Development and commercialization of a device for measuring the degree of impregnation, including wet-out, with resin
　→ By measuring higher reliable impregnation coefficient, improvement of the simulation accuracy can be achieved.
　→ At the same time, trial manufacturing/verification cycle is simplified.
　

・Establishment of a method of evaluating the degree of impregnation with resin
・Improvement of accuracy of CAE simulation
・Reduction of the frequency of trial manufacturing (contributing to cost reduction)

1) In RTM molding, micro fibers are distributed in a space, their tissues are directional, and the fibers exist in bundle in some parts and no fiber
exists in space in other parts. The resin fluidity (permeability) flow in the RTM molding is very complicated, and the flow only at the flow front has
been mainly observed so far. In the conventional permeability evaluation, only the flow front was observed, and therefore, defects in the early
stage of molding such as air bubble and poor impregnation were ignored while attention was paid only to the flow.

2) In preform of fibers, a great number of combinations in consideration of fiber orientation, lamination sequence, fiber pattern (form), Vf and others are conceived.

3) Collection of basic data for basic properties in each fiber form is needed, which is important in creating preform using their combination.

4) Combination of properties (mainly, viscosity) of matrix resin as well as fiber and compatibility of fiber and resin (wettability) are also important to
impregnation.

5) With the conventional resin impregnation measuring device, the pressure, permittivity or the like at the flow front are measured, and when resin has reached the flow front, it is determined that the flow of resin is completed. However, actually, the impregnation is not always completed.

6) It is important that in FRP, basically, single fibers have been impregnated with resin and adhered to each other. It is considered that defects that generate during molding (poor impregnation, involution of air bubbles) relate to product strength, fatigue, life or unevenness and influence the
quality.


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1) We devise and develop a test device having a structure that reproduces the RTM (VARTM) molding method and conduct research focusing on
each process of wet-out and wet-through in which the factors (resin viscosity, contact angle of fiber surfaces, fiber form, fiber content, etc.)
that affect the permeability of resin are represented in the impregnation process.

2) Concerning the combination of fibers in preform, various combinations of cases shall be verified by using different forms of fibers and changing
the lamination constitution and the number of laminations.

3) By repeating the verification of 2), the basic data that has been accumulated is measured and used as material for preparing a preform.

4) The properties of resin and the compatibility between fiber and resin are verified by using resins having different viscosities and various
surface-treated fibers.

5) Besides the test device of 1), we develop a method of evaluating the wet-out and wet-through by capillary flow and channel flow, and data is
accumulated, together with the verification data obtained from the test device of 1), in order to realize RTM molding without recourse to
experience, intuition or guts.

6) In this development, we measure not only the flow front but the flow in fiber bundle, flow outside of fiber bundle and flow through lamination
from the viewpoint of wet-out and wet-through and make effort to develop an optimal measurement method as well as numerical analysis.
In addition, we would like to contribute to wide use of RTM molding technology by discovering a method of controlling the wet-out level and
by clarifying the relationship between inside defects and strength or fatigue property.

7) Concerning a measurement method, the optimal method will be selected using various methods. A visualization method using video or the like
has been also adopted.