A two layer model of permeability in the unsaturated flow regime for a woven RTM preform
- Univ. of Delaware, Newark, DE (United States). Dept. of Mechanical Engineering
In Resin Transfer molding (RTM) with woven fiber preforms, the preforms are placed in a closed mold and are impregnated by a resin. This process of permeation is modeled as the flow of resin through porous media formed by the preform. Woven preforms are tows of fibers knitted together. This architecture introduces dual length scales in the porous media which causes the resistance to the flow of resin to be much higher inside the tows than outside the tow regions. Numerical simulations of mold filling in RTM assign a permeability value to each location before the start of the simulation which does not account for the ``sink`` effect. In this paper, the concept of dynamic permeability is developed. This will permit us to incorporate the ``sink`` effect in the unsaturated region close to the resin front. The model is constructed by considering a woven preform as an equivalent tow layered preform such that one layer corresponds to the more permeable inter-tow region in the woven preform and the other corresponds to the less permeable intra-tow region. Cross flow of resin from more permeable region to the low permeable region reproduces the ``sink`` effect. Numerical simulation of 1-D flow through this two layered preform yields information about the gradation of permeability close to the front which can later be used to assign permeability dynamically during the simulation of an RTM part. Results of this model reproduces the trend of the experiments conducted in 1-D flow of resin through a woven preform qualitatively.
- OSTI ID:
- 89768
- Report Number(s):
- CONF-9409291--; ISBN 1-56676-220-0
- Country of Publication:
- United States
- Language:
- English
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