalence evaluation are presented in Volume 1; however,
many of the details of such an evaluation remain at the discretion
of the certifying or procuring agency.
Most certifying and procuring agencies prefer, and some may
require, that composite material systems used in critical
applications be characterized in accordance with Volume 1 testing
and data analysis guidelines. When the guidelines or data
requirements of CMH-17 cannot be followed, the certifying or
procuring agency should be contacted to determine data requirements
and other documentation which may be necessary to justify data
values proposed or used during structure development.