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

hold these values, with R(k) being used to hold the RHS constant for row k. The Gauss-Jordan
algorithm from Chopra (2005) is used to solve for the unknown CV resin pressure values. When
a resin pressure is known, that value is used to generate a pressure drop that is transposed to
the RHS.
3.21 Flow Direction Monitoring
It is suspected that the direction and magnitude of the resin flow is critical, and changes
to either/both may signal the conditions for fiber waviness. For each CV, the model monitors per
time its resin flow rate and direction so that significant changes to magnitude and direction can
be detected. A flow direction sign convention (- and +) is used to indication flow from the center
of each contact area towards the left or right side, respectively. When additional CVs become
included in a contact area, the flow direction exiting a particular CV can reverse. The magnitude
of colliding resin flow directions is given a value that is monitored as a possible condition for
fiber waviness to occur. The model supports multiple possible contact areas as well as the initial
2 on which the tool lid rests on the laminate top surface at time = 0. It is expected that both
these 2 possible contact areas will expand in area with laminate consolidation, ultimately
becoming a single contact area covering the entire laminate top surface.
3.22 Summary of the Consolidation-Resin Flow Submodel
The following bullets briefly describe the highlights of the composite laminate
consolidation-resin flow submodel. The next section presents the sequence of execution of
steps for the model software code.
• The resin pressure, permeability, height, viscosity, and other properties are assumed to
be uniform within any CV.
• The Pappl to any CV or contact area is = Force/contact area.
• For any CV, Gutowski’s expression gives the resin pressure as a result of Pappl and
the current ESS.
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