TOOLED THICK COMPOSITES by ARVEN H. SAUNDERS III ...

CHAPTER 5
CONCLUSIONS
This dissertation work has been dominated by the development and validation of a
model for press cure of thick laminate to satisfy the major objectives. The first objective was to
develop an integrated physical model of the press cure of thick laminate composites for two
different material systems. A representative rotorcraft flexbeam laminate was designed with its
press tooling. The model for this cure process has been shown to be a realistic reflection of the
material properties and challenges that characterize the cure process in a press cure closed
cavity tooling environment for both these materials. While not as elegant as a FEM, the
simplified and practical model was found to provide a realistic, useful, and practical framework
for process evaluation and development. The flat laminate approach was verified with
experimental data and then applied within the flexbeam model. All requisite variables and
parameters were featured within the model in an integrated fashion.
The second objective was to apply this model within an optimization scheme to
determine the most time-efficient cure cycle processes. It was found that for this part,
regardless of material system, optimizing the time can be accomplished but the trade-off of
temperature, viscosity and cure uniformity can be large. The only variables that can be
manipulated are temperature and pressure. Due to the interdependency and nonlinearity of
factors within the cure process model, a self-directed approach was selected to seek thermal
and pressure optimization, utilizing both literature and rotorcraft industry-based rules as
guidance. The model attempted to raise temperature as fast as possible in order to shorten the
overall cure process time, while the constraints were used to avoid unacceptable laminate
temperature conditions. An estimate of the future cure rate was used to provide proportional
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